Glaucoma and Corneal Pathology: An Overview

Educational Objectives

The goal of this program is to improve management of coexisting glaucoma and corneal pathology. After hearing and assimilating this program, the clinician will be better able to:

1. Identify corneal features that increase risk for glaucoma.
2. Prescribe treatment options for glaucoma that optimize corneal health.

Summary

Epidemiology: the prevalence of glaucoma in the United States is 3.5%; the prevalence of dry eye disease and keratoconus is 20% and 1%, respectively; the incidence of meibomian gland disease is high in patients treated for glaucoma; uncontrolled intraocular pressure (IOP) is the second most common reason for graft failure; the prevalence of ocular surface disease (OSD) in patients with glaucoma is between 48% and 59% based on symptoms and ≤78% based on signs observed on examination

Evaluation of Glaucoma

Tonometry: consider central corneal thickness (CCT) and corneal hysteresis (CH) when using tonometers; CCT — the OHTS trial (Brandt et al [2001]) highlighted the relevance of CCT in glaucoma; CCT is highly heritable, and low CCT is an independent risk factor for glaucoma; CCT may influence the accuracy of applanation tonometry, diagnosis, screening, and management of patients; in the presence of high CCT, rebound tonometer (eg, iCare tonometer) considerably overestimates IOP compared with Goldmann applanation tonometer and indentation tonometers (eg, Tono-Pen XL); children with high CCT may be misdiagnosed with glaucoma when using rebound tonometers, and alternate tools should be used; CH — surrogate marker for biochemical properties of tissue in the back of the eye; CH is lower in patients with glaucoma compared with healthy controls; lower CH is associated with an increased risk for disease progression; CH complements other structural and functional assessments

Treatment Considerations

Ocular surface disease: drying time on the cornea with the addition of one drop of benzalkonium chloride (BAK) is significantly decreased; low-grade inflammation from chronic use of topical medications is caused by preservatives and the drugs themselves; addressing OSD should be part of glaucoma treatment; use of preservative-free artificial tear supplements, autologous serum eye drops, and cyclosporine-containing formulations should be considered; a 0.1% cyclosporine formulation (dissolved in a semifluorinated alkane) that was recently approved by the Food and Drug Administration (FDA) has good penetration and surface residence, and leads to a decrease in fluorescence staining on the cornea

Medical management: ineffective in 0.3% of patients with no preexisting glaucoma compared with 8% with prior history of glaucoma; patients with corneal disease are more likely to require glaucoma surgery; consider switching or discontinuing medications (eg, decrease or stop steroids); using microdroppers or mist sprays to reduce drop size may help reduce ocular surface toxicity; consider non-BAK options; sustained-release intracameral delivery systems can help improve ocular surface issues; bimatoprost intracameral implant (BII) — approved by the FDA for a single intracameral administration in the anterior chamber; Medeiros et al (2020) and Bacharach et al (2021) found that ≈80% of patients who received BII had treatment-free controlled IOP at 12 mo after the third implant; titanium travoprost intracameral implant (TII; eg, iDose TR) — designed for continuous drug delivery into the anterior chamber and elutes travoprost for ≤3 yr

Endothelial cell loss (ECL): the FDA considers >30% loss of endothelial cell density to be significant; a suprachoroidal microstent (eg, CyPass) was withdrawn because 27.2% of patients experienced >30% ECL at 5 yr; in an exchange study in which TII was exchanged after the third year, no patients had ECL at 5 yr; in the study in which patients received BII every 16 wk, 5% had significant ECL; BII has been approved for one-time use

Glaucoma and corneal pathology: patients with corneal transplantation may develop glaucoma and lose their graft after a drainage implant; Iverson et al (2018) found that graft failure occurred earlier after Descemet’s stripping endothelial keratoplasty (5.82 mo) than after penetrating keratoplasty (14 mo) in patients who previously underwent glaucoma surgery; risk for graft failure increases after glaucoma surgery; risk for glaucoma surgery after corneal transplantation is 10% in patients with preexisting glaucoma vs 5.3% in patients without preexisting glaucoma

