It is a cloudy patch in the eye's otherwise clear lens. The lens is made mostly of water and various proteins, and as we age, the proteins can start clumping together. This makes a non-translucent spot in the lens, where light cannot fully pass through to the retina, a layer of light-sensing cells lining the back of the eye, which sends the image to the brain via the optic nerve. Because the brain cannot clearly interpret the incomplete or distorted image, vision is blurred.
Cataracts can also develop as a result of family history, eye injury, previous eye surgery, eye diseases, medications such as steroids, medical problems such as diabetes and long-term, unprotected exposure to sunlight.
At first you may not know. You may attribute unclear vision to the need for better lighting or stronger glasses. An eye examination done by a qualified eye doctor would discover the cataract.
There is no way that the lens can be cleared of the cloudiness, so it must be removed altogether and replaced with a artificial lens implant known as an intraocular lenses (IOL). A standard (monofocal) IOL yields clear vision at only one range, typically distance. This technology has been used for decades. In recent years, several advanced IOLs have been developed which give clear vision at most, if not all, distances.
Cataract surgery is typically considered when a cataract causes vision problems which interfere with daily activities.
Accommodation refers to the eye's natural ability to switch focus instantly from near to distant objects and vice versa. We tend to take it for granted, as being part of the eye's daily functioning. Presbyopia is the loss of this ability in middle age, requiring us to start using reading glasses.
The part of the eye which performs accommodation is the lens. It is controlled by the ciliary muscle which contracts and relaxes, thereby, changing the curvature of the lens. This change in curvature results in the ability to focus seamlessly at multiple ranges. If the lens is removed to treat cataracts, accommodative ability is lost; therefore, near vision is poor without glasses unless an advanced IOL is implanted.
There are three advanced IOLs which restore near vision: Crystalens, ReZoom, and ReStor. Crystalens is an accommodating IOL meaning that the lens moves inside the eye, in response to contraction and relaxation of the ciliary muscle. This lens provides seamless focusing at multiple ranges. ReZoom and ReSTOR are considered multifocal IOLs. Multifocal IOLs are fixed lens implants meaning that they are stationary and do not move inside the eye like an accommodating IOL. Concentric rings of power in the lens optic enable the eye to focus at multiple ranges. Multifocal IOLs produce more glare and halos than a standard IOL and Crystalens.
Cataracts were treated with the monofocal IOL before the accommodating and multifocal IOLs were developed, and it is still done in some cases. A standard (monofocal) IOL restores clear sight at a certain chosen distance- typically distance. Patients receiving this type of IOL usually require glasses for reading and even for intermediate activities (i.e. computer work) resulting in the need for bifocals and trifocals after surgery. Patients with a significant amount of astigmatism before cataract surgery may need glasses full time, even for driving, unless the patient chooses to purchase an additional procedure to reduce/eliminate astigmatism.
If you would like more information on all these options, please contact Dr. Carter today to schedule an initial consultation. He can answer your questions in detail and suggest the best option for your eyes.