In rare cases there can be complications to cataracts surgery. There can be loss of vision, bleeding, double vision and infection. Inflammation and fluctuating eye pressure can be a side effect of this surgery as well. While instances of side effects are documented it should be said that they happen rarely.

Retinal detachment is a condition that occurs when fluid seeps through a tear in the retina. The seepage causes the retina to detach from the back of the eye. While cataracts surgery isn't the only cause of this problem it occurs in approximately one half of one percent of cataracts surgery patients. Retinal detachment also occurs in patients who have had previous eye surgeries and who are extremely nearsighted. Symptoms of retinal detachment are flashes of light or dark spots in the field of vision. Some of these symptoms occur naturally after cataracts surgery, but patients who experience them should contact their doctors immediately. Another symptom is a shadow that seems to move across part of or the entire field of vision. If this occurs the physician should be contacted immediately.

Cystoid macula edema is decreased vision in the central part of the visual field due to swelling in the layer of nerve cells that covers the entire back part of the eye, called the retina. The macula is the part of the retina that responds to light in the central part of the visual field. After a cataracts surgery that has had no complications, the blood vessels in the retina can swell and leak and as the fluid accumulates the macula can swell. As time progresses after a cataracts surgery and the patient notices decreased vision he should contact his doctor and tests can be done, such as ocular coherence tomography, to determine the extent of the swelling. This condition can be treated by anti-inflammatory eye drops or injections of steroids to the back of the eye. In some cases vitrectomy surgery can resolve the problem.

Posteriorly dislocated lens material is the rare occasion that fragments of the cataractous lens have fallen into the cavity behind the membrane that surrounds the lens. A procedure called a vitrectomy can remove the particles and reduce swelling.

Endophthalmitus is an infection inside of the eye. Symptoms include pain and excessive redness and swelling, sensitivity to light and perhaps loss of vision. Usually these symptoms reveal themselves within the first few days after surgery. Antibiotic eye drops are administered the day of surgery. In spite of this, 1 in 3,000 patients develop endophthalmitis.

Choroidal hemorrhage is when the choroid, the web of fine blood vessels that supplies blood to the retina, begins to bleed during surgery. It usually occurs in older patients or patients who have high blood pressure or have glaucoma. A hemorrhage confined to a small area will have very little visual loss but if the hemorrhage is severe then significant visual loss can occur. Modern micro surgical techniques, however, rely on small incisions and so therefore the severity of hemorrhages has reduced dramatically.

Secondary cataracts are cataracts that develop years after cataracts surgery. It is a condition that clouds the back of the lens capsule. This is part of the lens that wasn't removed during the first surgery and that supports the lens implant (IOL). This condition can also be called 'aftercataracts' and posterior capsule opafication. The problem is treated quickly and simply with a laser called yttrium-aluminum-garnet, or YAG for short. Cells have grown on the back of the lens and the laser is used to make a small incision in the lens to let light pass through. It is a quick painless procedure that usually takes less than 5 minutes to complete. The patient can resume normal activity within hours.