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273 Cards in this Set
- Front
- Back
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Visible light lies between what wavelengths (in nanometers)?
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Approximately 400-800 nanometers
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The wavelength of light makes a difference in how the eye perceives it. Which characteristics of visible light is determined by its wavelength?
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Color
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Which color has the longest wavelength? The shortest?
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The longest: Red 650 nm-750 nm The shortest: Blue 446 nm-500 nm
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Polarized lenses block all light rays except those the do what?
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Vibrate in the same direction
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What common in-office test uses glasses with polarized lenses?
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Stereopsis (Titmus fly)
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Because of refraction a prism bends light rays toward the base or the apex of the prism. In what units is the power of the prism measured?
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Toward the base
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The power of a prism to bend light depends on the size of the angle at the apex of the prism. In what units is the prism measured?
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Prism diopters
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What does the formula P=C/D represent?
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This formula explains the relationship between the power of prism and ability to bend light. P is prism diopters, C is the displacement of the object in centimeters, and D is the distance between the prism and the virtual image in meters
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Two prisms places base -to-base form the basis of what type of lens?
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Convex (plus)
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Convex (plus) lenses do what to light rays?
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Converge them
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Two prisms places the apex-to-apex form the basis of what type of lens?
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Concave (minus)
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Concave (minus) lenses do what to light rays?
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Diverge them
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Fresnel prisms are usually applied to the front surface or the back of a patient's eyeglasses?
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Back surface
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What is Pretice's rule?
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Its formula to calculate induced prismatic effect caused by spectacle lenses whose optical centers have been decentered so they are not in line with a patients visual axis (pupil center). The formula is: Induced prism (in prism diopters)=lens power (in diopters) X Optical center displacement (in cm)
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Find the total amount of prism induced in the following situations: Glasses RX OD +12.00 sph OS +10.00 sph - Both optical centers are displaced 5 mm temporally (decentered out)
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OD has 6 prism diopters of Base Out / OS has 5 prism diopters of Base Out / The total is 11 prism diopters of Base Out
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Name the variable focusing power of the eye provided by the flexibility of the crystalline lens.
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Accommodation
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Clinically, infinity is determined to be at what distance?
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20 feet (6 meters) and beyond
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What is the Prince rule used to measure?
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Near point of accommodation, and bifocal and trifocal add power
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Explain amplitude of accommodation.
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It’s the crystalline lens change (in diopters) from a state of no accommodation to maximum accommodation
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What happens to a person's amplitude of accommodation as they age?
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It decreases
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The loss of accommodation due to increasing age is called what?
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Presbyopia
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What is the focal length (in meters) of a 3 diopter lens?
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P = 1/f (meters), 3 = 1/f (meters), 3f (meters) = 1, f (meters) = 1/3, or 33cm
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The strongest the power of a plus lens, the (more/less) distance it needs to focus?
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Less
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Snell's law determines what?
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Whether the refracted ray will be bent toward the normal or away from it
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Index of refraction (IR) compares what?
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Speed of light in a vacuum to the speed of light in a given substance
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What's the IR of water? What is the IR of crown glass?
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Water 1.000; crown glass 1.517
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What is axial length?
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The length of the eye from the front surface of the central cornea to the macula
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Hyperopic eyes often have axial lengths longer or shorter than average?
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Shorter (<22mm)
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Hyperopic eyes focus light behind the retina - do they have to much or to little plus power?
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Too little
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Myopic eyes often have axial lengths longer of shorter than average?
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Longer (>24mm)
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Can myopic eyes use accommodation to being the distance objects into focus?
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No
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What is astigmatism?
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A refractive error caused by the nonsperical (cylindrical) surface of the cornea or lens, or both
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How is astigmatism corrected?
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With spherocylindrical lenses
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"With the rule" astigmatism is corrected by plus cylinders at or near what axis?
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90 degrees
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"Against to rule" astigmatism is corrected by plus cylinders at or near what axis?
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180 degrees
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Name the clinical procedure performed by ophthalmic personnel for determining a patients refractive error.
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Refractometry
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When using a streak retinoscope, if you see "with" motion, this indicates the need to place what kind of lens power in front of the eye?
