Dear Editor, I read with great interest the recent study examining retinal thickness differences between type 1 and type 2 diabetes mellitus. The authors deserve appreciation for addressing retinal neurodegeneration—an increasingly important aspect of diabetic eye disease.1 Future research, however, might benefit from some methodological clarifications. First, the authors mostly use the ETDRS grid to give mean retinal thickness data without sectoral analysis. Since neuroretinal thinning in diabetes often begins in localized parafoveal or perifoveal zones, subfield-wise reporting could provide deeper insight into early structural changes.1 Second, adjustments for axial length and refractive status were not included. These biometric factors significantly influence optical coherence tomography (OCT) measurements, especially peripapillary RNFL and macular thickness. Controlling for these parameters would help differentiate true pathological thinning from magnification-based measurement variation.2,3 Third, while the use of normative comparisons is commendable, mean ± SD alone may limit clinical applicability due to ethnicity- and device-specific variations. Presenting percentile-based normative ranges (5th–95th percentile) would facilitate better applicability in clinical decision-making.4 Additionally, a brief statement on statistical power and the minimum detectable difference would reassure readers of the study’s ability to detect clinically meaningful retinal thickness changes. Finally, OCT segmentation and inter-observer variability represent significant contributors to measurement error. Confidence in the outcomes given would be increased if it were made known whether graders were masked and the automated boundaries were manually examined.3 All things considered, the research greatly advances our knowledge of the early neuroretinal alterations associated with various forms of diabetes. The aforementioned ideas would encourage more investigation and continued discussion about the application of retinal layer analysis in diabetes treatment. I am grateful for the opportunity to comment on this work. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.
Vazrala et al. (2026) studied this question.