Term
| What is the Stiles Crawford 1 effect? |
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Definition
| Rods/cones orient themselves towards the entrance pupil, regardless of where it lies |
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Definition
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Definition
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Definition
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Definition
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| S, M, L cones: what doe the letters stand for? |
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Definition
| Short, Medium, and Long wavelengths |
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Term
| What are the most common cone types? |
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Definition
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Term
| What are the least common cone types? |
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Definition
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Term
| What is the photochromatic interval? |
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Definition
| Scotopic is more sensitive than photopic; rods 100x more sensitive than cones |
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Term
| How many times more rods are there than cones? |
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Definition
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Term
| What is the purkinje shift? |
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Definition
| The shift in peak absorbance when going between photopic/scotopic dominance |
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Term
| What are the two parts of a photopigment? |
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Definition
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Term
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Definition
| 11-cis-retinal backbone of all PR's |
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Term
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Definition
luminance x time = constant
a stronger stimulus for a shorter time equals the effect of a weaker stimulus for a longer time if below 100ms threshold |
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Definition
luminance x time = constant
The effects of a small numbers of photons per unit area over a larger area is equal to the effects of a larger number of photon per unit area over a smaller area |
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Definition
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Definition
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Term
| When is the rod/cone break? |
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Definition
| 12 minutes after retina is put in the dark. This is when the rods overtake the cones in sensitivity |
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Term
| What is the peak sensitivity for contrast sensitivity? |
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Definition
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Term
| What does 20/20 equal in CPD? |
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Definition
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Term
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Definition
| Divide 600 by the snellen denominator |
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Term
| In Snellen, what is the peak contrast sensitivity? |
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Definition
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Term
| What is a Bailey-Lovie chart? |
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Definition
| contrast (20%) is held constant, letter size/spacing is held constant like a logMAR |
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Term
| What is a Pelli-Robson chart? |
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Definition
| Letter size is held constant and contrast sensitivity is modulated |
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Term
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Definition
| Perceptual addition whereby cortex highlights the edges of fuzzy contrast to bring attention to edges/stairs/walls |
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Term
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Definition
Seeing a percentage change in light under photopic conditions
JND = background illumination x constant |
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Term
| Is hyperacuity affected by defocus (blur) |
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Definition
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Term
| What are the 3 cone photopigments? |
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Definition
| Erythrolabe, Chlorolabe, Cyanolabe |
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Definition
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Term
| What ganglion cells see flicker best? |
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Definition
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Term
| What is the Ferry-Porter law? |
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Definition
| the dimmer it is, the harder it is to see motion/flicker |
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Term
| What is the Brucke-Bartley effect? |
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Definition
| 10 hz = optimal flicker detection |
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Term
| What is the Broca-Sultzer effect? |
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Definition
| Flashes of 100 ms appear brighter than shorter or longer flashes |
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Term
| What is the Granit-Harper law? |
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Definition
linear increase in CFF with log retinal area
i.e. the larger the target, the more likely to see the flicker |
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Term
| What is the Tablot-Plateau Law? |
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Definition
| a blinking light is equally bright as a constant light of the same averaged luminance |
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Term
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Definition
| The visibility of a target is reduced by the subsequent presentation of a spatially adjacent mask |
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Term
| What is the Troxler effect? |
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Definition
| Amacrine cells shut down non-moving, "unimportant" stimulus |
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Term
| What is dynamic visual acuity? |
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Definition
| A moving target will have less detail perceived |
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Term
| What is the pulfrich effect? |
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Definition
| asymmetric media clarity will slow down signal in one eye inducing elliptical motion of a pendulum (right hand rule) |
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Term
| What cortical area is damaged in akinetopsia? |
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Definition
| MT/V5 in the parietal lobe |
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Term
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Definition
Only foveal points correspond properly in a normal pt. Thus the peripheral areas appear curved due to parallax of off axis targets binocularly
Periphery will curve towards the pt |
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Term
| What is the retinal disparity for eso vs exo? |
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Definition
| Eso is uncrossed, Exo is crossed |
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Term
| What is the Ponzo illusion? |
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Definition
| Two equal horizontal lines appear different lengths if depth cues differ |
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Term
| What is the Muller-Lyer illusion? |
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Definition
| Vertical qual lines appear of different lengths if depth cues differ |
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Term
| What is the additive property of metamers? |
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Definition
| If two colors appear equal prior to an equal amount of another color is added, they should still appear equal after another color is added equally |
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Term
| What is the most common and second most common color defects? |
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Definition
| 3/4 are deutan; 1/4 is protan; Tritan apparently far less than either |
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Term
| How many times more often are deutans seen than tritans? |
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Definition
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Term
| How are color defects transmitted? |
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Definition
Deutan, Protan: X-linked recessive
Tritan: autosomal dominant |
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Term
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Definition
| Media/Choroid/outer damage causes blue-yellow defects Inner retinal damage causes red-green defects (except for glaucoma) |
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Term
| What is the Farnsworth D-15? |
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Definition
A color test where 15 colored caps are put in order of spectral hue.
