More than half of patients with glaucoma experience chronic ocular surface disease (OSD) due to eyedrop therapy that decreases their ability to create a proper tear film.¹ A stable tear film depends on maintaining specific levels of aqueous, lipid and mucin secretion, mainly by the lacrimal and meibomian glands and goblet cells.

These levels are affected by ocular inflammation from chronic drop therapy, which can be caused by the toxicity of both the therapeutic agent and preservatives.^1,2 This destabilizes the tear film, resulting in punctate staining of the cornea as well as neurotrophia. Ultimately, the tools used to treat glaucoma can promote another disease process altogether.

Evaluating for OSD

Evaluating glaucoma patients for OSD is critical to detecting symptoms that they may not otherwise mention, such as hyperemia, foreign body sensation, pain, tearing and fluctuating vision due to punctate keratitis. Patients may also be asymptomatic but have corneal staining that impacts their vision.³ One study assessing the prevalence of OSD in patients preparing for cataract surgery found that 40% of the patients had corneal staining despite 85% being completely asymptomatic.³ Thus, it is critical that eyecare providers evaluate glaucoma patients for OSD to ensure that patients experience optimal visual outcomes.

Patients with symptoms of OSD may be less likely to adhere to their glaucoma medications.¹ Two of my patients with these compliance issues come to mind.

I started a 45-year-old female glaucoma patient on a prostaglandin analog, which adequately reduced her intraocular pressure (IOP). However, during her follow-up visit, she reported such extreme pain, throbbing and foreign body sensation that she refused to take the drops, saying, “I would much rather go blind from glaucoma than take this medication another minute.”

Another example is an 85-year-old monocular patient who was blind in one eye from retinal disease and had moderate-to-severe glaucoma in the other eye. When I started treating him, he was on four different topical therapies and had chronic staining and decreased tear film breakup time. At a subsequent visits, the patient’s eye looked white and pristine, and he happily reported that he had stopped all of his medications and that his eye felt much better. We had to significantly improve his ocular surface before he would even consider restarting topical medication.

Reducing Drop Burden

Preventing irreversible damage from OSD in glaucoma patients depends on reaching for non-drop therapies to reduce eyedrop burden as much as possible. One way to do this is to utilize non-topical, sustained-release glaucoma therapies, such as a bimatoprost intracameral implant⁴ or a travoprost intracameral implant.^5,6 These products have been shown to provide long-term IOP control without the use of topical medication.

Selective laser trabeculoplasty (SLT) is another option to treat glaucoma without medication.⁷ SLT treats the drainage mechanism of the eye to reduce IOP, and was recently shown in the LIGHT trial to be extremely efficacious in patients with glaucoma, even as a first-line therapy.⁷ A newer laser technology, direct SLT, has been shown to be as efficacious as SLT but is faster to operate and may cause fewer complications due to improvements in methodology and ergonomics.⁸ Other laser interventions may be available in the near future, such as the Elios laser that is currently approved for use in Europe.⁹ Regardless of the exact modality used, these strategies are important tools for medication sparing and may particularly benefit contact lens wearers and patients with dementia.

Those who are not candidates for surgically implanted drug-delivery devices or laser therapy may be well suited for glaucoma surgery. Historically, such surgery was so invasive that it was diligently avoided, even in patients who required multiple medications to control their IOP. However, in recent years, the development of minimally invasive glaucoma surgery (MIGS) has provided a viable early option without the OSD associated with anti-glaucoma therapies.¹⁰ Some procedures target the Schlemm’s canal without making an external incision—for example, the implantation of stents or simultaneous canaloplasty with trabeculotomy. These procedures avoid significant postoperative complications such as blebs, hypotony and infection, making MIGS an excellent option for many glaucoma patients.

Mitigation Strategies

Successful treatment of OSD in patients with glaucoma requires screening at their first glaucoma consultation. In my practice, we perform meibomian gland imaging to assess the level of gland loss from the outset, and give patients questionnaires to identify all dry eye symptoms. We also evaluate the tear film for signs of inflammation, perform corneal staining and assess the degree of osmolarity issues using tear lab measurements. These assessments are critical steps of the initial consultation as they may influence the choice of first-line treatment.

When I do choose to treat with topical glaucoma medications, one important way to prevent OSD is by preferentially choosing preservative-free drop formulations.² I have had positive results with preservative-free latanoprost,¹¹ for example, and there are other preservative-free
branded and generic options available. For my patients with meibomian gland dysfunction (MGD), who require proactive inflammation reduction on the ocular surface,¹² I choose the preservative-free perfluorohexyloctane ophthalmic solution, which has been approved by the FDA to treat MGD.¹³

Platelet-rich plasma (PRP) serum eye drops also have a role in healing the ocular surface,¹⁴ though only a few dry eye centers nationally are currently equipped to create them. If doctors do not have access to serum drops for their patients, therapeutic agents such as lifitegrast and cyclosporine can be helpful in treating the disease.¹⁵ There is also substantial evidence supporting treatment of MGD with intense pulsed-light therapy and the LipiFlow thermal pulsation system.¹⁶ We currently employ both of these options.

Another important treatment option is cryopreserved amniotic membrane (CAM), which has been shown to not only reverse punctate keratitis,¹⁷ but also to treat neurotrophic keratitis.¹⁸ The regenerative properties of CAM are from a unique hyaluronic acid/pentraxin complex derived from cryopreserved tissue, which is essential for the rapid healing of the cornea and improvement of the neurotrophia.^19-23 The rapid efficacy of CAM²⁴ has made it a mainstay of dry eye treatment for glaucoma patients in our practice and also for optimization prior to their cataract surgery.

We have published a retrospective chart review describing the use of self-
retained CAM for approximately five days in patients with primary open-angle glaucoma who presented with OSD induced by chronic use of glaucoma medication.¹ These patients were using up to four different medications with various degrees of OSD symptoms, and they had already failed topical therapies that included artificial tears, gels, lifitegrast ophthalmic solution and cyclosporine. All patients had decreased corneal staining, reported increased comfort and improvement of their symptoms, and had one to two lines of improvement in their vision. Moreover, patients reported four to six months of symptom relief with a single application of self-retained CAM, demonstrating the lasting benefits of this treatment. This effect chiefly differentiates CAM from other dry eye treatment modalities for our glaucoma patients.

Clinical Pearls

Managing OSD in this population requires a proactive approach, starting with establishing the patient’s baseline at their first glaucoma evaluation. Patients often do not mention their OSD symptoms during this evaluation, so a dry eye questionnaire should always be included.

Staff must proactively perform the testing necessary to identify a condition, even in asymptomatic patients. I recommend investing in diagnostic technology to evaluate the meibomian glands, and identifying specific personnel who will be trained to lead the process.

Patients must be educated about OSD (especially if they are asymptomatic) to ensure that they prioritize its treatment along with their glaucoma treatment.

Providing the best care for glaucoma patients requires diligently screening for OSD and equipping our offices with the knowledge and technology to treat it, so that these solutions can be provided to our patients as soon as they are needed. OM

For article references, please see the online version of this article at www.ophthalmologymanagement.com. 

Zarmeena Vendal, MD is a board-certified ophthalmologist and surgeon who is a diplomate of the American Board of Ophthalmology and the founder of Westlake Eye Specialists in Austin, TX. Dr. Vendal can be reached at: zvendal@westlakeeyes.com.