Binocular treatment for amblyopia: a systematic review

The treatment of unilateral amblyopia involves refractive adaptation, occlusion therapy or penalization with atropine drops. However, in recent years, the use of binocular digital therapy has shown promising results. Aim of this systematic review was to evaluate the effectiveness of binocular treatment of amblyopia compared with standard treatments or placebo therapy.

This systematic review was conducted in accordance to PRISMA statement. Electronic literature was thoroughly searched for articles published between 2013 and May 2024, in the following electronic database; Pubmed, CENTRAL, MedlinePlus, Medline Europe, PLOS, Scopus, Clinicaltrials.gov. The review comprised randomized control trials (RCTs) including patients with unilateral amblyopia, who received binocular therapy or standard amblyopia or placebo treatment for more than two weeks and who had visual acuity assessment pre- and post-treatment. Only articles written in English were included. Risk of bias was assessed with the Rob2 tool, while study quality was evaluated with the modified Jadad scale.

Twenty RCTs, including 1769 patients, were incorporated into this systematic review. Twelve different types of binocular amblyopia treatments were identified and categorized into two main types. The first type involves the presentation of low-contrast images in the fellow eye, including stimuli presented only in the amblyopic eye. The second type combines this approach with complementary dichoptic deficits in the images presented to both eyes to encourage their simultaneous use.

Binocular amblyopia treatment has shown promising results in addressing unilateral anisometropic, strabismic or mixed type of amblyopia. Nevertheless, further randomized controlled trials are essential to establish the exact dosage, type and duration of binocular therapy as a standard component of amblyopia care.