Term
|
Definition
| usually unilatera, diminished visual acuity due to anatomical or sensory deoiviration, not a pathology |
|
|
Term
| other than not seeing well, why is amblyopia a concern |
|
Definition
| lack of neurosensory stimulation due to conflicting or blurred immages |
|
|
Term
| what is the general cause of amblyopia? what are three specific causes? |
|
Definition
any interruption in visual development (birth to 6-8 yo)
strabismus
refractive errors
occlusion |
|
|
Term
| what is the most common cause of amblyopia? define it |
|
Definition
strabismus
eye is structurally abnormal causing misalignment
visual axis is not at the same fixation point |
|
|
Term
| what is the pathogenesis of strabismus |
|
Definition
| loss in bioncular vision because the deviated eye's image is supressed by the brain which interrupts normal development of higher vision centers in the brain (not corelated with degree of deviation) |
|
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Term
|
Definition
| difference in refractive error between the eyes |
|
|
Term
| what is the pathogenesis of refractive amblyopia |
|
Definition
eye with the lesser refractive error provides a more clear image
so the image from the eye with more error is supressed |
|
|
Term
| how can you detect refractive amblyopia |
|
Definition
no ovbious physical signs
visual acuity testing |
|
|
Term
| what are some examples of causes of occlusion amblyopia (4) |
|
Definition
| cataract, corneal scaring, ptosis, tumor |
|
|
Term
| what is the pathogenesis of occlusion amblyopia |
|
Definition
| obstruction blocks stimuli from coming into the eye |
|
|
Term
| what are the three keys to testing for ambyopia |
|
Definition
early detection
family history
eye exam |
|
|
Term
| what is done on a newborn eye exam to test for amblyopia (3) |
|
Definition
corneal light reflex
red reflex
fundus exam |
|
|
Term
| what is done on a infant to 2yo eye exam to test for amblyopia (3) |
|
Definition
assess visual function (not accuity)
determine central eye fixation location
assess eye motility |
|
|
Term
| what is done on a 2-5yo eye exam to test for amblyopia (1), how can you tell if the test is normal |
|
Definition
picture card or tumbling E visual acuity test
(accuity 3yp = 20/30) |
|
|
Term
| what is done on a 5yo+ eye exam to test for amblyopia (1) |
|
Definition
|
|
Term
| how is amblyopia treated? (2) |
|
Definition
treat the underlying cause (strabismus, anisometropia, cataract, ptosis, etc)
occlude the bettwe seeing eye, titrating the time to the amblopia depth and age of child |
|
|
Term
| what is the problem with eye patching as a treatment |
|
Definition
| can cause amblyopia in the good eye if patched too long (reverse amblyopia) |
|
|
Term
| what are the four ways to categorise strabismus, in one or two words describe each |
|
Definition
concomitant- non paralytic
non comitant- paralytic
phoria- latent deviation
tropia- manifest deviation |
|
|
Term
| define concomitant tropia |
|
Definition
| angle of misalignment is EQUAL in all directions of gaze |
|
|
Term
| who gets concomitant tropia (2) |
|
Definition
adults who lost an eye
children with abnormal anatomy |
|
|
Term
| define non-comitant tropia / imcomitant tropia |
|
Definition
| angle of misalignment VARIES with direction of gaze |
|
|
Term
| what causes incomitant tropia (2) |
|
Definition
| muscle of nerve dysfunction or mechanical restriction |
|
|
Term
| give examples of three conditions that cause incomitant tropia |
|
Definition
CN palsy
orbital disease
orbital trauma: blow out fracture |
|
|
Term
|
Definition
| binocular vision of fusion interrupted, you can only see the problem whent the patient looks around, fowrard gaze is fine |
|
|
Term
|
Definition
| deviation present when both eyes are open, you can see the problem in forward gaze right away |
|
|
Term
| what are the types of tropia |
|
Definition
| consistant and intermittent |
|
|
Term
|
Definition
Esoteopia: light reflex is temporal, pupil is nasal
Exotropia: light reflex is nasal, pupil is temporal
Hypertrophia: light reflex is inferior, pupil is superior
Hypotrophia: light reflex is superior, pupil is inferior |
|
|
Term
| what are the three steps in testing for strabismus |
|
Definition
general inspection
corneal light reflex
cover test |
|
|
Term
| what are the 4 parts of the general inspection for strabismus, what are their relivence |
|
Definition
Epicanthus evalulation: prominent folds or wide nasal bridges can cause pseudostrabismus
Motility exam
Nystagmus exam: nystagmus means poor vision
Head tilt exam |
|
|
Term
| how is strabismus treated (4) |
|
Definition
rule out neurological causes
normalize vision: treat amblyopoia (patch)
equalize vision: treat refractive errors
surgery if these dont work and there is still a misalignment |
|
|
Term
| what are the two approaches to strabismus surgery, in general how are they done |
|
Definition
Weaken muscles: cut and attach muscle more anterior
Strengthen muscles: cut and attach muscles more posterior |
|
|
Term
| corneal light reflex testing: what does it test for, who do we do it on, how is it measured |
|
Definition
Assessment of ocular alignment
Helpful in newborns and young kids
1 mm of deviation of the light = 7 deg deviation = 14 prism diopters of deviation |
|
|
Term
| cover test: what does it detect, who do we do it on |
|
Definition
detects tropias
adults and kids |
|
|
Term
| cover test: how is it done, what should you see |
|
Definition
Cover strabismus eye and uncover and the straight eye will always stay fixated on the object
When the straight eye is uncovered the strabismus eye will not be fixed, but when you cover the straight eye it will fix on the object |
|
|
Term
| alternate cover test: how is it done, what does it detect |
|
Definition
detects phorias
cover is moved back and forth |
|
|
Term
| alternate cover test: how is it done, what should you see |
|
Definition
When the straight eye is uncovered it will not move
When the strabismus eye is uncovered it will deviate to one side |
|
|
Term
| red reflex test: tip for bettwe results |
|
Definition
| dilate pupils if needed for better view |
|
|
Term
| what does it mean if leukocoria is found on red reflex test (4) |
|
Definition
white pupil
retinal detachment, cataract, retinoblastoma |
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