Editor,—We refer to the interesting article by Maaret al1 published in theBJO. The authors should be congratulated for presenting a new method of screening for diabetic macular oedema. However, the paper contains some statistical errors, and we believe the results can be interpreted in other ways.

Firstly, there are some internal inconsistencies with some of the results reported in the paper. Specificity of the Mollon T test (score >1) for detecting clinically significant macular oedema (CSMO) was reported as 88.9% and specificity was reported as 99.3%. These values could not possibly be obtained with the subject numbers specified, and we believe …