Optics Theoryflashcards.txt

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captnslo
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Optics Theoryflashcards.txt
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2010-11-02 12:32:24
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SCO Optics Theory
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SCO Optic Theory I
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  1. AC/A
    • Accomodative convergence in prism diopters used by he patient per D of accommodation
    • Relationship remains relatively constant
    • Changes slightly inside 20cm
  2. AC/A is less than 6/1
    • Convergence response is less than convergence stimulus
    • Gets more exo closer in
  3. AC/A greater than 6/1
    • Convergence response is greater than convergence stimulus
    • Gets more eso closer in
  4. Gross value
    • Retinoscopy
    • Final neutrality in phoropter with working distance included
  5. Net value
    • Retinoscopy
    • Neutral lenses that make patient emmetropic
  6. Detection Acuity
    The visualization of an object on a background different from the object itself
  7. Resolution (VA)
    • Ability to just recognize a lateral misalignment on a frontal plane
    • Most accurate type of acuity
  8. Recognition (VA)
    Determination of a threshold of recognition of two or more targets or objects on a contrasting background
  9. Contrast Sensitivity
    • Minimum contrast which is required to distinguish that there is a bar pattern rather than a uniform grey
    • Measured by test gratings of equal width, bright and dark bars in a sine-wave pattern
    • 30 cycles = 20/20
  10. 5 minutes of arc
    Amount of detail human eye is able to resolve
  11. Amblyopia
    Diminished VA w/out structural abnormality of eyes or visual pathway, and uncorrectable by optical means
  12. Height of letter at 20 ft in Snellen chart
    8.73 mm
  13. HArdest letter to read
    B
  14. Easiest letter to read
    L
  15. What causes less spherical and chromatic aberration?
    Smaller pupils
  16. Size of pinhole for VA?
    1 mm diameter
  17. Increased VA with introduction of a pinhole means...
    Acuity can be increased by refractive means
  18. What does lack of increased VA after introduction of a pinhole?
    Organic or pathological inhibition
  19. Vasc.
    Visual acuity without correction
  20. Vacc.
    Visual acuity with correction
  21. Sphere correction/uncorrected VA relationship
    • 20/50 = 1.00 D
    • 20/100 = 1.50 D
    • 20/200 = 2.50 D
  22. Anisometropia
    Different refractive powers in the eyes of one patient
  23. What is broken while performing cover test?
    Fusion
  24. Unoccluded eye moves when paddle is presented in cover test
    Tropic patient
  25. Uncovered eye turns in during alternating cover test
    Exophoric patient
  26. How do you quantify phorias and tropias?
    Adding prism to eyes
  27. Patient sees paddle and object moving in same direction during cover test
    Exo diagnosis
  28. Base out prism
    • Brings image in for all
    • Manages esophoria and esotropia
  29. Pituitary lesion causes
    Temporal vision loss
  30. Quadrantanopsia
    1/4 of the visual field gone in one eye
  31. Hemianopsia
    1/2 of visual field gone in one eye
  32. Homonymous
    Both eyes involved, same side
  33. Scotoma
    Isolated area of visual field loss
  34. Glaucoma
    • Intraocular pressure causing a degeneration of the ptic nerve
    • Nerves must be degrading in order to be diagnosed
  35. Facial Amsler test
    • Checks for macular defects
    • Chin is 10 degrees
    • Ears are 5 degrees
  36. Extraocular motilities test
    • Evaluates cranial nerves 3, 4, & 6
    • Evaluates fixation
    • Evaluates bony orbit
  37. Hering's of Equal Innervation
    Both members of a yoke pair receive equal innervation
  38. Pursuits
    • Tested binocularly
    • Tests under or overactions
    • Use physiological H
    • Checks 6 vardinal positions of the eye
    • Ask about pain or double vision
    • Test monocularly if abnormal
  39. Rotations
    • Test binocularly
    • Monocularly if restricted
  40. Saccades
    • Test binocularly
    • Monocularly if abnormal
  41. Complete third nerve palsy
    Eyes are positioned down and out
  42. Complete sixth nerve palsy
    • Affected eye is turned in due to relaxation of lateral rectus
    • Susceptible to: diabetes, toxins, alcohol
  43. Fast crisp constriction of pupil
    Recorded as 4+
  44. Slow, sluggish constriction of pupil
    Recorded as 1+
  45. Corectopia
    A misplaced pupil
  46. Anisocoria
    Unequal pupil size
  47. Miotic
    • Small, constricted pupil
    • Also a drug classification Of a substance that constricts the pupil
  48. Mydriatic
    Drug classification that dilates pupil
