I wanted to write everyone and go over diagnosis / management / treatment of glaucoma. Glaucoma is the second leading cause of blindness in Belize, USA, the industrialized world and the emerging world. As we all know, once vision is lost with glaucoma ( optic atrophy ) there is no drops, surgery, laser, that can restore the patient's vision in Belize, or Guatemala, or Mexico, or USA, etc. This is a "hard sell" to explain to most of our patients. Who wants to hear that?
The most important test we do on any patient is to check their V.A. Right? If they have distance glasses then check V.A. with the glasses. Not with the bifocal. P. H. can be useful but many patients don't understand the Pin Hole ( P.H. ) test. If the V.A. is in doubt, refract. The refraction should be done before putting any drops in the eyes what so ever. Always do refraction first.
The second most important test we ( eye health care workers ) do is to check the intraocular pressure ( IOP ). Checking IOP once is not enough. There is a normal fluctuation ( diurnal curve ) of the IOP. The normal variation in someone without glaucoma is 4 - 6 mm. The variation ( diurnal curve ) for someone with glaucoma is greater --- perhaps 5 - 10 mm. What that means is, you can check someone's IOP at 16mm but 6 hours later the IOP could be 25 mm. Unless you check, and check and check you really can't get a feel of any patient's IOP range. Anyone over age 20 should have the IOP checked especially with African ancestry. Anyone with glaucoma should have the IOP checked with each ( every ) visit.
Any patient with high risk factors for glaucoma should have their IOP checked with each visit. The leading high risk factors are: #1. African ancestory #2. family history of glaucoma. #3. older individuals. Those are the big three but there are some other risk factors. You should ask the glaucoma patient if anyone in his / her family went blind. That strongly suggests a family history glaucoma. The older you are, the more likely you are to have glaucoma.
All glaucoma patients should be told their siblings and other family members should be checked for glaucoma at least every two years. This is true whether the siblings are in Belize or elsewhere. Many patients have early or moderate glaucoma and think everything is OK because they have no eye symptoms. Patients with glaucoma often have no visual symptoms until their glaucoma is severe / advanced. Some patients will not have glaucoma initially but will develop glaucoma as they get older.
If we don't check our patients for glaucoma then certainly the early diagnosis will be missed. We should try not to make the diagnosis of glaucoma only when our patients have marked loss of vision in both eyes ( optic atrophy ) but early on. To do this we must check IOP routinely ( and also evaluate the optic disc ).
Any glaucoma drop that is prescribed for a specific patient may or may not be of benefit. That is why you need to have patients come back and come back to recheck the IOP if you change the regiment ( treatment ). Any new drop may or may not be helpful.
Having said all that, the diagnosis and treatment of glaucoma is more than just "what is the IOP". Some people have glaucoma and yet their IOP is never above 20 mm ( normal tension glaucoma ). Some patients have an elevated IOP ( say 28 mm ) and yet do not have glaucoma ( ocular hypertension ), do not need drops, and will never lose vision. We can not just "treat the number ( IOP )" but checking the IOP and the appearance of the disc is important. Glaucoma is unfortunately more complex than just the IOP number but the higher the IOP the more likely the patient really does indeed have glaucoma. If you treating glaucoma with just the IOP number then you are treating many patients that really don't have glaucoma ( ocular hypertension ) and you are also not treating many patients that really do have glaucoma ( normal tension glaucoma ). If you are starting to get the idea that glaucoma diagnosis / treatment is not easy, you are correct.
Visual fields can be useful but the initial field test is often unreliable as the patient needs to " learn " how to take the test. Visual fields are often useless if the patient does not look straight ahead ( fixate the test light ). Repeat visual fields are often more reliable than the first set. The patient should always be given a copy of their visual fields to take with them ( for their records ). Visual fields done in the States or elsewhere are not useful if the patient does not have a copy. If you send the patient else where ( ? out of town ) for visual fields, then the patient must call the day before to be sure someone will be there to do the visual field test. Quite important. Patients are not happy campers if they show up for a visual field test and for some reason the test can not be done that day. Please don't do that to your glaucoma patients.
The OCT ( nerve fiber thickness ) can sometimes be helpful in making the diagnosis or following for progression.
As we all know, adherence ( compliance ) is poor with glaucoma. This is true everywhere --- USA, UK, Canada, Mexico, Belize, etc. Initially, as a general rule, the best drop to start is a prostaglandin analog --- GAAP ( latanoprost, Xalantan ) one drop once daily at night. Lumigan ( brimatoprost ) and Travatan ( travoprost ) are also in the same family. Most patients will require more than one type of eye drop to get the IOP down sufficiently. The greater the optic nerve damage, the lower the IOP needs to be in order to stop further damage ( progression ). The diagnosis / treatment / management of glaucoma is often not simple. 20% of patients do not respond to GAAP ( Xalantan ) drops. Obtaining frequent IOP readings is important / useful.
One drop is all you need. Putting two or three drops in the eye is not necessary and wastes the drops ( costly ). If available, Trusopt ( dorzolamide ) or Azopt ( brinzolamide, shake well ) or Cosopt ( combination ) is usually a better choice than timolol for a second drop. Most patients get little extra benefit ( IOP reduction ) from timolol if they are already on a prostaglindin analog. ( Xalantan ). But you do need to check and recheck IOP to see if any drop is helping. Many patients unfortunately want to use just timolol as it is cheaper. Many patients can not afford the glaucoma drops. Timolol is usually prescribed twice daily but if being used once daily then the timolol should be used in the morning rather than afternoon or night. Timolol works better in AM rather than PM.
Laser trabeculoplasty can sometimes reduce the IOP but will not restore vision. Sometimes the laser trabeculoplasty is not useful / successful no matter who does it where. 20% failure rate. That's another reason to check IOP frequently. Sometimes repeat laser trabeculoplasty will help some.
Well I hope some of these suggestions will be useful. Averall I think we do a good job with glaucoma but it's a difficult disease to say the least.
Baxter McLendon MD