Saturday, June 15, 2024

Glaucoma “the silent thief of sight”


What is glaucoma?
Glaucoma is one of the leading causes of blindness in the world. It is a serious disease that affects all types of races, all age groups, all economic levels, both genders, urban and rural populations alike with no discrimination!
The term glaucoma consists of a group of diseases that cause damage to the nerve responsible for our sight (optic nerve). Any damage to the nerve will result in visual deterioration or even blindness!
Is it a serious disease?
Yes it is! If we consider blindness as a serious disability!
There are different types of glaucoma. But they can be grouped in to two main classes. The most common is called open angle glaucoma which is responsible for the majority (90%) of the cases. The second one is known as angle closure glaucoma (much less common) which is caused by blockage of the filtration angle through which aqueous humor drains out of the eye.
The problem of open angle glaucoma is that it does not cause any symptoms like pain or visual disturbance in the early stages until very late in the course of the disease.Because of this insidious progression of the disease, it is called the silent thief of sight. It is common for eye doctors to face patients with advanced stages of the disease. Some may even be totally blind with no hope of visual recovery.
So what can we do to safeguard our sight?
We need to have a regular eye and general medical check-up at least once a year. Regular eye examinations are the key factor that helps us avoid untimely blindness. A general medical examination will help us catch even a deadly disease like cancer at an early stage and the chance of total cure will be very high.
The problem is we haven’t developed the culture of having medical checkups at all. We don’t want to think about the possibility of harboring some health problem creeping in our body. We don’t go to a health facility unless we fall sick. In short, we take health for granted. This may be because of the fact that our population is not well informed about health issues. How about the rest of us with some form of information? Are we any better? The issue of timely medical
checkup is of grave concern even in the western world as well. It is said that, in developed countries, 50% of patients with glaucoma haven’t been diagnosed and are not on treatment.
What are the risk factors for developing glaucoma?
Glaucoma is mainly associated with an increased intra ocular pressure. The normal eye pressure is less than 21 mm Hg. If it is more than that, the patient has to be monitored to rule out glaucoma. Intra ocular pressure is maintained at a normal level when the fluid produced in the anterior part of the interior of the eye (called aqueous humor) is secreted and then removed from the eye in a balanced way. If the secretion of aqueous humor continues in the absence of a proportional exit from the eye,it will lead to a build-upof pressure. This high intra ocular pressure damages retinal nerve fibers and the optic nerve leading to nerve fiber loss and optic atrophy.
People in their old age are at higher risk of developing glaucoma. Any person over the age 40 years has to get determination of the intra ocular pressure at least once in year.
The other important risk factor for optic nerve damage is the presence of hypertension (high blood pressure). All patients with hypertension mustundergo strict follow up and take their treatment regularly as directed by their doctors. Not only that, they have to have annual eye examination to rule out the presence of retinal problems and glaucoma.
Glaucoma is known to run among family members(heredity). If there is glaucoma in your family, you will have a much higher risk of developing it. It is, therefore, advisable for family members to have regular eye check-ups at least twice a year.
The other risk factor for glaucoma is the presence of diabetes mellitus(poorly controlled blood sugar level). Such patients need thorough eye examinations on a regular basis. The attending eye doctor will determine if there are any problems in the retina associated with diabetes and also the presence of glaucoma.
People usingsteroid medications frequently or for a prolonged period may develop glaucoma. Topical steroids (eye drops) are prescribed for conditions like allergic eye problems. Other steroid ointments applied to the eye lid skin or anywhere on the body may be absorbed and cause elevated intra ocular pressure. Similarly, steroids taken orally or as inhalants or by injections are known to elevate intra ocular pressure. This type of drug-related glaucoma is known as steroid-induced glaucoma.The risk of glaucoma development increases with the dose of the medication and the duration of use. These drugs in their various forms are commonly misused as they are obtained from pharmacies and drug stores very easily.
How do we know that we have glaucoma?
We have seen that the majority of glaucoma casesare asymptomatic (no presenting feature) until late in the course of the disease. Only people with regular eye follow-up will know about their problem early and can prevent visual loss.
In the case of angle closure glaucoma, the filtration angle is narrow and makes drainage very slow leading toan increase in intra ocular pressure. When these people sit in the dark (cinema or theater halls), their eyes dilate to enable them see better. The dilatation causes further narrowing or blockage of the passage of aqueous humor leadingto a sudden increase in intra ocular pressure. This causes acute eye pain, blurring of vision,appearance of colored haloes around lights, tearing and headache. There may even be nausea and vomiting. This type of glaucoma is “good” in the sense that it causes acute pain and patients will seek medical help as soon as possible. Treatment will be instituted and the glaucoma will be controlled with medications, laser or surgery and visual loss will be prevented!
Glaucoma does occur in babies and small children as a result of developmental abnormality in the anterior aspect of the eye(congenital glaucoma). These children will develop hazy corneas (central part of the eye), with tearing and fear of light. The child is uncomfortable in the presence of bright light. The glaucoma will progress causing enlargement of the corneas. Parents must take such children to an eye doctor for immediate evaluation and treatment. Otherwise permanent visual loss will follow.
Glaucoma can also be caused by trauma, following eye surgery and inflammation of the front part of the interior of the eye (anterior uveitis), etc…
Basic Eye Examinations for glaucoma cases
These will include:
Visual acuity assessment.
Intra ocular pressure measurement with instruments called tonometers.
Examination of the front of the eye especially the drainage angle (gonioscopy). This will helpdetermine the state of the drainage angle whether it is narrow or open.
Examination of the interior of the eye after dilation of the pupillary aperture.
Visual field assessment. There are other more sophisticated diagnostic modalities.
How is glaucoma treated?
This is mainly done in the form of different types of eye drops and tablets.
Laser treatment may be done to open the aqueous humor drainage channels
Surgery that will create a new draining channel to help the out flow of aqueous humor
There are different types of eye drops for the treatment of glaucoma. Your eye doctor will determine the type and dosage of the drug. Some drugs may cause some eye discomfort. When this occurs, tell your doctor about your problem and the eye drop will be replaced by another one. It has to be noted that glaucoma treatment should continue for life. Many patients forget or stop using their medications after a few months. Some may have economic problems. In such cases, surgical management is a better alternative.
In general, it is advised to work closely together with your eye doctor to prevent blindness from glaucoma. Healthy life style with regular exercise, eating a healthy diet, avoiding smoking, and maintaining a healthy weight are also important factors that help reduce the risk of glaucoma.

Negussie Zerihun, M.D.,D.C.E.H.,M.P.H
Consultant Ophthalmologist
Aroma Specialised Eye Clinic and Optical Center

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