  49. Direct light reflex
    The constriction of the pupil to light, as observed in the illuminated eye
  50. Consensual light reflex
    The constriction of the pupil to light, as observed in the fellow eye
  51. Sphincter muscle
    • Iris muscle responsible for constriction
    • Parasympathetic innervation
  52. Dilator muscle
    • Iris muscle responsible for dilation of pupil
    • Sympathetic innervation
  53. Accommodative/Near reflex
    The constriction of the pupil in response to acommodation or a near stimulus
  54. Marcus-gunn reflex
    • Paradoxical dilation to a bright light stimulus
    • Sign of optic nerve disease
    • Also called afferent pupillary defect (APD)
    • Poorer direct response than consensual
  55. Pupillary pathway
    • Optic tract
    • Pretectal nucleus
    • Edinger-Westphal Nucleus
    • Cranial nerve 3
    • Ciliary ganglion
    • Inferior branch of Cranial nerve 3
    • Sphincter
  56. Amaurotic pupil
    Manifested in eye with no light perception
  57. Argyll-Robertson Pupil
    • Small, irregular pupils, which do not react to light, but do have positive accommodation response
    • Caused by syphilis, diabetes, alcoholism, and mid-brain tumors
  58. Aide's Tonic pupil
    • Benign
    • Dilated pupil
    • No immediate response to bright light; some after prolongued exposure
    • Unilateral
    • Common in females 30-50s
  59. Horner's syndrome
    • Ptosis, miosis, anhydrosis
    • Affected pupil will not redilate quickly after bright light exposure
  60. Presbyopia
    Loss of accommodation due to age
  61. Amplitude of Accommodation
    The maximum ability to accommodate of a person
  62. Most comfortable amount of accommodation to use
    Half of amplitude o accommodation
  63. Minus lens
    Pushes light back; more makes you blurry
  64. Plus lenses make a myope...
    Worse
  65. Punctum Remotum
    The far point of clear vision with accommodation relaxed
  66. Punctum Proximum
    The nearest point of clear vision
  67. Tonic Accommodation
    Resting state of accommodation
  68. Psychic accommodation
    Stimulation of accommodation caused by the nearness of a target
  69. Reflex accommodation
    Automatic response to blur
  70. Aberrational accommodation
    • Range in accommodation due to chromatic aberration
    • Varies on power depending on color
  71. Excessive accommodation
    Constant parasympathetic stimulation of accommodation when there is no need to accommodation
  72. Spasm of accommodation
    Ciliary muscle is in a state of spasm
  73. Tonic spasm
    Prolonged, uniform spam of accommodation
  74. Cycloplegic/Mydriatic
    • Drug that paralyzes accommodation and causes pupil dilation
    • Bottled with RED caps
  75. Anisometropia
    Condition where refractive conditions are not the same for the two eyes
  76. Antimetropia
    Specific anisometropia where one eye is myopic and the other eye is hyperopic
  77. Biocular
    • Each eye focussing on object
    • Double vision
  78. Binocular
    • Two eye focussing on object
    • One image
  79. Stereopsis
    • Highest level of binocular vision
    • Having depth perception
  80. Keratometer
    • Objectively measures curves of the cornea
    • Indicates cylinder power and axis
    • Tests corneal integrity
    • Used exclusively in contact lens patients
  81. Precorneal film
    • Outer oil layer
    • Aqueous middle layer
    • Mucin inner layer
  82. Epithelium of Cornea
    • 5 cell layers thick
    • Very fast regenerating capabilities
  83. Bowman's Membrane of Cornea
    • Basement membrane that epithelium adheres to
    • Scarring occurs if penetrated
  84. Stroma of Cornea
    • Bulk of cornea mass
    • Maintains cornea shape
  85. Descement's Membrane of Cornea
    Membrane the endothelium adheres to
  86. Endothelium of cornea
    • Corneal pump gets rid of edema
    • No recovery if damaged
  87. Calibrate Keratometer
    • Contactometer is placed in the head rest
    • Readin taken of curve (standard steel ball)
    • Power wheel adjusted by loosening the set screw and moving dial
  88. Extend Keratometer range
    • Too steep cornea: place +1.50 lens of central aperture
    • Too flat: place -1.00 lens in front
    • Consult conversion table
  89. K
    Flattest meridian of the cornea
  90. Cornea flatter than 42.00
    Hyperopia
  91. Cornea steeper than 44.00
    Myopia
  92. With the rule astigmatism
    • Most converging power in vertical meridian
    • Use minus cylinder axis 180 to correct
  93. Exo diplopia
    • Heteronymous
    • OD image is left
    • OS image is right
  94. Eso diplopia
    • Homonymous
    • OD image is right
    • OS image is left
  95. First degree fusion
    • Biocular
    • Diplopia
  96. Second degree fusion
    • Binocular
    • No depth perception
  97. Third degree fusion