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More plus power
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When using a streak retinoscope, if you see "against" motion, this indicates the need to place what kind of lens power in front of the eye?
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More minus power
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What is the spherical equivalent of the following prescription: +2.00 +1.50 X 090?
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"= +2.75 sphere (half the CYL + SPH)"
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Transpose the following eyeglasses Rx into the minus cylinder form: +2.00 +1.25 X 173
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"+3.00 -1.00 X 003"
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Transpose the following eyeglasses Rx into the minus cylinder form: -2.00 +1.25 X 173
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"-0.75 -1.25 X 083
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Give 3 examples of clinical use of Keratometry readings.
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(1) detecting the amount and direction of corneal astigmatism, (2) selecting contact lenses, (3) determining the power of an IOL to be implanted, (4) detecting keratoconus
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Give the prescription represented by the following optical crosses:
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a) +3.00 b) "-2.25 +2.25 X 180 or plano -2.25 X 090 c) 1.25 +3.25 X 135 or +2.00 -3.25 X 045"
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Abnormal visual acuity in children can be improved to normal with vigorous training until what age? After that age is becomes difficult to change the visual patterns.
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Age 6; After that age is becomes difficult to improve visual acuity.
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What does CSM stand for?
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Central - indicates that the corneal reflex is the same in both eye; Steady - means that fixations is not wandering and nystagmus is not present; Maintained - denotes that fixation is sustained by a given eye through a blink or following of an object.
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What test is performed to determine an estimations of misalignment when looking at corneal light reflexes of both eyes?
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Hirschberg test
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When prisms are used to equalize position of corneal light reflexes, this test is called the ________________________________.
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Krimsky test
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When the eyes appear misaligned due to epicanthal folds, but no strabismus is found, this condition is called _______________________.
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Pseudostabismus
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What test is used to differentiate pseudostrabismus from true starbismus?
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Hirschberg test
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What are versions?
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Simultaneous movement of both eyes in the same direction.
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What is duction?
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Movement of one eye only
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What is vengeance?
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Simultaneous movement of both eyes in opposite directions, such as convergence or divergence.
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What is phoria?
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A latent ocular deviation made intermittent by disrupting fusion. Deviation occurs when a cover is placed over an eye; when uncovered, the eye straightens.
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What is tropia?
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A constant ocular deviation caused by extraocular muscle imbalance.
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To measure vertical and/or horizontal phorias or topias at either distance or near, what device is used?
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Maddox rod, red lens along with the Risley prism, or hand-held prisms
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What is NRC, normal retinal correspondence?
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The images of each eye form or similar (corresponding) parts of the retinas of each eye, e.g., the fovea's. This results in binocular vision and steropisis.
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When the fovea of one eye corresponds to a nonfoveal point in the other eye, this is called ARC, abnormal or anomalous retinal correspondence, and _______________________ or _________________ occurs.
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Strabismus / suppression
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What test is performed to detect the presence of fusion or the suppression of one eye?
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Worth four-dot test, stereo test (Titmus Fly test), red filter, or amblyoscope
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What are the clear, finely striated, non-cylindrical lenses used for evaluating correspondence in patients with deviations called?
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Bagolini lenses
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What is amblyopia?
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Lazy eye. Decreased vision of 20/40 or worse in one or both eyes without detectable anatomic damage in the eye or visual pathways. Uncorrectable by optical means after the age of six, although many ophthalmologists might try therapy until the age of nine.
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What is strabismus?
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Misalignment of eye(s) caused by extraocular muscle imbalance.
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What are causes of amblyopia?
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Starbismus, significant refractive error, anisometropia or uncorrected refractive error, ptosis, cataract, or corneal opacities.
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What treatment is used to correct a strabismic amblyopia?
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Patching of the good eye to force the amblyopic eye (lazy eye) to work harder.
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When a muscle assists the primary muscle in the same eye to make a particular movement what is this muscle called?
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Synergist muscle
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A pair of muscles, one in each eye, work together to achieve a desired version movement, this pair of muscles is called _________________.
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Yoke muscles
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The __________________ muscle is the prime mover for a desired direction of gaze.
