The effects of low- and hyper-Dk contact lenses on corneal epithelial homeostasis

Contact lens wear and eyelid suturing diminish overall Bcl-2 expression in the corneal epithelium, yet nuclear Bcl-2 in the exposed surface epithelial cells seems to be retained for longer periods when compared with the retention in control eyes. This observation may explain why there is a decrease in surface cell exfoliation during CTL wear, because nuclear Bcl-2 loss needs to precede apoptotic surface cell exfoliation. In addition, if the hypothesis is true that Bcl-2 also has a regulatory function in the proliferation and differentiation of tissues, the overall reduced expression of Bcl-2 (nuclear plus cytoplasmic) may clarify the decrease in proliferation of the corneal epithelium seen during CTL wear. Future studies should clarify the role of Bcl-2 in the homeostatic dynamics of the corneal epithelium. CTL wear and eyelid suturing provide excellent noninflammatory models to advance knowledge of Bcl-2 and its regulatory roles. Additionally, these models should help researchers gain a better understanding of the CTL-associated effects on corneal epithelium.