What is a cataract?
A cataract is a clouding of the lens of your eye.
In a young eye, the lens is usually clear. As a cataract develops, the lens becomes opaque and it blocks light rays passing through the lens to the retina. This is why the vision gradually worsens.
Causes of cataract
Most people develop cataracts as they age. However some conditions, such as diabetes, certain medications or a significant injury to the eye can contribute to earlier development of cataracts.
How is a cataract treated?
Surgery to remove the cloudy lens is the only treatment that is currently available to treat cataracts. The natural lens is replaced with a new acrylic implant.
When is surgery required?
In many cases cataracts are harmless and it is usually safe not to have treatment, particularly if you feel you do not have a problem with your vision or do not wish to have an operation
You may wish to consider cataract surgery when poor vision starts to affect your daily life, such as driving, reading, shopping or watching television, etc.
Before your surgery, you will need to attend a pre-operative assessment clinic. This is to ensure that all necessary investigations are carried out before admission. It is also to give you information related to surgery before admission. You will be able to ask any questions you may have about the procedure.
You will see a trained eye nurse and, if necessary, an eye doctor. Measurements of your eye will be taken and your eyes will be examined. This is to help the surgeon decide the strength of lens implant to be used for you. To get accurate measurements, it is important if you wear contact lenses, to leave them out for the following times:
- Soft daily disposable – 24 hours
- Soft two weekly and monthly contact lenses – 48 hours
- Extended wear soft contact lenses – 1 week
- Rigid gas permeable contact lenses – 2 weeks
It is also important to not wear contact lenses for 48 hours before cataract surgery If you are having a second cataract operation soon after your first cataract operation and you are fit and well, you may be offered a telephone pre-assessment. A trained nurse will telephone you and ask you questions regarding your health and your recovery since your previous surgery, check your current medications and ask who will be taking you home from hospital on the day of surgery.
Previous Laser Treatment
It is very important to tell the doctor or nurse, if you have had previous laser refractive surgery to reduce the need for glasses.
Previous refractive laser treatment affects the calculations that are used to determine the strength of the replacement artificial lens implant that is used during surgery. This means that patients can become more long or short sighted than planned following cataract surgery. This may require spectacles or contact lenses to be worn after surgery. Very rarely it may also involve further surgery. Laser refractive surgery is currently unavailable on the NHS.
The surgery removes the cataract (cloudy lens) through a small incision and replaces it with an acrylic lens implant. It is not done using a laser, as many people think, and your eye is not taken out of the socket.
A small incision (3mm or < 1/4”) is made to remove the cataract. The cataract is removed by ultrasound, which fragments the lens, allowing it to be removed by suction.
It is usual for the eye to feel gritty or feel like it has “something in it” for 2-3 weeks after the operation. Mild inflammation occurs after cataract surgery, which settles with eye drops but sometimes may last up to 6 weeks.
Complications of cataract surgery
- Bruising around the eye or eyelids
- Allergy to the eye drops
- High pressure inside the eye.
- Clouding of the cornea.
- Dislocation or suboptimal strength of the artificial lens implant.
- Swelling of the retina (macular oedema).
- Retinal detachment.
- Posterior capsule rupture and/or vitreous loss (a split in the thin membrane containing the cataract).
- Refractive surprise (unexpected need for glasses).
- Part or the entire cataract falling into the back of the eye (usually requires further surgery to remove it).
- Endophthalmitis - infection of the eye.
In some cases, further surgery may be required. Very rarely, some complications can result in blindness or loss of the eye.
One of the commonest occurrences after surgery is posterior capsular opacification - thickening behind the lens implant. This causes similar symptoms as a cataract (cloudy or blurred vision) and is easily corrected with laser treatment in the clinic.
What about glasses
After the procedure, you still need to use glasses, particularly for reading. You may sometimes need glasses for both (distance and reading). About 6 weeks after surgery you will be able to visit the optician for new glasses. You will be informed at your follow up appointment when to go to the optician.
If you are keen to reduce your dependency on glasses after cataract surgery, this may only be possible using a premium lens; however these lens implants are not available on the NHS.
If you have any queries or concerns, please contact the Eye Unit Helplines:
- Ashford Hospital: 01784 884402
- St. Peter’s Hospital: 01932 722686