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Agonist muscle
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The voluntary rapid eye movements of both eyes, controlled by the frontal lobes of the brain, in the same direction to re-fixate is called ___________________.
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Saccades
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The antagonist muscle of the same eye works directly against the ___________________ muscle.
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Agonist
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All of the extraocular muscles, except the inferior oblique, originate at the ________________ ________ ___________________.
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Annulus of Zinn
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The medial rectus muscle is innervated by what cranial nerve?
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CNIII (cranial nerve III), also known as Oculomotor cranial nerve.
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What is the primary function of the medial rectus?
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Adduction - rotate the eye medially towards the nose.
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What muscle, as its primary function, ABDucts the eye?
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Lateral rectus
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This muscle is innervated by the abducens nerve (CN VI).
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Lateral rectus
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What are the four cyclovertical muscles?
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Superior rectus, inferior rectus, inferior oblique, and superior oblique
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What are the 3 actions (in order) of the superior rectus muscle?
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a) primary action - elevation, b) Secondary action - intorsion, c) Tertiary action - adduction
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The only muscle that is innervated by the trochlear nerve (CN IV) is the ________________________.
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Superior oblique
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To test the inferior rectus muscle, the patient needs to look _________________________ and ________________________.
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Down and Out
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The primary action of the inferior oblique is _______________________.
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Extorsion
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What two muscles are responsible for torsional movements of the eye, as their primary function?
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inferior oblique and superior oblique muscles
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Dextroversion is movement of both eyes to the ____________________.
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Right
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What law applies agonist and antagonist of one eye?
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Sherrington's law of reciprocal innervation
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What law applies to the yoke muscles of each eye?
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Hering's law of equal simultaneous innervation
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What is diplopia?
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Double vision - perception of two images from a single object
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When the eyes cannot be pulled inward (towards the nose) sufficiently to maintain single vision when attempting to fixate on a near object (to read) and is characterized by eye fatigue or double vision, this insufficiently is called?
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Convergence insufficiency
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Paralytic vertical deviations are caused by what?
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Cranial nerve palsies caused by motor vehicle accidents, stroke, etc
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Vertical deviations are usually accompanied by ______________ or _______________.
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Esodeviations or Exodeviations
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_____________________ deviations are eye muscle misalignments that measure the same amount in all directions of gaze.
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Comitant
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The Risley prism is used to measure eye deviations and ________________.
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Fusional amplitudes
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Another name for the "head tilt test" is the _____________________.
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Bielschowsky Test
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What are the 9 diagnostic positions of gaze?
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Straight ahead, left, right up & right, up & left, down & right, down & left, down, up
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What is the longest muscle in the eye and what are its actions?
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Superior oblique - primary function, intort: secondary function, depress: and tertiary function, abduct.
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What two muscles are the synergistic muscles for the medial rectus?
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Superior rectus and inferior rectus
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What are the 6 cardinal positions?
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Up & right, right, down & right, up & left, left, and down & left.
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What is the room illumination that is necessary for adequate visual field testing?
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Approximately 7 foot-candles of illumination
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Where in the visual field is the physiological blind spot located?
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15 degrees temporal to fixation
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What are the peripheral limits of a normal visual field?
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60° nasal, 60° superior, 70° inferior, 90° temporal
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What portion of a patient's visual field is tested using a Tangent screen?
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Central 30 degrees
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What is the term for an area of partial or complete blindness within the confines of a normal or relatively normal visual field?
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Scotoma
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Which method so perimetry is the most widely used and is essentially a screening test?
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Confrontation
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When calibrating a Goldmann perimeter the light meter should read at which measurement?
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1,000 Apostilbs or 1430 lumens
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What is the term for a contour line representing the limits of sensitivity to a specific test stimulus?
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Isopter
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Which ganglion fibers of the retina cross thought the center do the chiasm in the opposite lateral optic tract?
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The nasal fibers
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What is the term for the map of visual space seen without moving the eye?
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Visual Field
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In 1930, what analogue did Traquair use to liken the visual field of an eye?
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"Island of vision in a sea of darkness"
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Which type of perimetry devices uses mostly kinetic (moving) targets to map out the visual field?
