—Cartwright et al presented an interesting hypothesis regarding a possible relationship between NTG and immune-related disease. They compared medical records of 67 patients with NTG with those of a control group of patients with OHT. They reported that their preliminary results "... indicate an association between normal tension glaucoma and immune-related disease" although this "retrospective chart review... must therefore be viewed with caution." In addition to the problems inherent with a retrospective review of medical charts that were discussed by the authors, we wish to address other points that could affect their results and conclusions. First, the medical histories of patients with OHT are not valid controls for those of patients with NTG. Patients in whom the diagnosis of NTG is being considered would be more likely to have had an extensive medical workup and to be asked to provide an extensive and detailed medical history than those
