Risks of Cataracts and Cataract Surgery


It's important to understand that there are real risks involved in having cataracts, and in having cataract surgery. It is important to balance these risks against each other when deciding whether to have cataract surgery or not. There is a balance between the deteriorating vision you may have from a cataract, versus the risks involved in surgery to correct it. When the risks of cataract surgery are outweighed by the functional problems caused by the cataract, it is reasonable to consider proceeding with surgery.

One way to think of cataract surgery is the way you think of driving: that most of the time, you get where you want to go, but you understand that sometimes it's possible to have an accident, even a catastrophic one. You still need to drive sometimes, but you don't drive unless you need to. You can think of cataract surgery the same way: don't do it unless you need to, but if you do, it's reasonable to proceed.

Please read on for some of the risks of having cataracts, versus the risks of cataract surgery. Please understand that it's not possible to list all possible risks. The lists below try to hit the most common and important ones.

Risks of cataracts

Everyone who lives long enough gets cataracts. Simply doing nothing has risks to your vision, as the cataracts will eventually degrade your ability to see, and may pose other health problems for your eyes.

Risk Description
Blurred vision Blurred vision worsens as cataracts progress. In the early stages of cataracts, vision is usually good. As the cataracts progress, however, vision deteriorates to the point where everything looks blurry, and no glasses are able to make it clearer.
Glare and halos Cataracts scatter light as it enters the eye. This causes rings around lights, particularly at night. Glare and halos can make night driving difficult.
Decrease in contrast sensitivity Cataracts decrease the ability to distinguish shades of grey. This degrades the quality of vision and can make driving in fog and rain difficult.
Optical changes As cataracts develop, the innate optics of the eye can change. This may mean you have to change your glasses more frequently than in the past. In some cases the change can actually be for the better ("second sight"). This can actually make some patients less dependent on glasses for a while as the cataracts develop. In the end, though, the cataract blurs vision to the point that with or without glasses, it's difficult to see.
Glaucoma As the cataract develops, the lens in the eye becomes physically larger. In rare cases, this can cause the lens to press on the eye's drainage system and close it off. This produces high eye pressure and can damage the nerve in the eye, a condition called glaucoma. If the glaucoma is bad enough, it can permanently damage vision.
Degraded view of the inside of the eye In order to evaluate the health of the eye, your eye doctor must be able to see inside it. Cataracts block the view inside the eye. Your doctor may not be able to make good decisions regarding the care of some diseases (diabetes, macular degeneration, glaucoma and others) if he or she can't see inside the eye.
Blindness Very advanced cataract can degrade vision to the point of blindness. In these cases, there is not total darkness, but vision can be so poor that it is impossible to see much beyond the presence or absence of light.

Risks of cataract surgery

Cataract surgery is a generally safe procedure, but is not risk free. Some people think it is a "simple procedure where they peel a film off the eye." This is not true. Cataract surgery is a complex procedure that requires years of training to perform. Problems, and even true disasters, are possible. Evaluating and accepting these risks is very important prior to surgery.

Please understand that this is not a complete list of all the possible risks of cataract surgery. There are conceivable risks beyond the ones described below.