    Depth perception, or stereopsis
  98. Monocular depth perception cues
    • Relative size
    • Light and shade
    • Overlap
  99. Binocular depth perception cues
    • Disparity between two images
    • Eyes stimulated at corresponding points of fovea
  100. Global Stereopsis
    • Disparity of visual field evaluated without monocular cues
    • More sensitive
    • Have to be binocular w/ bifoveal vision
    • Tested w/ shapes of the Randot test
  101. Local Stereopsis
    • Presence of smaller, more localized object
    • Aided by monocular cues
    • Less sensitive
    • Tested by Wirt circles
  102. Stereoacuity
    • Measured in "seconds of arc"
    • Best measurement is 20'
  103. Factors affecting Stereopsis
    • Binocularity (do they have it)
    • Refractive error (especially large anisometropia)
    • Strabismus
    • Age
  104. Cones
    Responsible for color vision
  105. Erythrolabe
    Long wavelength sensitive protein
  106. Chlorolabe
    Medium wavelength sensitive protein
  107. Cyanolabe
    Short wavelength sensitive protein
  108. Congenital color defect
    • Usually red-green
    • 8% of males
    • 0.5% of females
  109. When testing color defects ___ is critical
    • Lighting
    • Monocular testing
  110. Acquired color defects
    • Usually result of disease
    • Blue-yellow defect
    • Can be monocular
  111. Protonopia
    Do not see red
  112. Deuteranopia
    Do not see green
  113. Tritanopia
    Do not see blue
  114. Amsler grid
    • Tests macular function and central vision quality
    • Portable
    • @ 30cm
    • Tests central degrees of vision
    • Near correction
    • Full illumination
    • Monocular
    • Focus on older patients
    • Neovascularization
    • High risk medications
    • Unexplained vision loss
  115. Scotoma
    • Loss of vision due to malfunction of photoreceptors
    • Black areas reported
  116. Relative Scotoma
    • Decreased sensitivity to light
    • Dim vision
    • Reports blur or graying vision
    • Hard to see areas
  117. Metamorphopsia
    • Disturbance to light caused by physical change in retina
    • Distortion of vision
  118. Adnexa
    accessory structures and organs of the eye; e.g., eye brows, skin around orbit
  119. Orbit
    bony orifice in which the eye ball sits
  120. L.L.L.
    lids, lashes, lacrimal system
  121. Hordeolum
    staph infection of lid glands, with pus, pain, and redness
  122. Chalazion
    sterile clogging of lid glands, with no pus, pain, or redness
  123. Ptosis
    drooping of eye lid
  124. Lagopthalmus
    eye lids do not completely close
  125. Entropion
    in-turning of lids
  126. Extropion
    out-turning of lids
  127. Blepharochalasis
    drooping of skin of the eyelids
  128. Xanthelasma
    • lipid deposit in the skin of the eyelid
    • do blood tests
  129. Eye lashes
    normal lashes are in proper placement without any deposits or foreign substances at the base of the lashes or throughout lashes
  130. Blepharitis
    inflammation of eyelid margins and lashes
  131. Madarosis
    loss of eyelashes
  132. Trichiasis
    in-turning of lashes
  133. Meibomianitus
    inflammation of the Meibomian glands at the base of the lash
  134. Dacryocystitis
    infection of the lacrimal sac with swelling and redness near the nose
  135. Dacryodenitis
    inflammation of the lacrimal gland, with swelling and pain in the area of the lacrimal gland
  136. Palpebral conjunctiva
    conjunctiva that lines the lids
  137. Bulbar conjunctiva
    conjunctiva that overlies the sclera
  138. Injection
    • the amount of redness or vascularization
    • recorded as 1+-4+
  139. Follicle
    white to yellow, translucent avascular elevation of the conjunctiva
  140. Papilla
    vascularized clear conjunctiva elevation, often giving a velvety appearance to the affected area
  141. Pinguecula
    • a hyperplasia of the conjunctival tissue, usually in respones to environmental irritation
    • prevention is key
  142. Pterygium
    • a degeneration of the bulbar conjunctiva involving the cornea
    • prevention is key
  143. Sub-conjunctival hemorrhage
    a hemorrhage that causes great alarm in patients by the overall appearance of the conjunctiva
  144. Chemosis
    • swelling of the conjunctiva
    • often an allergic response
  145. Sclera
    normal sclera is white with few blood vessels seen
  146. Episcleritis
    • an inflammation of the outer layer of the sclera with pain in the red area
    • arthritic patients are predisposed
  147. Corneal scar
    when a foreign object has penetrated the first five layers of the cornea, into the stroma
  148. Arcus senilis
    a cholesterol deposit in the periphery of the cornea
  149. Keratitis
    inflammation of the cornea
  150. Tears
    • tear break up time should be about 10 seconds
