Effect of hyperprolactinaemia on intra‐ocular pressure

Abstract

We have read with great interest the article by Mansouri et al. (2013) published in your journal. The authors reported marked reduction in intra-ocular pressure (IOP) in a female patient during sexual activity with the timing of the largest drop of the IOP corresponding to the recorded moment of orgasm. They hypothesized that the rapid increase in prolactin and dopamine levels occurring during orgasm (Kruger et al. 2005) may have an IOP-lowering effect resulting in immediate reduction in the IOP in this distinct patient. Actually, previous studies have already reported the IOP-lowering effect of dopamine in vivo, while low IOP values have been correlated with low prolactin levels in the plasma of women with seasonal affective disorder (Mekki & Turner 1985; Stojek et al. 1991). Hereby, we would like to share our experience of IOP measurements in patients with hyperprolactinaemia, but without any documented ocular pathology. In a prospective case series of five patients, data were collected for healthy eyes in patients with hyperprolactinaemia. Data included IOP and blood prolactin levels. Mean IOP for the right eyes (OD) was 8.4 mmHg and for the left eyes (OS) 8 mmHg, which is significantly lower than the mean IOP of the normal population (Leydhecker 1976). Mean prolactin blood level was 432.4 ng/ml, while the normal range is 2–18 ng/ml in males and 2–29 ng/ml in (non-pregnant) females. Significant negative correlation was found between IOP and prolactin blood levels for both eyes (OD: Pearson's correlation coefficient, r = −0.9368, p = 0.019; OS: Pearson's correlation coefficient, r = −0.922, p = 0.026) suggesting that the higher the levels of blood prolactin the lower the IOP. Detailed status of patients is depicted in Table 1. These preliminary data are in agreement with the clinical hypothesis of Mansouri et al., indicating that sex hormones such as prolactin, may have an important role in the physiology of IOP regulation. Of course, it should be interesting to investigate IOP changes in these patients after establishing normal levels of blood prolactin. Larger studies are required to delineate the exact nature of the IOP effects induced by sex hormones such as prolactin.