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Manual, such as a Goldmann perimeter
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What color stimulus on an automated perimeter would be chosen to test for macular defects?
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Red
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What is the benefit of using a blue stimulus on a yellow background in automated perimetry?
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Earlier detection of visual field loss
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What amount of visual field is measured using an Amsler grid at the proper distance?
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Central 20 degrees (or 10 degrees from fixation in any direction)
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A lesion in the inferior nasal portion of the retina would cause a defect to appear in which portion of the visual field?
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Superior temporal
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Lesions in what area of the brain results in defects that respect the vertical meridian?
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Defects in the visual pathway posterior to the optic chiasm (Neuro-Ophthalmic)
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During Goldmann perimetry when would the examiner use the patients near correction?
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For testing the central 30 degrees in patients over the age of 30
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When performing manual perimetry, at what rate of speed should the target be moved?
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A constant rate of speed, approximately 5 degrees or ¼ inch per second from non-seeing to seeing area
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What is the average size of a physiologic blind spot?
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Approximately 6 degrees wide and 10 degrees high
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How often should the Goldmann perimeter be calibrated?
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Before each day of testing
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Which automated perimeter printout most resembles the isopter pattern recorded with kinetic perimetry?
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Grayscale pattern
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At what mark on the chart is the recording arm positioned and locked for calibrating a Goldmann perimeter?
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70 degrees
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During manual perimetry, how is the test object introduced to the patient?
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From non-seeing to seeing areas
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Which perimetry device consists of a portable box, a series of 10 cards each exhibiting a distinctive pattern printed in fluorescent material?
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Harrington-Flocks screener
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What is the most common type of visual field defect indicated in a hysterical patient?
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Tubular or spiral
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What is the optimal pupil dilation that would reduce the chance of a constricted field due to pupil size
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2.5 mm or larger
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A lesion affecting the chiasm would produce which type of visual field defect?
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Bitemporal hemianopsia
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What is a peripheral decrease in retinal sensitivity with a precise border on a the nasal horizontal meridian?
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A nasal step
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Which type of defects wither extend from the blind spot or point toward it?
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Paracentral
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How many degrees of the visual field would macular pathology affect?
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Central 10 degrees
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Damage to what area of the eye would cause a visual field defect that corresponds in size and location to the area of damage in the involved eye?
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Outer areas of retina closer to the choroid (choroid, retinal pigment epithelium, and that photoreceptor and bipolar cells)
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The binocular visual field equals how many degrees?
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120 degrees
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What is the cause of bitemporal hemianopsia?
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A defect in the optic chiasm, e.g., a pituitary tumor
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TRUE or FALSE: The perimetrist should try to expedite the test and not allow the patient to waste time by giving breaks.
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FALSE
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What is a "false positive response, or presented in a non-seeing area"?
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When a patient buzzes during visual field testing when no stimulus is presented, or presented in a non-seeing area
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When should the perimetrist add complete cylindrical power to the lens holder as opposed to spherical equivalent?
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If cylinder is greater that one diopter
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What is the term when a patient fails to respond to a stimulus greater that the threshold already established for a given point?
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A false negative response
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What visual acuity would you expect to see in a patient with loss of central vision?
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20/200 range
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On the examination print-out, what is the term used to isolate the defects by finding the degree to which the shape of the patient's field differs from the shape of a normal age-corrected field?
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Pattern Standard Deviation or PSD
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In the patient responds to a target presented in the physiologic blind spot this is referred to as a ________________________________.
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Fixation loss
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Which defect is a complete nerve fiber bundle defect emanating from the blind spot, arching over or under the macula and ending on the nasal horizontal line?
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Bjerrum's scotoma or arcuate scotoma
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When calibrating the Goldmann perimeter, the background illumination should read at what measurement?
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31.5 Apostilbs
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What type of scotoma has a complete blindness to test objects of all sizes?
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Absolute
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What is a relative term and represents the level where a stimulus can be seen 50% of the time?
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Threshold
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Ultra this lenses have _____________________ oxygen transmission compared with lenses of standard thickness.
