Interfacial Phenomena and the Ocular Surface

Abstract

Ocular surface disorders, such as dry eye disease, ocular rosacea, and allergic conjunctivitis, are a heterogeneous group of diseases that require an interdisciplinary approach to establish underlying causes and develop effective therapeutic strategies. These diverse disorders share a common thread in that they involve direct changes in ocular surface chemistry as well as the rheological properties of the tear film and topographical attributes of the cellular elements of the ocular surface. Knowledge of these properties is crucial to understand the formation and stability of the preocular tear film. The study of interfacial phenomena of the ocular surface flourished during the 1970s and 1980s, but after a series of lively debates in the literature concerning distinctions between the epithelial and the glandular origin of ocular surface disorders during the 1990s, research into this important topic has declined. In the meantime, new tools and techniques for the characterization and functionalization of biological surfaces have been developed. This review summarizes the available literature regarding the physicochemical attributes of the ocular surface, analyzes the role of interfacial phenomena in the pathobiology of ocular surface disease, identifies critical knowledge gaps concerning interfacial phenomena of the ocular surface, and discusses the opportunities for the exploitation of these phenomena to develop improved therapeutics for the treatment of ocular surface disorders.

External eye symptoms in indoor environments

“…For instance, reported DE symptoms among young and middle‐aged Japanese office workers were significantly higher among those with clinically diagnosed DED (12%) than in those with probable (54%) or undiagnosed DED (34%); a similar prevalence of DED was reported among the Singapore population by Tan et al . This implies that immanent DED on the ocular surface, affecting 20% of the population, in general, may contribute to the overall reported prevalence; in addition, environmental and occupational exposures, and personal factors may further contribute. Thus, the ophthalmic clinical picture is hampered by the temporality of office‐related eye symptoms vs DED.…”

“…It is unclear how the mixed composition of these lipids may retard the TE . It is speculated that branched and hydroxylated wax esters form a more uniform LL that more efficiently retards the TE; alternatively, compositional changes of the lipids may alter the interfacial viscosity and elasticity of LL forming two separate interfaces, air/lipid and water/lipid . For instance, bacterial lipases may break down the various esters or they may be broken down by ambient pollutants.…”

Tear Film–Oriented Diagnosis and Tear Film–Oriented Therapy for Dry Eye Based on Tear Film Dynamics

“…48,50 In TFOT using 3% DQS eye drops, the improvement of TF stability can be expected, not only through the supplementation of aqueous fluid and MUC5AC to the TF, but also through the supplementation of the membraneassociated mucins (especially MUC16 11 ) to the corneal surface epithelium to enhance its wettability; and those two actions presumably contribute to the reported continuous improvement of DE in the long-term clinical use of DQS. 51 MUC16 reportedly plays a key role in ensuring the low corneal contact angle, 52 and its spatial distribution reportedly differs between healthy eyes and dry eyes. [53][54][55] Alternatively, the glycocalyx may become contaminated with lipids, for example, due to dimple formation below lipid ''globs,'' 37 and lipid particles supposedly precede the spreading of the major part of the TFLL.…”

Effect of Stratification on Surface Properties of Corneal Epithelial Cells

“…Although the International Dry Eye Workshop categorized the types of dry eye as (1) aqueousdeficient and (2) evaporative, 1 dry eye syndrome and other ocular surface disorders also involve the interaction between the cellular surface of the eye and the liquid film constituted by the tears. 4 It is widely believed that the stability/instability of tear film depends on the surface properties of the epithelium, especially its wettability or degree of retention of tear film in contact with the ocular surface. [5][6][7] Although wetting properties have conventionally been attributed to the presence of a hydrophilic glycocalyx, 8 specifically to the highly O-glycosylated membrane-associated mucins of the ocular surface (principally MUC1, MUC4, and MUC16), 9 to our knowledge, there are no studies that directly correlate the expression and spatial distribution of cell associated mucins to the physicochemical surface properties of the ocular surface.…”