Amblyopia, commonly called lazy eye, occurs when the brain does not adequately process visual input from one eye. The visual pathway may appear anatomically normal, but the input reaching the brain is poorly coordinated or insufficient for normal visual development.
Misalignment of the eyes, as in squint, can affect binocular vision. Congenital cataract, corneal opacity and other conditions that obstruct visual input can also cause stimulus-deprivation amblyopia. A child may simply learn to rely on the eye with better vision and continue with everyday activities without complaint. The gap is particularly significant among preschool children and those living in rural or semi-urban areas where access to an ophthalmologist may be limited. Also, families dependent on daily wages may find it difficult to lose a day’s work for hospital visits. Even where preschool screening is available through Anganwadi centres, completing the referral to an ophthalmologist can be a challenge. Treatment is not usually a matter of a few weeks and can continue for months or even years, depending on the child’s condition and response. Dr. With appropriate preparation and continuing engagement, adherence roughly doubled. Digital therapies can be useful in children aged four to five years and above, although cost remains a limitation. Doctors also point to early comparative data suggesting that some binocular approaches may achieve higher adherence than conventional patching.
Because of an uncorrected refractive error such as farsightedness, nearsightedness or astigmatism, the condition can develop. In one such study, only about 45% of families achieved the adherence target set by the treating doctor. In one study comparing a gaze-tracking binocular device with patching, median adherence was about 94% with the binocular treatment compared with about 84% with patching.
“There’s no red eye, no visible squint in most cases, no clinical sign that we can make out,” says Aparna Bhatnagar, senior consultant, ophthalmology, Apollo Speciality Hospitals, Vanagaram, Chennai. Kalpana R, senior consultant, Ophthalmology, SIMS Hospital, Chennai, says school screening programmes can help identify children, particularly around four to five years of age, and allow treatment to begin early. Bhatnagar says electronic monitoring studies have highlighted the gap between treatment prescribed and treatment actually received.
