by Dan Roberts
Originally published and updated 2/2/09
A cataract causes clouding of the normally transparent lens of the eye. As the lens becomes more opaque, the rays of light are prevented from focusing on the retina, leading to symptoms such as blurriness, light sensitivity, glare, distortion, and fading of colors and vision. Cataracts are very common in older adults, and can develop in approximately 50% of people between the ages of 65-75. About 70% of people over the age of 75 have cataracts. Cataracts can only be removed surgically, which is successful in about 90-95% of all cases.
Most retinal surgeons say that there is minimal danger of complications from cataract surgery on patients with retinal degeneration. The retina is located in the interior of the back of the eye, and cataract surgery does not interfere with this area. The surgery, most doctors maintain, will not improve vision lost from retinal degeneration, but it will not make the retinal condition worse. A 2003 study, however, concluded that cataract surgery in older persons may, in fact, be associated with an increased risk for developing wet ARMD. (Cataract surgery and the 5-year incidence of late-stage age-related maculopathy: pooled findings from the Beaver Dam and Blue Mountains eye studies. Ophthalmology. 2003 Oct;110(10):1960-7.)
A more recent study, presented at the annual meeting of the American Academy of Ophthalmology in October 2005 (Controversy of Cataract Extraction and AMD Progression. Changing Concepts and Controversies. Ferris FL, Chew EY, Gensler G, Milton R, and the Age-Related Eye Disease Study Research Group.) showed that those patients who had cataract surgery did not have a higher risk of progressing to more advanced forms of macular degeneration, when compared to those who did not have cataract surgery.
This conclusion was supported by further research published in the February 2009 issue of the same journal. Led by Emily Chew, MD (also involved in the 2005 study), the team reported that, after reviewing 11 years of patient follow-up data from the large Age-Related Eye Disease Study (AREDS), “The frequency of neovascular age-related macular degeneration, geographic atrophy, and central geographic atrophy did not differ between patients who had cataract surgery and those who did not. . . [This] may provide some reassurance to patients with age-related macular degeneration who are considering cataract surgery.”
Cataract surgery has been known to cause retinal detachment in approximately 1.5% of patients. This risk, however, is lessened now with extracapsular surgery, in which the posterior capsule of the natural lens is left in place to support the plastic replacement lens that is implanted during the operation. Patients should contact their ophthalmologists immediately if they develop a “curtain” blocking the vision, flashes of light resembling lightning streaks, or new floating spots in the visual field. These symptoms can sometimes be indicative of a retinal detachment. People at increased risk of retinal detachment include those who are very myopic, or have conditions such as Stickler Syndrome or Wagner’s disease.
Even with serious retinal problems, cataract surgery may be beneficial if performed by an experienced and skilled doctor, and most professionals say that it can be undertaken with reasonable confidence. According to MD Support medical advisor Martin Mainster, M.D., “The risk of adverse events from cataract surgery is low, but I’ve always counseled patients with AMD to defer cataract surgery until their vision loss from cataract formation significantly reduces their quality of life (the same advice I give all my other patients). At that point, the benefit/risk ratio is sufficiently high to warrant the procedure.”
Should a person continue to wear contact lenses after cataract surgery? This is a question that will become more common as the younger generation advances in age.
An artificial corrective lens is usually implanted into the eye, ending the need for glasses or contacts. There are, however, some cases in which additional correction is necessary following surgery:
- The patient’s vision changes over time.
- Implanting a replacement lens may not be feasible, due to the patient’s condition.
- Temporary correction is needed until the patient’s vision stabilizes.
With the advances in cataract surgery there are few people who will need contact lenses after surgery, and that will be increasingly true with the increasing use of focusable IOL’s (e.g. Crystalens). But if a person who has had cataract surgery needs further correction then contact lenses are no more of a safety issue than prior to surgery, as long as usual precautions are followed. This is true for single vision contacts or multifocal contacts.
For further information about cataract surgery, see Cataracts as a Complication of Retinal Surgery.