Interventions for strabismic amblyopia

Amblyopia is reduced visual acuity in one or both eyes in the absence of any demonstrable abnormality of the visual pathway. It is not immediately resolved by the correction of refractive error. Strabismus develops in approximately 5% to 8% of the general population. The aim of treatment for amblyopia is to obtain the best possible level of vision in the amblyopic eye. Different treatment options were examined within the review.

By reviewing available evidence we wanted to establish the most effective treatment for strabismic amblyopia. In particular this review aimed to examine the impact of conventional occlusion therapy for strabismic amblyopia and analyse the role of partial occlusion and optical penalisation for strabismic amblyopia.

We searched CENTRAL, MEDLINE, EMBASE and LILACS in October 2007. There were no language or date restrictions in the electronic searches for trials.

We included randomised controlled trials (RCTs) for the treatment of strabismic amblyopia including participants of any age.

Two authors working independently extracted and entered data into Review Manager 4.2 using the double data entry facility to check for errors.

We included two RCTs. The studies reported mean logMAR visual acuity achieved. Mean difference in visual acuity was calculated. When comparing conventional part-time occlusion (with any necessary glasses), PEDIG 2006 reported this treatment was more beneficial than glasses alone for strabismic amblyopia. Mean difference between groups was -0.18 (statistically significant 95% CI -0.32 to -0.04). Supplementing occlusion therapy with near activities may produce a better visual outcome compared to non-near activities after four weeks of treatment (PEDIG 2005). Mean difference between groups was -0.17 (95% CI -0.53 to 0.19). However, this data is from a pilot study and the full data set will be added to updates of the review when available.

Occlusion, whilst wearing necessary refractive correction, appears to be more effective than refractive correction alone in the treatment of strabismic amblyopia. Combining occlusion and refractive correction with near activities may be more effective than occlusion and refractive correction alone. Further study of the role of near activities is necessary before a more definitive conclusion can be made. Results of a full trial are expected within the coming year. No RCTs were found that assessed the role of either partial occlusion or optical penalisation to refractive correction for strabismic amblyopia.