Correlation between axial length and choroidal changes in high myopia

Abstract

Background Swept-source optical coherence tomography (SS-OCT) can furnish high-resolution structural images of the choroid for chorioretinal atrophy in high myopia. Aim The present study aimed to detect the axial length and choroidal thickness correlation in high myopia using SS-OCT. Using SS-OCT seeks to establish the choroidal thickness and axial length correlation in extreme myopia individuals. Patients and methods A prospective cross-sectional study that was carried out on two groups of patients, group A involved 60 high myopic eyes with myopic refractive error less than or equal to −6.00 diopters (D) and axial length greater than or equal to 26.5 mm which was divided into group A1 which included 30 eyes with axial length less than 29 mm and group A2 that involved 30 eyes with axial length greater than or equal to 29 mm. Group B (control group) included 30 emmetropic eyes with a normal range of axial length (23.5–24.5 mm). Results A high significant axial length was detected in group A2 in contrast to groups A1 and B with P value less than 0.001. The subfoveal choroidal thickness and choroidal thickness in other locations (1 mm superior, 1 mm inferior, 1 mm nasal, and 1 mm temporal to the fovea) were significantly thinner in group A2 than groups A1 and B (P <0.001). A statistically significant inverse correlation (P <0.001) was identified between the choroidal thickness at various locations and the axial length in groups A1 and A2. Conclusion Negative correlation was detected between axial length and both subfoveal choroidal thickness and best corrected visual acuity in patients with high myopia. There was a significant positive correlation between axial length and myopic refractive error.