Reply to Letter: Spectral‐domain optical coherence tomography as a potential biomarker in Huntington's disease

We have read the article titled “Spectral-Domain Optical Coherence Tomography as a Potential Biomarker in Huntington’s Disease’’ by Andrade and colleagues. The authors investigated the retinal and choroidal changes in 15 eyes of 8 patients with Huntington’s disease and analyzed any potential correlations with the stage of the disease. They found that the mean, central, and inferior macular choroidal thickness (CT) were significantly reduced in patients with Huntington’s disease when compared with controls. However, no differences were observed in the macular retina or peripapillary retinal and choroidal measurements. We congratulate the authors for this valuable study. We would like to raise some additional points for consideration by the authors. First, it has been known that a number of local and systemic physiologic and pathological conditions may affect CT, including diurnal variation, systemic and local diseases, use of drugs, axial length of the globe, intraocular pressure, and a number of other factors. Andrade and colleagues referred to several factors, however, some other points may also be important. For instance, the authors mentioned that 5 of 8 patients included in the study were women, and 7 of them used at least 1 antichorea drug. The effects of menstrual cycle and use of drugs on CT have been demonstrated. Therefore, we would like to ask whether the authors took the menstrual cycles of the patients into consideration. We would like to get the opinions of the authors on the effects of the drugs used on the data obtained from the study and their statistical analysis. We also wonder whether axial length, sleep, and exercise statuses of the participants, smoking, consumption of alcohol, or caffeinated/noncaffeinated beverages were taken into consideration before the optical coherence tomography measurements. We also want to ask whether the systemic blood pressures and the body mass indexes of the participants were considered in the study because those parameters affect CT significantly.