Glaucoma is a serious eye disease caused by increased fluid pressure within the eye, which can damage the optic nerve that transmits images to the brain. One of the leading causes of irreversible blindness, the estimated number of cases of glaucoma in India is 12 million. This is around one fifth of global burden of glaucoma.Glaucoma is known as the “silent thief of sight” as it is a symptomless disease, and people usually do not realize that they are suffering from glaucoma unless they visit the ophthalmologist or have reached an advanced stage of disease. If undiagnosed and untreated, glaucoma can lead to irreversible loss of vision and even cause blindness. Though the disease is not curable, the progress of glaucoma can be halted and total blindness can be prevented if it is detected early.
In glaucoma the fluid pressure inside the eye increases, and this leads to progressive damage of the optic nerve, resulting in a gradual loss of vision. Initially, the loss of vision starts from periphery and progressively affects the central vision. The central visual acuity is affected only in the advanced stage. The front half of the eye is filled with a clear fluid known as the “aqueous humor”. This fluid is continuously produced and constantly flows in and out of the eye, maintaining a steady pressure inside the eye. If there is either reduced drainage or excessive production of this fluid, the pressure in the eye will increase. This increased eye pressure, if left untreated, can damage the eye (optic) nerve and cause permanent vision loss. Not everyone with high eye pressure will develop glaucoma, and some people with normal eye pressures may also develop glaucoma. The disease usually affects both eyes, though one may be more severely affected than the other. Unfortunately, the damage to the eye nerve due to glaucoma is irreversible and the loss of vision cannot be reversed. However, this condition can be halted and the remaining vision can be retained if glaucoma is diagnosed on time and appropriate treatment is started.
The different types of glaucoma include:
Primary open angle glaucoma –is the most common type of glaucoma. In this type of glaucoma, the part of the eye through which the fluid of the eye flows out is open, permitting the outflow of fluid, but the patient still has high pressure. This type of glaucoma develops slowly without any symptoms. Initially it affects the peripheral or side vision and very gradually progresses to the centre. This is the reason why many people are not aware that they have the condition until they have significant vision loss affecting central vision.
Risk factors for primary open angle glaucoma are:
Angle closure glaucoma or closed angle glaucoma –is a less common type of glaucoma which occurs due to narrow drainage channels in the eye. Gradual closing of the angle is called chronic angle closure and if the drainage angle closes suddenly, it causes an acute angle closure attack. Acute angle closure glaucoma usually presents as an emergency. A patient who is in an acute angle closure attack will have symptoms of eye pain, nausea, vomiting, redness and blurred vision due to a rapid increase in the eye pressure. In such cases the patient needs immediate treatment by an eye specialist.
Risk factors for angle closure glaucoma:
Normal tension glaucoma /Low tension glaucoma –In this type of glaucoma the optic nerve can get affected even though the pressure in the eye is normal. Although its cause is not entirely known or understood, normal tension glaucoma is believed to occur either because of an extremely fragile optic nerve that can get damaged even though the pressure in the eye is normal, or because of reduced blood flow to the optic nerve. Because of its silent nature, people usually do not have any visual complaints until a very advanced stage of the disease.
Risk factors for normal tension glaucoma are:
Secondary glaucoma –There are certain other types of glaucoma where there is an identifiable cause for increased eye pressure resulting in optic nerve damage and vision loss. These are called secondary glaucoma. It may be caused by prolonged, indiscriminate use of steroids, severe diabetic retinopathy, injuries to the eye, inflammation of the eye (uveitis) or advanced cases of cataract. If you believe you have any of these risk factors get an eye examination done. Always remember to inform your eye doctor about the risk factors that you have. This will help your doctor decide how often you need to get your eyes examined.
Primary open-angle glaucoma, which is the most common type of glaucoma, is hereditary. If members of your immediate family such as a parent or sibling have glaucoma, you are four to nine times more likely to develop this disease than the rest of the general population.
Be informed about your family’s medical history and understand the hereditary risks of glaucoma. Speak to your doctor if you have a family member with glaucoma, it may save your sight. Be vigilant about eye check-ups and alert to possible glaucoma symptoms. Since early symptoms or pain may not show up in people with glaucoma, this disease is often diagnosed at a later stage when visual loss has already happened. If you’re over the age of 40 and have a family history of glaucoma, you should get a comprehensive eye exam, which includes dilated eye exams and eye pressure checks every year, even if your vision is healthy. Without treatment, glaucoma can cause total permanent blindness within a few years. As this damage is irreversible, loss of vision due to glaucoma cannot be regained. However, if detected early, vision loss can be avoided, or delayed with the use of eye drops, laser treatment or surgery. Even a small reduction in pressure can make a big difference in slowing vision loss.
