Effect of oral contraceptives on lacrimal fluid peroxidase activity in women

Lacrimal fluid peroxidase has been supposed to be involved in the protection against oxidative damage to the ocular surface. Our recent findings showed the existence of significant cyclic variations in lacrimal fluid peroxidase activity that were positively correlated with those of 17beta-estradiol plasma levels throughout the menstrual cycle of fertile women. In the present study lacrimal fluid peroxidase activity of 8 healthy normocyclic women using low-dose oral contraceptives during the monthly cycle was determined. Data showed that low-dose oral contraceptives caused a decrease in lacrimal fluid peroxidase activity and a lack of its cyclic pattern with respect to the enzyme activity of 8 untreated age-matched women. Moreover, this result suggests that lacrimal fluid peroxidase activity could be regulated by estrogen.