An Observational Study on Recurrence of Amblyopia After Discontinuation of Treatment

• To identify factors associated with recurrence to be considered in designing a subsequent trial
• To collect data to estimate the recurrence rate of amblyopia after treatment is discontinued

Amblyopia is the most common cause of monocular visual impairment in both children and young and middle-aged adults. Patching has been the mainstay of amblyopia therapy. It is generally held that the response to treatment is best when it is instituted at an early age, particularly by age two or three, and is poor when attempted after eight years of age.

After amblyopia has been successfully treated, there is no accepted standard of care for how it should be managed. Can treatment be stopped or is a period of maintenance therapy needed? At present, there are little quality data available on the recurrence rate of amblyopia and whether there are any factors that can predict which patients are likely to have a recurrence and which are not. Therefore, a prospective study warranted to provide an estimate of the amblyopia recurrence rate and associated factors.

The observational study will determine the recurrence rate and factors associated with recurrence when treatment is discontinued in patients whose amblyopia has been successfully treated. It will consist of about 200 children. The study will last for 12 months and each child will have at least four follow up visits. Visual acuity is assessed at the 12-month exam.

Patients must be less than 8 years of age with original cause of amblyopia (at start of current cycle of treatment) due to strabismus or anisometropia (a refractive error difference of more than one diopter between the two eye.) At time of enrollment child must have had continuous treatment for amblyopia in the last 3 months consisting of at least 2 hours per day of patching (14 hours per week) or at least one drop of atropine per week. At start of current treatment cycle, acuity in the amblyopic eye must be 20/40 or worse with at least 3 lines of acuity difference between the two eyes.

No longer recruiting. Comments: Completed. Recruitment began in May 2001 and closed in November 2002 after 176 patients were enrolled.

Completed, with results not yet published. Comments: Completed.

None. Manuscript submitted to Journal of AAPOS in March 2004.