Strabismus might be a risk factor for amblyopia recurrence
Part of this study was presented as a poster at the 2005 meeting of the European Association for Vision and Eye Research (EVER) in Vilamoura, Portugal, October 5-8.
Received 21 February 2006; accepted 21 January 2007. published online 13 April 2007.
Background
Previous reports have suggested that one-fourth of amblyopic subjects present with recurrence of amblyopia even after successful primary treatment. Risk factors for amblyopia recurrence are insufficiently studied, but therapy weaning has recently been suggested as a method for reducing the risk of recurrence.
Methods
In the second phase of a prospective study examining the results of treatment for amblyopia, all 35 children with successful primary amblyopia treatment were put on maintenance therapy. Maintenance therapy consisted of low-intensity patching, atropine, or blurring filter, and all children were regularly examined up to at least 8 years of age. Mean age at start of maintenance therapy was 4.3 years (range, 2-7 years).
Results
Of the 35 cases with successful primary treatment, 6 cases deteriorated ≥0.2 logMAR, which was considered recurrence of amblyopia. Two of these cases had a second recurrence. Notably, all six subjects presenting with recurrence had microstrabismus. This finding was just outside statistical significance at the 95% confidence level (p = 0.06), but the sample size was small. All but one of the recurrences appeared within 6 months after successful primary treatment. Age at successful primary treatment or initial interocular difference of visual acuity did not affect the risk of recurrence.
Conclusions
Recurrence of amblyopia occurred in 17% of patients despite maintenance therapy and was associated with microstrabismus. The majority of recurrences occurred within the first 6 months after primary treatment.
aDepartment of Clinical Neurophysiology, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden
bDepartment of Ophthalmology, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden
Reprint requests: Josefin Nilsson, MD, PhD, Department of Clinical Neurophysiology, Sahlgrenska University Hospital, SE 413 45 Göteborg, Sweden.
ABSTRACT