Among people aged ≥ 50 years, the most important causes of blindness were cataract (65.1%), followed by corneal opacity (10.4%). However the most important causes of cumulative visual impairment were cataract (43.4%) and refractive error (39.8%). Most important cause leading to early visual impairment is uncorrected refractive error (81.9%).
Out of all causes of blindness, 5.8% causes were unavoidable and 26.8% were preventable. Nearly two-third causes if treated well in time could prevent blindness. Among causes of cumulative visual impairment (PVA better eye <6/18), 3.4% were unavoidable, 11.0% were preventable and more than 85% causes if treated could prevent visual impairment to occur. For moderate severe visual impairment (PVA better eye <6/18-3/60), 88.9% treatable, 8.1% preventable and 3.0% unavoidable
Presenting visual acuity < 3/60 in better eye
Presenting visual acuity < 6/60 – 3/60 in better eye
Presenting visual acuity < 6/18 – 6/60 in better eye
Presenting visual acuity < 6/12 – 6/18 in better eye
Presenting visual acuity <6/18-3/60 in better eye
Presenting visual acuity < 6/18 in better eye
A person with impairment of visual functioning even after treatment and/or standard refractive correction, and a visual acuity of less than 6/18 to light perception, or a visual field of less than 10 degree from the point of fixation.
Cataract Surgical Coverage (Person) indicates how many persons received cataract surgery (one or both eyes) among all who were bilaterally pinhole blind due to cataract.
The numerator includes persons with one operated and one pinhole blind eye and persons with bilateral (pseudo) aphakia. The denominator includes the numerator, plus persons bilaterally pinhole blind due to cataract. Besides this, the indicator can also be calculated separately for PinVA <6/60 and <6/18.
Cataract Surgical Coverage (Eye) measures the proportions of eyes pinhole blind due to cataract, which have been operated so far.
The numerator includes all (pseudo) aphakic eyes. The denominator includes the numerator, plus eyes pinhole blind due to cataract. Besides this, the indicator can also be calculated separately for PinVA <6/60 and <6/18.