Comparison of Choroidal Vascularity Index, Retinal, and Optic Nerve Changes in Diabetes Mellitus Patients Without Diabetic Retinopathy

OBJECTIVES: To report changes in the choroid, optic nerve, and macula in diabetes mellitus patients without diabetic retinopathy, and to compare these findings with age and sex-matched healthy volunteers. Furthermore, the duration of the disease was recorded and the impact on these parameters was aimed to be analyzed.
METHODS: In this study, 60 right eyes of diabetes mellitus (DM) patients without diabetic retinopathy who applied to our department for routine examination were enrolled. To evaluate the peripapillary retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL), Swept-Source Optical Coherence Tomography imaging was performed. In addition, images were recorded and processed by the image-j program and the ‘choroidal vascularity index’ (CVI) was calculated. The measurements were compared with 60 right eyes of age-sex-matched healthy volunteers. Furthermore, the patient group was divided into 2 subgroups according to disease duration and the measurements were compared with each other as well.
RESULTS: Both RNFL and GCL thickness values were observed to be thinner in DM patients group compared to the control group. CVI was found to be lower in DM group compared to the control group. In addition, the duration of the disease was significantly associated with the RNFL and GCL thinning and lower CVI.
DISCUSSION AND CONCLUSION: DM can lead to a decrease in RNLF and GCL thickness and also a decrease in CVI which can impair visual acuity even in the absence of diabetic retinopathy. Therefore, monitoring changes in the optic nerve, retina, and choroid layer is crucial in these patients.