Dec 12, 2009
glaucoma is an extraordinarily complex disease. It's actually a whole group of diseases-depending on how you want to classify them there may be as many as 10-20 types. When the word "glaucoma' is used and not further qualified, what is meant is "Primary Open Angle Glaucoma" (POAG) also sometimes call Chronic Open Angle Glaucoma (COAG).
You can't simplify it as you did. You can have glaucoma with pressures less than 20 (lo tension or normal tension glaucoma), you can have pressures over 30 and not have glaucoma (glaucoma suspect). However if damage to the visual field and optic nerve is present then glaucoma is likely present. By the way damage to the optic disk occurs first--so its possible to have an abnormally large and damaged cup/disk ratio and normal visual fields.
Ophthalmologists are extremely excited over a new technology called optic nerve OCT (optical coherence tomography). OCT is a leading indicator. It measures the first evidence of glaucoma damaging the nerve fiber layer of the retina (it becomes thinner). When enough damage occurs the optic nerves starts to get 'cupped" then finally after enough damage is done to the ganglion cells of the retina and the nerve fiber layer (Perhaps as much ad 50% of more damaged) the visual field changes.
You should take heart as ophthalmologists (Eye physicians and surgeons or Eye MDs) have 4 family of drugs to work with that are additive in pressure lowering effect. Within each of the 4 families there are several different brands that can be tried. Then there are two different kinds of lasers (ALT of argon laser trabeculoplasty and the newer SLT or selective laser trabeculopasty) to try is drops don't work or if the patient cannot put drops in their eyes. Lastly there are several types of traditional surgery usually called "Filtering" surgery that can be used.
You should take heart. Most cases of glaucoma can be controlled one way or another. Most of the people that go blind due to glaucoma either were not diagnosed until most of the optic nerve was severely damaged or are non-compliant and don't use their medications or keep their appointments to see their ophthalmologists.
Your use of your eyes has no effect on your eye at all. It will not cause glaucoma or any other eye disease. Perhaps some eye strain or watering but never, ever will it cause glaucoma, cataracts or physical damage.
JCH III MD Eye Physician & Surgeon