The vast majority of patients who have cataract surgery-about 98 percent-have excellent outcomes with restoration of vision and high satisfaction rates. But cataract surgery can cause complications in a small percentage of cases. Most risks of cataract surgery are well known. Although procedures are designed to prevent them, they may even occur in the hands of an experienced surgeon who performs the procedure flawlessly.

Risks of Cataract Surgery:

Endophthalmitis. This is an infection inside the eye. To prevent endophthalmitis, topical antibiotic eyedrops are administered on the day of surgery. The area around the eye is carefully cleaned with special sterilizing solutions, and the face is covered with sterile drapes. After surgery, antibiotics are administered. Despite these precautions, endophthalmitis occurs in about 1 of 3,000 cases.

Symptoms of endophthalmitis include pain, excessive redness of the eye, sensitivity to light, and loss of vision. Although symptoms usually appear within the first few days of surgery, endophthalmitis may not cause noticeable symptoms or be detectable by examination until later. Patients who have any of these symptoms should call their ophthalmologist immediately.

To treat endophthalmitis, antibiotics may be injected into the eye to control the spread of the infection. In rare instances, additional surgery, called a vitrectomy, is indicated. During this procedure, the vitreous (a jelly-like material inside the eye) is removed to control infection.

Cystoid macular edema. The back part of the eye is lined by the retina, a layer of nerve cells that can sense light. The central portion of the retina is called the macula, which responds to light in the center of the visual field. Rarely, after uneventful cataract surgery, inflammation develops that can cause the fine blood vessels in the retina to leak fluid that accumulates in the macula and causes it to swell. The result is decreased vision in the central part of the visual field. This swelling is called cystoid macular edema. To determine the extent of the swelling, a test called a fluorescein angiogram or ocular coherence tomography may be done. A patient who notices a decrease in vision as time goes by after cataract surgery should contact his or her ophthalmologist immediately. Macular edema is treated with anti-inflammatory eyedrops. Sometimes, injections of steroids behind the eye or vitrectomy surgery are done to resolve the problem.

Retinal detachment. In some patients, cataract surgery may increase the risk for retinal detachment, which occurs when vitreous fluid seeps through a tear in the retina. The seepage may cause the retina to separate from the back of the eye. Cataract surgery is not the only cause of retinal detachments; they also occur in patients who have not had previous eye surgery. Patients who are highly myopic (nearsighted) are more likely to develop this condition. Retinal detachments after uneventful cataract surgery are infrequent, occurring in about one half of one percent of patients.

Patients with retinal detachments may notice what appears to be a curtain moving across part or all of the field of vision. Early symptoms of retinal detachment include flashes of light and dark spots that appear to float in the visual field, but these symptoms occur frequently during the normal recovery from cataract surgery. Patients who notice flashes, floaters, or loss of part of their visual field should contact their ophthalmologist immediately.

Posteriorly dislocated lens material. On rare occasions, fragments of the cataractous lens fall into the vitreous cavity behind the thin membrane that normally surrounds the lens. The ophthalmologist may recommend a vitrectomy to remove the lens material and prevent inflammation.

Choroidal hemorrhage. The retina receives its blood supply from a delicate web of fine blood vessels called the choroid. On rare occasions during cataract surgery, the choroid begins to bleed, a condition known as a choroidal hemorrhage. It is more likely to occur in elderly patients and those with glaucoma or high blood pressure, but it is an unpredictable complication. If the hemorrhage is confined to a small area of the choroid, patients often recover without significant visual loss. However, in the most severe cases of choroidal hemorrhage, patients can have complete and permanent visual loss. In modern cataract surgery, the use of small incisions has reduced the severity of choroidal hemorrhages.