Many believe that a cataract is a growth or membrane which develops over the eye. Actually, cataract describes a cloudiness or opacification of the natural lens of the eye. The lens is found within the eye, just behind the colored structure known as the iris.
Much like the lens of a camera, the eye’s lens functions to focus light entering the pupil upon the retina, a thin membrane in the back of the eye. The retina functions like film, sending what the eye sees on to the brain through the optic nerve. Just as a dirty camera lens will take a blurry photograph, a cataractous human lens can cause a number of visual disurbances, including blurring, haziness, glare, difficulty judging colors, and eventually significant loss of vision in the eye.
Nearly everyone develops cataracts over time, though the rate at which the lens undergoes these changes is quite variable. Some may note significant visual disturbances in their 40s, while others may live into their 80s and never be very bothered by their vision. The reasons for these differences are not well understood. Genetics may play a part, with some simply more succeptible to cataract at an earlier age. Environmental factors, such as exposure to sunlight or certain diets, may one day be found to play a role, however current data regarding the effects of these elements are not conclusive.
While most cataracts are age-related, some are not. Some people are born with cataracts. Others may develop cataracts due to illness or disease, trauma, or use of certain medications. For example, those on chronic corticosteroids such as prednisone often develop lens opacities. By understanding your full medical history, your doctor can determine whether your cataracts are related to any of these factors.
Cataract surgery may be right for you if you experience any of the symptoms noted above, such as significant blurring, haziness, or glare. If any of your work or leisure activities are affected by poor vision, a complete eye examination will help your physician determine the cause. Patients with cataracts often complain of difficulty reading or performing close-up work, trouble driving- especially at night due to glare and starbursting around lights, or difficulty following a golf ball.
Modern cataract surgery is performed without discomfort on an outpatient basis. Gone are the days of large incisions, multiple sutures, and prolonged bedrest. Today, incisions are tiny, typically measuring only three millimeters, or about an eighth of an inch. Stitches are seldom necessary, and recovery, both physical and visual, is rapid. Many patients drive and return to their usual level of activity the day following surgery. Cataract surgery is safe and effective, capable of rapidly improving your vision and putting you back into life. Don’t let poor vision slow you down. Call us today to schedule an appointment with one of our doctors to find out if cataract surgery can help you.
Intraocular Lens Implants (IOLs)
Modern cataract/lens surgery is safe and effective, capable of rapidly restoring lost vision and allowing a return to an active lifestyle. (Click here to read more about cataracts and cataract surgery.) When a cataract or clear lens is removed, an intraocular lens implant (IOL) is nearly always placed in order to restore vision. IOL technology has advanced significantly since the first lens was implanted in 1949, with improvements in lens materials and designs. Today many IOL choices exist, allowing postoperative vision to be tailored to the individual patient’s needs.
Standard monofocal IOLs
he majority of IOLs implanted today are this type. These implants have a single focal length, providing clearest vision at a set distance and requiring glasses for other distances. Most patients elect far distance correction, allowing clear unaided vision for activities such as driving, golf, and even television viewing, but generally requiring eyeglasses for near tasks such as computer viewing or reading. Many people are quite accustomed to this type of vision prior to surgery, as reading glasses become necessary as presbyopia develops after about 40 years of age. If desired, however, IOLs can be implanted to provide good near vision, with glasses worn for distance, as might be desired by someone who has always been myopic (nearsighted). This is ultimately a personal decision, dependent on individual lifestyle considerations.
Advanced IOL Options
While most patients are quite happy with the vision provided by standard monofocal IOLs, some are interested in a surgical option that provides good unaided vision at both distance and near. For those looking to minimize dependence on postoperative glasses or contact lenses, a number of options now exist. These are detailed below.
- Monovision: this describes the use of standard monofocal IOLs in each eye, with one eye focused at distance and the other at near. A disadvantage of monovision is diminished depth perception. Additionally, some are unable to tolerate this arrangement due to the imbalance between the eyes, and surgical monovision is only recommended for those patients who have comfortably and effectively achieved good results with contact lens monovision prior to surgery. For those who have succeeded with contact lens monovision, this is often a very good surgical option.
- Multifocal IOLs: these lenses allow each eye to focus at both distance and near, somewhat like bifocal or progressive eyeglass lenses. There are presently two main types of multifocal IOLs.
- Non-accommodating IOLs: like standard monofocal IOLs, these lenses are implanted and remain in a fixed position within the eye. They rely on concentric rings or zones within the optical portion of the implant, allowing light from different distances to be properly focused upon the retina. Today, two such implants have been approved by the FDA for implantation in the United States.
- Accommodating IOLs: Unlike non-accommodating multifocal IOLs, which are fixed in position and utilize zones or rings to achieve their variable focus, true accommodating IOLs shift position slightly within the eye, mimicking the natural ability of the human lens to change focus. There is currently one such IOL approved by the FDA for implantation in the United States.