The following tests help in finding out the presence of glaucoma and also its progression in the subsequent follow-ups.
Tonometryis a diagnostic test that measures the fluid pressure, known as intraocular pressure (IOP), inside your eye. The tonometry test is important as it can help your doctor evaluate whether or not you may be at risk of glaucoma.
Gonioscopyis a painless eye examination of the front portion of your eye (anterior chamber), to examine whether the area where fluid drains out of your eye (drainage angle) is open or closed. This test is important as it helps your doctor to diagnose and monitor various eye conditions associated with glaucoma.
The Visual Field testis a method of measuring your peripheral or side vision (which is affected first by glaucoma), through which your doctor can diagnose and monitor glaucoma. The data from the test is used to determine the severity of your glaucoma, level of vision loss, damage to the visual pathways of the brain, and other optic nerve diseases.
In today’s world, people are quite aware about how lifestyle choices affect our overall health, and the same goes for glaucoma. Lifestyle choices can, to some extent, influence eye pressure and affect the risk of developing glaucoma, but there aren’t enough proven studies about the same in glaucoma patients. However, a shift towards a healthier lifestyle makes for an overall positive change
Exercise –Research indicates that regular exercise and an active lifestyle can help reduce their risk of glaucoma. Activities which raise your pulse by 20 to 25, like walking briskly, can help reduce IOP. The more number of steps a person walks throughout the day, less likelihood of an increase in IOP. Aerobics is known to cause a temporary decrease in the intraocular pressure but it has not been tested in glaucoma patients. Swimming reduces vulnerability of the optic nerve to an increase in the intraocular pressure.
Diet –Various studies have been undertaken to study the role of diet in glaucoma. A diet rich in green leafy vegetables is supposed to lower the eye pressure. Dietary nitrates in green leafy vegetables lowers risk of developing open angle glaucoma. DHA (docosahexanoeic acid) is an omega- 3 fatty acid and it is helpful in preserving a healthy retina and lowering the IOP. Rich sources of DHA such as salmon, shellfish, tuna should be consumed twice or thrice a week. If its natural addition to the diet is not possible, DHA supplements in the form of fish oil supplements can be taken. A diet rich in lutein and zeaxanthin helps in lowering intraocular pressure. It avoids oxidative damage to the optic nerve. Spinach, broccoli and sprouts are rich sources of lutein and zeaxanthin. Antioxidants provide nutrients and strengthen the muscles and nerves in the eye. Rich sources of antioxidants are blueberries, grapeseed extract, goji berries, pecan nuts and cranberries.
Exercise – Lifting of heavy weights is known to cause a temporary increase in the intraocular pressure. Hence, patients who already suffer from glaucoma are advised to avoid lifting very heavy weights. Yoga, which is a very popular form of exercise includes various ‘asanas’ or positions. Some of these asanas, particularly those with the head – down position (sheershasana) have been proven to cause an increase in the eye pressure. Therefore, patients with glaucoma are advised to avoid such positions.
Diet –Foods which are rich in trans-fats, the kind found in deep fried food, prevent the optimal functioning of omega 3- fatty acids and increases eye pressure. Such food should be avoided.
Habit forming substances –such as caffeine, alcohol, tobacco and marijuana are known to have a negative effect on eye pressure. Caffeine, which is consumed widely, is known to cause a temporary increase in the eye pressure. Consumption of caffeine in small quantities is alright, but an excessive intake of caffeine is has been proven to increase the risk of glaucoma. Alcohol is known to decrease the eye pressure for a short duration but a daily consumption of alcohol is supposed to increase the risk of glaucoma. Smoking cigarettes is known to increase the risk of glaucoma. Though marijuana is known to lower eye pressure, it is not recommended for treatment due to its side effects.
Musical instruments –such as the trumpet and the saxophone are known to cause an increase in the eye pressure. Glaucoma patients are advised to avoid playing such high resistance wind instruments which can increase the intraocular pressure.
Glaucoma affects the quality of life of millions of people. In the early stage of glaucoma, patients experience compromised vision which affects their quality of life. This worsens as the disease progresses. Ocular discomfort, psychological factors, economic factors, and social constraints contribute to the burden of the disease.
A better understanding of your treatment and medications can make it easier to live with glaucoma and easier for your doctor to control your disease. Early diagnosis, and therefore early intervention, is crucial in delaying the progression of the disease process.
If you have undergone any surgery or laser treatment for glaucoma, it is important to understand that these procedures are performed to reduce the intra-ocular pressure and are an attempt to restore the remaining vision.
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