Glaucoma: New Approaches for Detection and Treatment
by Dr. Samuel P. Solish
Glaucoma is a group of eye diseases which causes damage to the optic nerve. The damage results in a typical pattern of vision loss. Most of the time a lot of peripheral vision is already damaged by the time symptoms of blurred vision, central visual field loss and decreased contrast are present. Vision loss is usually slowly progressive making accurate and early detection important.
The optic nerve is the cable that connects the eye to the brain. The nerve is a bundle of over one million nerve fibers which are very small and delicate. These small fibers carry all of the complex vision information to the brain. Glaucoma is damage to these fibers. The damage may occur because of a family history of nerve damage, presumed poor blood flow to the nerve or most often, elevated eye pressure. Eye pressure is often elevated in the most severe forms of glaucoma. Eye pressure can be elevated without signs of damage to the nerve or visual field. Recent research has shown that those individuals with high pressure and normal optic nerves may be at high risk for glaucoma. If there is damage to the optic nerve, treatment would be necessary.
The first step in checking for glaucoma is recognizing important risk factors. Groups at higher risk are people with advanced age, family history of glaucoma and race (African Americans have 5 times the risk that Caucasian Americans). Other risk factors include previous eye trauma, previous eye surgery, diabetes and history of inflammation inside the eye. The second step is a complete eye exam to look not only at pressure but the other structures of the eye (such as the optic nerve) as well. An important initial test is to make sure the drainage apparatus of the eye, the trabecular meshwork, looks healthy. This observation is called gonioscopy.
After basic testing and examination, if the eye exam indicates a possibility of glaucoma, special testing would be indicated. Visual fields, photographs, computerized optic nerve and nerve fiber layer measurements with instruments such as Optical Coherence Tomography (OCT) and Heidelberg Retinal Tomography (HRT) would help determine the need for treatment. OCT and HRT are used to detect very small changes in the appearance of the optic nerve and the nerve fibers. These are the most accurate methods available for detecting changes.
When it is clear that glaucoma is present, treatment is aimed at lowering eye pressure. Eyedrops have been used since the 1870’s to control glaucoma but it is only in the last few years that we have the benefit of very safe and effective medications which have few annoying (or dangerous) side effects. Research has demonstrated that other treatments such as laser and surgery are also very effective in safely lowering eye pressure. Research from the National Eye Institute and other studies have shown that early treatment of glaucoma can prevent serious vision loss.
Glaucoma is a “silent” disease which requires an eye exam to detect. All adults should have regular eye exams to identify the presence of glaucoma or other eye conditions.