Science and Medicine

Cataract surgery

Cataract 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 glare from lights, especially at night, blunting of colors in vision and reduced visual acuity at low light levels. During cataract surgery, the cloudy natural lens is removed from the posterior chamber of the eye, either by emulsification in place or by manual removal. An IOL (intraocular lens) is usually implanted in its place (PCIOL), or less frequently in the cilliary sulcus, to restore clear vision. Cataract surgery is performed by an ophthalmologist in an out-patient setting at a surgical centre or hospital. Local anaesthesia (injection) or topical anesthesia (drops) are 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 takes about a month. Well over 90% of operations are successful in restoring useful vision, and there is a low complication rate. Same day, minimally invasive, small-incision phacoemulsification with quick post-operative recovery has become the standard of care of cataract surgery in much of the world. Manual small incision cataract surgery (MSICS), which is considerably more economical in capital equipment and consumables, and 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 cataract.

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