Glaucoma means that the pressure of the fluid inside the eye gradually increases. This causes increased pressure on the light-sensitive cells of the retina at the back of the eye, and a deterioration of vision. It may gradually worsen, the child often being unaware of it.
Glaucoma affects 1-2 per cent of people over 40. In most cases the symptoms appear slowly over a period of years, with the patient being unaware of their occurrence. There is a gradual loss of peripheral vision as pressure of fluid inside the eyeball increases and presses on the sensitive retina, eventually destroying it.
Once visual loss has taken place in this manner it is not reversible. Unless the condition is diagnosed relatively early, it will inevitably progress, probably resulting in blindness. Nearly all cases are termed “open-angle glaucoma,” and give the symptoms described. About 5 per cent of cases are due to “angle-closure glaucoma” and produce sudden pain, inflammation of the eye and blurred vision. This often constitutes a surgical emergency, with immediate attention necessary to save vision.
Although the treatment of glaucoma is carried out by an eye specialist, more doctors can now perform a diagnostic test that can detect glaucoma at an early stage. This is called tonometry, and involves placing an instrument on the eyeball for a short time and recording the intraocular pressure. If this is higher than normal, it is presumptive evidence that glaucoma may be developing, and further investigation and treatment indicated. Other methods are also available. The patient should be referred to an eye specialist for further appraisal.
In the front chamber of the eye, fluid is produced regularly, and follows a particular system of circulation. It is manufactured by the ciliary body at the base and back of the iris, flows forward through the pupil and moves peripherally to be collected by channels absorbing it in the general blood circulation. If excessive amounts of fluid are formed, or if the rate of collection of the fluid is lower than normal, the pressure inside the eye gradually increases. This causes pressure on the retina, and gradual loss of visual acuity. In acute cases where symptoms come on suddenly, there is a sudden block to the outflow of the fluid, causing an emergency.
Sometimes the child may find bright light disturbing or it may make the eyes water. Vision gradually becomes reduced. This may affect one eye or both. In the affected eye the pupil may dilate, making it obvious that something is wrong, so drawing attention to the condition.
Regular eye checks. Anybody over the age of 40 years should have regular checks on eye pressure by tonometry. This is quick, simple, and does not cause discomfort. It can give an accurate indication of potential problems. If pressure readings are above normal, immediate referral to an eye specialist is usually recommended.
Eye drops. The regular use of eye drops called miotics facilitates efficiency of the outflow channels, enabling more aqueous to escape and thus reducing the intraocular pressure. Drugs most commonly used are pilocarpine, 1-4 per cent, two drops in each eye five times a day.
Certain drugs such as acetazolamide (Diamox) are sometimes used if drops are not adequate. If these methods fail to maintain minimal pressure, surgery may be necessary. Fortunately respond relatively well to medical treatment to an extent where surgery can be avoided.
In acute glaucoma—a surgical emergency—an operation may be essential if pressure in the eyes has not started to reduce within four to six hours of medical treatment. Peripheral iridectomy is the standard surgical operation. In any acute condition giving the symptoms mentioned, prompt medical attention is essential. There is no place for home remedies or hoping for the best and wasting valuable time by doing nothing.
It is essential that treatment occur as soon as the disability has been discovered. In the early stages drops may be used. Pilocarpine has been used for many years with good results. Since the advent of the beta-blocker family of drugs, Timolol has been effective, and more recently Betaxolol. These are probably the best drugs to date. Sometimes fluid tablets are given orally as well.
Is it ever a question of surgery for relief? Often it may progress to this, and surgery may be required to permanently reduce pressure. In severe cases with marked visual loss and acute pain, removal of one of the eyes may be essential.
In some children it may be a difficult task to treat. This all boils down to the fact that the sooner any eye disorder is recognized, and treatment commenced, the higher are the chances of a satisfactory outcome.
Please, mothers, always bear this in mind. Actually, the same admonition goes for virtually any childhood disorders. Please keep your eyes alert and be observant at all times—which I am sure you are to the best of your ability. This book is merely to keep you looking along the right tracks.