Published in Ocular Surface

The Ocular Surface Burden in Glaucoma: What the Evidence Actually Shows

Mile Brujic, OD, FAAO

Mile Brujic, OD, FAAO

Eric E. Schmidt, OD, FAAO

Eric E. Schmidt, OD, FAAO

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Join Drs. Brujic and Schmidt as they discuss pearls for managing patients with concomitant ocular surface disease, Demodex blepharitis, and glaucoma.

In this episode of Hidden Drivers, Mile Brujic, OD, FAAO, speaks with Eric Schmidt, OD, FAAO, immediate past president of the Optometric Glaucoma Society, about the ocular surface burden of glaucoma treatment.
Their discussion returns to one central tension: the drops that lower intraocular pressure (IOP) can burden the ocular surface, and that burden deserves its own diagnosis and treatment plan.

“The moral of the story is just stop, look, and listen a little bit more than we're doing.”

OSD and glaucoma fast facts

  • Ocular surface disease (OSD) is common among patients receiving topical glaucoma therapy, even when symptoms are minimal.
  • In one study, 59% of patients with glaucoma or ocular hypertension reported dry eye symptoms, including 27% with severe symptoms.1
  • Benzalkonium chloride (BAK), a preservative in many multidose glaucoma drops, can contribute to inflammation and epithelial damage.2
  • Chronic topical IOP-lowering therapy is associated with meibomian gland dysfunction (MGD), which can destabilize the tear film.3
  • Collarettes at the eyelash bases are characteristic of Demodex blepharitis, which can resemble medication-related OSD.
  • In the phase 3 SATURN-2 trial, 56% of patients receiving lotilaner ophthalmic solution 0.25%, an antiparasitic eye drop, achieved collarette cure, compared with 12.5% receiving vehicle.4

Why ocular surface disease matters in glaucoma

Glaucoma care has traditionally focused on lowering IOP and preserving the optic nerve. Dr. Schmidt points out the irony that patients may begin treatment seeing well and feeling fine, only to develop redness, irritation, or fluctuating vision after starting daily drops.
Leung and colleagues evaluated 101 patients with glaucoma or ocular hypertension and found that 59% reported dry eye symptoms, while 78% had abnormal tear-film breakup time.1 These findings reinforce why symptoms alone cannot determine ocular surface health.
Dr. Schmidt recommends fluorescein staining to identify superficial punctate keratitis (SPK) and epithelial changes before concluding that the surface is healthy.

The impact of preservatives and chronic treatment

Benzalkonium chloride (BAK) is a detergent-like preservative used in multidose glaucoma drops to prevent microbial contamination. Repeated exposure can damage the corneal epithelium, disrupt the tear film, and contribute to inflammation. Risk may increase with greater medication exposure and treatment duration.2
Preservative-free formulations offer an alternative for some patients, provided adequate IOP control is maintained. The relationship between glaucoma treatment and ocular surface health deserves consideration when long-term tolerance becomes a concern.
Dr. Schmidt also urges clinicians to examine the eyelid margins. Chronic topical therapy is associated with MGD, which disrupts the tear film's lipid layer and contributes to evaporative dry eye.3 Evaluating gland obstruction, meibum quality, and lid inflammation may reveal problems that corneal staining alone cannot explain.

“Maybe we should press on the lids.”

Distinguishing Demodex from medication-related disease

Demodex blepharitis and medication-related OSD can produce similar findings at the slit lamp. Dr. Schmidt identifies collarettes, the cylindrical debris surrounding eyelash bases, as an important diagnostic clue.
Treatment differs according to the cause. In the randomized SATURN-2 trial, patients received lotilaner ophthalmic solution 0.25% or vehicle twice daily for six weeks. At day 43, 56% of the lotilaner group achieved collarette cure compared with 12.5% of the vehicle group.4
Dr. Schmidt favors treating an identifiable condition first, then reassessing. If collarettes resolve but SPK or gland dysfunction persists, clinicians can evaluate medication-related toxicity, MGD, or other contributing conditions.

