What a cataract is, and why it forms
Dr. Swati Goyal · 24 September 2024 · 5 min
Cataract is a familiar word. Most of us know roughly that as age advances — as hair greys and wrinkles appear — a cataract forms in the eye.
Inside the eye there is a transparent lens. With age it clouds over and vision turns foggy — as though dust had settled on a pane of glass. Some people describe it as a web coming across their sight.
What is actually happening
From birth the lens is clear, and light passes straight through it. But with age — or when the lens is injured in some other way — its protein fibres begin to change. The lens turns cloudy, and light can no longer pass through.
Causes besides age
Age is not the only reason. Several other things can bring a cataract on earlier than expected.
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An injury to the eye, in childhood or at any age.
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Previous eye surgery — for glaucoma, or on the retina.
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Diabetes. In people with diabetes a cataract can form ahead of time.
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Oral or topical steroids taken for a skin problem or other illness.
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Living at altitude, where exposure to UV light reflected off snow is much higher.
Treatment
The treatment for cataract is surgery — a small incision is made, the clouded lens is removed, and a new lens is put in its place.
What people commonly call “laser” or “doorbeen” surgery is in fact phacoemulsification, in which a foldable lens is implanted. The most common foldable lens is monofocal — it corrects distance vision, and you may still need glasses for close work.
There are several other lens options, and more than one surgical technique. Those are covered in detail in the companion post on surgical techniques and lens types.