Posterior Capsular Opacity (PCO)
Any time from 2 weeks to 2 years after cataract surgery, the vision can again become cloudy or blurry. Glare around lights may also become noticeable. Patients often report that they feel as if the ‘cataract is coming back.’ This can be due to posterior capsular opacity. When removing a cataract, the lens is removed but the lens capsule is normally left in place. This lens capsule is a very thin layer that is a bit like cling-film. This is intentional so that the new artificial intraocular lens sits inside the original lens capsule and is important so that the lens power can be chosen and the final refractive outcome can be predicted. The back part of this capsule, the posterior capsule, is the part that becomes cloudy.This cloudiness in the lens capsule develops in 20-30 per cent of patients after cataract surgery. It can be treated simply, safely and effectively with a laser treatment called a YAG laser capsulotomy. This is an outpatient treatment, which only takes a matter of minutes. It may be needed in one or both eyes. The YAG is short for neodymium-doped yttrium aluminium garnet, which is a lasing medium. Light is pumped into the YAG medium and emits pulses of infrared light, which
To have the procedure, the eyes need to be dilated and this means that the vision in the treated eye will be blurred for a few hours afterwards. It is best to avoid driving to the appointment for this reason and to arrange appropriate transport.
The eye drops take a while to work and to make the pupil large enough to perform the YAG laser capsulotomy. Another set of anaesthetic drops will be given just before the procedure. These numb the eyes and allow a contact lens to be placed on the eye. This prevents blinking and moving for the few minutes it takes to perform the procedure. Laser is a form of highly focussed light that travels through the cornea and intraocular lens, and makes an opening in the posterior capsule of sufficient size to let light through and clear the vision but not so large as to disrupt the lens position.
Once the procedure has been performed, the contact lens is removed from the eye and the vision is a little blurred for a few minutes after the procedure. The vision gradually returns to normal over a few hours as the dilating drops wear off.
The main risks of the procedure are transient pressure rises afterwards, damage to the lens during treatment or retinal detachment. In practice, problems are rare and the procedure usually has excellent results and rarely if ever needs to be repeated if performed correctly.
Spectacles or contact lenses should not need to be changed but the opticians will be able to perform a more accurate test if the posterior capsular opacity has been lasered and may need to change your glasses afterwards.