Ismail A, et al. - Authors assessed and compared the temporal changes in pulse waveform parameters of ocular blood flow (OBF) between non-habitual and habitual groups due to caffeine intake. They conducted this study on 19 healthy subjects, non-smoking and between 21 and 30 years of age. Significant modulation of OBF and a different response was demonstrated by caffeine in non-habitual and habitual groups. To differentiate between the two groups, suitable biomarkers were mean blur rate (MBR)and blowout time (BOT).