Updated: Aug 22, 2020
One of the commonest questions when people are contemplating cataract surgery is “Will the cataract come back again?”. The answer is no, once your cataract has been removed, it will not grow back, however a condition called posterior capsular opacification or “PCO” can make it seem as though it is.
A cataract is a clouding of the eye’s natural lens, most commonly an age-related process (Figure 1).
When a cataract is surgically removed, it is replaced by an artificial plastic lens, which will generally last a life-time without causing any problems. The artificial lens is usually placed inside the remains of the “capsule”, the outer membrane surrounding the natural lens, which is purposely not removed from the eye (Figure 2).
To gain access to the cataract, a circular opening is made in the front surface of the capsule. It is best to leave the rest of the capsule (the posterior capsule) behind and undamaged to provide support and centration for the artificial lens.
Posterior capsular opacification (PCO) is a clouding of the remains of the capsule (Figure 3) which interferes with light entering the eye, and is the most common problem after cataract surgery.
PCO can cause vision to become foggy or blurred, and can cause glare with bright lights. Often it is picked up by an optician at a routine eye test. PCO is not serious, and can easily be treated with a laser treatment called YAG posterior capsulotomy to create an opening in the posterior capsule (Figure 4).
YAG laser treatment is pain-free, and is done as an outpatient procedure with local anaesthetic eye drops on a machine similar to what is used to examine the eyes in the clinic. It is non-invasive, meaning it does not require any incisions (cuts) to be made into the eye. Complications after this procedure are uncommon and usually temporary when they do occur. It is possible for the pressure in the eye to become raised after the treatment, or for the eye to become inflamed. Both of these problems are usually dealt with using a short course of eyedrops, tablets or both. Extremely rarely, the laser can cause the light-sensitive layer at the back of the eye to come away from the wall of the eye – a retinal detachment.
Normally YAG laser treatment is completed in one sitting, and assuming there are no new eye problems affecting vision, results in rapid restoration of sight to what it was following cataract surgery. Occasionally, the gap in the capsule needs to be enlarged with a further treatment session.