The evolution of amblyopia treatment: from patching to binocular approaches

Looking at the history of amblyopia treatment is the shortest route to understanding today's approaches, because while the methods changed, what really changed was the understanding of where the problem sits.

The idea of covering the strong eye to force the weaker one into use has been known for centuries and became one of modern ophthalmology's established methods.

The logic is clear: if the weaker eye is not being used, make it be used. The approach delivered real gains in acuity and is still widely used.

Over time, though, two limits became visible: the difficulty of delivering it, and the fact that the eyes working together is never targeted directly.

The second phase questioned not patching itself but its dose. Whether full-time patching was necessary in every case was studied, and shorter regimens were shown to give comparable results in many cases.

In the same period atropine drops became established as an alternative: blurring the strong eye's near vision temporarily targets a similar effect and is easier on adherence for some patients.

The common theme of this phase was practical: finding more deliverable routes within the same logic.

The real turn came with understanding amblyopia not merely as one eye seeing less but as a breakdown in the relationship between the eyes. It became clear that the brain suppresses the weaker eye, and that fusion and stereopsis suffer along with it.

That view changed the target of treatment: not only raising acuity but reducing suppression and getting the eyes to work together again.

The approach born from it is binocular treatment: delivering separate but complementary stimuli to the two eyes, and making the task completable only with both contributing.

Screen technology made the idea deliverable: adjusting contrast precisely, tailoring difficulty to the individual and measuring adherence all became practical in a digital setting.

The field is now examined in randomized controlled and multicenter trials, and multicenter data have been published showing digital dichoptic treatment producing outcomes not inferior to patching (Wygnanski-Jaffe et al., Ophthalmology, 2023; see also Xiao et al., Ophthalmology, 2022).

Evidence that the adult brain can respond to this kind of training has also reopened the discussion about what is possible beyond the critical period (Li et al., Current Biology, 2013).

Optical correction remains the common starting point of every approach. Beyond it, clinicians have more than one tool, and the choice follows both the clinical picture and what can actually be delivered.

The direction of the field is clear: the target is increasingly the two eyes working together, which is more than the sharpness of a single eye.