Remediation of refractive amblyopia by optical correction alone

Abstract

Amblyopia--the commonest vision abnormality of childhood--is characterized by a loss of visual acuity usually of one eye only. Treatment aims to promote function of the amblyopic eye and does this by restricting, usually through occlusion, the competitive advantage of the fellow eye. Recent experimental evidence demonstrates that the recovery of vision following early deprivation is facilitated by increasing visually evoked activity. An analogous approach in humans is to minimise image blur by correcting refractive error prior to treatment--a practice which may account for the poorly quantified improvements in visual acuity sometimes attributed to 'spectacle adaptation'. Here we describe clinically significant gains in visual acuity obtained over a period of 4-24 weeks in a group of amblyopic children arising solely in response to the correction of refractive error. Consequences for the clinical management of refractive amblyopia are discussed.

The effect of amblyopia treatment on stereoacuity

“…All children with significant refractive error were instructed to wear spectacles full-time and were scheduled to return for four vision assessments at 6-week intervals from week 0 (onset of spectacle wear) until 18 weeks of refractive adaptation was completed-a period that our previous research indicated would allow for all significant improvement attributable to spectacle wear to have occurred. 14 Children remaining eligible for occlusion (see below for inclusion criteria) entered the occlusion phase and were prescribed 6 hours occlusion per day (a dose considered moderate, allowing for underand over-concordance). Occlusion episodes received were recorded to the nearest minute by an occlusion dose monitor.…”

Electronic monitoring of occlusion treatment for amblyopia in patients aged 7 to 16 years

“…Before study entry, all patients had a full ophthalmic assessment including cycloplegic retinoscopy and fundoscopy, and a full orthoptic examination. Inclusion criteria were: age>7 years and amblyopia (strabismic, anisometropic or combined), and acuity difference between the eyes of at least 0.2 logMAR (logarithm of the minimum angle of resolution) for single and crowded optotypes after refractive adaptation [15,20,21]. While most patients received their glasses several months before entering the study, two received their first glasses 8 and 6.5 weeks respectively before baseline acuity was assessed, and in one patient there was a change of the astigmatic component of 0.75 D 7 weeks before.…”

Eye patching as a treatment for amblyopia in children aged 10–16 years

“…Those studies that show a progressive improvement in acuity for up to 18 weeks in some patients after refractive correction alone in anisometropic amblyopia patients use the term ''refractive adaptation period'' [22,23]. In the present study, we did not wait for the refractive adaptation period because, as the duration of treatment increases, treatment compliance decreases.…”