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Higher -- when any thickness is reduced by 50% the transmission of oxygen is doubled
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A parasite organism found in hot tubs, swimming pools, or contaminated water, which can cause serious infections in those who wear contact lenses.
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Acanthamoeba
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Extended wear lenses are lenses that can be worn for ________________.
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24 hours
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Keratitis Sicca refers to ___________________.
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Dry eyes
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What is always the first step with insertion or removal of any contact lens?
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Always thoroughly wash your hands
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TRUE or FALSE: The wetability of a contact lens surface is measured in terms of its contact or wetting angle.
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TRUE
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TRUE or FALSE: Bells Palsy (7th nerve palsy) precludes the use of contact lenses.
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TRUE
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Back vertex power refers to what?
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Effective power of the lens as measured from the posterior surface
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What is the total contact lens diameter or the chord diameter?
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Measurements from one edge of the contact lens to the opposite side
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TRUE or FALSE: A thick heavy plus contact lens will tend to ride high under the upper lid.
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FALSE - it will ride low due to its weight and the force of the lid on the thinnest portion
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What is the basic principle behind fitting minus contact lenses and wearing a high + glasses over them?
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To create a telescopic system
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What is the annular bifocal contact lens?
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The central optical zone contains distance prescription and the outer peripheral ring contains the near prescription
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What is the corneal cap?
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The central zone of the cornea
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What causes arc staining on the cornea?
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Poor insertion technique for a sharp junction line between the central posterior curve and the intermediate or peripheral posterior curve
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With regard to the axis and refraction with toric soft contact lenses - what is LARS?
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Left Add Right Subtract -- The mnemonic used for toric soft lens adjustments in which right and left refer to the examiner, and not the patient
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What is the meaning if diffractive contact lenses?
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Concentric echellettes (circular areas) are designed to deflect light separating distance and near components
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Name one specialty lens for keratoconus.
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Soper - bicurve design with a central curve cut steeper that peripheral curve; McGuire or "nipple" cone - contour design with four peripheral curves reflecting the peripheral cornea. (5.5 mm optical zone - 8.1 mm diameter), Globus Cone - 6.5 mm optical zone and a 9.1 mm diameter, Piggyback lenses - a soft lens carrier with rigid lens centrally
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What is monovision?
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Correct dominant eye for distance with single vision lens and bifocal contact lens for the non-dominant eye.
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What is the sagittal depth of a contact lens?
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The height of the lens - distance between a flat surface and the back surface of the central portion of the lends
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What is the optic zone of a contact lens?
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The central zone that contains the refractive power and generally corresponds to the central corneal cap of the cornea
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What is Posterior Apical Radius (PAR)?
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It refers to the radius of the curvature of the back surface of a lens at its apex
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What is an Intrapapebral fit lens?
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A lens that fits within the palpebral tissue limits - is bicurve
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What is the lenticular bowl?
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Refers to the diameter of the optical portion of the lens and is used with higher power lens
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What is the taco test for soft contact lenses?
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Method to make sure a soft contact lens is not inside out by folding the lens is so edge will role inward if not inverted
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The plastic material used as the first molded scleral contact lens.
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PMMA (polmethylmethacrylate)
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What is the instrument used to measure the curvature of the cornea?
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Opthalmometer or Keratometer
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What is hypoxia?
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Low oxygen to the tissue in the cornea caused by poor fitting lenses
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Name the five factors that cause corneal edema from contact lenses.
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Flat lens causing compression of cornea; Steep lens - causes stagnation of tears; Poorly centered lens causes pressure in one area; Improper blinking; Improper cleaning of the lens
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What is a Shadowgraph?
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A magnifier and projector used to check the details of the lens material and edge for chips, thickness, roughness or sharpness. Also used to check diameter, width of peripheral curve, blending areas and intermediate curve
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What is the spectacle blur?
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Blurry vision that occurs when the contact lens is removed and glasses are worn. It is caused by corneal edema
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Astigmatism is best corrected with what type of contact lens?
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Toric contact lens
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Are contact lenses required to be removed before a visual field test?
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No
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Is a contact lens to be removed before an evaluation with use of a non-contact tonometer, which uses a burst of air?
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Yes
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Tonometry measures what?
