Evaluation of the relationship between periodontal disease severity and retinal layer thickness in patients with diabetic retinopathy using optical coherence tomography

Evaluation Of The Relationship Between Periodontal Disease Severity And Retinal Layer Thickness in Diabetic Retinopathy Patients Using Optical Coherence Tomography Objective: The aim of this study is to evaluate the relationship between the severity of periodontal disease and retinal layer thicknesses in individuals diagnosed with Diabetic Retinopathy (DRP) using Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA), and to comprehensively investigate the potential effects of periodontitis on retinal microstructures. Materials and Methods: Our study is a prospective study in which retinal layer thickness and microvascular structures were evaluated using Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) imaging techniques. A total of 100 individuals aged 60 years and older (56 women and 44 men) were included in the study. Participants were divided into five groups:(1) Systemically healthy individuals (n=20),(2) Individuals diagnosed with Diabetes Mellitus (DM) but without diabetic retinopathy (DRP) (n=20),(3) Individuals diagnosed with nonproliferative diabetic retinopathy (NPDRP) with diabetic macular edema (DME) (n=20),(4) Individuals diagnosed with NPDRP without DME (n=20),(5) Individuals diagnosed with proliferative diabetic retinopathy (PDRP) (n=20).Ocular measurements of all participants were performed using an OCT device. With OCT, measurements of retinal layer thickness, the choroid–scleral interface (CSI), the ganglion cell layer (GCL), the retinal nerve fiber layer (RNFL), and the peripapillary CSI were obtained. OCTA was used to measure vessel densities in the superficial and deep retinal layers, as well as the FAZ (foveal avascular zone) values. Periodontal indices were also recorded for all individuals to assess their periodontal status. Results: In the OCT findings of our study, a significant increase in retinal layer thickness was observed in individuals with diabetic macular edema (DME) and in the PDRP group, particularly in the presence of stage 3 and 4 periodontal disease. GCL+ thickness was significantly reduced in all regions except for the 3 mm nasal and inferior areas in the PDRP group among individuals with stage 3 and 4 periodontal disease. Peripapillary CSI values showed a significant overall decrease in individuals with stage 3 and 4 periodontal disease. Similarly, RNFL thickness was significantly reduced in the PDRP group, especially in those with advanced periodontal disease. In the OCTA findings, a significant thinning in specific regions of the superficial retinal vessel density was detected in the NPDRP DMÖ- and NPDRP DMÖ+ groups in individuals with stage 3 and 4 periodontal disease. Regarding deep retinal vessel density, marked reductions were observed in various regions in the NPDRP DMÖ-, NPDRP DMÖ+, PDRP, and DM+ DRP- groups in the presence of stage 3 and 4 periodontal disease. Additionally, a significant enlargement of the foveal avascular zone (FAZ) was observed in both the superficial and deep layers in the DM+ DRP- and PDRP groups among individuals with stage 3 and 4 periodontal disease. Conclusion: The findings suggest that periodontal inflammation may lead to structural alterations in retinal microvascular and neural tissues, indicating that periodontitis could be a potential risk factor in the pathogenesis of diabetic retinopathy. Keywords: Periodontitis, OCT, OCTA, Diabetic Retinopathy, Diabetic Macular Edema