Reproducibility of choroidal thickness manual measurement results using spectral-domain optical coherence tomography in patients with pathological myopia

Abstract

Changes in choroidal thickness (CT) may indicate the presence of macular diseases and be used to monitor their course and treatment. Automatic segmentation of the choroid is not currently available, and semi-automatic segmentation is laborious and time-consuming. Purpose. To evaluate the reproducibility of CT manual measurement results using spectraldomain optical coherence tomography (SD-OCT) in patients with pathological myopia. Material and methods. A retrospective analysis of SD-OCT (Optovue RTVue-100) data from the macula of patients with myopic choroidal neovascularization treated with anti-VEGF therapy (ranibizumab, aflibercept) was performed. The study group consisted of 37 patients (43 eyes), incl. 31 women, mean age 53.4 years, mean length of the anterior-posterior axis of the eye – 28.42 mm. Three researchers performed independent measurements of CT in manual mode at five points (subfoveolar, nasal, temporal, upper and lower, located 3 mm from the center of the foveola) before the start of antiangiogenic therapy and in dynamics after 1 year of treatment. Results. CT values before treatment were minimal at the nasal point (mean – 35.5 µm) and increased in the following sequence: lower point (60.9 µm), subfoveolar (74.1 µm), temporal (85.7 µm), upper (91.0 µm). The same ratio of indicators persisted at 12 months after the treatment initiation, however, the absolute values decreased, amounting to 35.1, 56.5, 66.3, 83.7 and 85.8 µm, respectively. Statistical analysis performed using the Kruskal – Wallis test showed a statistically significant (p < 0.05) difference in the data obtained between researchers 1 and 2 in one case, between researchers 2 and 3 in 5 series of measurements; the difference between the results obtained by researchers 1 and 3 did not find statistical confirmation. Conclusion. Our results correspond to the literature data and confirm the importance of CT assessment in patients with degenerative myopia, and manual measurement of the parameter using SD-OCT, due to its simplicity and accessibility, can be used by ophthalmologists to solve daily clinical issues. For a more accurate quantitative assessment of CT in scientific research, it is advisable to use more sensitive and reproducible methods. Keywords: choroidal thickness, spectral-domain optical coherence tomography, manual mode, pathological myopia, myopic choroidal neovascularization