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Intraocular pressure
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One of the first and oldest methods used to determine intraocular pressure is __________________________.
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Tactile (finger) tension
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What is the name of the tonometer that consist of a footplate with a central moveable plunger fitted into a barrel?
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Schiotz tonometer
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When using the Schiotz tonometer, indentation of the _________________ provides a reading on the scale from 0 -20.
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Cornea
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When checking the calibration of the Schiotz tonometer, the scale should read _________________.
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0 (zero)
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To perform Schiotz tonometry on a patient the patient needs to be in what position?
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Laid back with face straight upward (supine position)
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If a technician exerts pressure on the lid when performing Schiotz tonometry, this will produce erroneously _________ reading.
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Low reading on the Schiotz 0-20 scale
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Schiotz tonometry: If the reading is 3 or less, what do you do next?
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Add additional weight
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What two weights accompany the Schiotz?
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7.5 gram and 10.0 gram
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What tonometry instrument measures the force required to flatten the cornea?
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Applanation techniques such as Goldmann, pneumotonometer, and TonoPen
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A calibration bar is used to check the calibration of Goldmann tonometer and is checked at what settings?
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0, 2, and 6
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How much tolerance is allowed when checking the calibration of the Goldmann tonometer?
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"+/-0.05to1g"
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What dye and filter are used to perform Goldmann applanation tonometry?
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Fluorescein dry and cobalt blue filter
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A correct reading using the Goldmann tonometer is when the semi-circles of the mires touch __________________.
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On the inside of each semi-circle
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Pulsation of the semi circles is an indication of the _________________.
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Heartbeat
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A wide fluorescein pattern on Goldmann applanation tonometry indicates there is _______________________.
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Too much fluorescein and tears
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A wide fluorescein pattern will produce a pressure reading that will be much ______________ than the actual pressure.
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Higher
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If there are too little tears or fluorescein, the applanation pressure reading may be too _________________.
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Low
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If the prism is not aligned properly at the axis of the minus cylinder, an incorrect IOP reading may be obtained if the cornea has _____________ of astigmatism or more.
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Three diopters
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To obtain an accurate reading when 3 diopters of astigmatism or more is present the prism axis in minus cylinder is set at the __________________.
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43° mark or red line
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What is the name of a handheld instrument that is used in the same manner as the applanation instrument?
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Perkins or Kowa
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What are factors that could cause erroneous readings when using a Schiotz tonometer?
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Scleral rigidity (such as a high myope), uncalibrated instrument, improperly placed instrument on the cornea, and squeezing of the lids.
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What factors are evaluated when determining the diagnosis of glaucoma?
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Intraocular pressure, optic nerve cupping, visual field loss, and cornea thickness
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What glaucoma type typically is associated with a sudden rise in the intraocular pressure caused by mechanical obstructions of the angle, with sudden decrease in vision, red-eye, halos around lights, nausea and excruciating pain?
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Acute angle-closure glaucoma
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Hyperopic patients tend to have a shallower anterior chambers and are at higher risk for _____________________________?
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Angle-closure glaucoma
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What clinical technique is used to view the anterior chamber angle structure?
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Gonioscopy
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Which glaucoma type is typically termed the "silent thief of sight" and why?
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Chronic open angle / primary open angle, due to the gradual, slow progressive loss of vision
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What anterior chamber angle structures are seen through the goniolens?
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Ciliary body, scleral spur, trabecular meshwork, and Schwalbe's line
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What classic sign is characteristic of congenital glaucoma?
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Bupthalmos - an abnormally large eyeball ("ox-eye")
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What is the condition called when the iris balloons forward blocking aqueous outflow through the angle causing a papillary block and sudden increase in IOP?
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Iris bombé
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What procedure is performed to relieve the pressure in the anterior chamber secondary to an angle-closure glaucoma?
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Laser Peripheral Iridotomy (LPI)
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Primary open angle glaucoma is a disorder of the outflow of aqueous humor from the _________________.
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Trabecular meshwork
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Aqueous humor is produced by the ___________________.
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Ciliary body
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Ocular hypertension is characterized by ______________________.
