The lens behind your pupil
Inside your eye, just behind the iris and pupil, sits a small, transparent, flexible structure called the natural lens. Along with the cornea, it focuses light onto the retina so your brain can form a clear image. In youth, this lens is crystal clear and flexible enough to change shape and shift focus between near and far objects — a process called accommodation.
A cataract develops when the proteins in this lens begin to break down and clump together. Instead of letting light pass through cleanly, the clouded areas scatter and block it, the same way a clean window turns hazy when it fogs up. The lens itself does not move, grow, or spread to other parts of the eye — the change happens within the existing lens tissue.
Clouding is usually gradual
For most people, a cataract does not appear overnight. It develops slowly, often over several years, which is why early cataracts frequently go unnoticed. Vision may seem only slightly duller or a prescription may need adjusting more often than usual, long before anyone thinks to call it a cataract. Learn about the symptoms to watch for →
Cataracts are extremely common
Cataracts are not a rare condition — they are a normal part of aging for most people. The majority of adults will develop some degree of lens clouding if they live long enough, and cataract removal is one of the most frequently performed surgical procedures in the world. Being told you have a cataract is not, by itself, an emergency or a sign that something has gone wrong. It is a signal to start paying attention and, eventually, to plan for treatment on your own timeline. Understand what causes them →
Cataracts only affect the lens
It's worth being clear about what a cataract is not. It is not the same as glaucoma (a separate condition involving pressure and the optic nerve), macular degeneration (which affects the retina), or a corneal problem. A cataract is specific to the lens, and it does not damage the rest of the eye on its own — although living with severely reduced vision for a long time can affect quality of life and safety, which is part of why timing surgery well matters. See how surgery works →
The only effective treatment is surgery
No eye drop, medication, supplement, or exercise has been shown to reverse or slow a cataract once it has formed. The only proven treatment is surgery: removing the clouded natural lens and replacing it with a clear, artificial intraocular lens (IOL). This is precisely why the choice of replacement lens matters so much — it isn't a temporary fix, it's the lens you'll likely have for the rest of your life. Explore your IOL options →