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.
For most people, cataracts are simply a matter of age.
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.
Presently, the only available treatment for cataracts is surgery.
Many often ask if cataracts can be prevented. Given our current lack of understanding of their causes, the simple answer is no. Some eye doctors advocate the use of ultraviolet light-blocking sunglasses. While not definitive, some studies have suggested that ultraviolet light may be partly responsible for cataract progression, as well as for other eye diseases such as age related macular degeneration. The use of sunglasses may therefore help, and certainly will not cause any harm. Similar advice might apply to antioxidants such as vitamins A, C, and E. While studies have produced conflicting information, some indicate that these vitamins may slow cataract growth. Speak with your medical doctor prior to starting any high-dose vitamin program.
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. Stiches 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.
The surgical procedure: phacoemulsification
The details of cataract surgery, known as phacoemulsification, will be described next. Please visit our
Outpatient Surgery Center page for additional information about your surgical day experience in our state-of-the-art facility.
Once adequate anesthesia has been achieved, the area around the operative eye will be cleansed for sterility and a surgical drape will be placed. A small device known as a speculum will then be placed to keep your eye open during the procedure. There will be no discomfort. A small incision is then made in the cornea, or clear window at the front of the eye, and a viscous gel is injected into the eye in order to maintain space and protect the other ocular structures during surgery. The “main” corneal incision is then carefully made using an extremely sharp and precise blade made of diamond. Next, a circular opening is created in the front of the thin membrane, or capsule, which surrounds the lens, and fluid is injected inside to separate the entire lens from its attachment to the capsule. The cataractous lens is then removed using phacoemulsification, the amazing technology behind modern cataract surgery. The phacoemulsification machine produces ultrasound waves within a tiny handpiece, pictured to the left, which is inserted into the eye. This causes the metal tip of the instrument to vibrate very rapidly, up to 40,000 times each second, dissolving the cataract material which is then aspirated out of the eye. Additional instruments are used to clean all the cataract from the lens capsule, which is then refilled with more viscous gel. An artificial, permanent lens implant, made of a type of plastic, is then inserted into the capsular “bag,” taking the place of your natural lens. This implant, which helps focus the incoming light on your retina, is held in palce by two haptics, or curved arms, as seen in the photo below. Once the implant is in place, the incisions are closed, usually without stitches, and the surgery is complete.
Pre-operative measurements and intraocular lens implants
Prior to surgery, your eye will be carefully measured for the proper strength of lens implant. (Read about eye measurements and IOL calculations here). The implant can be chosen to focus your eye at any distance you desire. While most choose to focus at distance, some prefer to see most clearly at near, particularly if they have always been myopic, or nearsighted. At Fishkind, Bakewell & Maltzman we perform these measurements with the Zeiss IOL-Master, the most advanced, accurate device for this purpose, which uses a laser to scan the eye in just seconds. While these calculations are extremely accurate in most cases, the expected results are not always achieved. Most patients obtain vision good enough to drive without glasses. Rarely, the post-operative refraction (eyeglass prescription) will be significantly different than exptected. In these unusual cases, additional surgery, including removal and replacement of the lens implant, may be required to achieve the desired result. The appearance of an implant in the eye at the end of surgery is shown below.
The majority of lens implants inserted during cataract surgery are considered ‘monofocal,’ meaning that they focus light at only one location, usually in the distance. This means that reading glasses will be required for close-up tasks such as reading- without them near vision will be blurred. Another option is the ‘multifocal’ lens implant. Such implants allow for clear vision at distance, as well as good vision at mid-range and near. Each type of lens has specific advantages and disadvantages. You can discuss these options with one of our physicians during your evaluation. Please click here to read in greater detail about lens implant options.
Management of astigmatism
Astigmatism is a form of refractive error in which perpendicular lines are focused at different distances within the eye. Significant astigmatism occurs in as many as one in three people and can cause blurred vision, visual fatigue, and squinting if not corrected with glasses or contact lenses. In early life, most astigmatism is due to an irregular shape of the eye, in which the cornea is steeper in one meridian than the other. As we age, many develop astigmatism due to irregular thickening of the lens as cataracts develop. This latter form of astigmatism will disappear when a cataract is removed, however any remaining corneal astigmatism will blur vision, increasing the likelyhood that glasses will be necessary for clear vision postoperatively.
Fortunately, for those who desire the best possible uncorrected distance vision after surgery, astigmatism can be reduced or eliminated surgically at the time of the cataract operation. This is performed in one of two ways, depending upon the amount of astigmatism present prior to surgery. For lesser degrees of irregularity, extra incisions called “limbal relaxing incisions” can be made in the cornea using a very precise diamond blade. These incisions serve to flatten the steeper meridian of the cornea, making it even in all directions. For larger amounts of correction, limbal relaxing incisions are not enough to overcome the irregularity. In such cases, a special lens implant known as a “toric IOL” can be placed in the eye. Like eyeglasses, which are crafted with cylindrical lenses placed in a specific axis to correct one’s particular degree of astigmatism, a toric implant with the correct cylindrical power is carefully rotated into the precise position within the eye to neutralize the corneal astigmatism.
However, the back side of the lens capsule, which remains intact at the time of surgery in order to support the implant, can become cloudy over time. This opacification, sometimes referred to as a “secondary cataract,” can affect vision much the way the cataract once did. If this occurs, a brief, painless laser procedure performed in the office can clear the opacity from the implant. The capsular opacification does not recur once this is performed.
Modern 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. Please click on the contact us link above.
These links are offered to provide you with further information about this condition. They will open in a separate browser window.
National Eye Institute- Cataracts
National Library of Medicine: MedlinePlus- Cataracts