The evaluation of optic nerve head in myopia with the results of optical coherence tomography angiography and retina nerveus fiber analysis

Purpose: The aim of this study was to evaluate the retinal nerve fiber layer (RNFL) thickness in optic nerve head (ONH) with optical coherence tomography (OCT) and vascular density of ONH with optical coherence tomography angiography (OCTA) in axial myopia patients. Materials and Methods: This study was performed retrospectively with the data obtained from OCT, OCTA and patient files taken between June 2017 and May 2019 in patients who were followed up and treated in the Retinal Unit of Ophthalmology Department of Dicle University Medical Faculty with the diagnosis of myopia. In this study, 37 eyes of 23 patients who were previously diagnosed with myopia but no pathological findings due to retinal examination and 34 eyes of 24 patients with degenerative myopia were evaluated. Blood flow and RNFL thickness of ONH were evaluated and compared with eyes without ophthalmopathology. Results: The mean axial lengths and refraction defects respectively of the patients were 22,510 ± 0,559 mm, -0,236 ± 0,363 D in the control group; 26,495 ± 0,702 mm, -8,567 ± 2,885 D in the first group and 30,025 ± 1,126 mm, -15,838 ± 3,903 D in the second group and significant differences were observed in all comparisons. In the RNFL measurements performed with OCT, it was observed that there was a statistically significant decrease in RNFL thickness in other quadrants other than temporal quadrants in the second group when compared with the first and control groups. In addition, the first group; when compared with the control group, there was a statistically significant decrease in RNFL thickness in the quadrants other than the temporal and temporal inferior quadrants. No correlation was found between RNFL values and axial length and refractive error. The vascular density of ONH was evaluated with OCTA. In the control group, OCTA parameters did not show statistically significant differences with the first group, but show statistically significant differenceswith the second group. There was also a statistically significant difference between the first and second groups in NH and RPC segments in the same regions. As the axial length increased in both the first and second groups, there was a decrease in the ONH perfusion measured by OCTA, ie there was negative correlation. It was found that the correlation between OCTA and RNFL parameters varied in different segments. Conclusion: In patients with axial myopia, vascular density density measurements can be performed with OCTA, which is a noninvasive method and the optic disc and peripapillary area can be evaluated for complications, diagnosis and follow-up. Key Words: Myopia, axial myopia, axial length, retinal nerve fiber layer, optical coherence tomography, optical coherence tomography angiography.