Eye defects and how to recognise them

Press, 21 January 1982, Page 8

Eye defects and how to recognise them

Normally we don’t think much about our vision until our eyes feel hot and gritty or sting when they are tired. Yet. we know that we should see a dentist every six months. Most people do so without waiting for raging toothaches that's sure to force us there.

However, symptoms of eye defects are usually more evident when the error is less serious. The eye will strain to overcome a small defect, but it can do nothing about a serious problem — one that you may be unaware of until it is too late. Because eye defects are not always obvious, optometrists and ophthalmologists (medical practitioners who specialise in the total care of the eyes) recommend that they see patients on a regular basis. whether anything is suspected or not. One optometrist says: “People come in for regular check-ups and tell us they've had no problems with their eyes, then we find out they have a cataract or their glasses need changing. The problem is that if these people did not come in regularly we would not know what’s going on in the eye.” From 45 to age 60 most people notice a deterioration in their eyesight. They have to hold the newspaper further away, or get someone else to thread a needle for them. Many of these people borrow someone else's specs for a close-up job.

This condition is known as presbyopia, and it occurs when the once pliable crystalline lens begins to harden up. The process is usually complete when the 60s are reached.

While borrowing someone else’s glasses or buying cheap, ready-made magnifying lenses will not hurt your eyes, or very rarely will it do so, no trained expert is there to make a ready identification of the defect, and that could be harmful.

Presbyopia is often confused with long-sighted-ness (where someone is unable to focus at close-range). ■ People who are long-

sighted can often strain their eyes to overcome the condition. Often a long-sighted child will be performing badly at school. He can still see the blackboard and can see his work, but without a proper eye examination it will not be detected. That child is using all his concentration to see and not to do his work. Glaucoma is a major cause of blindness today. Justifiably termed the “Sneak Thief of Sight.” chronic glaucoma is a disorder for which there is no early symptom and no pain. In a system where good health services are availalble. glaucoma should be diagnosed early and then be treated successfully. Glaucoma is a defect of the eye’s plumbing, whereby the eye’s fluid, aqueous, gels out of balance. This causes raised pressure within the eyeball which damages the fibres of the optic nerve. In chronic glaucoma this high pressure affects vision slowly over many years and there is no way of reactivating any of these damaged nerve fibres. Central vision is not affected until last, so the patient is still able to see. However, the outer vision in the visual field gradually decreases. The patient is not aware of vision loss that is away from central fixation vision as the loss is so gradual. An optometrist or ophthalmologist can detect, glaucoma by measuring the pressure in the eye. Final diagnosis and treatment is done by an ophthalmologist. In some cases eye drops will be the treatment but in other patients, eye surgery is necessary to keep fluid pressure within normal limits. Lost vision through glaucoma can never be regained. Acute narrow angle glaucoma is another type. You can recognise the symptoms of this one because without warning the patient is subject to excruciating pain and vomiting. An ophthalmic surgeon has to operate within a short time if sight is to be saved.

because intra-ocular pressure (within the eye) has risen to an acutely damaging level.

F’eople prone to narrow angle glaucoma will sometimes notice the television becoming blurry if they have watched it for a long time in a darkened room, street lights may be seen with a rainbow effect, and the eyes may get red and ache. While these symptoms could suggest glaucoma they could also mean that your eyes are just tired. But, you can't tell that yourself. Glaucoma exists in two per cent of people past the age of 35. Acute glaucoma is not nearly as common as chronic glaucoma and the patient is usually aware of it.

Headaches too are sometimes associated with the eyes, although there is a certain amount of controversy over this. One optometrist says. “It is a headache to sort out a headache."

When myopic (shortsighted) people leave their teens behind them the eyes usually will not change until presbyopia, from the 40s to the 60s. If people in the older age groups find that they are suddenly getting more shortsighted. one possibility is the changes occurring in the crystalline lens. One of the major causes of this type is diabetes.

"People with these symptoms are often unaware that they have diabetes but I will send them to their general practitioners for diabetes tests.” the optometrist says. Nine per cent of Caucasian males and 0.1 per cent of females are colour deficient. Testing for this is becoming more common at schools today and is an important factor when young people consider choosing a vocation. It used to be thought that as one got older the eyes stabilised and regular consultations were not necessary. They are. One specialist says that it is possible to correct, wholly or partly, about 95 per cent of all vision defects. You cannot always recognise what is wrong with your eyes yourself even if you have a few symptoms.