Occlusion therapy in amblyopia: an experience from Hong Kong

OBJECTIVES. To review the results of patching for amblyopia management in Hong Kong. DESIGN. Retrospective case series. SETTING. Regional hospital, Hong Kong. PATIENTS. Records of all patients attending Paediatric Ophthalmology Clinic at United Christian Hospital, Hong Kong from 1 January 2009 to 31 March 2009 were retrospectively reviewed. Records of all children who underwent patching for amblyopia in the study period were evaluated. RESULTS. The mean age of 50 children (50 eyes) was 4 (standard deviation, 1; range, 2-7) years and mean pretreatment visual acuity was 0.35 (0.15; 0.02-0.63) [~20/60]. The values for mean, standard deviation, and range of treatment duration were 27, 16, 4-67 months respectively, and corresponding values for prescribed patching per day were 4, 1, 2-8 hours. The mean, standard deviation, and range of visual acuity at final post-treatment assessment were 0.66, 0.16, 0.1-1.0 (~20/30), respectively. The overall success rate (ie final visual acuity >0.7 or 20/30) was 62%. Children with moderate amblyopia (20/40-20/80) and severe amblyopia (20/100-20/400) had success rates of 74% and 55%, respectively. The mean visual acuity improvements for moderate and severely amblyopic children were 2.3 lines and 5.8 lines, respectively. The mean, standard deviation, and range of patching prescriptions for moderate and severely amblyopic children were 5, 1, 2-7 hours and 5, 1, 3-6 hours, respectively. Recurrence ensued in 7% of the children with moderate amblyopia and 46% of those with severe amblyopia. Reported compliance was good (>75% of the time) in 68% of the children. CONCLUSION. Occlusion therapy is the mainstay of treatment in Hong Kong. The overall success rate was comparable to that achieved in the Amblyopia Treatment Study. Recurrence was more common in patients with severe amblyopia, for whom maintenance therapy may reduce the risk of recurrence. The duration of treatment was much longer in our locality than in western countries. Reported compliance was suspicious possibly due to traditional cultural contexts. It is important to emphasise compliance to all parents.