YAG capsulotomy: when vision goes cloudy after cataract surgery

"My cataract has come back." It hasn't. It can't. A cataract is the eye's own lens becoming cloudy, and at surgery that lens was removed and replaced with a clear plastic implant. Plastic does not develop cataract.

What has almost certainly happened instead is something called posterior capsule opacification, and it is fixed with a laser, in the outpatient clinic, in about five minutes, without touching the eye.

What actually happened

Your natural lens sits inside a very thin, clear, elastic membrane called the capsule. Imagine a grape inside its skin. At surgery, the surgeon opens the front of that capsule, removes the cloudy lens from inside it, and places the artificial lens implant into the capsule that is left behind.

The back wall of that capsule is deliberately kept. It holds the implant in exactly the right position and keeps the front and back of the eye properly separated. It is a good thing that it is there.

But a few of your own lens cells always remain along the edge of the capsule after surgery. Over months or years, in some people, those cells migrate across the back of the capsule and multiply. The membrane becomes hazy, wrinkled or pearly.

Light now has to pass through a cloudy layer again, and the symptoms are almost identical to the cataract you had before.

How common is it?

Common. Somewhere around one in five people develop it to a degree that warrants treatment. It is more likely in younger patients, in people with diabetes, uveitis or myopia, and in eyes that had complicated surgery.

It is not a sign that anything went wrong with your operation. It is a normal, expected, easily treated consequence of the eye healing.

What it feels like

Gradual blurring or clouding of vision, months to years after surgery. Glare and haloes, particularly driving at night. Difficulty reading in poor light. Colours looking dull or washed out. Vision that seems worse in bright sunshine. And the frustrating sense that the operation has worn off.

It is gradual, painless, and can affect one eye or both. If your vision has changed suddenly, this is not the explanation and you should be seen promptly.

What the laser does

A YAG laser delivers extremely short, precisely focused pulses of energy. Focused onto the cloudy capsule, each pulse creates a tiny disruption in the membrane.

A series of these pulses is placed in a circular pattern, and the central portion of the cloudy capsule falls away, leaving a clear round opening directly behind your lens implant.

The implant is untouched. The rim of capsule that supports it is untouched. Light now passes through a clear window. Nothing enters the eye. There is no cut, no needle, no stitch.

The more important part of the appointment is confirming that this is the reason your vision has dropped. Cloudy capsule and macular degeneration can coexist quite happily, and lasering the capsule will not help if the macula is the problem. So the retina and the pressure are checked as well, usually with an OCT scan.

What happens on the day

Before: a dilating drop, which takes around 20 to 30 minutes to work. Sometimes a drop to lower eye pressure beforehand. An anaesthetic drop to numb the surface.

During: you sit at a machine very like the one used for a routine eye examination. A contact lens is placed gently on the front of the eye with some clear gel. It holds the lids open and focuses the laser. This is the least comfortable part, and most people describe it as odd rather than unpleasant.

You are asked to look at a target light and keep still. You will see flashes of light and hear a series of clicking sounds, which is the laser firing. It does not hurt: the eye is numb and the laser is not felt. The whole thing takes two to five minutes.

After: the contact lens is removed and the eye is rinsed. Pressure is often rechecked after 30 to 60 minutes. Anti-inflammatory drops for a few days, and sometimes a pressure-lowering drop. You go home the same day. There is no patch and no dressing.

Can I drive afterwards?

No. Please arrange a lift.

Your pupil will be widely dilated for four to six hours, your vision will be blurred and glary, and you will be light-sensitive. Bring sunglasses and bring someone with you. Allow two hours at the clinic in total.

When will my vision improve?

Often within a day, sometimes within hours. Many people notice it almost immediately once the dilation wears off.

You will very likely see new floaters for a few days to a few weeks. These are the fragments of capsule drifting in the vitreous. They settle and the brain learns to ignore them. It is expected and not a problem.

Risks

It is a low-risk procedure, but not a zero-risk one.

A rise in eye pressure in the hours afterwards, usually transient, which is why it is checked. Floaters, very common and usually temporary. Inflammation inside the eye, usually mild. Small pits in the lens implant from the laser, almost always visually insignificant. Cystoid macular oedema, uncommon and treatable.

And retinal detachment. Rare, quoted at well under 1 per cent, but higher in short-sighted eyes and in people with previous retinal problems.

Contact us urgently if in the days after the laser you develop a shower of new floaters, flashing lights, a shadow or curtain across your vision, or a genuine drop in vision. These need same-day assessment.

Common questions

Will it need doing again? No. Once the opening is made, it stays open. This is a one-off for that eye.

Can both eyes be done on the same day? Usually they are done separately, a short interval apart.

Is it done under general anaesthetic? No. Drops only, sitting up, fully awake.

What if I blink or move? The contact lens holds the lids. Small movements are anticipated and the laser is only fired when the target is correctly aligned.

Do I have to have it? No. If the haze is mild and your vision does not trouble you, it is entirely reasonable to leave it and review.

Referrals

GPs and optometrists can refer directly. Bon Secours Limerick: hollyfitzgibbon@bonsecours.ie. Eyes, Lids and Face Clinic, Ennis: info@eyeslidsandface.ie. Healthmail, for healthcare professionals only, Ennis clinic: shane.oregan@healthmail.ie

Patients can contact Bon Secours Hospital Limerick on 086 034 8727, or the Eyes, Lids and Face Clinic, Ennis, on 065 672 4160.

This page is general information and not personal medical advice. Vision standards for driving are set by the Road Safety Authority and it is the driver's responsibility to meet them.