Thickening of the posterior capsule & laser treatment: laser after cataract surgery
The film behind your lens implant can thicken.... like frosted glass (arrow). It can only occur after cataract surgery. animation.
Normally light enters the eye from the front, passes through a clear lens, and reaches the back of the eye so you can see. When the lens becomes cloudy, like frosted glass, light cannot not pass through, and the sight becomes misty: this is called a 'cataract' . See animation.
A side view of an eye showing a cataract scattering light.
In a cataract operation, a clear plastic lens is placed in the 'bag' left behind when the cataract is removed. The new lens focuses the light onto the back of the eye, just like the original human lens. See animation.
Light passes through the clear lens implant.
the capsule behind the lens implant (arrow)
The 'bag' is called a capsule: the capsule supports the implant. This capsule is normally clear like a glass window. It is very thin, like cellophane.
In a small number of patients the capsule thickens,
and becomes a little opaque, like a frosted glass window. This stops
the light reaching the back of the eye.
If this happens, the sight become misty, and it can become difficult to see at night, or in sunlight.
Capsule thickening can happen in the months after your cataract operation, but more commonly occurs two or three years after.
The capsule thickening does not damage the eye in any way; it merely makes the sight fuzzy. See a photograph another before/after laser. photos on this page
The thickened capsule scatters light. animation
The laser is applied in a ring (or a cross, not shown).
Laser treatment makes a small hole in the centre of the capsule, and can restore the vision to how it was after the cataract operation. The treatment does not hurt, and is hardly noticeable . It takes about fifteen minutes; the laser machine is in the outpatient clinic.
To carry out the laser, the front of your eye is anaesthetised with an anaesthetic drop, and a small contact lens is placed on your eye. Placing your head on the frame of the laser machine to keep your eye still, the doctor focuses the laser on the capsule.
The laser then makes small holes in the capsule, often in a circle. The holes join up and, like tearing a postage stamp, a small hole is made in the capsule. The capsule segment drops to the bottom of the eye (over minutes or hours). Larger capsulotomies are helpful.
Laser makes a small hole in the capsule. Light can then pass directly onto the retina, without being scattered. See animation
For a few days after the laser you may notice a lot of floaters. The capsule segment drops to the bottom of the eye over a few days, and is normally not very noticeable. You may notice large or small floaters at this time. See the floaters.
The laser is considered very safe, with very few complications. Occasionally a little more laser is need to release the capsule on a second occasion. Only a small hole is needed, so the lens implant still has enough support.
the retina of the eye: this is like the 'film' of a camera
Less often, the laser can disturb the retina. Very rarely a little fluid can build up in the retina. Also very occasionally the laser can disturb the retina, damaging it a little months or a year or two later. If this happens and makes a tiny tear in the retina, you may notice
- flashes of light during the daytime
- floaters in your vision (it is normal to have these in the weeks after the laser)
- a 'curtain' drifting across your vision
If there are a lot of flashes and floaters all of a sudden, the eye needs to be examined to check if there is a small tear in the retina. If a 'curtain' or 'shutter' drifts across the vision, an examination is needed the same day to check for a retinal detachment (this usually means attending an 'Emergency' Eye Department, such as that at Birmingham and Midland Eye Centre, City Hospital). In addition there are other very unusual complications.
floaters are normal just after the laser, but if there is a sudden shower of floaters months afterwards, suspect a retinal disturbance
It is normal to have floaters for 3 weeks after laser. The retina of the eye may be VERY OCCASIONALLY affected by the laser causing a more serious problem (see above ).
You should have your eyes checked each year by your optometrist after this treatment, for glaucoma and other problems.
If you have a slightly unusual eye, these check ups are critical. For example, if an injury caused your cataract, have your eyes checked one month after treatment and every year. Similarly, if you have glaucoma a pressure test soon after the operation is helpful.
Yag Laser capsulotomy after laser, a clear visual axis larger