Posterior capsular opacification
A cataract is a clouding of the lens in your eye and normally occurs as part of the ageing process, although there are other reasons why a cataract can develop earlier in life.
During cataract surgery the natural lens of your eye, which has become cloudy, is replaced by a clear artificial lens also known as an intraocular lens or IOL.
This new artificial lens is placed inside your lens capsule, the membrane that originally held your natural lens. Your lens capsule is clear and remains clear following your cataract surgery.
PCO occurs because cells remaining after cataract surgery grow over the back (posterior) of the capsule causing it to thicken and become slightly opaque (cloudy).
This means that light is less able to travel through to the retina at the back of your eye. Sight can become blurred and cloudy, or you may have problems with bright lights and glare.
The effects of PCO on your sight are very similar to the changes you may have had when your cataract first started to cause you problems. If you have had cataract surgery in both eyes, PCO can affect both eyes, but each eye may be affected at different times.
Why do some people get PCO?
Although PCO is quite common, there are some reasons why you may be more likely to develop it. The younger you are when you have cataract surgery, the more likely it is that this thickening will occur.
PCO is also more common in certain situations, such as where inflammation (swelling) is present in your eye or if someone has the genetic eye condition retinitis pigmentosa. However, it’s not unusual to develop PCO even if you don’t have these conditions.
What happens when I go for laser treatment?
PCO is treated by a very low risk, quick, painless laser treatment. It is carried out in the outpatient clinic. If you have PCO in both eyes, then it is possible to have treatment for both on the same day.
At the appointment you will be given some eye drops to dilate (widen) your pupil. These can make your vision blurrier.
Sometimes, but not always, the ophthalmologist (hospital eye doctor) may use a contact lens to help to keep your eye in the right position.
If this is needed, then you will also be given a drop to anaesthetise (numb) the front of your eye so that you do not feel any discomfort.
Once your pupil is dilated, you will be asked to sit and place your head on the headrest of the laser machine.
This will help to keep your head and eye still while the ophthalmologist uses the laser to remove part of the capsule. There may also be a nurse present while the treatment takes place.
The ophthalmologist focuses the laser exactly onto the back of the lens capsule in order to cut away a small circle-shaped area.
This leaves some of the capsule to keep your artificial lens in place (like a cuff around the lens), but removes enough in the middle to allow the light to pass directly through to the retina.
The laser uses a wavelength of light that cannot be seen, but you may notice a red light, which helps the ophthalmologist focus the laser beam.
Each laser pulse is over in a fraction of a second and you should not feel any pain or discomfort.
You may notice a few flashing lights or hear some faint clicks coming from the machine as the laser works. The procedure does not take very long; normally it will take about 5-10 minutes.
What are the risks of laser treatment?
The laser treatment is considered very safe. All procedures carry some aspect of risk, but serious side effects from laser treatment for PCO are very rare.
Laser treatment for PCO is carried out using a very low energy laser called “Nd: YAG”, sometimes referred to as just “YAG”. The Nd: YAG laser can delicately cut the lens capsule without any risk of damage to other parts of your eye. Because the laser can travel through the front of your eye (the cornea) without cutting it, there is no risk of infection from this treatment.
Sometimes, if a contact lens was used to steady your eye during the treatment, your eye may be a little sore afterwards, but this should soon wear off.
For some people, laser treatment for PCO can cause eye pressure to rise. This can be an issue if you already have a pre-existing eye condition such as glaucoma, as your eye pressure may already be higher than normal. If your ophthalmologist is concerned about this, they will check your eye pressure soon after the laser treatment. If your eye pressure has increased, you will be given some eye drops or a tablet to bring it back down.
Rarely, laser can cause a retinal detachment which can happen days, weeks or months after the treatment. This is more likely to happen if you are very short sighted. If it does occur, retinal detachment can be treated with surgery to re-attach the retina.
It is important to stress that these risks are extremely rare complications of the laser treatment. The vast majority of people get an excellent and permanent improvement in their vision following laser without experiencing any issues.
What will my sight be like after treatment?
It may take a few days for your sight to become clear again, and you may notice “floaters” after your laser treatment. Floaters are harmless clumps of cells which move around inside the vitreous (a jelly-like substance which fills the inside of the eye).
You may see floaters as dots, circles, lines, clouds or cobwebs. Over time these will settle down and become less noticeable.
Because the laser treatment does not require any incisions or stitches, you are normally able to return to your daily activities straight away.
However, immediately after treatment, your pupils will still be dilated so your vision may be blurred for a few hours afterwards. You will need to avoid driving until this blurriness has gone.
OPTOMETRY-SHARP VISION
Optometrist