Effect of iris show on perceived upper eyelid height

Abstract

Objective: To introduce “iris show,” the amount of visible iris tissue between the superior pupil border and the upper eyelid margin, to evaluate the effect of iris show on perceived upper eyelid height, and to discuss potential nonsurgical treatment options for mild blepharoptosis. Methods: Participants completed a survey containing 4 subject photographs. These photographs depicted images of varying iris colouration (blue, green, light brown, and dark brown) with identical upper eyelid marginal reflex distance (MRD1) values, but asymmetric pupil size/amount of visible iris show. Study participants were asked to select the eyelid that appeared “droopier,” or choose “same height.” Statistical analyses used 1-tailed and 2-tailed t tests. Results: 390 participants completed the survey. In photographs of blue and green irides, both eyelids had equal MRD1s, but the eyelid with less iris show was perceived as more ptotic (p = 0.002 and 0.03, respectively). In patients with dark brown irides, eyelid heights were perceived as identical despite differences in iris show (p = 0.002). Conclusions: Decreased iris show corresponds to perceived lowering of the upper eyelid in light-coloured irides (e.g., blue and green), but may be less impactful in brown and/or dark brown irides where the iris tissue is less distinguishable from the pupil. Topical instillation of apraclonidine may represent a nonsurgical option for treatment of mild blepharoptosis in patients with light irides as it both elevates the upper eyelid margin and induces miosis, resulting in an increase in iris show and corresponding enhanced perception of upper eyelid elevation.