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Increased IOPs with no changes in the visual field or in the optic discs. Thick corneas are a common finding.
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The prism tip of the applanation tonometer flattens an area of the cornea _______________mm is diameter.
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3.06
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Scleral rigidity introduces a potential error when measuring the intraocular pressure with which tonometry method?
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Indentation tonometry
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Tonometer tips should be wiped clean and disinfected with ___________.
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Alcohol preps, or 3% hydrogen peroxide for 10 minutes, or a 1:10 dilution of liquid bleach for 3 minutes.
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What are some factors that could cause erroneous readings during applanation tonometry?
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The patient holding their breath, squeezing their eyes, straining at the slit lamp, the technician applying pressure to the eye, too little/too much fluorescein, tip properly set on the applanation prism.
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Patients who hold there breath or wear tight collars during the tonometry test may produce a ___________ ____________ reading.
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False high
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TonoPen tonometry utilizes what technique to measure the intraocular pressure?
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Applanation -- measures the force needed to flatten the central cornea
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When preparing to perform Goldmann applanation tonometry at the slit lamp, it is important to align the patient carefully. Name the ways of assuring correct alignment.
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Forehead should easily reach the head band and chin should be resting in the chin rest; the patient's lateral canthus should be lined up with the black marks on the slit lamp
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What is the most notorious or potentially damaging organism to contaminate ophthalmic solutions?
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Pseudomonas Aeruginosa
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Why are some solutions such as Neo-Synephrine and Epinephrine packaged in dark or opaque bottles?
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They can oxidize in the presence of air or bright light
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Subconjunctival injections are used primarily to treat what?
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Intraocular infections
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What medication route is used to treat conditions such as cellulites, uveitis and acute allergic reactions?
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Systemic meds
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TRUE or FALSE: Atropine is one of the most likely ophthalmic preparations to cause allergic reactions of the skin of the eyelid.
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TRUE
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A(n) _____________ is a constitutional peculiarity in which an individual reacts in a bizarre fashion to a drug.
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Idiosyncrasy
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Autonomic drugs that affect the eyes are divided into what 3 agents?
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Mydriatic, Cycloplegic & Miotic agents
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Why are cycloplegic drops essential in the refraction of children's eyes?
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They paralyze the ciliary muscle so that the eye is no longer able to accommodate.
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How is the sterility of a drug achieved by the manufacturer?
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By autoclaving pr passing the solution through a bacterial filter
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Mydriatic drops act on what musculature to dilate the pupil?
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Iris dilator muscle
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Cycloplegic drops act not only on the iris sphincter muscle by dilating the pupil, but also on what other muscle?
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Cycloplegics paralyze the ciliary muscle
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What mydriatic agent can be used in establishing the diagnosis of Horner's Syndrome?
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Paredrine or Cocaine eye drops
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Miotics act by stimulation of what muscle?
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Sphincter muscle of the iris
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Timolol is used in glaucoma management by decreasing what?
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The formation of aqueous humor
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The most common side effects of Glycerol (glycerin) are what?
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Nausea, vomiting, and headaches
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Why is it more difficult to anesthetize an inflamed eye?
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The blood vessels carry away the anesthetic from the cornea
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Why is epinephrine combined with injectable anesthetics?
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To produce vasoconstriction which reduces the vascularirty of tissue and minimize bleeding
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____________ steroids are used for disorders involving the anterior segment of the eye.
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Topical
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____________ steroids are employed for diseases of the posterior segment of the eye & acute allergic posterior segment of the eye & acute allergic reactions of the eyelids.
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Systemic or intraocular
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Steriod therapy is used in all the following eye disease except: 1) rosaces, 2) Iritis, 3) open angle glaucoma, 4) contact dermatitis
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Open angle glaucoma
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Antibiotics that act by directly killing bacteria are what?
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Bactericidal agents
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Antibiotics that act by inhibiting bacterial growth are what?
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Bacteriostatic agents
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What type or class of medication is used for the treatment of Herpes Simplex of the cornea?
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Anti-viral agents such as acyclovir tablets, Viroptic®, vidarabine (Vira-A®) ointment
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Viroptic is an anti-viral agent used in the treatment of what?
