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What are secondary cataracts?

secondary cataract, also known posterior capsule opacifcation, is the most common complication after cataract surgery. It happens in 3-50% of cases five years after cataract surgery, and is a result of the migration and proliferation of the epithelial cells that lead to reduced visual acuity. 

Cataract surgery involves extracting the opacified crystalline lens, leaving the capsule containing it empty and replacing it with an intraocular lens. The crystalline lens capsule is the fine transparent membrane surrounding it. To extract the cataract, we have to make a window in the anterior part of the capsule, leaving the posterior capsule intact in order to implant the lens. 

This capsule can opacify months or years after cataract surgery, leading to a secondary cataract. 


The most common symptoms of a secondary cataract are a reduction in visual acuity months or years after cataract surgery, which impedes both far and near vision; in addition to glare from the sun, car headlights at night and a reduction in the perception of colours.


The advances in surgical techniques, exhaustive polishing of the epithelial capsule cells during cataract surgery and a variety of more advanced intraocular lenses help to prevent or delay such secondary cataracts.


To restore the vision lost, an opening or window is made in the centre of the posterior capsule (capsulotomy) using a YAG laser.

The YAG laser capsulotomy is a simple and painless outpatients procedure. It is performed in a few minutes after dilating the pupil using anaesthetic drops. The patient can return home immediately with an eyedrop treatment. 

Visual recovery is complete (if there aren't any further eye issues concerning the retina, optic nerve or cornea) and quick, with an improvement being seen in just a few hours. After a few days, we perform a check-up to monitor the progress and an exam to assess the need (or lack thereof) for glasses. In any case, a capsulotomy will improve vision insofar as possible.

Despite being a very safe procedure, some patients state that they see "floaters" in the following days, possible due to small residual fragments of the capsule that are usually reabsorbed and disappear in a few days, although in isolated cases this sensation may persist for a more extended period. 

It is a definitive treatment in a single session, although in very exceptional cases the opacity reoccurs making it necessary to repeat the process.

Professionals who treat this pathology

Frequently asked questions

  • No, the lens is supported by a surface known as the posterior capsule.  The migration of the epithelial cells to this capsule causes a lack of transparency, resulting in a loss of visual quality.

  • Recovery is very quick. Practically once the procedure finishes you can see an improvement in vision and, in particular, after a few hours, once the effects of the drops used to dilate the pupils wears off. The only thing that you might see is floaters over the first few days, but this is temporary.