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Cataract Surgery Risks: What Are They?

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Cataract surgery is considered a low-risk surgery. Over 98 percent of these surgeries do not have any adverse effects and successfully restore useful vision.

Some problems can develop if a patient has a pre-existing visual disorder or other health concerns that might complicate the recovery.

Endophthalmitis, an infection inside the eye, is a condition that can develop in the aftermath of cataract surgery. Retinal detachment is another potential issue that can occur. The risk of either occurring is very low. More details are provided below.

Improving technology means that cataract surgery remains a very safe remedy for cataracts.

Is Cataract Surgery Safe

Cataract surgery has high rates of both success and safety, with Harvard Medical School explaining that the treatment is “low-risk, fast, and effective.” Over 98 percent of patients report no outstanding issues.

However, in that 1-2 percent, there is still some risk when it comes to cataract surgery. Even though the procedure is almost always safe, it is important for patients to be aware of what might go wrong.

In the unlikely event of complications that might arise after cataract surgery, most can be rectified with further surgery and treatment.

In a study of more than 200,000 people who received cataract surgery between 1994 and 2006, the American Refractive Surgery Council writes that as many as 99.5 percent of them had no severe risks that followed their surgery. Furthermore, as cataract surgery has improved with technological advancements in surgical tools and techniques, the rate of complications following cataract surgery has significantly declined.

Cataract Surgery Risks

Though rare, the following issues are possible with cataract surgery:

Cataract Surgery RisksBrief Explanation
SwellingOften a temporary response post-surgery.
Droopy EyelidsCan occur after cataract surgery but often resolves over time.
BleedingVery rare but could be a sign of more serious complications.
Infection (Endophthalmitis)
A serious eye infection that can occur post-surgery, requiring immediate medical attention.
InflammationNormal to an extent, but excessive inflammation could indicate issues.
Dislocation of Artificial LensMay result in vision disturbances requiring further treatment.
Retinal DetachmentA severe but rare complication requiring immediate medical attention.
GlaucomaIncreased intraocular pressure that could potentially lead to optic nerve damage.
Loss of Vision
In extremely rare cases, loss of vision could occur.
Posterior Capsule Opacification (PCO)Also known as a “secondary cataract,” it’s a relatively common and easily treatable complication.

Patients who have other eye conditions or serious medical conditions have a higher risk of developing problems after their cataract surgery. It is vital that they inform their doctor of these potential complications.

In some cases, cataract surgery may be ineffective at improving vision. For example, glaucoma and macular degeneration cause their own damage to the eye. It might be necessary for those other conditions to be treated first before the cataracts can be successfully removed via surgery.


Endophthalmitis, a serious infection inside the eye that is typically bacterial can develop after cataract surgery.

The two most common bacteria associated with endophthalmitis infections are the staphylococcus (“staph”) and the streptococcal (“strep”) bacteria, which normally live on human skin. The infection tends to develop in the first week after cataract surgery. Patients experience pain and redness in their eye, a loss of vision, and a yellowish discharge emanating from their eye.

The Journal of Current Ophthalmology wrote in September 2016 that the chances of developing an endophthalmitis infection after cataract surgery is 0.1 percent. Though rare, it is still very important to seek medical care immediately if it happens. Without quick treatment, patients might suffer a permanent loss of vision in the affected eye.

Treatment is usually in the form of antibiotics injected directly into the eye or surgery and antibiotics.

Retinal Detachment

Another risk of cataract surgery is retinal detachment , which happens when the retina (the light-sensitive tissue that covers the back surface of the eye) develops a hole or a tear and falls away (or detaches) from the wall of the eye. If this happens, the retina loses access to the blood supply it needs to keep its cells healthy.

Without this supply, the cells die off and do not regenerate. This can lead to a permanent loss of vision because the retina processes visual information and communicates that to the brain.

In “The Incidence of Retinal Detachment After Cataract Surgery,” the Open Ophthalmology Journal writes that retinal detachment happens in 1 out of every 3,000 cataract surgeries and requires its own surgery to address it.

Posterior Capsule Opacification

Posterior capsule opacity, also known as posterior capsule opacification or PCO is not specifically a complication of cataract surgery, but is relatively common. This condition is sometimes known as a “secondary cataract,” but in reality, a cataract doesn’t grow back once it is removed.

The story behind PCO is that the doctor removes the natural lens of the eye (clouded over by the protein clumps that are responsible for the cataracts) and replaces it with an intraocular lens (IOL) during cataract surgery. Most of the thin, clear membrane that covers the eye’s natural lens (known as the lens capsule) is not touched during the surgery. Instead, it is left intact, and the IOL lens is typically supported within the lens capsule.

During the process of removing the cataract, the doctor will try to keep the lens capsule untouched. Not interfering with the lens capsule is what helps patients enjoy clear vision after they have their cataracts removed.

The Ophthalmology journal writes that despite uncomplicated surgery, 20 percent of eyes develop haze in the posterior portion of the lens capsule at some point during the recovery period of the cataract surgery: months or even years afterwards. This is because lens epithelial cells, inevitably left over after the surgery, start to grow over the lens capsule. This is what causes posterior capsule opacity and why it is incorrectly known as a “secondary cataract.”

Dislocated Intraocular Lens

Another risk that might develop as the result of cataract surgery is a malpositioned or dislocated intraocular lens. When this happens, a patient may be able to see the edge of the implanted lens or may develop double vision. Visual acuity could suffer considerably if the intraocular lens is significantly dislocated.

In October 2011, the American Journal of Ophthalmology reported on a group of more than 14,000 cataract surgeries performed between January 1980 and May 2009. A review of those surgeries found that the risk of late-stage intraocular dislocation was very low. Ten years after the surgery, the risk was 0.1 percent; by 20 years, it was 0.7 percent; and 25 years after the surgery, the risk of intraocular dislocation was 1.7 percent.

Cataract Surgery Success Rate

Over 95 percent of patients who opt for a standard single vision intraocular lens to address their cataracts have their vision fully restored to pre-cataract conditions. Patients who choose to get a premium intraocular lens might have even better vision than they did before.

The American Refractive Surgery Council reiterates that over 98 percent of cataract surgeries are performed without notable complications. While any kind of surgery carries a small amount of risk, patients who have pre-existing vision or health conditions should disclose these to their doctor before their surgeries, so every possible precaution can be taken.


  1. Considering Cataract Surgery? What You Should Know. (September 2016). Harvard Medical School.
  2. Is Cataract Surgery With Vision-Correcting IOLs Safe? American Refractive Surgery Council.
  3. Post-Cataract Surgery Endophthalmitis: Brief Literature Review. (September 2016). Journal of Current Ophthalmology.
  4. The Incidence of Retinal Detachment After Cataract Surgery. (September 2012). The Open Ophthalmology Journal.
  5. A Systematic Overview of the Incidence of Posterior Capsule Opacification. (July 1998). Ophthalmology.
  6. Risk of Late Intraocular Lens Dislocation After Cataract Surgery, 1980-2009: A Population-Based Study. (October 2011). American Journal of Ophthalmology.

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