Overview of glaucoma
Glaucoma is a major cause of vision loss throughout the world.1 It includes a group of diseases, which occur when the normal fluid pressure inside the eyes slowly rises, damaging the eye’s optic nerve, ultimately resulting in vision loss and blindness. While glaucoma can affect anyone, the risk is much greater for people over 60 years.2,3
Glaucoma, known commonly as the ‘silent thief of sight,’ makes 1.2 lakh Indians blind annually. Yet, over 74% Indians don’t know what glaucoma is and over 72% have never undergone an eye pressure test or tonometry that determines fluid pressure inside the eye. It is estimated that between 2010 and 2020, India will be the world’s glaucoma capital. Only 10% of people with glaucoma have been diagnosed in India compared to 50% in Europe.4
Clinical Presentation (Symptoms of glaucoma)
The signs and symptoms depend on the type of glaucoma:
- Primary open-angle glaucoma
- Acute angle-closure glaucoma
Primary Open-Angle Glaucoma
This condition progresses with few or no symptoms until the condition reaches an advanced stage. The increased eye pressure continues to damage the optic nerve, leading to more and more loss of the peripheral vision. If not treated, one can develop tunnel vision and ultimately go blind. This type of glaucoma usually affects both eyes, although vision loss occurs in only one eye.
Acute Angle-Closure Glaucoma
This condition develops suddenly in response to a rapid rise in eye pressure. It is a medical emergency since permanent vision loss can occur within a day of the attack.
The signs and symptoms of this type of glaucoma include:
Risk factors for glaucoma
Risk factors are ocular and non ocular
- Increased intraocular pressure
- Central corneal thickness
- Optic nerve structure
- Disc hemorrhage
- Other ocular disorders
- Family history/genetic predisposition
- Vascular disease (hypotension and vasospasm)
Diagnosis of glaucoma
The following tests are done to diagnose glaucoma.3
1.Visual acuity test: This eye chart test measures how well one can see at various distances.
2.Visual field test: This test measures the peripheral vision. This helps to find out if there is a loss of the peripheral vision, which is a sign of glaucoma.
3.Dilated eye exam: The pupils are dilated, by administering specific eye drops and then the retina and optic nerve are examined using a special instrument, to check for any damage.
4.Tonometry: This is a procedure where the pressure inside the eye is measured. Anesthetic drops may be applied to the eye for this test.
5.Pachymetry: Here the thickness of the cornea is measured using an ultrasonic instrument. Anesthetic drops may be applied to the eye for this test too.
Treatment of glaucoma
Glaucoma if diagnosed early can be treated, and further complications like blindness can be avoided. Management of glaucoma includes various therapeutic modalities as described below. These treatments only prevent further vision loss, but do not help regain the vision that is already lost due to glaucoma.3
These include eye drops and oral tablets and are commonly given early in the course of the disease. These medications either decrease the fluid formation in the eye or others lower the eye pressure by increasing the fluid drainage from the eye. The following are few important points to keep in mind while taking glaucoma medications:
Some of these medications may cause headaches or other side-effects. Eye drops may cause stinging or burning sensation and redness of the eye. If the side-effects become unbearable, either the dosage or the medication itself can be changed.
Many a time, since glaucoma has no symptoms, people may want to stop taking, or may forget to take their medicine. This should not happen. Regular use is very important.
It is important to mention to the doctor if one is taking any other medications since glaucoma medications may interfere with the way these medicines work.
This procedure is done to drain the fluid out of the eye. In many cases, glaucoma drugs are required even after this procedure. This procedure would be done in the doctor’s clinic itself. Like any surgery, laser surgery can cause side-effects, like inflammation. Eye drops would be prescribed for any soreness or inflammation inside the eye. In case of glaucoma in both eyes, only one eye will be treated at a time. Laser treatments for each eye will be scheduled several days to several weeks apart.
Here, a new opening is made surgically for the fluid to leave the eye. Conventional surgery often is done after medicines and laser surgery have failed to control pressure. For several weeks after the surgery, eye drops are required to fight infection and inflammation. Just like laser surgery, conventional surgery is also performed on one eye at a time. Usually, the operations are 4–6 weeks apart. This mode of treatment is about 60–80% effective at lowering eye pressure.
This can cause side-effects, like cataract, problems with the cornea and inflammation or infection inside the eye. The buildup of fluid in the back of the eye may cause some patients to see shadows in their vision. If any of these problems occur, it is important to inform the doctor, so that they could be addressed appropriately.
1.Whitson JT. Glaucoma: A review of adjunctive therapy and new management strategies. Expert Opin Pharmacother. 2007; 8(18): 3237–3249.
2.Glaucoma. NIH Senior Health. Available at: http://nihseniorhealth.gov/glaucoma/toc.html. Accessed on: 13 July, 2008.
3.Glaucoma. National Eye Institute. National Institutes of Health. Available at: http://www.nei.nih.gov/health/glaucoma/glaucoma_facts.asp. Accessed on: 13 July 2008.
4.Glaucoma makes 1.2 L Indians blind. The Times of India. 2nd July 2008. Available at:http://timesofindia.indiatimes.com/HealthSci/Glaucoma_makes_12_L_Indians_blind/rssarticleshow/3187053.cms. Accessed on: 13 July 2008.
5.Wilson MR. In: Clinical Guide to Glaucoma Management. Oxford: Butterworth Heinemann; 2004.
6.Medeiros FA, Sample PA, Zangwill LM, Bowd C, Aihara M, Weinreb RN. Corneal thickness as a risk factor for visual field loss in patients with preperimetric glaucomatous optic neuropathy. Am J Ophthalmol. 2003; 136: 805–813.
Written by: healthplus24.com team
Date last updated: January 19, 2015