Cataract surgery

Cataract surgery, also called lens replacement surgery, is the removal of the natural lens of the eye that has developed a cataract, an opaque or cloudy area. The eye's natural lens is usually replaced with an artificial intraocular lens (IOL) implant.

Over time, metabolic changes of the crystalline lens fibres lead to the development of a cataract, causing impairment or loss of vision. Some infants are born with congenital cataracts, and environmental factors may lead to cataract formation. Early symptoms may include strong glare from lights and small light sources at night and reduced visual acuity at low light levels.

During cataract surgery, the cloudy natural lens is removed from the posterior chamber, either by emulsification in place or by cutting it out. An IOL is usually implanted in its place (PCIOL), or less frequently in front of the chamber, to restore useful focus. Cataract surgery is generally performed by an ophthalmologist in an out-patient setting at a surgical centre or hospital. Local anaesthesia is normally used; the procedure is usually quick and causes little or no pain and minor discomfort. Recovery sufficient for most daily activities usually takes place in days, and full recovery about a month.

Well over 90% of operations are successful in restoring useful vision, and there is a low complication rate. Day care, high-volume, minimally invasive, small-incision phacoemulsification with quick post-operative recovery has become the standard of care in cataract surgery in the developed world. Manual small incision cataract surgery (MSICS), which is considerably more economical in time, capital equipment, and consumables, but provides comparable results, is popular in the developing world. Both procedures have a low risk of serious complications, and are the definitive treatment for vision impairment due to lens opacification.