Part 3 of 14 of “Adjusting the Faucet or Opening the Drain – Currently Available Methods to Treat the Plumbing Problem of Open Angle Glaucoma” | A San Gabriel Valley Optometric Society (SGVOS) Continuing Education Dinner Event – 2 hours CE | Featured Speaker: Dr. David Richardson, MD | April 12, 2017
Currently Available (FDA-approved) Medical Treatments (Eye Drops)
Prostaglandin analogs – there’s a whole bunch of them available now. They open the drain but not through the regular drain. They open up the drain through the uveal scleral outflow. They work quite well but they do have some local side effects that can be—depending on the patient—either desirable or bothersome. Conjunctival Hyperemia almost always bothersome, iris color change almost always thought bothersome and it only happens in the pigmented areas so if you got somebody that has blue eyes and there’s no pigment they’re going to stay blue. If you’ve got somebody that’s got blue with brown spots the spots are going to become more noticeable. Hazel eyes become more brown. If you’ve got somebody with a dark brown iris it’s not going to matter. Lash growth most people appreciate that although some of the prostaglandins do tend at least under this Slit lamp to provide more of **** spidery, unruly lash growth which isn’t always appreciated. And men don’t always appreciate it but the other thing we’ve been seen recently is prostaglandin associated periorbitopathy (that’s a mouthful), which is essentially a reduction of the tissue around the eye now early on again it can be rather desirable right so you’ve got somebody with some excess bags under the eyes, apply the prostaglandins things seem to tighten up a little bit like they’ve had a little laser surgery tightening or sometimes it even looks like they’ve had a lower lid Bleph. That’s great early on but if it progresses too far it can actually tighten the lid so much that it’s difficult to obtain a pressure measurement using Goldman applanation tonometry so this can actually get in the way of your ability to monitor glaucoma. Now there’s some other things you can get intraocular inflammation. This is controversial but the prostaglandins are part of the inflammatory cascade. So it makes perfect sense that they are pro-inflammatory and indeed there’s evidence that they can increase the risk of macular edema at least in those patients who are already at risk for macular edema, herpes virus reactivation can be an issue so you should generally not use this particular drop to lower the pressure in somebody who has a history of herpes virus infection at least of the eye, and then headaches— there have been reports of pretty severe nocturnal headaches.
Cholinergic Receptors Agonists
Speaking of headaches, Cholinergic Receptors. Pilocarpine that’s the one thing we all think about with pilocarpine is headache. Now these are still around because they can still be quite useful for those of our patients with narrow angles but there also still worth being aware of just in terms of general practice. Because they do work pretty well — they open the drain through a different mechanism than the ones we’ve talked about. Essentially they provide some tension on the posterior trabecular meshwork and allow increased outflow. But brow ache poor night vision due to the meiosis induced myopia and then there are these other issues—retinal detachment more of an issue with high myopias but of course if you’ve got a retinal detachment and somebody who has a small pupil that you can’t dilate, that’s an issue. And then less likely but something that was more commonly seen with the older agents in this class and also when we were using this drop a lot more, cicatricial conjunctival pemphigoid, corneal endothelial toxicity, so it’s not just the carbonic anhydrase inhibitors that can give you issues with the corneal endothelium it’s also pilocarpine. And then band keratopathy.
Fixed Combination Agents
Fortunately we now have these Fixed Combination Agents. We have three of them here in the US Cosopt® – Timolol + Dorzolamide, Combigan® ® – Timolol + Brimonidine, Simbrinza® which is Brimonidine + Brinzolamide. My current favorite is Simbrinza® simply because it doesn’t have a Timolol component.
Now the other thing to keep in mind here is that these agents, Cosopt® and Combigan® , the two that are Fixed Combination Agents which do have Timolol in them, you’re using these twice a day. It’s a twice a day agent where you’re using timolol twice a day which really is best used once a day in the morning because the night-time dose doesn’t really help you all that much in terms of the aqueous production which drops at night anyway. But the other thing is we now know that using Beta-blockers at night can potentially put patients at risk for what’s called dipping, which is where their blood pressure drops by 10 points patients who dip are at a much, much higher risk of progression with their glaucoma. So why in the world would you want to use a drop that places a beta blocker in the eye but then moves systemically in most patients at night? Now the other issue here is we’re dosing these twice a day Cosopt® and Combigan® . Well, Dorzolamide and Brimonidine both work best three times a day. So the Cosopt® and Combigan® — I’ve almost entirely eliminated from my practice because in my mind these are just bad compromises. You’re not getting the right dosing on the Brimonidine and the Dorzolamide and you’re getting too much Timolol and potentially actually putting your patient at risk if they’re a dipper. Now if you’re worried about dipping, you can get a 24-hour blood pressure monitoring. It’s not that expensive. It’s not that much of a hassle. Generally you work with the internist. Most internists are happy to do it because it’s information they’d like anyway but for that reason I’ve really moved to Simbrinza® using— recommending it three times a day. The patients don’t get that middle of the day dose so I tell them don’t feel guilty about it just try to do it. We’ve all got more guilt than we need. So those are the drops.
Currently Available Methods to Treat Open Angle Glaucoma Series:
- Currently Available Methods to Treat Open Angle Glaucoma
- Beta-blockers, Selective Alpha Adrenergic Agonist, CAIs
- Prostaglandin Analogs, Cholinergic Receptors Agonists, Fixed Combination Agents
- Carbonic Anhydrase Inhibitors (CAIs)
- Laser Trabeculoplasty
- Continuous Wave and Micropulse® Cyclophotocoagulation
- Trabeculectomy and Glaucoma Drainage Devices
- Ab-Externo Canaloplasty
- Ab-Interno Canaloplasty
- IStent®, Cypass® Microstent, Xen® 45 Gel Stent, Cataract Surgery
- Next-Generation Glaucoma Medications and Surgeries
- iStent Supra®, Hydrus™ Microstent, and InnFocus MicroShunt®
- Canaloplasty with Stegmann Canal Expander