SD-OCT in Sickle cell haemoglobinopathies

Dear editor, We studied the article titled “Comparison of central macular thickness using spectral domain optical coherence tomography in sickle cell hemoglobinopathy patients and age-matched controls—A comparative cross-sectional observational study” by Dhanbad et al.[1] We have a few observations. The study group has included sickle cell hemoglobinopathy (SCH) without any clinical evidence of retinopathy. In such a scenario, we feel that only eyes with best-corrected visual acuity of 6/6 should have been included. Few patients with vision less than 6/60 have also been included. The authors have mentioned that the vision in such cases was less because of cataract. With vision less than 6/60, the thickness of the cataract will be significant and this can compromise the quality of the optical coherence tomography (OCT) scans. These eyes should not be included. It will also be informative to know if patients on medications that can be retinotoxic were excluded from the study. Similarly, if patients with positive smoking history were also excluded. We would also like to know how the results of the study are clinically significant. Even though the central macular thickness (CMT) in eyes with SCH was found to be statistically thinner as compared to normal control eyes, it was still within the normal range for age and gender. It would have been much more informative if the patients were sub-divided according to the duration of disease and a correlation found between CMT and disease duration. Similarly, a correlation could also have been found between CMT and patients with a history of sickling crisis. Ideally, a correlation should also have been studied between blood parameters and retinal indices. Finally, addition of OCT angiography related retinal indices, could have increased the significance of the study. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.