AMBLYOPIA Binocular Vision Anomalies Ralph P. Garzia

Amblyopia definition traditional –best corrected ≤20/40 or –2 line difference in VA modern –<20/20 + –behavioral or performance deficits

The father of amblyopia treatment George Louis Leclerc, Conte De Buffon ( ) In 1742 suggested that the good eye be occluded to force use of the amblyopic eye.

Amblyopia - mechanisms neurocompetition form deprivation

Epidemiology - prevalence depends Flom & Neumaier ≤20/401% others % acceptable level 2.0%

Amblyopia of extinction Amblyopia of arrest Chavesse’s visual acuity levels, 1939 it’s right & wrong arrested development of visual acuity- irreversible extinguished visual acuity development- reversible

Classification based on etiology Strabismic amblyopia –esotropia –hypertropia, hypotropia –exotropia Anisometropic amblyopia –hyperopic –astigmatic –myopic

Anisometropia & amblyopia

Classification based on etiology Refractive amblyopia –hyperopic –astigmatic –myopic

Classification based on etiology Deprivation amblyopia –congenital cataract –congenital nystagmus –congenital ptosis –occlusion Hysterical amblyopia –juvenile onset –non-malingering syndrome of Streff, John

Amblyopia - distribution 1/3 strabismic amblyopia 1/3 anisometropic amblyopia 1/3 remainder most of these are combined strabismic and anisometropic

Amblyogenic conditions constant, unilateral strabismus significant anisometropia bilateral isometropia form deprivation

Components of visual acuity loss sensory loss eccentric fixation oculomotor dysfunctions perceptual disturbances

Amblyopia as a syndrome reduced visual acuity reduced contrast sensitivity reduced oculomotor function reduced accommodative function increased crowding effects decreased fixation stability eccentric fixation spatial distortion