Double trouble: Glaucoma and corneal pathology

Image Credit: AdobeStock/Анна Ковальчук

Reviewed by Oluwatosin U Smith, MD.

For patients with glaucoma and corneal pathology, often there can be a double whammy with 2 pathologies present.

About 3.5% of people in the US have glaucoma. Statistics from the Department of Health and Human Services and the National Keratoconus Foundation reported that 1.0% have keratoconus, 20% have dry eye disease, and 4.0% over age 40 have Fuchs’ dystrophy. These numbers make it inevitable that some have both glaucoma and corneal disease, according to Oluwatosin U Smith, MD, who discussed dealing with dual pathologies at the Glaucoma 360 annual meeting in San Francisco. She is a clinician and surgeon from Glaucoma Associates of Texas, and Clinical Associate Professor of Ophthalmology, University of Texas Southwestern Medical Center, Dallas.

Her most valuable piece of advice is to avoid the vicious cycle in which treating one disease makes the other worse.

Instillation of drugs or surgical interventions can impact the cornea. A common problem resulting from use of anti-glaucoma medications is dry eye disease, which develops in about half of patients using topical anti-glaucoma drugs. Likewise, use of steroids over the long term for corneal disease can increase the risk of glaucoma development.

Patient treatment

There are a myriad of considerations in this patient population, with ocular surface toxicity associated with glaucoma therapy one of the most important. The best course may be the use of preservative-free or benzalkonium (BAK)-free drugs.

The considerations for management of paramount importance are ocular surface disease, the effect of glaucoma procedures, glaucoma medical management option in the presence of corneal pathology, and glaucoma surgical management options in the presence of corneal pathology or after corneal surgery, Smith noted.

The prevalence of ocular surface disease in patients with glaucoma ranges from 48% to 59% based on symptoms and from 22% to 78% based on signs.¹

Cyclosporine 0.1% has great potential to control dry eye disease when administered twice daily. It is free of oils, surfactants, and preservatives with superior spreading properties. Most patient benefit within 2 weeks.

Another approach may be to use the sustained-release bimatoprost intracameral implant (Duryst, (Allergan), which has an acceptable safety profile and was shown to control intraocular pressure (IOP) for 12 months after the third injection of the 10-microgram dose when compared with topical timolol.² The most common ocular adverse reaction in 2 randomized, active-controlled clinical trials in patients with open-angle glaucoma or ocular hypertension was conjunctival hyperemia, which was reported in 27% of patients. Low percentages of ocular adverse effects were reported.

The iDose TR (travoprost, Glaukos) is another sustained-release drug that is a good alternative to topical drops and addresses compliance problems.

The glaucoma surgical management options inpatients with corneal pathology or after corneal surgery are micropulse laser cyclophotocoagulation, the Ex-PRESS Mini Glaucoma Shunt (Optonol Ltd.), minimally invasive glaucoma surgery (MIGS), ie, subconjunctival MIGS such as the Xen Gel Stent (Allergan), and trabecular bypass/stripping procedures such as the iStent (Glaukos) and gonioscopy-assisted transluminal trabeculotomy (GATT).

Cyclophotocoagulation and the Ex-PRESS Mini Glaucoma Shunt resulted in successful sustained outcomes after keratoplasty.

A case of implantation of the Xen Gel Stent after Descemet membrane endothelial keratoplasty³ was considered a promising minimally invasive procedure in a complicated case with low side effects, good visual acuity, and adequate IOP control.

GATT performed to treat glaucoma after corneal surgery showed good results in most patients; 4 of 21 patients needed additional surgery and graft failure occurred in another 3 patients.

Smith found that GATT can be considered a reasonable, safe and effective alternative for surgically lowering IOP in a series of 39 eyes of 32 patients who underwent a previous corneal transplantation. Seven eyes required reoperation for uncontrolled glaucoma at a median of 8.5 months (range, 1.6-16.2 months) after GATT. The cumulative proportion of eyes undergoing repeat corneal surgery was 2.6%, 2.6% and 14.3% at 12, 24, and 36-months, respectively, after GATT.

Smith summarized, “It is important to consider the interaction of corneal and glaucomatous disease whenever treating glaucoma or corneal issues. Many patients present with both problems, and our treatments can trigger or worsen either problem. Knowing that, we should go out of our way to avoid starting the vicious cycle in which treating one makes the other worse. MIGS procedures can prevent that from happening, leading to better outcomes, fewer additional drugs and surgeries, and happier patients.”

References:

1. Kolko M, Gazzard G, Baudouin C, et al. Impact of glaucoma medications on the ocular surface and how ocular surface disease can influence glaucoma treatment. Ocul Surf. 2023;29:456-468.

2. Craven ER, et al. Phase 3 evaluation of bimatoprost sustained-release implant in patients with glaucoma or OHT: Results at primary database lock. Presented at the American Academy of Ophthalmology annual meeting; October 11-15, 2019; San Francisco.

3. Donaghy CL, Vislisel JM, Greiner MA. An Introduction to Corneal Transplantation. Department of Ophthalmology and Visual Sciences, University of Iowa. EyeRounds. Published May 21, 2015. Accessed February 15, 2024. https://eyerounds.org/tutorials/cornea-transplant-intro/