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Guide Health: Guarding your eyesight against glaucoma

An estimated half of patients with eye drops don’t remember to use them, or don’t use them correctly

If you’re young, glaucoma may not even make it on to the list of health conditions that you’re at all concerned about. As you age, however, your thinking will change, especially if you experience the eyesight loss associated with glaucoma!

Worldwide, glaucoma is the leading cause of blindness, and according to CNIB about 250,000 Canadians have open angle glaucoma.

The eye consists of two chambers surrounded by the sclera, conjunctiva and cornea. Much like a camera, light enters through the pupil, passes through the lens, then hits the retina at the back of the rear or anterior chamber.

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This light then activates “rod” and “cone” cells in the retina, and they produce messages that are sent via the optic nerve for decoding into visual images in the brain.

With glaucoma, the problem is that the pressure of the fluid in the eyeball becomes so high, it presses against the optic nerve and causes damage.

Glaucoma disease develops slowly over time, and you may not notice it until you lose some of your peripheral vision.

In a healthy eye, fluid in the eye is continually being produced, with the excess drained from the eye’s rear chamber.

Primary open angle glaucoma is the most common form of the disease, representing 90 per cent of cases, and here the “drainage” does not work well, similar in a way to a plugged sink.

Secondary open angle glaucoma has the same drainage malfunction, but occurs secondary to another condition like an injury, inflammation, eye surgery and diabetes.

Treating the underlying condition usually helps with the glaucoma.

Closed angle glaucoma is the least common form, representing only about five per cent of cases, but it is the most serious, occurring quickly with sudden eyesight loss and pain. In closed angle glaucoma, as the name suggests, the “drain” is closed.

Glaucoma usually develops slowly over decades. Only two per cent of affected people are under 40, but the number rises as you age. In addition, family history and myopia or shortsightedness are also risk factors, but you cannot alter these.

Intraocular pressure checks enable early detection and treatment. The normal range for intraocular pressure is 10 to 20 mm Hg, measured with a test done using a “puff” of air aimed at your eye.

With early detection, treatment with the wide variety of eye drops will help maintain your vision. Beta blockers like timolol, levobunolol, and betoxolol reduce the production of ocular fluid. Also able to reduce the production of ocular fluid are the alpha adrenergic agonists like brimonidine, and the carbonic anhydrase inhibitors like dorzolamide and brinzolamide. The prostaglandin analogs such as latanoprost, travoprost and bimatoprost increase the outflow of ocular fluid.

Usually a combination of eye drops is used to obtain the best effect, and many eye drop products combine drugs from more than one category.

It is estimated that about half of people using eye drops for glaucoma don’t remember to use them or don’t use them correctly. The underlying reason may be because there is no cure for glaucoma, just control, which means a lifetime of using eye drops.

Combination eye drops and long-acting ones may simplify regimes. Using reminder systems, even reminder phone apps, may help. And, of course, asking family and friends to ask you from time to time if you used your eye drops may also help.

The correct technique for using eye drops is important in that you don’t want to miss your eye with the drop. Many drops have instructions included, so from time to time it’s good to read them and brush up on your technique.

If you need to use two different eye drops, wait five to 10 minutes so the first drops can be absorbed. Also don’t forget to wash your hands before and after using eye drops and never touch the dropper to your eye or anything else; you want to avoid contamination.

Remember, early detection is key to effective treatment of glaucoma and good eyesight. And, even with glaucoma, proper eye drop use will help you maintain your vision; don’t forget to use your drops!

About the author

Contributor

Marie Berry is a lawyer/pharmacist interested in health and education.

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