Blinking without eyelids: first video-documented evidence of a blink-like reflex in Ophisops elegans (Reptilia: Lacertidae)

Eyelids play a crucial role in protecting the eyes of vertebrates; however, certain reptile species, such as Ophisops elegans, completely lack movable eyelids. In this study, we present the first video-documented evidence of a blink-like reflex in O. elegans, captured through endoscopic field observations and corroborated by laboratory video analysis. The observed movement consisted of a brief convex deformation of the ocular surface, lasting approximately 0.3 s and resembling a blink despite the presence of a fixed transparent brille. This behavior was observed once in the field and twice under controlled laboratory conditions. We propose that O. elegans may employ subtle contractions of the ocular musculature to mimic the protective function of blinking. These findings indicate a novel compensatory mechanism in eyelidless lizards and underscore the need for further research into ocular adaptations among reptiles.