Becoming a suspect

I was lucky. When I noticed that my eyes tired quickly and I saw more halos around bright lights than I used to, I decided to see a doctor. The first doctor was a good friend in Germany with whom I was staying briefly; I had been evacuated from Haiti where I worked for the UN during a period of extreme violence and death threats. One of his friends was an ophthalmologist. He discovered that my intra-ocular pressure (IOP), the pressure of the fluid inside my eyeballs, was higher than normal. Normal pressure is between 16 and 20 millimeters of mercury (mmHg). Mine ranged around 24 mmHg. A special instrument, a tonometer, which gently pushes the surface of the eyeball with a small cup while the patient looks at a lovely blue light, measures the ocular pressure. Just before measuring, the doctor put a couple of drops in my eyes of a special medicine to desensitize the surface of the eye. Although it looks frightening, the procedure is not at all painful. But it is a bit bothersome at first, particularly if one blinks, a natural reaction. There is a new method that uses a puff of air to measure the pressure; unfortunately it is not terribly accurate.

High IOP slowly, painlessly, and virtually unnoticeably destroys the optic nerve cells, eventually resulting in blindness. Since the eye is tough, the increased pressure attacks the weakest point, the optic nerves at the back of the eye. Usually the IOP increases because the ducts that drain the eye fluid to the exterior of the eye don't do so fast enough. In what is called primary open-angle glaucoma (POAG), which is the most common type, the blind spots usually develop in the peripheral field of vision, the outer edges of vision. This results in tunnel vision.

POAG is chronic and its causes are unknown, but they are suspected to be genetic. There are other kinds of glaucoma, such as normal tension glaucoma, acute closure glaucoma and acute glaucoma (a very sudden increase in IOP), but POAG is the most common. Unfortunately it is also one of the most frequent causes of blindness in developed countries.

Glaucoma seems to be related to stress, as well as the level of nitrous oxide in the blood supplying the eyes. High blood pressure is often linked to glaucoma, and the condition is more prevalent among older people. It has become clear that a good diet (plenty of green and red veggies!) and regular aerobic exercise help prevent glaucoma.

My Assessment

The ophthalmologist gave me a sophisticated field of vision test with a computerized machine that measures any loss of peripheral or central vision. This instrument has a field of small lights on a white screen that blink on and off intermittently in a random pattern. When one sees the light one pushes a button. If there are any areas in which one doesn't see the blink of the light, it indicates a possible blind spot. Each eye has a naturally occurring blind spot, due to an absence of vision cells at the area in the retina where the optic nerve leaves the eye.

Again I was lucky; there was no loss of the field of vision. After visually examining the optic nerve to check for damage (there was none), he handed me three little bottles of eye drops called Timoptic and told me that these would be my friends to use for the rest of my life. So at age 47, I was what is termed a 'glaucoma suspect' who could develop POAG if not treated.

My Treatment

Every morning from that day on, unless it is physically impossible, I have placed drops in my eyes to control the ocular pressure, bringing it down to a normal 16 to 18 mmHg. I've tried a number of drugs: Timoptic, Timoptol, Timoptol XE, pilocarpine and Trusopt, in various dosages. In my case they all had a couple of side effects in common. They slightly irritated my eyes and they caused blurred vision for some time after application. Pilocarpine, one of the oldest drugs, had the most side effects, which included a sharp headache and shortsightedness for some hours. Timoptic XE is a gel; it slightly blurred my vision for most of the day, although it irritated my eyes less and prevented dryness. I continue to search for the perfect eye drop that has no side effects for me and yet will prevent the destruction of the optic nerve.

My next full check-up was in New York at the Cornell Medical Center. Again I had a field of vision test and an examination by a special video camera that creates a large image of the optic nerve. I sighed with relief as the doctor told me that there was still no damage.

As the years progressed, tests showed that my peripheral vision has not been affected, but I do have trouble at times, especially early in the morning with high contrast light, and I do see halos around strong lights at night. I have always had a slight astigmatism that has slightly worsened with age. My close vision has deteriorated, but this is probably due to age and increasing inflexibility of the eyeballs, a normal occurrence for those over 40 years old. But glaucoma does affect close vision. Watching television and using my computer for long periods of time do tire my eyes.

Glaucoma can damage the optic nerve even with normal ocular pressure. The experts are not quite sure how and why. And just as there are different types of glaucoma, there are different types of glaucoma medication. Some new developments promise greater protection and even some restoration of damaged optic nerves. A drug developed for multiple sclerosis, Copaxone, which is already approved by the FDA, has shown some promise in protecting the optic nerve. Copaxone reduces the loss of nerve cells from 28% to 4% in rats with high IOP. There is a great deal of new research that might soon provide a cure for glaucoma.

And Today?

Although it is annoying to have to put slightly stinging drops in my eyes each morning or evening, it is a small cost for vision. I feel delighted to have discovered my problem early on. Perhaps, otherwise, I'd be blind by now. I can look forward to relatively clear vision for the rest of my life. My most recent test in June of this year still shows no damage to my optic nerves.

I can only suggest that everybody have their eyes checked regularly, especially older people (every year!); if high ocular pressure is detected use your eye drops rigorously, according to the physician's instructions. One must remember that, according to the Glaucoma Foundation, 3 million people have glaucoma in the US and 67 million in the world; most don't realize it. If you have regular eye testing, you can move from being just lucky to being smart!