Treatment of unilateral amblyopia: factors influencing visual outcome.
OBJECTIVE
To identify factors that influence the outcome of treatment for unilateral amblyopia, as a part of the Monitored Occlusion Treatment of Amblyopia Study (MOTAS).


METHODS
This was an intervention study consisting of three nonoverlapping phases: "Baseline", "refractive adaptation" (18 weeks of full-time spectacle wear), and "occlusion" (6 hours of patching per day, objectively monitored). Condition factors: type of amblyopia, age of participant, initial severity of amblyopia, fixation, and binocular vision status; treatment factors: refractive adaptation and occlusion (total dose [hours] and dose rate [hours per day]) were assessed for their influence on visual outcome. Visual outcome was expressed in three ways: logMAR (logarithm of the minimum angle of resolution) change, residual amblyopia, and proportion of the deficit corrected.


RESULTS
The study included 85 participants (mean age, 5.1 +/- 1.4 years) with amblyopia associated with strabismus (n = 32) or anisometropia (n = 20) or associated with both anisometropia and strabismus (n = 33). Treatment factors: cumulative occlusion dose exceeding 50 hours, and dose rates > or =1 hour per day resulted in (P < or = 0.01) lower residual amblyopia and a greater proportion of the deficit corrected. Condition factors associated with poor outcome (high residual amblyopia) were presence of eccentric fixation, severe initial amblyopia, and no binocular vision.


CONCLUSIONS
Factors influencing outcome with treatment for amblyopia are occlusion dose (the rate of delivery and cumulative dose worn), the initial severity of the amblyopia, binocular vision status, fixation of the amblyopic eye, and the age of the subject at the start of treatment.
Stewart
Catherine E
CE
Department of Optometry and Visual Science, City University, CM 466 Tait Building, Northampton Square, London EC1V 0HB, United Kingdom. c.e.stewart@city.ac.uk
Fielder
Alistair R
AR
Stephens
David A
DA
Moseley
Merrick J
MJ
D000367:Age Factors; D000550:Amblyopia / Q000503:physiopathology / Q000628:therapy*; D015858:Anisometropia / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012683:Sensory Deprivation; D012720:Severity of Illness Index; D013285:Strabismus / Q000503:physiopathology; D016896:Treatment Outcome; D015348:Vision, Binocular; D014792:Visual Acuity / Q000502:physiology*