A complete eye examination is needed to diagnose glaucoma; you may be given eye drop to widen (dilate) your pupil. The eye doctor can look at the inside of the eye when the pupil is dilated. (Miller. et al., 2008).
THE TEST FOR DIAGNOSIS ARE:
- GONOSCOPY: This is used to examine the area where the fluid drains out of the eye. It helps to determine whether the angle between the cornea and the iris is open or blocked (closed).
It is used to check eye pressure. However, eye pressure always changes. It can be normal in some people with glaucoma, and this is called normal tension glaucoma. Ophthalmologist will need to run other tests to confirm glaucoma. (John and Chris, 2003).
- PERIMETRY TEST
It is also known as a visual field test. It determines which area of the patient’s vision is missing. The patient is shown a sequence of light spots and asked to identify them. Some of the dots are located where the person’s peripheral vision is the part of vision that is initially affected by glaucoma. If the patient cannot see those peripheral dots, it means that some vision damage has already occurred (Rosentretre A. et al., 2011).
- SLIT LAMP EXAMINATION
Slit lamp is a low power microscope combined with a high intensity light source that can be focused to shire in a thin beam. You will sit in a chair with the instrument placed infront of you. You will be asked to test your chin and forehead on a support to keep your head steady.
Your eyes especially eye lids, cornea, conjunctivitis, sclera and iris will be examined by a health worker (opthalmolagist).
A dye called fluorescein is used to examine the cornea and tear layer. The eye will raise out the eye with tears as you blink.
A drop of the dye will be added to your eye to dilate your pupils. The drop will take about 15-20 minutes to work. This slit lamp examination is then repeated using another small lens held close to the eye, so that the back of the eye can be examined. (Thomas and Parikh. 2006).
- VISUAL ACUITY
It is a test used to determine the smallest letters a person can read on a stand raised chart.
The test is done in a health care, school, work place, you will asked to remove your glasses and stand or sit 20 feet from the eye chart, you will keep both eyes open. Gently cover one eye with a palm of your hand, a piece of paper or a paper cup while you read out and the smallest line of letters you can see on the chart. Numbers or pictures are used for people who cannot read especially children. This is done one each eye at a time. It is repeated while you wear your glasses. You may also be asked to read the letters or numbers from a card held 14 inches from your face. This will test your near vision (Wade and Jones, 1997).
It uses an ultra-sonic wave instrument to help determine the thickness of the cornea and better evaluate eye pressure (Ducker. et al., 2007).
This method is used by the doctors to examine the interior of the eye by looking through the pupil with a special instrument, this can help to detect damage to the optic nerve caused by glaucoma. (Hatt. et al., 2006).
- OPTIC NERVE IMAGING
This is used to document optic nerve changes over time-nerve imaging techniques includes stereo optic nerve photographs, scanning laser polarimetry (GDX), confocal scanning laser ophthalmoscopy (Heidelbeig Retinal Tomograph) and optical coherence tomography (OCT). All four techniques are painless and non-invasive. A doctor will determine which method(s) to use.
- VISUAL FIELD TESTING
This measures the entire area seen by the forward-looking eye to document straight-ahead (central) and side (peripheral) vision. It measures the dimmest light seen at each spot is perceived. (Shabana. 2005).
TREATMENT OF GLAUCOMA
The modern goals of glaucoma management are to avoid glaucomatous damage and nerve damage, and preserve visual field and total quality of life for patients with minimal side effects (Noecker. 2006; Parikh. et al., 2008).
This requires appropriate diagnostic techniques and follow-up examinations and judicious selection of treatments for the individuals patient. Although intraocular pressure is only one of the major risk factors for glaucoma, it can be lowered through pharmaceuticals or surgical technique. (Rosentreter. Et al., 2010).
Glaucoma treatment often starts with medicated eye-drops. The eye-drops will be exactly used as prescribed, otherwise your optic nerve damage could get over worse. If your doctor prescribed more than one eye-drop, then you should ask how you will use it.