Risk Frequency Description
Temporarily blurred vision Common In the days after surgery, vision can be blurry, sometimes severely so. This is usually produced by swelling on the surface of the eye (the "cornea"). This normally resolves in a few days.
Temporary irritation Common After surgery, the eye may be irritated and scratchy. This usually resolves in a few hours or days.
Floaters Common You may see floaters after the surgery. Floaters come from a disturbance in the jelly inside the eye. They look like little spider webs floating around in your vision. By disturbing the inside of the eye, cataract surgery can cause floaters. Sometimes you can see more floaters after cataract surgery because you simply see better.
High eye pressure Common Inflammation caused by the surgery can elevate the pressure in the eye. This is usually temporary, and can be treated easily. In most cases, the high pressure produces no ill effects. In rare cases, however, the high pressure can damage the nerve in the eye and cause permanent visual loss.
Dark crescent in side vision Common For reasons that are not fully understood, a dark crescent can be visible in a patient's side vision after surgery. This can be annoying, and sometimes interfere with function. It often resolves over time, but in some cases does not. In severe cases, additional surgery may be required to correct it.
Optical error Common We have good formulas for calculating the power of the lens to implant. These usually allow us to predict the optics in the eye after surgery, but they are not perfect. There is usually some minor error after surgery in the final result (astigmatism, nearsightedness, and/or farsightedness). In some cases this is significant, and rarely quite severe (a "refractive surprise"). This can be particularly disappointing for patients trying to reduce their dependence on glasses and contact lenses after surgery, such as those receiving astigmatism-correcting or multifocal lens implants. In some cases, additional procedures may be required to reduce this optical error.
Glare and/or halos Uncommon Cataract surgery usually improves glare symptoms. Some patients, however, experience glare after surgery that is worse than before surgery, or that does not fully resolve with surgery. Glare after surgery is more common with patients receiving multifocal lenses than monofocal lenses.
Failure to achieve intended result Uncommon Cataract surgery improves vision in the vast majority of patients. However, in some patients, there is no improvement. This can happen if there is co-existing eye disease, such as macular degeneration or diabetes. Rarely, vision can be worse after surgery, as in the case if there is a surgical complication, or post-operative issue such as retinal detachment or persistent swelling of the cornea or retina.
Droopy eyelid Uncommon Sometimes patients can develop a droopy eyelid after cataract surgery. This may be temporary or permanent. If it does not resolve and is a persistent problem, it may require surgery to correct.
Human error Uncommon Surgery is a very human process. Although there are strict protocols in place to reduce the chance of human error, it is still possible. Implanting the wrong lens, operating on the wrong eye, or making some other avoidable mistake is possible with surgery. Human error could produce unforeseen and and undesireable outcomes.
Persistent swelling Uncommon After cataract surgery, the surface of the eye (the "cornea") or the layer of nerves inside the eye (the "retina") can become swollen. These are usually temporary conditions, and can usually be treated with drops or by other means. In cases of swelling of the cornea, corneal transplant may be required to improve vision. In some cases, however, swelling of either the retina or cornea can permanently degrade vision.
Retinal tears and/or detachment Uncommon There is a layer of nerves that wallpapers the inside of the eyeball. It is called the "retina." Cataract surgery increases the likelihood that this layer of nerves will separate from the inside wall of the eyeball. This is a serious condition called a "retinal detachment." It can happen at any time after surgery, even years later. It is often preceded by a tear in the retina. If not repaired in time, it can lead to blindness. Patients who are severely nearsighted before surgery are at higher risk of this occuring.
Capsular rupture Uncommon A thin capsule surrounds the natural lens in the eye. The capsule holds the natural lens in place in the eye, and is used to hold the new (plastic) lens implanted during cataract surgery. It is about one one-hundredth of a millimeter thick, and can rupture during surgery. This can allow lens fragments (or the entire lens) to fall back in the eye. Additional surgeries may be required to remove these fragments. Rupture of the capsule can increase the possibility of other complications of surgery, such as infection, retinal detachment, and swelling of the retina.
Retained lens fragments Uncommon During the surgery, your surgeon normally breaks up the cataract inside your eye with an ultrasound probe. The fragments of the lens are vacuumed out with the same probe. Sometimes there can be fragments that are inadvertently left inside the eye, particularly if they becomed tucked behind the iris and are hidden from your surgeon. If there are retained fragments after your surgery, your surgeon may elect to leave them (they often dissolve with time). In some cases they need to be removed with a separate procedure, particularly if they are causing high eye pressure.
Lens dislocation Rare The lens in the eye (either the natural one or the implant) can become detached from its support system in the eye during surgery. This can require additional maneuvers to replace or remove it, either during the original surgery later, with other surgeries. In some cases, (mostly in patients with predisposing conditions) the lens can dislocate months or years later.
Infection Rare Infection with modern cataract surgery is fortunately rare. If it does happen, however, it can be difficult to treat, and can cause blindness, or even loss of the eye.
Severe hemorrhage Rare Some minor bleeding from cataract surgery is common. This can occur on the surface of the eye from the incisions, or inside the eye during the surgery. In either case, the bleeding does not usually interfere with achieving good vision. In rare cases, however, severe bleeding in the eye can cause loss of vision, or even loss of the eye ("suprachoroidal hemorrhage" or "expulsive hemorrhage").
Blindness Rare We normally perform cataract surgery on one eye at a time, and do not perform it on the other eye until the first eye has healed adequately. However, true blindness in both eyes is possible if there is a blinding complication in one eye, in a patient who has only one good eye. If you have one eye that is permanently impaired, it is important to take extra care in weighing the risks of surgery in the other eye.
Death Rare Death around the time of surgery is extremely rare, but could occur from complications of anesthesia, an allergic reaction, a concurrent medical condition, or from a car accident on the way to or from surgery.

If you have questions about the risks of cataract surgery you should discuss them with your surgeon prior to undertaking the procedure.