John C Hagan III, MD, FACS, FAAO  
Kansas City, MO

Specialties: Ophthalmology

Interests: Eye-Medical Blog
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General Information on Glaucoma

Dec 12, 2009 - 6 comments

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

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by allene916, Dec 13, 2009
Thanks for the Post Dr Hagen, I'm 63..was diagnosed w/ Normal Tension Gla. in my mid 40's..had already some vision loss. My Op Dr at Vanderbilt medical University TN..did SLT..no difference in pressures.then did trab surgery..which lowered pressure to 8-10.....yrs passed using drops in other eye, this past March 09..had to have a iridotomy first..to prevent an angle closure attack, ..then a trab in other eye..while she did the trab..she took a cataract first then proceded to do the trab..my optic nerves are damaged..and visual fields..I still can see to do house work..I choose not to drive..as I have blind spots..in vf. ...I feel good, my pressures are around 9-10. I use no drops..my mother had this very same condition, but refused treatment..and was blind by 60 yrs old...I'm thinking I have done the right things to KEEP what I have of my vision..and see my op Dr..every 4 months...It is however a burden to carry, I can't help but think...how could I handle being with no sight....Thanks for letting me unload Dr. Hagen..my life has changed..but is still a good life..
Allene 916

Avatar universal
by BUTTERCUP109, Dec 13, 2009
Dr. Hagan,
What is your thinking on steroid-induced ocular hypertension as it related to glaucoma. Is it generally safe to have periods of elevated IOP that are controlled with medication while using steroids (drops or intravitreous) to treat other eye conditions?  I assume transient elevations are not dangerous unless very high. Is this correct? I've read that elevated IOP from steroids is almost always reversible, but not 100% of the time. Comments?

Steroids are strange medications. Can't live with them, can't live without them. (like computers).  Steroids are usally only used when nothing else works and then only as much as needed and watching for and telling patients about side effects. I have some patients with problems like chronic uveitis that I have treated for 20 years with steroids, they have steroid glaucoma and have been on glaucoma meds for 20  years also. These meds have kept both the uveitis and steroid glaucoma from damaging the eye.

Certain steroid drops like FML, Vexol, HMS, are forumlated to be less likely to cause steroid glaucoma.

Usually when steroids are stopped the IOP returns to normal and the glaucoma drops are stopped but not always. Remember that open angle glaucoma is much more common in steroid responders than non responders. Some cases of steroid glaucoma morph into POAG.


Allene   in spite of the best of the new drugs and laser and surgery glaucoma remains a major cause of blindness in the world. Part of this is because there are mechanisms of damage that are pressure independent and we know little of this. New meds that give "neuroprotection" are being developed.

Make the most of your life and do the best you can with what you've got. When life gives you lemons you can make lemonade or you can make lemon concentrate.

Merry Christmas/Happy New Year.


Avatar universal
by kg17, Dec 20, 2009
Dr Hagan,

I have a question - are there OCT norms for the severely myopic?  I understand that my nerve layers are thinner than the normal population because of the myopia, so how can my doc use the OCT results accurately in my case?

Thank you very much for all the time you devote to this site. Your dedication and expertise does not go unnoticed.

Warm regards,


Avatar universal
by yanita, Jan 14, 2010
Thanks i've found this information helpful and instructive!Most old people have this disease...but i want to say that you can find on-line medication and other useful information about glaucoma treatment on http://24drug.com/

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