Amblyopia (referred to as lazy eye) is a common childhood condition, and is defined as defective visual acuity in one or both eyes, which is present with no demonstrable abnormality of the visual pathway and is not immediately resolved by wearing glasses. Treatment for amblyopia usually starts with prescribing necessary glasses to correct visually important refractive errors followed by promoting the use of the amblyopic eye. This systematic review aimed to synthesize the best available evidence regarding the effectiveness and safety of two different treatment options used to promote the use of the amblyopic eye: conventional occlusion (patching) and atropine penalization (drops). Conventional occlusion involves patching the non-amblyopic eye with an opaque patch for a set number of hours per day. Atropine penalization involves the instillation of atropine sulphate to blur the eyesight of the better-seeing eye.
We included three randomized or quasi-randomized controlled trials with a total of 525 amblyopic eyes. Evidence from three trials (one of good methodological quality) suggests both conventional occlusion and atropine penalization produce visual acuity improvement in the short-term (six months) and long-term (24 months) in the amblyopic eye after initiation of therapy. The results of this review show atropine penalization to be as effective as conventional occlusion, although the amount of improvement achieved differed among the three trials. Although both treatments were well tolerated, compliance was better with atropine penalization. Atropine penalization can be used as first line treatment for amblyopia.