Factors influencing visual rehabilitation after occlusion therapy in unilateral amblyopia in children.

BACKGROUND & OBJECTIVE: Amblyopia is one of the most common causes of visual impairment in adults and children, and visual loss may be permanent if not treated in time. Though many studies have been done on occlusion therapy which is the mainstay in the treatment of unilateral amblyopia, discrepancies exist in literature about quantification of treatment and follow up measures. The present study was undertaken to evaluate the factors responsible for the successful outcome of treatment and the optimum time required for the same in children with unilateral amblyopia. METHODS: Baseline characteristics of 63 verbal patients with unilateral amblyopia (strabismic, anisometropic, mixed) referred to the Strabismus and Amblyopia Clinic at the Dr Rajendra Prasad Centre for Ophthalmic Sciences, New Delhi between September 2001 to December 2002 who improved to the desired level of visual acuity after treatment for amblyopia in the mentioned time period, were analyzed to assess for factors that directly or indirectly influenced the optimum visual rehabilitation and the average duration of therapy required for the same. The evaluation included assessment of the baseline best-corrected visual acuity (BCVA) and refractive status in both eyes, the age at presentation, the type of amblyopia present, fixation pattern in the amblyopic eye, inter-eye visual acuity difference, and evaluation of compliance through a parental diary system. RESULTS: Baseline BCVA in the amblyopic eye was similar in all the three groups. Patients with anisometropic amblyopia showed a quicker response to therapy. Compliance to treatment was the major factor affecting the overall time required for a successful outcome in most cases. The overall time required for the treatment to be successful (including the period of maintenance) was about 1,089 h. INTERPRETATION & CONCLUSION: This hospital-based study showed that the average duration of occlusion therapy to achieve stable isoacuity was 7.2 months with an average occlusion of 6-7 h/day. Compliance to therapy was the most important factor affecting the duration of therapy. With increasing emphasis on paediatric eye diseases, amblyopia is at last getting its due importance as a cause of treatable correctable paediatric visual impairment which can have lifelong repercussions, both in terms of individual disability and financial burden to the society if not treated in time. As the therapy is simple and effective if started early, mass awareness, visual screening, and counselling would go a long way in treating the patients, thus decreasing the prevalence of amblyopia in the country.

Profile of amblyopia in a hospital referral practice.

OBJECTIVE: Evaluation of the clinical profile and distribution of different sub-types of amblyopia in a referral eye hospital in India. METHODS: This was a prospective hospital-based observational study, evaluating the clinical profile of patients with amblyopia presenting to a referral strabismology practice. The examination included assessment of the visual acuity, the refractive status, the fixation pattern, the grade of binocularity, and evaluation of the associated strabismus, if any before treatment was started. RESULTS: The average age of the patients at presentation was 7.97?6.18 years with 81 out of 683 patients (11.8%) presenting above the age of 20 years. The best-corrected visual acuity (BCVA) was less than 6/60 in the amblyopic eye in 121 out of 733 eyes (16.5%). Strabismic amblyopia was the most common sub-type of amblyopia seen (274/733 eyes, 37.38%). Though patients with anisometropic amblyopia presented at a later age (average of 10.03+/-6.92 years), they had better visual acuity, binocular functions, and centricity of fixation at all ages, relative to other sub-types of amblyopia. The BCVA did not show any co-relation with the age of presentation [co-relation co-efficient (CF) of 0.074], refractive status of the amblyopic eye (CF of 0.078), the type of amblyopia (CF of 0.196), or the type of strabismus present (CF of 0.079). However, a very significant co-relation was seen between the BCVA and the fixation pattern of the amblyopic eye (CF of 0.817). CONCLUSIONS: Lack of knowledge and awareness about amblyopia and its appropriate timely management has been the main cause for the late presentations and significant visual impairment associated with the condition.