OKOLI DABERECHI PASCHALIN

Caffeine is a widely consumed stimulant known to affect both visual and systemic physiology through activation of the sympathetic nervous system. This study investigated the short-term effects of caffeine consumption on amplitude of accommodation (AA), near point of convergence (NPC), pupil size, and blood pressure (BP). Forty healthy participants aged 18–30 years were recruited and assessed at baseline, 30, 60, 90, and 120 minutes following ingestion of a caffeine-containing beverage (160 mg/500 mL). Standard clinical procedures were used: the push-up to blur technique for AA, RAF rule for NPC, pupillary distance ruler
for pupil diameter, and sphygmomanometer for BP. Data were analyzed using Friedman and Repeated Measures ANOVA tests, with statistical significance set at p < 0.05. Results revealed a significant increase in amplitude of accommodation (p < 0.001), indicating enhanced focusing ability, while near point of convergence slightly receded, suggesting a temporary reduction in binocular efficiency. Pupil size increased, peaking at 90 minutes, and systolic blood pressure rose steadily across all time points (p < 0.001). In conclusion, caffeine exerts short-term, measurable effects on both ocular and cardiovascular functions. These
findings underscore the influence of caffeine-induced sympathetic stimulation on visual performance and systemic physiology, emphasizing the need to consider recent caffeine intake during clinical evaluations.