Journal of Medicine and Applied Clinical Sciences
Peer Reviewed Open Access Journal
Peer Reviewed Open Access Journal
This study aims to compare corneal tomographic and endothelial parameters in diabetic patients with both controlled and uncontrolled glycemic status, as well as to investigate the relationships between corneal parameters, glycemic control, and the duration of diabetes. Conducted in a hospital setting, this cross-sectional study involved diabetic patients categorized into controlled and uncontrolled groups according to their HbA1c levels. Corneal tomography was executed utilizing Scheimpflug imaging, while endothelial evaluation was performed through non-contact specular microscopy. To maintain statistical independence, the right eye was predetermined for all inferential analyses. Between-group comparisons were carried out using suitable statistical tests, with effect sizes presented alongside p-values. Correlation and multivariable regression analyses were employed to assess the associations among corneal parameters, HbA1c levels, and the duration of diabetes. The findings revealed that patients with uncontrolled diabetes exhibited a significantly steeper flat keratometry (K1) in comparison to those with controlled glycemic status, with a moderate-to-large effect size, suggesting potential clinical significance. Conversely, other tomographic parameters such as steep keratometry, mean keratometry, central corneal thickness, anterior chamber depth, and corneal volume did not show significant differences between the groups and were associated with small effect sizes. Nevertheless, a greater dispersion of various tomographic parameters was descriptively noted in the uncontrolled diabetes cohort, indicating heightened structural variability. The density of endothelial cells was numerically elevated in the uncontrolled diabetes group; however, it did not achieve statistical significance and was associated with increased variability. Indices of endothelial morphology, such as the coefficient of variation and hexagonality, were similar across the groups. Correlation and multivariable regression analyses indicated no significant independent relationship between HbA1c and central corneal thickness or endothelial cell density after controlling for age, sex, and duration of diabetes. The magnitude of the observed regression coefficients fell below thresholds deemed clinically significant. Uncontrolled diabetes is linked to subtle changes in corneal curvature and increased structural variability, rather than consistent alterations in corneal thickness or endothelial parameters. These results imply heterogeneous, subclinical corneal involvement in diabetes and underscore the multifactorial nature of diabetes-related corneal changes. Larger longitudinal studies are necessary to elucidate their clinical implications.
Diabetes mellitus, Corneal tomography, Endothelial cell density, Glycemic control, Specular microscopy
Su, D. H., Wong, T. Y., Wong, W. L., Saw, S. M., Tan, D. T., Shen, S. Y., Loon, S. C., Foster, P. J., Aung, T., & Singapore Malay Eye Study Group. (2008). Diabetes, hyperglycemia, and central corneal thickness: The Singapore Malay Eye Study. Ophthalmology, 115(6), 964–968.e1.
Varshney, A. S., Saraiya, A. B., Mahida, H. B., Patel, C. S., & Chauhan, M. D. (2024). Impact of diabetes mellitus on tear secretion, intraocular pressure, and contrast sensitivity: A comparative study of controlled and uncontrolled diabetics. IP International Journal of Ocular Oncology and Oculoplasty, 10(4), 213–219.
Al-Sharkawy, H. T. (2015). Corneal endothelial changes in type 2 diabetes mellitus before and after cataract surgery. Journal of the Egyptian Ophthalmological Society, 108(2), 79–85.
Dardyr, M., Mostafa, S., & Elsayed, S. (2024). Corneal endothelium and central corneal thickness changes in patients with type 2 diabetes mellitus. Delta Journal of Ophthalmology.
Pandey, S., Singh, A., Vannadil, H., & Agrawal, M. (2024). Corneal parameters in diabetics versus non-diabetics and correlation with various blood sugar parameters. Romanian Journal of Ophthalmology, 68, 128–134.
Beato, J., Esteves-Leandro, J., Reis, D., Falcão, M., Rosas, V., Carneiro, Â., & Reis, F. (2020). Evaluation of corneal structure and endothelial morphological characteristics in type 2 diabetic and non-diabetic patients. Clinical Ophthalmology, 14, 1993–1999.
Kadri, R., Sasalatti, N., Hegde, S., Kudva, A., Parameshwar, D., & Shetty, A. (2021). Corneal endothelial cell characteristics and central corneal thickness in patients with type 2 diabetes mellitus. Kerala Journal of Ophthalmology, 33, 56–60.
Çolak, S., Kazancı, B., Soba, D., Erol, Y., & Yılmazbaş, P. (2021). Effects of diabetes duration and HbA1c level on corneal endothelial morphology. European Journal of Ophthalmology, 31, 967–975.
Papadakou, P., Chatziralli, I., Papathanassiou, M., Lambadiari, V., Siganos, C., Theodossiadis, P., & Kozobolis, V. (2020). The effect of diabetes mellitus on corneal endothelial cells and central corneal thickness: A case–control study. Ophthalmic Research, 63, 550–554.
Jha, A., Verma, A., & Alagorie, A. (2022). Association of severity of diabetic retinopathy with corneal endothelial and thickness changes in patients with diabetes mellitus. Eye, 36, 1202–1208.
Shankar, C., Premnath, G., Balaji, A., Aila, L., & Sruthi, G. (2020). Study of impact of diabetes mellitus on corneal central thickness and endothelial parameters in Indian eyes. Indian Journal of Clinical and Experimental Ophthalmology.
Kim, Y., & Kim, T. (2021). The effects of type 2 diabetes mellitus on the corneal endothelium and central corneal thickness. Scientific Reports, 11, Article 7075.
Opala, A., Kołodziejski, Ł., & Grabska-Liberek, I. (2025). Impact of well-controlled type 2 diabetes on corneal endothelium following cataract surgery: A prospective longitudinal analysis. Journal of Clinical Medicine, 14, Article 3603.
Geilani, N., Julio, G., & Abdala, M. (2023). Corneal endothelial morphological alterations in type 2 diabetes: Associations with glycemic control, disease duration, and diabetic retinopathy severity—A cross-sectional study in Benghazi, Libya. Libyan International Medical University Journal, 8, 82–88.
Chowdhury, B., Bhadra, S., Mittal, P., & Shyam, K. (2021). Corneal endothelial morphology and central corneal thickness in type 2 diabetes mellitus patients. Indian Journal of Ophthalmology, 69, 1718–1724.
Taşlı, N., Icel, E., Karakurt, Y., Uçak, T., Uğurlu, A., Yılmaz, H., & Akbaş, E. (2020). The findings of corneal specular microscopy in patients with type 2 diabetes mellitus. BMC Ophthalmology, 20, Article 214.
El-Agamy, A., & Alsubaie, S. (2017). Corneal endothelium and central corneal thickness changes in type 2 diabetes mellitus. Clinical Ophthalmology, 11, 481–486.
Storr-Paulsen, A., Singh, A., Jeppesen, H., Nørregaard, J., & Thulesen, J. (2014). Corneal endothelial morphology and central thickness in patients with type II diabetes mellitus. Acta Ophthalmologica, 92, 158–160.
