Test 2 Flashcards
What does the inner and outer layer of the optic cup develop into
Inner layer of the cup develops into neural retina
Outer layer of the cup develops into the RPE
Most common primary intraocular malignancy in children and adults
Child- retinoblastoma
adults- choroidal melanoma
Define:
- The seg inset
- Total inset
- Inset
- The MRP to the center of the bifocal segment (distance pd - near pd/2)
- Geometric center of the lens to the center of the bifocal segment (frame Pd - near Pd/ 2)
- MRP to geometric center. (Frame pd- distance pd /2)
Side effects of amiodarone
Whorl K
Anterior sub capsular lens deposits
NAION
Micro saccades, micro tremors, micro drifts, and micro pursuits
Mico saccades, tremors, and drifts are responsible for maintaining fixation on an object. Micro pursuits are not associated with fixation.
Micro tremors and drifts are unintentional, disconjugate eye movements that cause the fovea to shift away from the target of interest.
Mico saccades are intentional conjugate eye movements that move the fovea back onto the object after micro tremors and drifts.
Scotopic system is sensitive to what wavelength
Photopic system is sensitive to what wavelength
What wavelength is equal sensitivity for both systems
Scotopic- 507
Photopic- 555
Both- 650
Average refractive error in full term newborns
+2
Lensometer formula
distance the target moved in meters = (focal length of the standard lens in meters ^2) (back vertex)
Most medically emergent cause of papilledema
Malignant HTN due to high risk of stroke
Send to ER
Co2 is this an acid or base
What
Co2 is an acid.
If you breathe out too much Co2, then the pH in your body will become more basic- higher pH.
What two types of aberrations can affect the image quality in spectacle lenses of any power and can be minimized by selecting the proper base curve using the Tscherning Ellipse?
Radial astigmatism and curvature of field
Color vision at the level of the photoreceptors is governed by the
Trichromatic theory
what characteristics increase flexure
Hyper Dk material
increased optical zone diameter
Steeper BC
Hereditary color vision defects are most often diagnosed in males due to what inheritance patterns
X linked recessive
Bloch’s law
Rocco’s law
Weber’s law
DeVries-Rose Law
Bloch’s law- temporal summation. Total number of photons for a stimulus below the critical duration is constant.
Ricco’s law- Spatial summation. (rocco’s is my favorite space)
Weber’s law- Light adaptation
DeVries-Rose Law- Light adaptation
Humphrey visual field uses which method to determine threshold
Stair step
What does each branch of the ophthalmic artery supply: Lacrimal LPCA Dorsal nasal Ethmoid
Lacrimal- Lateral rectus and lacrimal gland
LPCA- anterior choroid, iris, CB
Dorsal nasal- Lacrimal sac. Terminal branch.
Ethmoid- Sphenoid, ethmoid, frontal sinuses
Most common cause of unilateral disc edema in 20-40 years and 50+
Optic neuritis
NAION
On center bipolar cells
Inhibited by glutamate (released by RR cells when it is dark)
Activated by light, when there is less glutamate, and the bipolar cell will depolarize (graded action potential)
Chorda Tympani branch is from what nerve and does what
CN 7
Carries taste fibers from the anterior 2/3 of tongue.
Drug classes associated with floppy iris syndrom
Alpha 1 adrenergic antagonists
Tectospinal tract does what
Reflexive head movements
Visual form constancy
Visual discrimination
Visual figure ground
Visual form constancy- Ability to identify an object based on its shape, even when other features have changed such as size, color, orientation.
Visual discrimination- Correctly identify features of an object that differentiate it from other objects such as size, shape, color, direction.
Visual figure ground- Ability to identify an object within a background with distracting stimuli.
What AA is a precursor for epi and NE
Tyrosine, which is derived from phenylalanine.
Precursor for epi, NE, dopamine, and catecholamine NT
Glycine is precursor for heme
Arginine is a precursor for NO
Tryptophan is a precursor for serotonin
Glutamine is a preceptor for nucleotide synthesis
Isometropic refractive amblyopia
Bilateral high refractive errors
Which first gen oral antihistamine causes corneal endothelial pigmentation and pigmentary retinopathy, similar to the phenothiazines (Antipsychotic)
Promethazine. They have similar structure
Donders
Listings
Herings
Sherringtons
Donders- For any position of gaze, the eye has a unique orientation in 3 dimensions in space.
Listings- Eyes must rotate around axes to reach a certain direction of gaze.
Herings- Equal innervation of synergistic muscles (yoked muscles). 1 eye.
Sherringtons- Agonist and antagonist EOMs are reciporocally innervated. 2 eyes.
Image jump
Add x (disc between seg line and near OC in cm)
Which eye movement is responsible for keeping the image on the fovea during short head movements? What about long head movements?
Short- VOR
long- optokinetic reflex
Do you want your eyes to be comitant or non comitant?
Comitant- deviation of the eyes that is the same for all positions as gaze.
Oral CAIs are contraindicated in who
Liver or renal disease
COPD
Pregnancy
Sulfa allergies
Spec magnification compares what
Uncorrected retinal image size to corrected retinal image size
Relative spec mag compares
Retinal image size in corrected eye to the retinal image size of an emmetrope
Amblyopia occurs at the level of the
Visual cortex suppression
When can infants crawl
Walk?
9-10 months crawl
12 months walk
What do you predict this 5 year olds rx will be when they turn 14?
+1.75
+0.50-1.25
less than +0.50
+1.75 –> stay hyperope
+0.50-1.25–> emmetrope
less than +0.50 –> myope
How to determine axis with clock dial
Lowest number on clock that appears clear x 30
Ex: 12-6 o clock
6x30 = 180
children are first able to copy a circle when
square?
complex shapes?
3, 4, 5 years
what is in each layer of the eyelid:
Subcutaneous areolar
Submuscular
Tarsal plate
Posterior muscular
Subcutaneous areolar- CT and levator
Submuscular- Loose CT and levator aponeurosis, palpebral portion of lacrimal gland.
Tarsal plate
Posterior muscular- mullers muscle
What do layers 4, 5, an 6 of the striate cortex do
4- Location of first synapse between the optic radiations and neurons. Axons project to the higher cortical areas (v2-v5) for additional visual processing.
5- Sends axons to superior colliculus to control saccades
6- Provides feedback to LGN
3 tests used to dx eccentric fixation
Develops in an eye with a stable, constant, unilateral micro strabismus of longstanding duration during the critical period. The patient will use a non-foveal point for fixation in the strab eye under monocular conditions.
Haidinger’s
visuscopy
Maxwells
Which layers of the sclera contain elastin
Lamina fusca, cribrosa, and scleral spur
NOT episclera
6 findings in RP
Waxy disc Artery attenuation Bony spics PSC CME ONH drusen
How does each layer of the K respond to damage
Epithelium- regeneration Bowmans- incapable of regen/repair Stroma- Can replace itself but the collagen is less organized and larger= scar Descemets- regeneration Endothel- incapable of regen/repair
Average AC/A ratio
4/1 +/-2
Axial ametropes should wear specs according to what law
Knapps
How does spec lens change as the lens is brought closer to the eye
Minus becomes effectively stronger (more minus)
Plus lenses become effectively weaker (less plus)
Think: myopes will push glasses closer to eyes for more minus.
