(MENAFN- Gulf Times) World Sight Day is held each year on the second Thursday in October. The day is observed globally by those involved in preventing visual impairment or restoring sight. This year's main focus is 'eye care for all'.
Avoidable blindness is defined as blindness which can be either treated or prevented by known, cost-effective means. There are many different conditions that can affect the eye. Some are minor and resolve by themselves quickly, such as viral conjunctivitis, but others could be serious and lead to serious visual impairment, such as glaucoma.
Glaucoma is a group of diseases that damage the optic nerve (main nerve of the eye which send visual signals to the brain), and can result in vision loss and irreversible blindness. Unlike cataract (cloudiness of the lens), glaucoma cannot be cured but can only be treated to prevent serious vision loss and complete blindness.
Glaucoma is one of the leading causes of blindness among the elderly population, affects about 65mn people in the world.
Risk factors causing glaucoma
1) Increased eye pressure (intra ocular pressure): This is the most common cause for glaucoma. Normal range of eye pressure is 10-20 mm of Hg; increase in the eye pressure affects the normal function of the optic nerve (the main nerve of the eye) causes irreparable damage over a period of time.
2) Age: Glaucoma is more common in older individuals, usually above 40 years, though it is seen in small children also (congenital glaucoma).
3) Race: It's more common in blacks than whites.
4) Family history: First degree relatives of glaucoma patients have four times risk than the normal population.
5) Diabetes: Diabetics have more risk to develop glaucoma.
6) Myopia: Short-sighted people have extra risk to cause open angle glaucoma, whereas hypermetropia (far sightedness) has extra risk to develop narrow angle glaucoma (another type of glaucoma where the patient gets sudden increase in pressure)
7) Vascular diseases like hypertension, cardiovascular diseases and migraine have extra risk.
8) Potent steroid eye drops: A few percentages of people (steroid responders) can develop glaucoma after its usage for a long period.
Why glaucoma screening is so important?
Glaucoma is known as a silent killer of the eye as the patient loses vision over a period of time without his knowledge; the diagnosis is made with special tests by an ophthalmologist
Normal pressure glaucoma: Usually glaucoma damages the optic nerve due to increased eye pressure, but in 15 to 20% of the cases, the eye pressure will be normal, this is called normal pressure glaucoma or low tension glaucoma. This is even more difficult to treat.
Open angle and narrow angle glaucoma: There are mainly two types of glaucoma, the open angle and the narrow angle, depending on the anatomy of the eye. Open angle type damages the nerve very slowly without any warnings, the narrow angle type presents with pain, redness and headache and the patient may lose his vision within hours.
What happens in glaucoma?
Due to various reasons, usually due to increased eye pressure, slow cell death occurs in the main nerve of the eye (optic nerve) which consists of millions of nerve fibres, patient first loses the peripheral field of vision, so the patient is not aware of his problem until he loses his central vision also. Usually he experiences a tunnel like vision before he becomes totally blind. It will be difficult and risky for the patient to drive since he will miss the vehicles entering from the sides.
How the glaucoma can be detected very early?
Anyone above the age of 40 should undergo glaucoma screening once in a year. There are both basic screening and advanced tests to detect glaucoma. These include:
1. Measuring intraocular pressure by Tonometry.
2. Slit Lamp Examination to assess the changes of the optic nerve.
3. Pachymetry to measure the central thickness of the cornea.
4. Gonioscopy to visualise the angle of the anterior chamber of the eye to know if it is open or narrow.
5. Visual field examination by Perimetry.
6. OCT Scan of the eye (Optical Coherence Tomography). This can diagnose glaucoma in the early stage itself and is done in doubtful cases.
Treatment: Is usually by application of eye drops to reduce the eye pressure, those who do not get benefit and if there is progression of the field defect will need surgery. Sometimes laser procedure also tried before surgery.
Acute congestive glaucoma: This is an ocular emergency. Unlike the open angle glaucoma which is mentioned in the beginning, patient develops severe eye pain, redness and head ache and sometimes vomiting. In this type of glaucoma, patient should get immediate medical attention.
Congenital glaucomas: These glaucomas are seen in very young children, the causes and management differs from the adult type.
Points to remember
It's very important to have annual glaucoma screening for everyone above the age of 40.
Diabetic patients and those who got family history of glaucoma have extra risk to get glaucoma. Early diagnosis is very important as the treatment helps only to prevent further damage.
Treatment includes both medical and surgical, medical treatment is by eye drops, if not effective by eye drops, surgery is done to bring the eye pressure to the desired level.
Sometimes laser procedures are done before doing surgery.
Legal Disclaimer:
MENAFN provides the information “as is” without warranty of any kind. We do not accept any responsibility or liability for the accuracy, content, images, videos, licenses, completeness, legality, or reliability of the information contained in this article. If you have any complaints or copyright issues related to this article, kindly contact the provider above.