Sir,

We read with interest the article ‘Uveitis and the menstrual cycle’ by Sanghvi et al.1 In their study, the authors reported the relation between menstrual cycle and patient-reported onset of acute anterior uveitis (AAU), in 76 regularly menstruating women. They concluded that the onset of AAU was partially dependent on the levels of either oestrogen or progesterone, or both. They summarized that they have demonstrated a significant increase in the incidence of AAU arising late in the menstrual period. While we applaud the authors' efforts on this important issue, we felt that the authors have to clarify a few points before arriving at their conclusion.

First, the authors admitted that they have not performed any serum assay of hormones to demonstrate the relation between the onset of AAU and blood levels of oestrogen or progesterone. What they have shown in fact was a possible increase in incidence of AAU in late menstrual cycle. The authors considered that the incidence was significantly increased. However, as they have pointed out, in fact that was ‘just approaching statistical significance but not yet achieving it’. What is more, while the recall bias for the date of commencement of last menstrual period (LMP) was probably not great, that for the date of commencement of onset of uveitis was yet unknown. It is not unusual for mild anterior uveitis to be relatively silent and asymptomatic in the early phase of the disease. The relationship between menstrual cycle and onset of AAU that the authors presented was thus better described as a possible one.

Second, anterior uveitis is a heterogeneous group of diseases. It would be of value to know the aetiologies of anterior uveitis in this group of patients, and especially in those recurrent cases. Anterior uveitis is known to be much more subclinical when associated with certain aetiologies, such as juvenile rheumatoid arthritis2 and inflammatory bowel disease.3 That again has bearing as to the accuracy of self-reported onset of AAU. It would also be interesting to see whether there are specific aetiologies that are particularly dependent on menstrual cycle.

Third, 65 out of 76 patients were having a second or subsequent attack. It would be imperative to know whether they were ‘acute on chronic’ cases in which they might still be put on low tailing down dose of steroid before the attack, which might modify their self-perceived onset of recurrent AAU.

We suggest that the authors may also try to see whether the acute uveitic attacks were particularly severe with respect to, for example, intraocular pressure rise, frequency and dosage of steroid required to abort the attack, etc., during a particular phase of menstrual cycle. We believe that reliance on objective signs may be a better measure than self-reported onset of disease.