GLAUCOMA-RELATED OCULAR SURFACE DISEASE (OSD) PART-2

 

PATHOGENESIS OF OSD IN GLAUCOMA

Tear film instability triggers a chain reaction leading to the release of inflammatory cytokines and mediators that subsequently alter the quality of tears.

Reduced reflex lacrimation in dry eye syndrome (DES) results in higher ocular surface drug concentrations due to reduced dilution capacity.

Mechanisms of dry eye in patients with glaucoma are likely a combination of tear film abnormalities and instability due to decreased tear production from chronic inflammation and increased tear evaporation from Meibomian gland dysfunction further worsened by topical anti-glaucoma medications.

Ruiz-Lozano RE, Azar NS, Mousa HM, Quiroga-Garza ME, Komai S, Wheelock-Gutierrez L, Cartes C, Perez VL. Ocular surface disease: a known yet overlooked side effect of topical glaucoma therapy. Front Toxicol. 2023 Jul 21;5:1067942. doi: 10.3389/ftox.2023.1067942. PMID: 37547228; PMCID: PMC10403269.

Allergic reactions to topical antiglaucoma medications and repeated exposure to preservatives and excipients in the drops play a role.

In more severe cases, cicatricial conjunctival changes may occur from pseudo-pemphigoid reaction, induced by antiglaucoma medications.

Medical therapy for glaucoma can profoundly disrupt the homeostasis of the tear film and ocular surface.

The severity of toxic or allergic reactions to topical anti-glaucoma medications is related to the number of daily drops, the duration of treatment, and the presence of preservatives.

The main structural alterations caused by the chronic use of these eyedrops include dysfunction and loss of goblet cells, Meibomian glands, and accessory lacrimal glands.

These changes disrupt the corneal epithelium and cause a reduction in corneal sensitivity, resulting in disruption of the tear film and thinning of the mucus, aqueous, and lipid layers.

Ocular surface inflammation may manifest as early as three months after initiation of anti-glaucoma therapy.

Tear proteins detected in eyes with medication-induced dry eyes differ from those of primary dry eyes. These altered proteins could also be responsible for the ocular surface disease in glaucoma patients.

A study found significantly decreased goblet cell density, increased dendritic cell density, and increased subepithelial fibrosis altered after chronic use of anti-glaucoma eyedrops.

Low mucin production affects tear film stability, causing chronic ocular surface inflammation, and conjunctival scarring.