VALIDATION OF THE RECENTLY DEVELOPED ATN CLASSIFICATION AND GRADING SYSTEM FOR MYOPIC MACULOPATHY

Purpose: To validate the recently developed ATN grading system for myopic maculopathy to classify eyes with pathologic myopia. Methods: Cross-sectional study. A series of consecutive eyes diagnosed with pathologic myopia and signs of myopic maculopathy (grade >= 1 for atrophic, tractional, or neovascular components of the ATN), with a refractive error > -6.0 diopters (D), were included. All patients underwent complete ophthalmological examination including fundus photography and swept-source optical coherence tomography. Six observers graded each eye twice using the ATN system (>= 15 days between assessments) based only on the aforementioned data. Results: Sixty eyes from 47 patients (61.7% female) were graded. Mean patient age was 63.2 +/- 11.7 years. The mean spherical equivalent was -13.8 +/- 6.5 D. Mean axial length was 28.6 +/- 2.16 mm. Overall, the mean intraobserver agreement (%) for the same image was 92.0%, and the mean interobserver agreement for the second image was 77.5%. The weighted Fleiss k showed excellent correlation (k > 0.8) for the traction and neovascularization components and good correlation (0.75) for atrophy. Interobserver agreement for each of these three components was 95.2%, 98.4%, 95.0%, respectively. Conclusion: Application of the ATN resulted in high intraobserver and interobserver correlation, underscoring the reproducibility of the system.