• What is ‘intraocular hypertension’?
• How does this affect your sight?
• What do you need to do?
• What is the cause of intraocular hypertension?
• Looking after your general health
• Small print for professionals
• Summary
• Glaucoma Association page
  

‘Intraocular hypertension’ is the medical way of saying ‘too much pressure’ in the eye.

Your eye contains fluid. The fluid is made in the middle chamber of the eye. From this middle chamber, it then flows into the front chamber of the eye, and from there it drains out of the eye.

If the ‘drain’ blocks a little, the fluid will become trapped in your eye, and the pressure will go up. This is just like pumping a tyre up a little too much.

(The fluid is nothing to do with tears, which are on the outside of the eye.)

The eye is like a small ball, the size of a table-tennis ball. Fluid, a type of salt solution, is made in the eye (the ‘tap’). The fluid circulates to the front of the eye (the arrow), and then drains out of the eye (shown in green), into the blood stream.

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Generally your sight will be normal in this condition. But the condition is important, as sometimes you may develop ‘glaucoma’.

A few people with intraocular hypertension develop glaucoma each year; this occurs when the pressure on the nerve at the back of the eye actually damages the nerve.

In ‘intraocular hypertension’ the nerve at the back of the eye remains healthy. But in glaucoma the fluid pressure in the eye starts to press to hard on the nerve and damages it: this damages your sight.

(The nerve is the ‘electric wire’ of the eye. It takes the messages from the eye about what you see, and sends them on to the brain.)

If the drain blocks, the pressure in the eye builds up and may press on the nerve at the back of the eye, damaging the nerve and the sight.

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You need the three tests:

• eye pressure
• an examination of the nerve (by the ophthalmologist or optometrist looking in)
• a visual field test

The first two tests are quick. A visual field test takes a little longer. It is a test to see that the nerve at the back of your eye is working properly. You have to sit with your head still looking straight ahead, and a light flashes from the side. If you see all the lights of a certain brightness we can determine whether or not the nerve is damaged. (You have to press a button when you see the light.)

Remember, you will not know whether you have glaucoma in its early stages: this can only be detected by this examination. Glaucoma does not cause pain.

In addition to having the three tests above, a healthy lifestyle helps, as recommended by the Department of Health

Treatment is sometimes necessary to lower the eye pressure (as with Glaucoma) delaying glaucoma. In practice many patients with a pressure over 25mmHg, those with glaucoma in the family, those who have an optic nerve that may be slightly damaged from the pressure, are recommended treatment. Those with the lowest pressure (eg 22mmHg, none of these risk factors, may not need treatment. Many patients are 'in between' and a personal discussion may be helpful. See more evidence and a search.

measuring eye pressure is painless

The blockage is not caused by smoking or anything you have done. However, the condition can run in the family. Scientists have found genes that can cause the condition. The genes, which you inherit from your parents, control the chemistry of the tiny cells in the ‘drain’. The cells may work normally for 50 years, letting the fluid out of the eye, but then begin to stop working. The fluid then gets trapped in the eye.

Patients with intraocular hypertension who develop a retinal vein occlusion need to be treated as though they have early glaucoma, and need a low pressure.

Remember that your general health and lifestyle have a major impact on glaucoma and your sight.

• Smoking does increase the eye pressure, and will make your glaucoma worse. It also increases the risk of retinal vein occlusion (which occur in glaucoma), macular degeneration, cataracts, stroke, and heart attacks.
• Exercise lowers the eye pressure, 'an hour a day (walking) will keep the doctor away', and half an hour will help a lot. See.
• high blood pressure will be harmful as this may, together with the glaucoma, cause a retinal vein occlusion. A blood pressure of 140 systolic or less will be best, and the lower the better as long as you feel well. See   We now know that eye pressure and blood pressure are related; the implication of this is that lowering blood pressure will help in the treatment of glaucoma. So keeping your blood pressure is an important part of the treatment
• Oily fish will help the circulation and probably help prevent retinal vien occlusions. Red meat  (including pork/ham) increase blood pressure; they are best replaced, at least in part, by fish, and pulses such as lentils and beans. Nuts have some healthy fats, and may be helpful in small amounts...but they are 'fattening' and help to put weight on.
• 9 portions of vegetables or fruit a day will also help to keep your retinal veins and macula healthy, and prevent cataract formation...9 a day (men) 7 (women) keeps the doctor away...
• A high saturated fat diet is very harmful as it will contribute to many conditions. A balanced diet is recommended. Saturated fat comes from full-fat diary products such as milk, cheese, many cakes and biscuits, and red meat.
• binge drinking, e.g. 4 pints of beer in one day, or more that 3 glasses of wine/day, will cause a rise in blood pressure, again contributing to all these conditions.
• Obesity results in high blood pressure, lack of exercise, and indirectly will cause problems. Many obese patients suffer from sleep apnoea....
• Sleep problems. New research links sleep apneoa with glaucoma. Sleep problems are very common in obesity...these are likely if you snore a lot. Logically if you are overweight, it is important to lose weight to help your glaucoma. So if you do snore a lot, do lose weight, and ask your doctor if you need to be tested for sleep apnoea.
• Steroid medication puts eye pressure up. Even inhaled nasal steroids can increase the pressure 2.5mmHg. If you use nasal steroids (eg for allregic rhinitis), ask your doctor if you reduce or stop them. Steroid tablets certainly may put eye pressure up; ask your doctor if you can reduce the dose (Do not reduce steroid tablets without seeking advice.).

To detect glaucoma in the very early stages, you need three tests at your optometrists each year:

• eye pressure measurement
• examination of the nerve at the back
• visual field test (a test of your side vision)

You should look after your general health, and your brothers and sisters should be also be tested by their optometrist.

See the evidence: eyes with a central corneal thickness of 555 microns or less have a 3 times increase in risk of progressing compared to eye with a a thickness of 588 or more.

A  Microsoft Publisher document,