    • measured by using fluorescein dye instilled into the lowe cul-de-sac
  151. Anterior Angle
    • where the aqueous drains
    • size is graded from wide open (4+) to closed (0+)
  152. Cells
    white blood cells in the aqueous
  153. Flare
    smoky appearing precipitate of protein leaked from inflamed blood vessels
  154. Iris
    normal iris should have uniform color (sort of)
  155. Corectopia
    misplaced pupil
  156. Aniridia
    absence of iris
  157. Iritis
    inflammation of iris
  158. Cataract
    • an opacity of the crystalline lens
    • about 400 different kinds
  159. Aphakia
    no crystalline lens
  160. Pseudophakia
    artificial lens implant
  161. Vitreal Floaters
    • remnants of hyaloid artery
    • always there, but stiff vitreous keeps them out of the way; as vitreous ages, they can move around more
  162. Location of Optic Nerve
    toward the nose (medial) portion of the back of the eye
  163. Cup-to-disc ratio
    • most diagnostic tool for glaucoma
    • recorded as percentage of disc the cup occupies
    • should be same between the two eyes
    • should not ever change in lifetime
    • recognize big, medium, and small
  164. Papilledema
    • pathological elevation of the disc margins
    • could mean brain tumor, high CSF pressure, or nerve swelling
  165. Rim tissue color
    orangey-pink
  166. optic nerve atrophy
    • when the rim tissue has a white color and is dying
    • probably will have positive affarent pupillary deffect (+APD)
  167. Constriction
    impeded blood flow at a vessel crossing
  168. Foveal Light Reflex (FLR)
    the light reflection of the fovea in the macula
  169. Color of Macula
    • should be slightly darder than the rest of the retina, free of hemorrhages and pigment
    • blood supply of Macula comes from Choroid
  170. Macualr Degeneration
    • exactly what it sounds like
    • causes permanent loss of visual acuity
  171. Nevus
    an area of hyperpigmentation (similar to a mole on the skin)
  172. Hemorrhage
    • a leakage of blood outside of the vessel
    • appears as small red spots on retina
    • can pool blood in the bottom of the eye
  173. Cotton-wool
    • microinfarcts of the nerve fibers
    • swelling of the nerve fibers from occlusion of small arterioles
    • appear white and fluffy
  174. Exudates
    fluid leakage that has been reabsorbed leaving a yellow, flat appearance
  175. Lesion
    any break in the retinal layer from trauma, disease, or anatomical variations
  176. Manifest Refraction
    • the most PLUS that enables the patient to resolve the best visual acuity possible
    • determined subjectively
    • 0.25 more plus blurs letters
    • 0.25 more minus does not increase clarity of letters
  177. Spherical equivalent
    • all the sphere and half of the cylinder algebraically combined together
    • sphere + 1/2cylinder = spherical equivalent
  178. Step Down Technique
    • decreasing fog by 0.25 steps until best acuity is achievable
    • target is Snellen acuity chart
    • stop when no increase in visual acuity is achieved by more minus
    • mono or bino
  179. Red-Green Technique
    • based on aberrational accommodation or chromatic interval
    • decrease fog until chromatic interval is strattling the retina
    • use 20/40 to 20/60 row target
    • dim lighting
    • want equality of clarity of letters in both sides
    • still works on color-deficient people
    • mono or bino
  180. Three Click Blur Out Technique
    • there is 0.50D depth of focus, with an additional 0.25D plus causing a fog to the 20/20 row
    • target is 20/20 row (cannot perform if patient is not 20/20)
    • go three clicks down (0.75D more minus) from first blur out point
    • mono or bino
  181. Cylinder Power Technique
    • subjective diagnosis (patient decides what is best)
    • use JCC lens
    • target is 20/30 or 20/40 row
    • refine axis by straddling the axis scoped with the red and white dots, then "chase the red dots"
    • if patient runs around, increase cylinder power
    • refine power by placing dots on the principle meridians
  182. Patients with long-standing large amounts of uncorrected cylinder will...
    not like the cylinder correction and "kick out" any attempt to correct it
  183. JCC choices
    • quick response means lots of difference in choices
    • slow means little difference and close to equality
    • no response means patient could be "clueless"
  184. Biocular Aniso Balance
    • equally balance accommodation between two eyes
    • not balancing acuity
    • target is blurred 20/40 line
    • use vertical prisms to create two lines and ask which is clearer
    • make the two line equally clear or equally blurred
    • leave dominant eye clearer if no equallity is acheived

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