Ocular surface epithelia

The ocular surface epithelia consist of the specialized, non-keratinized stratified squamous cell layers covering the cornea and the conjunctiva. These epithelia function as a critical biological barrier, protecting the internal structures of the eye from mechanical trauma, pathogens, and environmental stressors while maintaining a smooth refractive surface for vision (Gipson, 2007). They play a vital role in tear film stability by producing membrane-associated mucins, such as MUC1, MUC4, and MUC16, which allow the aqueous layer of tears to spread evenly across the eye (Dartt, 2011). In diseases like dry eye syndrome, chronic inflammation and hyperosmolarity lead to epithelial damage, loss of goblet cells, and impaired barrier function (Bron et al., 2017). While 'ocular surface epithelia' refers to a tissue rather than a single molecular target, it is the primary site of pathology and drug action for most topical ophthalmic medications. Pharmacological interventions often target the underlying inflammatory processes or provide neurotrophic support to promote epithelial healing and restore the homeostatic environment of the ocular surface (Pflugfelder & Stern, 2020).

Other names

Corneal epitheliumConjunctival epitheliumOcular surface epitheliumCorneal and conjunctival epithelia

Drugs targeting the ocular surface epithelia typically act by reducing T-cell mediated inflammation, activating neurotrophic signaling pathways (e.g., TrkA receptor activation), stimulating P2Y2 receptors to increase mucin and aqueous secretion, or providing corticosteroid-mediated suppression of inflammatory cytokines (Gipson, 2007; Pflugfelder & Stern, 2020).