“Let's treat what we know, get it gone, see what's left.”

Treat the whole eye, not just the pressure

Pressure control is necessary but not sufficient. Ocular surface findings deserve their own assessment and treatment plan, particularly when chronic therapy threatens comfort or adherence.
Dr. Schmidt's approach is practical: examine the cornea with fluorescein, evaluate the lid margins, identify treatable conditions, and reassess. Managing OSD alongside glaucoma can improve treatment tolerance and support the long-term adherence needed to preserve vision.

This article was written by Dianne Barnard, RN based on the conversation between Drs. Brujic and Schmidt.

  1. Leung EW, Medeiros FA, Weinreb RN. Prevalence of ocular surface disease in glaucoma patients. J Glaucoma. 2008;17(5):350-355. doi:10.1097/IJG.0b013e31815c5f4f
  2. Asiedu K, Abu SL. The impact of topical intraocular pressure lowering medications on the ocular surface of glaucoma patients: a review. J Curr Ophthalmol. 2019;31(1):8-15. doi:10.1016/j.joco.2018.07.003
  3. Arita R, Itoh K, Maeda S, et al. Comparison of the long-term effects of various topical antiglaucoma medications on meibomian glands. Cornea. 2012;31(11):1229-1234. doi:10.1097/ICO.0b013e31823f8e7d
  4. Gaddie IB, Donnenfeld ED, Karpecki P, et al. Lotilaner ophthalmic solution 0.25% for Demodex blepharitis: randomized, vehicle-controlled, multicenter, phase 3 trial (Saturn-2). Ophthalmology. 2023;130(10):1015-1023. doi:10.1016/j.ophtha.2023.05.030
Mile Brujic, OD, FAAO
About Mile Brujic, OD, FAAO

Mile Brujic, OD, FAAO is a 2002 graduate of the New England College of Optometry. He is a partner of Premier Vision Group, a successful four location optometric practice in Northwest Ohio. He practices full scope optometry with an emphasis on ocular disease management of the anterior segment and specialty contact lenses. He is active at all levels of organized optometry. Dr. Brujic is on the editorial board for a number of optometric publications. He has published over 400 articles and has given over 1800 lectures, both nationally and internationally on contemporary topics in eye care.

More by Mile Brujic, OD, FAAO
Mile Brujic, OD, FAAO
Eric E. Schmidt, OD, FAAO
About Eric E. Schmidt, OD, FAAO

At Omni Eye Specialists, Dr. Eric E. Schmidt, a visionary in optometry, leads our team. With over 30 years of experience, he founded our practice in 2006 with a simple yet profound vision—to provide world-class, state-of-the-art eye care in Wilmington.

Dr. Schmidt's journey in eyecare began when he graduated from the University of Illinois in 1983. He furthered his education by earning his doctorate from the Pennsylvania College of Optometry. Dr. Schmidt's commitment to excellence led him to complete a residency in Ocular Disease at The Eye Institute in Philadelphia, followed by a prestigious one-year Fellowship in Glaucoma at the Scheie Eye Institute.

Not only is Dr. Schmidt an accomplished practitioner, but he is also an author of a textbook and a prolific contributor to medical journals. He shares his knowledge by lecturing internationally on critical topics such as glaucoma and dry eye therapy. He proudly serves as the President of the Optometric Glaucoma Society, an exclusive group consisting of the top 200 glaucoma providers in Optometry.

In addition to patient care and educating fellow professionals, Dr. Schmidt is a trusted consultant for many companies in the ophthalmic space. He is also the Vice President of Professional Development for KeplrVision, a founding partner of the organization.

Dr. Schmidt's patient care philosophy is grounded in providing exquisite care to each patient individually, always delivered with compassion. On a personal note, he is a loving father of three and has been happily married to his college sweetheart for over 30 years. Together, they enjoy the beauty of Wilmington and cherish their time on the water.

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Eric E. Schmidt, OD, FAAO
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