Glaucoma & Cataracts
A cataract is simply a clouding of the tissue that makes up the lens in the eye. It is a common condition, especially in people over the age of about 60, and it is readily treatable in the vast majority of cases.
Does glaucoma cause cataracts?
Glaucoma itself does not cause cataracts, although there are certain situations in which cataracts are made worse by glaucoma treatments. For example, glaucoma surgery like trabeculectomy, or putting in drainage devices like tubes and shunts may speed the rate of cataract formation.
Some situations that lead to glaucoma can also lead to cataract. For example, topical steroids used to treat inflammatory conditions can result in steroid-induced glaucoma and also in steroid-induced cataract formation.
What are the symptoms of cataract?
The lens is part of the focusing mechanism of the eye. It works with the cornea to focus a clear image onto the light-sensitive layer at the back of the eye (the retina). In order for the lens to provide a clear image it must itself be clear, but if a cataract exists it becomes progressively more cloudy and this causes three main symptoms:
- blurred vision
- excessive glare – especially from oncoming car headlights
- colours become dull
Because these symptoms develop slowly they may not be noticeable until quite a late stage, simply because we tend to get used to things and adjust our expectations naturally. But it’s important to remember that all of these symptoms can also be symptoms of other more serious eye conditions, so if you notice any of them it is worth seeing an optometrist or other eye specialist.
The vast majority of cataracts are first spotted during routine eye health checks by an optometrist. This doesn’t require any tests beyond the normal sight test, but the news that a cataract is present or that it may be causing some visual problems can be worrying.
Treating cataracts
The most common treatment for cataracts is surgical removal of the old cloudy lens material and the replacement of the lens with an implant. The procedure is relatively quick and very reliable, and is the most common operation performed in hospital eye departments across the country.
It is not necessary to wait until vision becomes poor (for the cataract to become ‘ripe’) before an operation is recommended, and in fact it’s usually done as soon as a change in vision starts affecting daily life. It may also be done to ensure that you remain within the visual standard required for safe driving.
Before the operation the eye will be checked to establish the strength of the lens that will be implanted and also to ensure that there are no other complicating factors or conditions present (this is known as the pre-operative assessment).
How does the surgery work?
Almost all cataract surgery in the UK uses a technique called phacoemulsification, which uses sound waves to break up the cloudy lens in your eye. The operation usually takes between 15 and 20 minutes and most people have a local anaesthetic delivered by eye drops and/or injection, so they’re awake during the procedure. The surgeon will let you know what is happening during the operation, but even though you’ll be awake, you won’t feel any pain because of the anaesthetic. Although you may see vague movements and changes in light and shadow, you won’t be able to see what the surgeon is doing. It is possible to request a general anaesthetic for the operation, but recovery from a general anaesthetic takes much longer and there are more risks.
Most people who have a local anaesthetic can go home on the same day as the operation.
After the operation
After the operation you will have a dressing put over your eye to prevent any accidental bumps or knocks and you’ll be given drops to put into the eye for at least two weeks in order to prevent infection and to control any inflammation.
When the eye covering is removed almost everyone notices an immediate improvement in the vision of that eye. Colours are much brighter and things are usually much clearer than before. Glasses will usually still be needed for reading and close work, but distance vision is usually very good indeed.
After the operation you’ll need to be careful about lifting heavy items, rubbing the eye (particularly when you are asleep) getting dust or other foreign bodies in the eye (on a windy day perhaps) and you should avoid swimming for a time, but once everything is fully healed, life should return completely to normal.
Can cataracts and glaucoma be treated at the same time?
Trabeculectomy and aqueous shunt surgeries can be performed at the same time as cataract surgery, or as a standalone surgery. Whether you have the two surgeries in one depends on your situation and your surgeon. Trabeculectomy surgeries are usually more successful when done separately to cataract removals.
Newer, minimally invasive glaucoma surgery (MIGS) is increasingly used together with cataract surgery. One advantage of this is that the MIGS surgery can be performed through the same small incision as the cataract surgery, and they are generally less risky than trabeculectomy and aqueous shunt surgeries. The disadvantage is that, in general, the MIGS does not lower the eye pressure as much as trabeculectomy or aqueous shunt surgeries.
Glaucoma surgery should be prioritised over cataract treatment if the glaucoma is not well controlled, since glaucoma causes permanent vision loss but cataracts do not.