The World Health Organisation has cited refractive errors (i.e. the need for glasses for near-sightedness or far-sightedness or astigmatism); cataract; glaucoma; diabetic retinopathy and age-related macular degeneration as the leading causes of reversible blindness worldwide.
VISION IMPAIRMENT is quoted globally as posing an enormous financial burden.
FOR A PATIENT, it is more than that. It is a LOSS of INDEPENDENCE and poor QUALITY of LIFE; loss of VOCATION. It is a social burden, and a cause of DEPRESSION for a multitude of reasons. It is important to realise that PRESBYOPIA is NOT an impairment or cause of reversible blindness. (It is the requirement of reading glasses around the age of 40. Some people need reading glasses earlier, others a bit later - this is not an impairment, but a shift in accommodation of your pupil-lens complex which is easily remedied by an inexpensive pair of reading glasses. A condition we all reach and adhere to whilst medical science works tirelessly to come up with better solutions - most of these solutions however, will not be contra-indicated in patients who have the diseases in our heading above.)
Screening and annual check-ups are imperative to preventing these causes of blindness. They are called "reversible" but the pathology can be reversed, it can only be halted if detected early enough in the case of glaucoma, diabetes and macular degeneration. In the case of cataracts, they have the least risk of complication if operated on timeously.