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Posterior Capsule Opacity (PCO)

What is Posterior Capsule Opacity (PCO)?

When we perform cataract surgery we remove the cloudy core of the cataract and in its place put an intraocular lens (IOL) to restore focus. The only original part of the cataract is the sac of the cataract (or capsule), part of which sits behind the IOL (Posterior Capsule). With time this capsule opacifies (becomes like frosted glass instead of clear glass) and impacts the vision. Depending on the type of cataract it can sometimes be present immediately after surgery (posterior subcapsular cataract), but usually is very gradual to develop taking anywhere from a year to 10 years. So Posterior Capsule Opacity (PCO) is an expected process after cataract surgery and one which can be readily fixed in the clinic. PCO is a membrane behind your Intraocular lens and so there is not typically anything wrong with your IOL.


Much like the original cataract, PCO causes progressively blurry or fuzzy vision, often described like having a ‘film over the eye’. Because it is usually so gradual we often don’t notice it in the early stages but with time it steadily worsens, impacting the vision more. It behaves much like the original cataract hence it is often referred to as ‘after-cataract’ or ‘secondary cataract’, but fortunately PCO does not require surgery to fix, instead this is a treatment that can be provided within the clinic. Without treatment PCO continues to steadily worsen vision which can cloud over completely.

The doctors at Launceston Eye Institute can restore vision impaired by Posterior Capsule Opacity by performing a YAG Laser Capsulotomy (making an opening in the posterior capsule). A YAG laser removes the central part of the hazy capsule by directing two tiny laser beams into the eye on a machine that looks much like the slit-lamp the doctors use to examine your eye. Where the two laser beams meet creates a microscopic pulse of energy. It is a tiny amount of energy so it doesn’t hurt, but because it is delivered in a billionth of a second (10-9) the laser can clear the PCO out of the way (photodisruption). It is a bit like when gladwrap covering something is pierced in the centre and scrolls away to the edges leaving an opening in the middle. Performing YAG laser capsulotomy returns clear vision to the eye almost immediately, however you can often be a bit dazzled for 15-30 minutes so usually only one eye YAG laser capsulotomy is done at a time. How much improvement in vision noticed depends on how bad the PCO has become.
Important notes

This treatment, like most ophthalmic treatments and requires your pupils to be dilated. The laser only takes a few minutes and doesn’t hurt as it is all done from outside the eye. Occasionally you will hear/feel a tiny ‘pop’ as the capsule is cleared from behind your IOL. Problems after YAG laser capsulotomy are very rare. The doctor will usually give you a drop at the time of the procedure to prevent any rise in intraocular pressure ‘spike’ (uncommon). Sometimes the doctor may give you drops to take for a few days after the procedure as well. The most common after effect of the procedure is you may notice some floaters (or floaters you have may stir up). Generally these floaters settle over a few weeks. If after your YAG laser procedure you get a more dramatic change in floaters (especially associated with flashing lights or a shadow in the vision) or if you have any other concerns (including if your vision is not improving), please contact the Launceston Eye Institute on 03 6344 1377.