Glaucoma is an eye disease characterized by increase in eye pressure (intraocular pressure) above normal range, resulting in damage of the optic nerve, which can be detected by visual field examination.

The main feature in glaucoma is intraocular pressure (IOP). Figure being considered as within the normal range of IOP is 21mmHg. This eye pressure is different from blood pressure, which is around 100mmHg. When IOP increased above 21mmHg, the blood circulation at optic nerve head is affected and this causes damage to the optic nerve fiber, which make up the optic nerve head.

There are two main types of glaucoma:

• Open Angle Glaucoma
• Close Angle Glaucoma.

Open Angle Glaucoma (CSG)

This is a chronic type of glaucoma, also called, Chronic Simple Glaucoma (CSG). The danger of this glaucoma is the slowness in blurring your vision. Over the years of progressive loss of vision, it does not affect your usual visual routine, until you are almost blind or you have already blind in one eye and one fine day you accidentally cover the good eye or less affected eye to find out that the affected bad eye already blind. This slowness in loss of vision due to open angle glaucoma causes the affected patient to procrastinate in attending to this condition, as there is no urgency. What is worse, they may even think it is due to cataract, because both conditions fall into the same age category.

Close Angle Glaucoma

This is an acute type of glaucoma. The anterior chamber angle between the edge of cornea and root of iris is usually closed during the acute attack, which cause severe pain in the eye, with blurring and colour halo around street lights, as well as headache, associated with nausea and or vomiting! Usually in this situation, patient will quickly seek eye specialist attention and get immediate treatment to prevent blindness. In normal situation, there is always a delay from one day to few days. Therefore, by the time the eye specialist treats the acute glaucoma, there is already damage to the optic nerve head. The delay in treatment is due to the awe hours the acute glaucoma happens. In addition, the patient may not suspect it is acute glaucoma initially, thinking that it may be migraine or food poisoning.

Other types of Glaucoma

Apart from the 2 main types of glaucoma, they are many other types, which are less common eg. Diabetes type of glaucoma (Rubeotic Glaucoma), glaucoma due to hypermature cataract (Secondary Glaucoma), glaucoma due to vascular occlusion (Rubeotic Glaucoma), glaucoma due to uveitis (Secondary Glaucoma), steroid induced glaucoma, traumatic glaucoma, congenital glaucoma, etc.

Treatment

Eyedrops: Currently, there are at least 7 types of eyedrops for treating glaucoma. For early glaucoma, one or two eyedrops of a combination of different mode of action will be sufficient to control intraocular pressure. If the glaucoma increases progressively in severity, then more than two eyedrops should be used. Under such situation, glaucoma operation (Trabeculectomy) should be considered even if the IOP is under control.

Operation: Trabeculectomy (drainage operation) is effective way of treating severe glaucoma. This may be repeated if necessary. Cyclocryotherapy (freezing operation) may be necessary in rubeotic glaucoma.

Glaucoma Screening

As glaucoma usually run in a family, family members of glaucoma patient should go to eye clinic for glaucoma screening, especially for those who are forty of age and above.

Glaucoma become progressively serious, as the patient grows older. All those patients who are forty or more years of age, should come for screening at least once in a lifetime if there is no family history of glaucoma.

Experience and hearsay

There is a hearsay that glaucoma cannot be treated and will eventually cause BLINDNESS! This hearsay has been proven wrong in Dr Lim experience in two cases of severe glaucoma, one lady and one gentleman both in their eighties. One patient consulted and treated by Dr Lim since 1987 and another since 1988 for over 20 years. Initially, both of them had one eye blind due to glaucoma and the fellow eye had severe glaucoma and vision was affected. After 20 years of treatment, although they are in their eighties, they can move around and come to Dr Lim clinic unaided!

Prevention of Acute Glaucoma

Laser Peripheral Iridectomy: Those patients with very shallow anterior chamber angle can be prevented from acute attack by a laser procedure called Peripheral Iridectomy. This procedure will prevent the anterior chamber angle (between edge of cornea and root of iris) from closure and therefore avoid the occurrence of acute glaucoma.

Prevention of Other Types of Glaucoma

Removal of Primary Cause: Adequate Argon Laser Photocoagulation in diabetes patient with retinopathy or vascular occlusion will prevent rubeotic glaucoma.

Early removal of cataract before maturity will prevent glaucoma from hypermature cataract.

Steroid eyedrops or medication should not be used in patient with steroid induced glaucoma.

FAQ

1. Is it true that glaucoma CANNOT be treated?

Not TRUE! Glaucoma can be treated at any stage, except when the eyesight is totally damaged by glaucoma, medically it is called Absolute Glaucoma. At this end stage, there is no point in treating the glaucoma because the blindness caused by glaucoma is irreversible.

2. If glaucoma can be treated, WHY THEN, there is still blindness as a result of glaucoma even the patient is under the care of eye specialist?

There is no simple answer to this question! However, we would look into this matter in more details. Glaucoma is a chronic disease, to be more specific, glaucoma is a life long disease, like high blood pressure and diabetes, it will stay with you for the rest of your life. Glaucoma patient has to be very, very patient and follow eye specialist advice closely. In any case, if there is any doubt, please obtain second opinion. In addition, glaucoma always worsens with age. Therefore, the glaucoma treatment has to be modified from time to time to achieve adequate and efficient control of the intraocular pressure.

This is complicated by two more factors: Firstly, there are many types of glaucoma, some are easily controlled depending on which stage the glaucoma is, and some are inherently difficult to treat and usually result in total blindness in majority of the cases eg. Rubeotic Glaucoma. Secondly, many a time, patient remembers to instill eyedrops only when it is time for follow-up with eye specialist. Therefore, the glaucoma seems to be under control during the short period when the patient consults doctor. But the glaucoma is actually not under control during the period between doctor consultation because the patient forget to instill eyedrops. With the second type of scenario, the chances is that the patient vision will deteriorate and may lead to blindness even under the care of eye specialist. Operation will then be a better option.

3. When glaucoma has already caused total blindness, is there any further eye complication?

Usually not. But in some cases of absolute glaucoma, it causes severe pain in the eye or severe headache due to the high eye pressure. It may also cause irritation or watery, red eye due to irregular corneal surface (bullous keratopathy) or corneal surface erosion or calcium deposit on cornea surface. All this complications can be treated accordingly.