Doctors often prescribe prostaglandin to threat open angle glaucoma. It increase outflow of the fluid in the eye and reduce pressure in the eye.
Examples are Latanoprost (xalatan) and binatoprost. (Aptel. 2008).
These reduces the production of fluid in your eye and pressure in your eye (intraocular pressure).
Example includes Timolol (Betimol, Timoptic) and Betaxolol (Betoplic). Side effects include, difficulty in breathing, slowed heart rate, lower blood pressure, impotence and fatigue.
- ALPHA ADRNERIC AGONISTS
These medications reduces the production of aqueous humor and increase out flow of the fluid in the eye.
Example includes; Apraclonidine (Lopidine) and brimonidine (Alhagan). Possible side effects are, irregular heart rate, high blood pressure, fatigue, red, itchy or swollen eyes and dry mouth.
- CARBONIC ANHYDRASE INHIBITORS
These are rarely used, but these medications may reduce the production of fluid in the eye. Examples includes; dorzolamide (Truspot) and brinzolamide (Azopt).
Possible side effects are, frequent urination and a tingling sensation in the fingers and toes.
- MIOTIC OR CHOLINERGIC AGENTS
These also increases the out flow of fluid in the eye. Examples includes pitocarpine (Isoptocarpine) and carbachol (Isotocarbachol).
Side effects includes, smaller pupils, blurred or dim vision or near sightedness. (Varma. et al., 2008).
- COMBINED MEDICATIONS
Some times doctors may prescribe a combined medication such beta blocker and alpha adrenegic agonist or a beta blocker and carbonic anhydrasc inhibitor.
These reduces pressure in the eyes, though how the lannabinoids in marijuana produces this effect remains unknown. (Marijuana and Medicine. 1999).
- ORAL MEDICATIONS
Oral medication is usually in the form of carbonic anhydrase inhibitor that reduces the eye pressure, it will be prescribed by the doctors if eye-drops alone do not bring your eye pressure down to the desired level.
Side effects are:- Frequent urination, atingling sensation in the fingers and toes, depression, stomach upset and kidney stones.
You may need surgery to treat glaucoma if you can’t tolerate medication.
These are some possible complications from glaucoma surgery, they includes inflammation, infection, bleeding, abnormal high or low eye pressure and loss of vision.
Having eye surgery also speed up the development of cataracts. Most of these complications can be effectively treated.
SURGERIES THAT MAY BE PERFORMED TO TREAT GLAUCOMA ARE:-
- LASER SURGERY
After giving you a number eye-drop, your doctor uses a high energy laser beam to open clogged drainage canals and help fluid drain more easily from the eye. This lowers pressure in the eye (intraocular pressure). (Lemiji and Reus 2008).
- FILTERING SURGERY
If eye-drops and laser surgery are not effective to control the pressure, trabeculectomy will be used. You will be injected an anesthetic drug to numb your eye.
The doctor will use a small instrument under a microscope and creates an opening in the sclera and removes the piece of the eye tissue and fluid will be drained from your eye.
- DRAINAGE IMPLANTS
In this case, the surgeon will insert a small tube in your eye to facilitate draining fluid from your eye to reduce the pressure.
In trabeculectomy and drainage implants, the fluid is directed to a blister on the outer layer of your eye ball where it can be absorbed.(Rosentreter. et al., 2011).
TYPES OF GLAUCOMA
THERE ARE TWO MAJOR TYPES OF GLAUCOMA WHICH INCLUDES:-
- Primary open angle glaucoma
- Primary closure angle glaucoma
PRIMARY OPEN ANGLE GLAUCOMA
Glaucoma and the Optic Nerve
The word “glaucoma” comes from the Greek Word meaning opacity of the crystalline lens. It is the major disease of nerve vision called the optic nerve. The optic never receives light generated nerve impulses from the retina and transmits these to the brain where those electrical signals will be recognized as vision. Glaucoma is characterized by a particular pattern of progressive damage