Investigation of optical coherence tomography angiography data in idiopathic macular telangiectasia cases

Introduction and Purpose: In this study, we aimed to analyze the optical coherence tomography angiography (OCTA) findings in patients with macular telangiectasia type 2 (Mac Tel type 2) to understand disease stages and evaluate the contributions of OCTA in diagnosis, follow-up, and treatment processes. Mac Tel type 2 generally appears in the 5th-7th decades of life. This disease is characterized by central vision loss and visual field distortions. It affects both eyes and is accompanied by neuro-sensory atrophic changes. The non-invasive nature of OCTA and its ability to provide three-dimensional imaging of vascular networks present a significant advantage, especially in the early detection of choroidal neovascularization and in treatment planning. By comparing Mac Tel type 2 cases with a control group and among disease stages, we aimed to assess the efficacy of OCTA in diagnosing the disease and evaluating vascular parameters. Materials and Methods: We examined 51 eyes of 26 patients diagnosed with Mac Tel type 2 who underwent OCTA. In the control group, 51 eyes of 26 individuals with no retinal disease and similar age and gender who also underwent OCTA were evaluated. The study analyzed best-corrected visual acuity (BCVA), demographic characteristics, fundus findings, and OCTA images and quantitative data of the participants. Results: The mean age was calculated as 61.16±6.72 in the case group and 58.47±4.68 in the control group. Female patients constituted 80.4% (n=41) of the 26 Mac Tel type 2 cases. The mean BCVA (logMAR) in the case group was 0.25±0.29, while in the control group, it was 0.00 (p<0.001). The mean FAZ values of the full-thickness retina in the case and control groups were 0.270±0.087 and 0.292±0.114 mm², respectively, with no statistically significant difference between the groups (p=0.276). Except for the foveal vascular density in the superficial capillary plexus, differences in superficial capillary plexus vascular density percentages were statistically significant between the groups (p<0.05). Significant differences were observed in the 50 deep capillary plexus in the superior hemisphere, parafoveal temporal quadrant, and perifovea vascular densities (p=0.05, p=0.009, p=0.017). The median flow density values of the full-thickness retinal FAZ were 52.71 in the case group and 55.46 in the control group, with a statistically significant difference between the FAZ_FD values of the case and control groups (p=0.01). The median flow density values of the full-thickness retinal FAZ in Mac Tel type 2 stages were as follows (stages 1-5): 54.72, 53.03, 48.39, 48.55, and 54.68. A statistically significant difference was observed between FD values across stages (p=0.013). Conclusion: We found significant differences in vascular density in the superficial capillary plexus, particularly in foveal vascular density and other regions. The use of OCTA as a non-invasive method provides advantages in the monitoring and evaluation of the disease. However, rather than being used as a definitive diagnostic tool, OCTA should be considered an auxiliary method in diagnosis. For the quantitative data assessed by OCTA to be used effectively in diagnosis, follow-up, and staging, multicenter studies with long-term follow-up of more cases are needed. Keywords: Idiopathic Macular Telangiectasia, Optical Coherence Tomography Angiography, Vascular Density, Foveal Avascular Zone, Superficial Capillary Plexus, Deep Capillary Plexus, Foveal Density