Glaucoma
Treatment aimed at controlling eye pressure and protecting the optic nerve from further damage
What is glaucoma?
Glaucoma is damage to the optic nerve, the cable that carries what you see from the back of the eye to the brain. In most people the damage is driven by the pressure of fluid inside the eye. The eye makes a clear fluid continuously and drains it through a fine mesh in the angle where the iris meets the cornea. When the drain cannot keep up with production, pressure builds and nerve fibres are gradually lost.
The fibres serving the edges of your vision go first, and the brain fills in the gap using the other eye, so sight can feel completely normal while a large amount has already gone. Damaged nerve fibres do not grow back. Everything a doctor does for glaucoma is aimed at protecting the fibres you still have.
There are two broad patterns. In the commoner one the drain becomes less efficient over years and pressure creeps up painlessly. In the other the angle itself is narrow and can close off, sending pressure up within hours. Age over forty, a parent or sibling with glaucoma, strong short sight, diabetes and long courses of steroid drops all raise the risk.
What you might notice
- Losing vision at the edges
- Eye pain with haloes around lights
- Blurry or dim vision
How it is diagnosed
An eye doctor measures the pressure in each eye, then examines the head of the optic nerve through a lens at the slit lamp. They are looking at the hollow in the centre of the nerve and how much rim of healthy tissue is left around it, and at whether the two eyes differ from each other. They also look directly at the drainage angle with a mirrored lens to see whether it is open or narrow.
Two measurements complete the picture. A field test maps where you can and cannot see, by asking you to press a button whenever a dim light appears. A scan measures the thickness of the nerve fibre layer in microns, which picks up thinning before the field test shows a gap.
One visit establishes the diagnosis. Several visits establish how fast it is moving, and that is the number your doctor treats to, so expect the measurements to be repeated on a schedule even when nothing feels different.
Recovery
Drops ask nothing of your day and are started the same afternoon. Give them a few weeks before judging comfort, since mild stinging and redness usually settle, and have your pressure rechecked at four to six weeks to see what they achieved.
Laser treatment is done in the clinic in a few minutes with numbing drops. Your vision is blurred for a few hours and you should arrange not to drive yourself home. Most people are back at work the next day.
Surgery is the longer road. Expect a night in hospital or a long day, blurred vision for two to six weeks while the eye settles, and drops on a tapering schedule for two to three months. Plan two weeks away from work, longer if your job is dusty or physical, and avoid heavy lifting, swimming and rubbing the eye for a month. Your surgeon will see you every few days at first, because the early reviews are what steer the result.
If it is left untreated
Glaucoma that is left alone goes on damaging the nerve at whatever rate it has been moving at. The field of vision narrows inward from the edges, obstacles and kerbs start being missed, driving becomes unsafe, and in the late stages only a small central island of sight remains. None of this is recoverable once it has happened.
The damage is painless and silent in the common form, so the absence of symptoms is a poor guide to whether it is progressing. Stopping the drops because the eye feels fine is the usual way sight is lost, and pressure returns to its untreated level within days of stopping.
A narrow angle that closes off is a different kind of problem and needs help the same day. A hard, red, painful eye with blurred sight, coloured haloes around lights, headache and vomiting is an emergency, and the sight in that eye depends on how quickly the pressure is brought down.
Questions about glaucoma
Will my vision come back once the pressure is controlled?
No, and that is the reason glaucoma is treated as early as it is. Optic nerve fibres that have already died do not regenerate, so any gap that has appeared in your field of vision is permanent. What treatment does is protect the fibres you still have, and for most people diagnosed before the damage reaches the centre, that is enough to keep useful sight for life. Your doctor will measure your field and scan your nerve at intervals to confirm that nothing further is being lost. A stable set of measurements over two or three years is the result you are looking for.
Do I have to use the drops every day, for ever?
Yes, for as long as the drops are your treatment. They work by lowering pressure while they are in the eye, and pressure returns to its untreated level within a day or two of stopping, so a course that is taken on and off gives roughly the protection of no course at all. Missed doses are the commonest reason a treatment appears to have failed, and they are worth admitting to your doctor before the treatment is changed to something stronger. If the routine is genuinely unmanageable, say so, because laser treatment and surgery both exist partly to answer that problem.
My father has glaucoma. Should I be tested?
Yes. A parent, brother or sister with glaucoma raises your own risk several times over, and it is the single most useful thing you can know about your eyes. Have a full examination now, whatever your age, and then at the interval your eye doctor sets, which is usually every one to two years from the age of forty. The examination includes the pressure, a look at the optic nerve and the drainage angle, and a baseline field test and scan. The baseline matters as much as the result, since the diagnosis often rests on change over time.
Other ophthalmology treatments
Removal of a cloudy natural lens and replacement with an artificial lens to improve vision
Day CareLaser vision correction that reshapes the cornea to reduce dependence on glasses or contact lenses
Day CareTalk to a care coordinator about glaucoma
Leave a number and a care coordinator calls you back with what the treatment involves and which hospital it would be at. They book a consult only if you want one