Effect of Fasting on Contrast Sensitivity in Healthy Males

To evaluate the effect of fasting on contrast sensitivity (CS) in healthy male individuals during the month of Ramadan. This study included 45 healthy male individuals, aged between 20 and 40 years, working in the same environment. Functional acuity contrast testing (F.A.C.T) was performed using the Optec 6500 vision testing system. Measurements taken during a state of satiety one week before Ramadan were compared with those taken a minimum of 12 hours after the start of fasting in the first and fourth weeks of Ramadan. Contrast sensitivity (CS) was increased at the spatial frequency of three cycles per degree (cpd) at the end of the first week of Ramadan in comparison to the CS measured before Ramadan ( = 0.03). The mean CS values were increased at the spatial frequencies of 3 and 12 cpd at the end of the last week of Ramadan in comparison to the mean values measured before Ramadan ( = 0.01 for both). Although we found statistically significant increases in CS at certain frequencies, we can conclude that Ramadan fasting has no negative effects on CS.