During cataract surgery, the natural lens in the eye is replaced with a clear intraocular lens designed to improve the patient’s vision. Once the natural lens with the cataract is removed, the cataract cannot grow back.

However, it is possible for blurred vision to develop following cataract surgery. While symptoms may resemble that of a cataract, it does not mean that your cataract has returned or grown back. Blurred vision after cataract surgery often occurs from a condition that can be treated easily without the need for surgery.

What is a Secondary Cataract?

Some patients who have successfully restored their eyesight with cataract surgery may experience another decline in their vision after several weeks or months of their procedure. This typically occurs due to cloudiness in the posterior lens capsule.

The lens capsule is a small sac or membrane that holds the natural lens of the eye in place. During cataract surgery, a significant amount of the lens capsule is removed to allow the surgeon to gain access to the cataract. This enables the doctor to break the cataract into smaller fragments, remove it with a suctioning device and replace it with a clear IOL.

The portion of the lens capsule that is behind the lens, also called the posterior lens capsule, is left intact during the procedure. The intraocular lens is placed directly in front of the posterior lens capsule. Occasionally the posterior lens capsule may become cloudy, resulting in posterior capsular opacification (PCO), also called after-cataract or secondary cataract.

How Does a Secondary Cataract Form?

A secondary cataract occurs because a few residual cells from the original lens (which are always left behind) begin to multiply in an attempt to regrow the natural lens that was removed. In most patients, these residual cells remain dormant. However, there is a higher chance that these cells will “wake up” in younger patients, resulting in the opacification of the posterior lens capsule.

The process in which residual cells multiply to recreate the original tissue is completely normal as it mimics other healing processes, such as wound healing. Therefore, a secondary cataract or PCO is not considered an adverse effect or complication of cataract surgery.

Posterior capsular opacification develops in approximately 25% of cataract surgery patients. Common symptoms associated with it include hazy or blurred vision, sensitivity to glare and bright lights and difficulty reading.

Treating Secondary Cataract

A secondary cataract is not actually a cataract and any vision lost from it can be easily restored using a procedure called YAG laser capsulotomy. This is a painless in-office procedure where the surgeon uses a specialized laser to form a clear opening in the clouded posterior lens capsule. The opening allows light to enter your eye, thus restoring your vision. The procedure normally takes only a few minutes and rarely needs to be repeated. There are currently studies looking at preventing secondary cataracts https://medicalxpress.com/news/2016-04-secondary-cataract.html.