Orthoptics Flashcards
What is binocular vision
Brains ability to perceive an image with each eye as a single image
Two different types of squint
Manifest: one eye is normal and the other is deviated in another direction
LAtent: normal eyes however one eye has a tendency to deviate
What happens to binocular vision in a squint
Have diplopia
However children are adaptable and they suppress one image so only see one image
What is amblyopia
Reduction of vision in one eye
Due to a lack of stimulation during the critical period of visual development
Due tp: stimulus deprivation (e.g. ptosis and cataracts), strabismus (lazy eye), anisometropic (difference in acuity in two eyes and the one with the better acuity develops amblyopia)
Management of amblyopia
Reversed if treated before <7yo
Occlusion of the ‘good eye’ by a patch so they are forced to use the amblyopic eye
Management of squints
-Correct refractive error
Convex lenses: help convergent deviations
Concave lenses: help divergent deviations
-Surgery
What is concomitant strabismus
A squint that remains the same in all positions of gaze
What is inconstant strabismus
A squint that changes in different positions of gaze
Due to an EO muscle imbalance
Action of Superior rectus muscle
Elevation, intorsion, adduction
Action of inferior rectus
Depression, extorsion, adduction
Action of superior oblique
Intorsion, depression, abduction
Action of inferior oblique
extorsion, elevation, abduction
How does myasthenia graves present
Ptosis
