Detect glaucoma early
There is no cure for glaucoma, the second most common cause of blindness in the world. The objective of treatment, therefore, is to preserve visual function, which makes it imperative to detect the disease at the earliest.
The effect of glaucoma on visual fields Patient with normal visual field.
GLAUCOMA is a condition of the eye in which the optic nerve is damaged. In many cases, this damage is associated with a rise in pressure within the eye. A clear fluid called aqueous humor produced inside the eye has to flow out of the eye through the angle. When a block to the outflow of aqueous humor occurs, the pressure inside the eye increases. The sustained increase in the pressure causes glaucoma.
Glaucoma is the second most common cause of blindness in the world after cataract. There are 7.5 million people who are visually handicapped due to glaucoma.
There are two types of primary glaucoma open angle glaucoma and angle closure glaucoma. The first is associated with a gradual and painless loss of visual fields. The most frequent symptoms include i) frequent changing of glasses. ii) gradual loss of vision without the patient being aware of it till the end stage.
The patient gradually starts losing his/her field of vision.
Angle closure glaucoma is a condition in which the angles (draining system of the eye) are closed and is usually associated with a sudden increase in intraocular pressure accompanied by severe pain, headache and vomiting. This condition is an emergency and needs to be treated immediately.
Normal tension glaucoma is a condition in which there is a damage to the optic nerve inspite of the patient having normal intraocular pressure (10-21mm Hg). The patient's field of vision deteriorates over a period of time if the condition is not detected. Creeping angle closure glaucoma is a condition which mimics the field changes of open angle glaucoma but the patient has narrow angles.
Who needs evaluation?
People at risk include those above 45 years; persons who have family history of: glaucoma; diabetes, patients with pain, watering and redness of the eye, and people with high refractive errors.
RAJAN EYE CARE HOSPITAL, CHENNAI
Patient with visual defects in the periphery (moderate glaucoma).
Screening the general population for glaucoma is neither cost effective nor logistically feasible. It is more effective to target those at high risk for the disease. The following are advised to seek complete examination from their ophthalmologist.
All patients over the age of 35 years. The risk for glaucoma increases with age.
People with a family history of the disease.
Those who are using steroid drops, tablets or ointment for any disease.
Those wearing glasses for short sight/myopia.
Anyone who complains of pain, redness and watering from the eyes.
Anyone who complains of seeing coloured rings around lights.
In fact, all patients seen by an ophthalmologist for whatever reason should have this comprehensive examination. This also helps to detect other "curable" eye diseases like cataract, disease of the retina, and retinal detachment.
Glaucoma can be managed medically, by laser or surgically.
RAJAN EYE CARE HOSPITAL, CHENNAI
Finally, patient with advanced defects (tunnel vision).
It is important to realise that there is no cure for glaucoma. Once the nerve fibres die and visual function is lost, it cannot be recovered. The objective of treatment is to preserve visual function, and this is certainly possible. It is, therefore, all the more imperative to detect the disease at its earliest stage.
The only proven way to preserve visual function at the moment is to lower eye pressure to a level compatible with the health of the patient's optic nerve. The management of glaucoma must be individualised.
Medical treatment of open angle glaucoma includes eye drops, systemic medications (tablets/injection). The new generation of eye drops do not affect the papillary size (thereby hampering disc evaluation). The only disadvantage is their relative high pricing. These drugs help to achieve good intraocular pressure control with decreased frequency of application, thereby increasing a patient's compliance for medication.
Laser Nd YAG Laser Iridotomy is done for angle closure glaucoma. This is an out-patient procedure requiring just a few minutes of laser treatment to the iris. This procedure can be done prophylatically for asymptomatic narrow angle glaucoma patients.
It is done for open angle or angle closure glaucoma, when the pressures are not adequately controlled with medication, under local anaesthesia. Surgical procedures include Trabeculectomy, Trabeculectomy with mitomycin-C/ 5-Fluorouracil.
Newer surgical techniques include Viscocanalostomy, Excimer Laser Trabaculectomy and deep sclerectomy.
Recent advances in detection
The Heidelberg Retina Tomograph (HRT) is a confocal laser scanning microscope for acquisition and analysis of three-dimensional images of the posterior segment. It enables the quantitative assessment of retinal topography and a follow-up of topographic changes. Its most important clinical routine application is in the topographic description and follow-up of the glaucomatous optic nerve head.
The GDx Glaucoma Scanning System is the new clinical model of the Nerve Fibre Analyser.
Optical coherence tomography (OCT) is an imaging technique that produces high resolution cross-sectional images of optical reflectivity.
Annual eye examination is a must for all persons above the age of 40 years and also persons who are at risk for glaucoma.
Do not treat red eye yourself, you may be suffering from angle closure glaucoma.
Finally, don't neglect your eye examinations.
A patient with glaucoma (or someone suspected to have diagnosed to glaucoma) needs life-long monitoring. The frequency of such a follow-up depends on the individual.
Dr. VIJAYALAKSHMI P.
Dr. S. SANJAY
Dr. SUJATHA MOHAN
Dr. MOHAN RAJAN
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