Stages of Glaucoma Treatment: Part 1

Glaucoma is a progressive eye disease which will lead to blindness if left untreated. For many years its diagnosis was based on results of eye pressure testing -- when the eye's internal pressure was a certain amount higher than average, it was thought that glaucoma was present.

More recently, diagnosis has been based on optic nerve damage. That is because many cases have showed up where:

• Internal pressure is high but no optic nerve damage is present; and conversely,
• Optic nerve damage is present but the internal pressure is not high

The optic nerves run from each eye's retina (back inside surface full of light-sensitive cells) to the brain vision center at the back of the head. They carry neural data that tells the brain what you are looking at, and the brain interprets that and finds names for it all.

What Makes the Eye's Pressure High?

It has to do with the eye's drainage system. Our eyes are filled with fluids and are continually creating and releasing fluid. Tiny channels run from the inside corners of the eyes, connecting with the nasal passages and sinuses, and this allows excess fluid to drain away.

When the drainage channels become blocked for some reason, pressure builds up in the eye. Alternatively, when the eye produces more fluid than it can drain off, pressure builds up.

Glaucoma's elevated pressures cause optic nerve damage which is irreversible. That damage prevents the nerve from carrying full information to the brain, which means that your vision becomes less and less full. Peripheral vision starts to disappear and you will not notice until some of the central vision becomes affected. So unless you have regular glaucoma tests, you can become partially blind without realizing it.

Treatment Stages

1. Glaucoma Eyedrops

There are several types of eyedrops developed at different times in the past 100 years or so, but they all have the effect of lowering internal eye pressure. Some increase fluid outflow and some reduce fluid production. The newer ones have fewer side effects and are most often used -- examples are Xalatan (generic: latanoprost), Lumigan (generic: bimatoprost), and Travatan (generic: travaprost).

Many patients at some point become immune to, or tolerant of, the eyedrops. For some, they don't work, for unknown reasons.

Please watch this space for Part 2 of Stages of Glaucoma Treatment. If you are in the North Florida area and would like to learn more about glaucoma, please visit The Eye Center in Panama City, Florida. They have Nine Doctors and One Vision -- Yours.

Who is a Good LASIK Candidate?

LASIK is an eye surgery to correct three refractive errors:

• Nearsightedness (myopia)
• Farsightedness (hyperopia)
• Astigmatism

LASIK can also correct a fourth condition -- presbyopia (age-related farsightedness), by correcting one eye for near distances and leaving the other eye is it is, for far distances. However, this is not LASIK's main focus.

So if you are myopic, hyperopic or astigmatic, you have passed the first candidacy requirement. Myopia should be mild to moderate. If it is very severe LASIK would not be safe.

You would need to be aged over 18 years and with a stable prescription. In other words, if you have changed your glasses or contacts within the previous two years, that would be considered too unstable for LASIK to be effective. Your eyes would probably change in another six months, undoing the LASIK improvement.

If you have any type of autoimmune disease, poorly controlled diabetes, or any eye disease, LASIK would not be safe. Although there are no stitches or bandages, LASIK is surgery, and good general health is a prerequisite for a successful recovery.

Most people achieve 20/20 vision or better after a LASIK procedure, but not all. Every surgery brings some risk. LASIK has its risks and potential complications, although you can avoid some of them by choosing a fully-qualified and well-experienced LASIK surgeon. Such a surgeon would want you to accept the possibility of problems arising during recovery, and the possibility that you might not achieve 20/20 vision. Realistic expectations are a pre-requisite for LASIK.

Your eye surgeon would expect you to follow his instructions before, during, and after your procedure. Your successful recovery would depend on this.

A Genetic Marker for Nearsightedness?

Studying twins is a helpful way to learn about genetic vs. environmental factors in any given health condition, and in Australia, there are large twin studies being done in the states of Tasmania, Victoria, and Queensland. Their goal is to identify the genes underlying common eye diseases such as glaucoma and myopia.

One group, headed by Dr. David Mackey and Dr. Gu Zhu, is investigating the theory that both myopia and hyperopia are primarily inherited. This group worked with 893 individuals to measure the eye's axial length -- its dimension from front to back.

How Does Myopia Work?

A myopic eye cannot see clearly at far distances because it has too great an axial length. The cornea (clear front cover) curves outward too far from the retina in the back of the eye, so that incoming light focuses in front of the retina instead of accurately on it. LASIK corrects this problem by slightly flattening the cornea, which reduces the axial length.

The Research Findings

Their sample included both genetic and fraternal twins. On a subset of 318 individuals, researchers found "strong evidence" for chromosome 5 being responsible for axial length. They have since started a larger study to confirm this finding. They also identified the probable location of genes that help determine the eye's axial length (on the long arm of chromosome 5). After adjusting for age and gender, they found that genetic factors account for about 80 percent of axial length values.

It has been found in unrelated studies that when children enjoy regular periods of outdoor play, rather than being confined to reading or computer play, they can apparently avoid some of the nearsightedness they might otherwise be susceptible to genetically.

Preventing myopia is a goal of many researchers, and Dr. Mackey and Dr. Zhu used new measurement techniques which they think will probably make measurement of axial length a routine procedure in future research on myopia and hyperopia.

If you would like to know more about myopia, the first step would be to contact a fully-qualified ophthalmologist and arrange for a consultation.