Experts urge regular eyesight tests to fight glaucoma

As hundreds of people could unknowingly be suffering from a disease that is slowly blinding them, an appeal was launched yesterday for regular eyesight tests.

Last year about 500 Maltese were diagnosed with glaucoma, the second most common cause of blindness that affects about 60 million people worldwide.

The number of diagnosed cases in Malta rose from 250-odd in 2003. Between 130 and 150 patients were diagnosed with borderline glaucoma every year between 2003 and last year. Glaucoma is a group of eye diseases that cause progressive damage of the optic nerve.

World Health Organisation data indicates that an estimated 4.5 million people around the world lost their sight to glaucoma, with this number expected to increase to 11.2 million by 2020.

During a press conference to mark the first World Glaucoma Day celebrated on Thursday, eye experts yesterday encouraged regular screening in a bid to catch the disease as early as possible.

Jan Janula, consultant at the Department of Ophthalmology, said that although the disease is potentially blinding it can normally be treated if caught early enough.

Screening is all the more important for those suffering from diabetes or circulatory problems, apart from those with a family history of glaucoma, who might have a predisposition for the disease, principal orthoptist Martin Francalanza said.

Dr Francalanza said a pilot study carried out about 20 years ago concluded that three per cent of over 40-year-olds suffered from glaucoma, with most not even knowing about it.

He pointed out that nurses working at government health centres have been trained in using equipment to screen for glaucoma. He stressed the importance of increasing and modernising equipment.

People over 40 years should start getting screened for glaucoma. As yet there is not cure for glaucoma and vision loss is irreversible, making early detection essential in limiting visual impairment and halting the progression of sight loss.

The World Glaucoma Association, together with the World Glaucoma Patient Association, declared March 6 as the first World Glaucoma Day. In Malta, a number of events were held to mark the event. These included a screening session during an open day at the new Mellieħa home for the elderly last Sunday and dissemination of information to outpatients at Mater Dei Hospital.

Narrow angle glaucoma and acute angle closure glaucoma

With the exclusion of injuries, acute angle closure glaucoma remains the number one medical eye emergency problem. Within a few hours of its onset, one may experience profound eye pain, nausea, and severe vision loss. If allowed to go untreated, extensive permanent vision damage may occur. In many situations, the condition is preventable simply by having regular examinations by your ophthalmologist who is trained to recognise those at risk.

The condition called narrow angle glaucoma exists when the aqueous fluid inside the eye is restricted from getting into the internal drain. This drain, known as the trabecular meshwork, lies at the outer periphery of the iris (the "coloured part" of the eye) where it meets the sclera (the "white" of the eye). At the junction of these structures is a recess called the anterior chamber angle.

The degree to which the trabecular meshwork is available is determined by how wide or narrow the recess is... in other words, how open the angle is. For the mathematically inclined, a very wide angle may be 40 or 45 degrees. A narrow angle may be less than 15 degrees.

As long as the angle is open, even if only a slit, the aqueous can get to the drain. A shallow but still open angle will pose a threat if it closes off completely since there is no longer any way the aqueous can drain out. The intraocular pressure can rise to levels well over 50 in just a few hours. This is dangerous and can lead to permanent vision loss.

During their eye examinations, eye experts evaluate the depth of the chamber angle of the eye. Most people have open angles that do not pose a problem. Those who have short eyes, usually fairly far-sighted, often have shallow angles. The natural aging process causes all angles to shallow. If you have a wide open angle early in life, it is not likely to ever be a problem. If you have a mildly shallow angle in your middle-age years, you might have trouble later in life. Narrow angle glaucoma is less common than the typical open angle variety. Some patients with narrow angles have very mild short-lived attacks during which the angle, or drain, closes off completely. This results in a spike in the intraocular pressure which frequently causes pain usually described as a headache around the eyebrow area. If the closed angle spontaneously opens a bit, the fluid drains out, the pressure drops, and the headache goes away.

Repeated attacks can result in mild degrees of damage with each episode. These are cumulative. Ultimately, by the time you are aware of vision problems, there is typically extensive damage.

If the attack does not spontaneously break, the drain stays closed, and the pressure continues to rise. This causes fluid to accumulate into the normally clear cornea, giving it the likeness of frosted glass rather than clear glass. The blood vessels in the eye become congested, and there often is intense pain which can cause nausea and vomiting. This attack of acute angle closure glaucoma requires prompt attention.

Eye drops and systemic medications usually can cause the attack to break with the resulting lower pressure and symptom relief. However, there may be damage to the drain caused by the attack itself. Treatment is aimed at keeping this from happening again.

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