Options for surgical management of glaucoma: include micropulse laser, minimally invasive glaucoma surgery, and subconjunctival filtration; for patients with OSD, selective laser trabeculoplasty is a good early option (as effective as topical medications); Descemet membrane endothelial keratoplasty and trabecular meshwork bypass stent (eg, iStent) procedures may be performed separately or concomitantly, but performing DMEK first may be preferred due to the complexity of both procedures; use of gelatin stent (eg, XEN gel stent) in patients with corneal grafts is effective, although it may be difficult to visualize the tip of the stent and may not be appropriate if considering contact lenses; gonioscopy-assisted transluminal trabeculotomy (GATT) — Smith et al (2022) reported significant reduction in IOP (≈30 mm Hg at baseline to ≈13 mm Hg) and number of medications (4 at baseline to 0.6) at 24 mo in patients with prior corneal transplantation; visual acuity also improved after an initial decline in the first month; GATT is a safe and effective option

Take-home points: corneal pathology and glaucoma coexist, and treatment of one could trigger or worsen the other; preventing or breaking the cycle is important

Readings

Bacharach J, Tatham A, Ferguson G, et al. Phase 3, randomized, 20-month study of the efficacy and safety of bimatoprost implant in patients with open-angle glaucoma and ocular hypertension (ARTEMIS 2). Drugs. 2021;81(17):2017-2033. doi:10.1007/s40265-021-01624-9; Brandt JD, Beiser JA, Kass MA, et al. Central corneal thickness in the Ocular Hypertension Treatment Study (OHTS). Ophthalmology. 2001;108(10):1779-1788. doi:10.1016/s0161-6420(01)00760-6; Ichhpujani P, Thakur S. iDose TR sustained-release travoprost implant for the treatment of glaucoma. Published online June 2, 2023. doi:https://doi.org/10.17925/USOR.2023.17.1.4; Iverson SM, Spierer O, Papachristou GC, et al. Comparison of graft survival following penetrating keratoplasty and Descemet’s stripping endothelial keratoplasty in eyes with a glaucoma drainage device. Int Ophthalmol. 2018;38(1):223-231. doi:10.1007/s10792-017-0451-4; 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. doi:10.1016/j.jtos.2023.05.012; Medeiros FA, Walters TR, Kolko M, et al. Phase 3, randomized, 20-month study of bimatoprost implant in open-angle glaucoma and ocular hypertension (ARTEMIS 1). Ophthalmology. 2020;127(12):1627-1641. doi:10.1016/j.ophtha.2020.06.018; Smith OU, Butler MR, Grover DS, et al. Twenty-four-month outcome of gonioscopy-assisted transluminal trabeculotomy (GATT) in eyes with prior corneal transplant surgery. J Glaucoma. 2022;31(1):54-59. doi:10.1097/IJG.0000000000001949; Zheng C, Yu F, Tseng VL, et al. Risk of glaucoma surgery after corneal transplant surgery in Medicare patients. Am J Ophthalmol. 2018;192:104-112. doi:10.1016/j.ajo.2018.05.004.

Disclosures

For this program, the following relevant financial relationships were disclosed and mitigated to ensure that no commercial bias has been inserted into this content: Dr. Smith has been a consultant for AbbVie/Allergan, Aerie, Alcon, Bausch and Lomb, Belkin Vision, Elios Vision, Glaukos, Iris Vision, New World Medical, and Sanoculis; held stock in Nova Eye Medical and Olleyes; been involved in research with Ocular Therapeutix; and been on the speaker’s bureau for Aerie, Bausch and Lomb, and AbbVie/Allergan. Members of the planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Smith was recorded at Glaucoma 360: 28th Annual Glaucoma Symposium, held on February 10, 2024, in San Francisco, CA, and presented by Glaucoma Research and Education Group. For more information about upcoming CME activities from this presenter, please visit https://glaucoma360.org/glaucoma-symposium-cme/. Audio Digest thanks the speakers and presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.50 CE contact hours.

Lecture ID:

OP621202

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

More Details - Certification & Accreditation