By Cristie Chau
Cataracts are the clouding of the crystalline lens of the eye. The lens is a clear, biconvex layer of the eye that bends and thickens, with the help of ciliary muscles, to focus light from the cornea to the retina to produce a clear image, and is mostly made of a highly concentrated protein solution. The proteins in the lens naturally break down at around age 40. When the balance of the proteins is destroyed, they clump together, creating clumps of proteins that get bigger and thicker over time, causing the lens to become cloudy. With a cataract, the vision would no longer be clear and sharp, as the light that would normally be focused by the lens is scattered and blocked because of the cloudiness.
The most obvious symptom of a cataract is blurriness in vision, but as the cataract grows larger over time, the lens may turn yellow or brown, which can change how you see colors. Other possible symptoms are double vision, halos around lights, and difficulties with bright lights and night vision.
Cataracts are a common condition in people over 60 years old, but a family history of cataracts, diabetes, and a serious eye injury are also factors for developing cataracts.
In this surgery, the surgeon removes the cataract and replaces the lens with an intraocular lens. To do this, the surgeon makes an incision into the edge of the cornea, then creates an opening in the membrane that surrounds the lens and injects saline into the capsule to separate the lens from the surrounding capsule, through a technique called hydrodissection. Fluid waves separate the lens nucleus and the cortex and capsule. An ultrasonic probe uses ultrasonic energy to break up the lens nucleus. Ultrasonic waves cause the molecules of the lens to vibrate vigorously due to their high frequency, and this causes the cataract lens to break into particles. The nucleus fragments that are generated are removed by a vacuum attached to the probe. This process is called phacoemulsification. A folded intraocular lens is inserted into the capsular bag through a thin tube and unfolds automatically. An intraocular lens focuses light that enters the eye onto the retina and works just like the crystalline lens of the eye, restoring vision.