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Herpes simplex keratitis
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What is topical Fluorescein used for?
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An ocular stain to show defects or abrasions in the corneal epithelium and to obtain intraocular pressure by Goldmann applanation
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What is Rose Bengal used for?
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A red dye the stains noviable epithelial cells
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Rose Bengal is used in making the diagnosis of what corneal condition?
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Keratoconjunctivitis sicca
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How do Fluorescein and Rose Bengal differ?
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Fluorescein stains living cells, whereas Rose Bengal stains non-living cells
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TRUE or FALSE: Eye drops penetrate the eye directly through the cornea and into the anterior chamber.
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TRUE
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TRUE or FALSE: The tonicity of an ophthalmic solution refers to the stability of the solution.
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False -- it refers to the concentrations of the chemical in the solution
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What are some clinical uses for Miotic agents?
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Open angle glaucoma, angle closure glaucoma, management of convergent strabismus, & management of accommodative insufficiency
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What is the name of the mechanical device that controls the duration of light the strikes the film on the camera?
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Shutter
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A 35mm camera with a commonly used lens has a focal length of _______________.
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50mm
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With all ophthalmic camera lenses, the higher the magnification (focal length) the narrower the _________________.
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Angle of view
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An "f" number refers to what?
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F-stop or lens aperture
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Film sensitivity to light is referred to as _________________.
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Film speed or ISO (international Standards Organization) numbers - the higher the number the more sensitive, or "faster" the film
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What film is generally used for fluorescein angiograms?
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Black & while film - ISO400
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What pictures are generally taken using color film?
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Fundus photos -- macula, optic nerve; external photos and slit lamp photos
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In order to achieve sharply focused photographs, the first step you should do is set the ____________________.
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Reticule
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Slit lamp photography is used to document conditions affecting the ______________.
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Cornea, anterior chamber, and lens
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Specular microscopy is a method of photographing and evaluating the _________________.
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Endothelial surface of the cornea
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Pictures of the posterior pole are obtained by what method?
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Fundus photography
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During fluorescein angiography, which two filters are use?
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Barrier and exciter filters
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Injection of sodium fluorescein in a vein has an average arm-to-eye circulation tome of ______________.
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8-15 seconds
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Contraindications for retinal fluorescein angiography are:
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Pregnancy, a preview history or reaction, multiple allergies, and adverse reaction of fluorescein dye
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When taking a picture, what term is used to indicate how much of the picture will come into sharp focus?
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Depth of field
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For slit lamp photography, in order for an image to be produced in each ocular and in the camera, a ______________ is necessary.
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Beam splitter
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The reticule in the slit lamp and fundus camera is compensate for the _______________ refractive error.
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Photographer's
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To set the camera eyepiece, you should keep __________ eye(s) _______________ in dim light darkness.
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Both, open
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When taking a fundus photo and you see a blue-gray halo around the eye, you should move the camera _____________.
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Closer
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As fluorescein dye circulates throughout the eye and rapid sequential pictures are taken, this is known as ____________________.
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Angiograms
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How many phases to a fluorescein angiograms?
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6 - pre-arterial (choroidal phase), arterial, artviovenous, venous, recirculation, and late
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What are the two types of fluorescence?
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a) Hyperfluorenscense - an increase in fluorescence or in the amount of dye b) Hypofluorescence - a decrease in fluorescence
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To eliminate crescent shaped and linear defects when aligning a patient, you would move the camera in the ______________ direction.
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Opposite
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Uncorrected induced astigmatism will cause blurring in ______________.
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One meridian
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Using the correction device in the fundus camera is used to compensate for ______________________.
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High corneal astigmatism or induced astigmatism
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When photographing a diabetic, how many fields of view are taken?
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Sever overlapping fields of view
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What is the primary area of interest when photographing a patient with macular degeneration?
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The macula
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take a photo of the cornea with the fundus camera, change the diopter setting to _______________.
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Plus (+)
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To obtain a sharp picture of an aphakic eye, you should change the _______________.
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Diopter compensation device
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Once the patient is in position and the fundus image is correctly positioned, ask the patient to _______________, the fire the camera.
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Blink
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