In Madurai today, there is usually a long line of people outside the free section of the Aravind Eye Hospital. It is not uncommon to find an elderly patient among them, wearing a crooked pair of spectacles fastened around the head with a piece of string. The lenses of these glasses are as thick as your index finger. They magnify the eyes, giving the wearer an air of absurd gravity.

These are cataract patients from the fast-dwindling era of aphakic surgery, a procedure that emerged in the mid-18th century and remained the standard for over 200 years. It involved making a large slit along the rim of the cornea and removing the clouded cataract lens. This lensless condition was referred to as aphakia. To replace ...

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