Pharmacological and light-driven pupillary accommodation in guinea pigs: comparative effects of muscarinic modulators and illumination across developmental stages

This study investigates pupillary responses in developing guinea pigs, revealing a direct pupillary light reflex (PLR) with light intensity-dependent responses, while indirect PLR was undetectable. The differential effects of muscarinic modulators on pupillary responses underscore the critical role of cholinergic signaling in ocular accommodation, with age-related variations in sensitivity. Additionally, a novel non-contact measurement methodology achieved a precision of 0.01 mm for pupillary quantification, enhancing accuracy in ocular studies.