When compared to a CIE diagram, reversals will be along the confusion lines which are equal to the following:
Deutan = Reversals along ~80*
Protan = Reversals along ~100*
Tritan = Reversals ~20* |
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Term
| What is the Bezold-Brucke phenomenon? |
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Definition
478, 503, and 578 nm will appear the same hue regardless of intensity; W shaped
All other colors will change apparent hue slightly as intensity changes |
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Term
| What is a nagel anomalcosope? |
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Definition
Gold standard for color vision testing
670nm + 546nm until it equals 590nm
Deutans = more green; Protans = more red |
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Term
| What is the EOG voltage potential in photopic vs scotopic? |
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Definition
| 6 mv photopic; 3 mV scotopic |
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Term
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Definition
| EOG light/dark voltage ratio; >1.50 normal |
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Term
| What is Balint's syndrome? |
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Definition
| simultagnosia w/ ocular apraxia and ocular ataxia |
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Term
| What are ocular dominance columns? |
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Definition
| Cortical areas that correspond to monocular and binocular vision. Alt XT will have bilateral monocular dominance columns, but no binocular dominance columns for example |
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Term
| How does glare recovery change with age? |
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Definition
| Severely drops off with age over about 90. Good reason for old fekkers to not drive at night. |
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Term
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Definition
| The orientation of the eye when looking in a specific direction is always the same |
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Term
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Definition
| When the two eyes move together, they should stay in the same plane and not retract into the orbit as it does in Duanes or unilateral proptosis |
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Term
| What is Sherrington's Law? |
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Definition
| Eye muscles must share the eye, if LR fires, MR is inhibited etc. |
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Term
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Definition
| Both eyes will receive equal innervation and those both eyes should move comitantly |
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Term
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Definition
| "Noise in the system" way too small to see even in slitlamp; disconjugate |
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Term
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Definition
| Disconjugate small, slow changes of fixation (after image drift on grid) Possibly to prevent amacrine cells from blocking out important stimuli |
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Term
| What are the vestibular nuclei? |
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Definition
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Term
| What are the three canals in the bony labyrinth? |
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Definition
Pitch = anterior
Roll = posterior
Yaw = horizontal |
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Term
| What eye does a given bony labyrinth control? |
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Definition
Horizontal --> contralateral and ipsilateral nuclei
Anterior --> contralateral nuclei
Posterior --> contralateral nuclei |
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Term
| What eye movements often violate Listings law? |
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Definition
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Term
| is there an OKN response with cortical blindness? |
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Definition
| Yes, it is not controlled in the cortex |
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Term
| What is the saccadic velocity range? |
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Definition
| 250-600 degress per second |
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Term
| Are saccades slower in the dark? |
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Definition
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Term
| Where are voluntary saccades and pursuits generated? |
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Definition
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Term
| Where are the reflexive saccades generated? |
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Definition
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Term
| What are the two components of nystagmus? |
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Definition
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Term
| What is the triad of Spasmus nutans? |
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Definition
| Nystagmus, torticollis, head nodding |
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Term
| What is the primary sign of Brown's syndrome? |
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Definition
| Disconjugate movement of eyes primarly when elevating due to hitch in the trochlea that primarly locks the eye in downgaze |
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