The factors affecting the success of treatment in amblyopia

PURPOSE: To evaluate the efficacy of occlusion treatment and the factors affecting the success of treatment in amblyopiaMATERIALS AND METHODS: The records of 173 patients who were treated for amblyopia by occlusion of the fellow eye between January 1997 and June 2011 were reviewed retrospectively. Age and level of visual acuity at initiation of treatment, type of amblyopia, occlusion time ( full-time, part-time ) and refractive errors on success rate and visual outcome were evaluated.RESULTS: Seventy four ( % 42,8 ) out of 173 patients were found to have anisometropic amblyopia. Fifty six ( % 32,4 ) patients had strabismic amblyopia and forty three ( % 24,9 ) patients had strabismic-anisometropic amblyopia. The mean age of the patients was 6,18 ± 1,50 years ( range between 3 - 10 years ) and the follow-up time was 44,35 ± 27,17 months (range between 24 - 128 months ). In 142 of the patients ( % 82,1 ), the visual acuity improved at least 3 lines at the end of the treatment . The success rate of treatment was significantly lower in patients with strabismic-anisometropic amblyopia ( p= 0,003). The mean visual acuity improvements were similar among the groups ( anisometropic amblyopia 0,41 ± 0,37 logMAR units, strabismic amblyopia 0,36 ± 0,23 logMAR units, strabismic-anisometropic amblyopia 0,39 ± 0,24 logMAR units ). Visual acuity improvement was found significant in both group of patients with full time occlusion and part time occlusion ( p<0,001, p<0,001, respectively). There was no significant difference in visual acuity improvement between the two occlusion groups ( p=0,948). The comparison of the required period to reach success for part-time and full-time occlusion groups revealed no significant difference between anisometropic amblyopia and strabismic amblyopia. However in strabismic-anisometropic amblyopia the required period to reach success was significantly shorter than the other two amblyopia groups. We found that the level of initial visual acuity and age at the initial treatment were the most significant factors on final visual acuity ( p< 0,001, p< 0,001, respectively ). We determined that the occlusion time and refractive error do not have a significant effect on the final visual acuity.CONCLUSİON: The level of initial visual acuity and type of amblyopia are the most significant factors determining the success of treatment in amblyopia. The most important factors on the final visual outcome are the level of initial visual acuity and age at the initiation of treatment. A successful outcome is reached in a shorter time in the patients who are treated with full time occlusion in the strabismic anisometropic amblyopia patients. In patient groups with anisometropic amblyopia and strabismic amblyopia no significant difference was found in the required period to reach success with full-time and part-time occlusion.KEYWORDS: Amblyopia, occlusion treatment, visual acuity, anisometropia, strabismus