Cataract Surgery – Risks and Post-Op complications
Sherman Reeves, MD
Individuals undergoing cataract surgery should feel reassured that it is typically an extremely safe surgery with a very low rate of complications. However, intraoperative and postoperative complications do occasionally occur. Encouragingly, the vast majority of these complications usually resolve with time or additional treatment. However, in rare cases, vision can sometimes be compromised after a complication has occurred.
In the hands of a skilled cataract surgeon, intraoperative complications occur in less than 1% of routine cataract surgeries. While the majority of these complications can be addressed during the cataract surgery and do not typically cause further problems, additional surgery is sometimes needed.
Posterior capsule rupture: The most common intraoperative complication that occurs during cataract surgery is posterior capsule rupture. An extremely thin membrane, called the capsule, holds the natural lens of the eye in place. During cataract surgery, the clouded natural lens of the eye is removed, but the capsule is left in place to hold the new plastic lens implant in the eye in appropriate position. If the capsule is perforated during the surgery, a capsular rupture is said to have occurred. This may allow vitreous jelly from the back of the eye to come forward into the front of they eye through the broken capsular membrane. The surgeon may then need to perform an anterior vitrectomy, in which the prolapsed vitreous is removed from the front part of the eye. A plastic lens implant can usually be safely placed in the eye after capsular rupture has occurred. In most cases, the surgeon can still place the lens in the ideal position behind the iris. Occasionally, though, the surgeon may need to place the lens in front of the iris if there is not sufficient support for it behind the iris after a capsular rupture has occurred.
Retained lens fragment: When a capsular rupture occurs, sometimes parts of the cataract fall into the back part of the eye. This complication is called retained lens fragment. Most cataract surgeons will typically handle these cases as they would a capsular rupture alone, removing prolapsed vitreous jelly from the front of the eye then placing an lens implant into the eye. Typically, after the surgery, then, a patient will be referred to a vitreoretinal surgeon for evaluation. If the lens fragment retained in the back part of the eye is large enough, the vitreoretinal surgeon may recommend a pars plana vitrectomy, in which all of the vitreous jelly and the retained lens fragment will be removed in a second surgery.
Bleeding: Severe bleeding inside or around the eye, which is called hemorrhage, is very rare during routine cataract surgery. The surgery usually has to be stopped and the patient typically watched for several weeks while the blood reabsorbs. Occasionally, as second surgery, such as a pars plana vitrectomy, is needed to help remove blood from they eye after this complication occurs. Historically, there was some concern by eye surgeons that patients taking blood thinners or aspirin may have been at more risk for this complication. Thus, patients were often asked to stop taking blood thinners around the time of cataract surgery. However, large, well-designed scientific studies have proven that there is not greater risk of severe eye hemorrhage in patients who continue taking blood thinners around the time of their cataract surgery. Hence, most surgeons are now comfortable with continuing these blood thinning medications in the perioperative period.
Most postoperative complications after cataract surgery resolve with time or additional medical treatment. A few of these complications may sometimes lead to loss of vision or require additional surgery to correct.
Corneal swelling: The most common postoperative complication after cataract surgery is swelling of the cornea, which is called corneal edema. Most corneal swelling resolves within a few days or weeks after the cataract surgery, and the vision gradually becomes more clear. Sometimes, corneal edema can persist for many months after the surgery. This may be the case if the cornea had a pre-existing condition called Fuchs dystrophy, or if the cataract was extremely dense and difficult to remove. In cases where the corneal swelling does not resolve, and additional surgery may be required where a partial corneal transplant is performed to replace the inside lining cells of the cornea.
High intraocular pressure: Another relatively common postoperative complication is high intraocular pressure. During cataract surgery, the surgeon uses special surgical gels, called viscoelastics, to help protect important structures of the eye during the surgery. Occasionally, small quantities of these gels are retained in the eye after the surgery. When this occurs, the drainage system of the eye can become clogged, causing the eye pressure to rise dramatically. Treatment with pressure lowering eyedrops can typically resolve this problem, though sometimes a small amount of fluid will be released from the eye by the surgeon to help quickly lower the eye pressure. High eye pressure problems such as this usually resolve in the first several days after surgery, unless there are other underlying eye pressure problems to blame, such as glaucoma, which may require more extended treatment.
Endophthalmitis: In less than 1 in 1000 cases of cataract surgery, a severe bacterial infection of the eye can occur in the first few days or weeks after the surgery is performed. This infection is called endophthalmitis. If not addressed quickly, it can cause loss of vision or rarely, even loss of the eye. Cataract surgery patients typically receive very powerful antibiotic drops in the first week or two after the surgery to help guard against severe infections postoperatively. If endophthalmitis does occur, additional antibiotics are usually injected into the eye to help clear the infection.
Floaters: New floaters can occur after cataract surgery due to a condition called posterior vitreous detachement. The back part of the eye is filled with a jelly called the vitreous humor. When a person is young, the jelly is attached to the back wall of the eye. As an individual ages, this jelly becomes more liquid and can start to become detached from the back wall of the eye. During this process, “floaters” can develop as small bits of the vitrous jelly float around the eye more than they previously did. Cataract surgery can sometimes accelerate this process of posterior vitreous detachment, and thus, more floaters can be seen after cataract surgery. Also, floaters that were already present in the eye are often more visible after the cloudy cataract is removed from the eye. Floaters typically improve with time, though it can take weeks or months for them to become less noticeable. Rarely, a sudden shower of new floaters can herald a small tear in the retina or early retinal detachemt.
Retinal detachment: Retinal detachment is a rare complication after cataract surgery. During cataract surgery, pressure changes in the eye can sometimes result in small tears occurring in the edge of the retina. Sometimes new floaters or flashes of light are seen as a symptom of a retinal tear occurring. If the retinal tear progresses, a retinal detachment can occur, in which the retina peels off the inside wall the eye like poorly attached wallpaper. Retinal detachment can cause loss of vision, and typical surgical repair is required to resolve the condition.
Retinal swelling: Swelling of the retina, called macular edema, can sometimes occur after cataract surgery. The surgical process causes inflammation inside of the eye. The steroid and anti-inflammatory drops prescribed after cataract surgery usually help this inflammation to resolve without problems. However, the portion of the retina responsible for central vision, the macula, sometimes can become swollen after cataract surgery due to intraocular inflammation. Eyedrops can typically be prescribed that over the course of several weeks help resolve macular edema, though sometimes injections of steroids or surgery are needed to help improve the condition.
Posterior capsule opacification: A relatively common complication of cataract surgery is clouding of the posterior capsule, the fine membrane that sits behind the newly implanted prosthetic lens. This clouding can occur months or even years after the cataract surgery. The condition is easily fixed with a laser procedure called YAG capsulotomy, in which a laser is used to painlessly open a hole in the posterior capsule, clearing the vision.