Q: What is the relationship between ocular surface disease (OSD) and glaucoma? Can you point to a few recent studies that elucidate this?

A: There is some evidence that glaucoma patients have dry eye disease or OSD at a higher rate than the general population, even before they use eyedrops. Further, the demographics of OSD and glaucoma overlap: both are more common in older individuals and can have a higher prevalence in postmenopausal females.

But the most common cause of OSD in glaucoma patients, by far, is topical therapy for the glaucoma. This includes both the active medication and the preservative. The worst offender in this case is benzalkonium chloride (BAK), which has several ill effects on conjunctival goblet cells.^1-3

Q: What are the patient care reasons that it is important for ophthalmologists to explore these connections?

A: Every eyecare professional treating glaucoma should be aware of the higher rate of OSD in this population, and every glaucoma patient should be asked about ocular surface symptoms.This is particularly important because we have alternative therapies that can be used to get patients off eyedrops that are decreasing their quality of life. 

As glaucoma specialists, we are used to seeing patients with red eyes come into our offices, but we owe it to our patients to ask how this is affecting their lives and offer an alternative.

Q: What are the available options for treatment?

A: For a patient who is not on any therapy, I will start with regular artificial tears, assess their blepharitis or meibomian gland dysfunction, and offer lid scrubs. If these measures don’t work, I will move on to topical cyclosporine or another prescription option.

If a patient is on drop therapy (like the vast majority of glaucoma patients), then the best solution is addition by subtraction. Try to reduce the drop burden by lowering IOP with laser trabeculoplasty, intracameral bimatoprost or travoprost, or minimally invasive glaucoma surgery. At the minimum, you can limit exposure to BAK by choosing preservative-free drops; there are more options available now. Most of my glaucoma patients are on artificial tears. If the tears are used twice a day or more and are still ineffective, then I will prescribe topical cyclosporine; there was one small study that noted its efficacy in glaucoma patients. I’ll also involve specialists from cornea or oculoplastics if I suspect that they can help.

Q: Are there clinic flow tweaks that ophthalmologists can make to help with screening and treating OSD in patients with glaucoma?

A: This is a great question. We haven’t done this formally in my office, but my technicians will usually ask the patient about dry eye symptoms before they see me. Another strategy is to screen with a short questionnaire.

Q: What are some best practices for ophthalmologists to help prevent OSD in glaucoma patients?

A:  Prevention is key! There is evidence that BAK causes permanent damage to conjunctival goblet cells, so reducing BAK exposure is important—particularly in a patient that already has OSD prior to starting topical glaucoma therapy. Again, this is best done by choosing laser trabeculoplasty or a BAK-free medication to start.

Q: Is there anything else that practices could be doing to reduce the risk of OSD for their glaucoma patients?

A: Offer more options. I am encouraged by the number of preservative- free drops now available. Not long ago, there were no preservative-free prostaglandin analogs, but now we can try tafluprost or preservative-free latanoprost. Non-BAK travoprost is available generically (although not always covered by insurance). Preservative-free dorzolamide-timolol is also available as a generic and can be kept at room temperature, which is
convenient. 

Also, I have referred a few patients to a compounding pharmacy that can make all drops preservative-free (perhaps with the exception of Netarsudil) and even make different combinations of drops. This takes a little extra work in prescribing and setting up an account, but it is a nice option for patients. Still, the biggest obstacle to getting medical therapy without BAK or preservatives is a lack of insurance coverage for them. OM

REFERENCES

1. Zhang X, Vadoothker S, Munir WM, Saeedi O. Ocular Surface Disease and Glaucoma Medications: A Clinical Approach. Eye Contact Lens. 2019 Jan;45(1):11-18.
   
   
2. Konstas AG, Boboridis KG, Athanasopoulos GP, Haidich AB, Voudouragkaki IC, Pagkalidou E, Katsanos A, Katz LJ. Changing from preserved to preservative-free cyclosporine 0.1% enhanced triple glaucoma therapy: impact on ocular surface disease — a randomized controlled trial. Eye (Lond). 2023 Dec;37(17):3666-3674.
   
   
3. Kolko M, Gazzard G, Baudouin C, Beier S, Brignole-Baudouin F, Cvenkel B, Fineide F, Hedengran A, Hommer A, Jespersen E, Messmer EM, Murthy R, Sullivan AG, Tatham AJ, Utheim TP, Vittrup M, Sullivan DA. Impact of glaucoma medications on the ocular surface and how ocular surface disease can influence glaucoma treatment. Ocul Surf. 2023 Jul;29:456-468.

Osamah J. Saeedi, MD is an MPOWER professor of ophthalmology at the University of Maryland, Baltimore, as well as an associate professor of bioengineering at the University of Maryland, College Park. He is an established NIH-funded clinician- scientist whose work focuses on the discovery of novel glaucoma biomarkers and ocular surface disease in glaucoma patients.