One of my patients has a cataract removed from her right eye and an intraocular lens inserted around a year ago. She is 50 years old and had cataracts at an age younger than most people who develop cataracts. Everything went well. She was happy with her vision and was discharged from the hospital. She came for an examination in my practice today. She says the vision in her right eye has reduced since she was discharged. She has 6/18 in her right eye today. What is going on?

This sounds like posterior capsular opacification. Some patients think that the cataract is coming back but of course, this is not what is happening. The crystalline lens itself has been removed during the surgery.

The outer capsule remains in the eye and supports the new lens or implant that has been put in. The cloudiness or thickening of the capsule, known as posterior capsule opacification can result in reduced vision and glare, much like a return of the cataract.

Posterior capsular opacification is caused by the proliferation and migration of residual lens epithelial cells, fibroblasts, macrophages, and iris-derived pigment cells on the posterior capsule. In other words, the surgery causes cells to move to the gap between the rear surface of the plastic intraocular lens and the front surface of the posterior capsule. Some of these cells multiply and form fibres that obscure the vision.

The posterior capsule is left in place to act as a scaffold or structure to support the new lens.

Some research has shown that patients <60 years, or who have diabetes, or a lens hard lens nucleus, who have had a vitrectomy, or a hydrophilic intraocular lens, or who did not undergo phacoemulsification surgery were significantly associated with the formation of posterior capsular thickening. Sound as if your patient had the young age risk factor.

The condition is treated using pulses of a YAG laser which makes a small circular opening in the visual axis. The treatment is usually done using topical anaesthesia with non-sedated patients. The procedure takes approximately 15 minutes, without the need for surgical cuts or stitches, and patients can return to normal activities straight away. Visual acuity, contrast sensitivity, and glare sensitivity improve in around 80% of patients.

Your patient needs to be sent back to the hospital for YAG laser capsulotomy.