The measurement and correlation analysis of scleral and choroid thickness in branch retinal vein occlusion

Abstract

Objective: To use Optical Coherence Tomography (OCT) to measure scleral thickness (ST) and subfoveal choroid thickness (SFCT) in patients with Branch Retinal Vein Occlusion (BRVO) and to conduct a correlation analysis. Methods: A cross-sectional study was conducted. From May 2022 to December 2022, a total of 34 cases (68 eyes) of untreated unilateral Branch Retinal Vein Occlusion (BRVO) patients were recruited at the Affiliated Eye Hospital of Nanchang University. Among these cases, 31 were temporal branch vein occlusions, 2 were nasal branch occlusions, and 1 was a superior branch occlusion. Additionally, 39 cases (39 eyes) of gender- and age-matched control eyes were included in the study. Anterior Segment Optical Coherence Tomography (AS-OCT) was used to measure ST at 6mm above, below, nasal, and temporal to the limbus, while Enhanced Depth Imaging Optical Coherence Tomography (EDI-OCT) was used to measure SFCT. The differences in ST and SFCT between the affected eye, contralateral eye, and control eye of BRVO patients were compared and analyzed for correlation. Results: The axial lengths of the affected eye, contralateral eye, and control group were (22.92±0.30) mm, (22.89±0.32) mm and (22.90±0.28) mm respectively, with no significant difference in axial length between the affected eye and contralateral eye (P>0.05). The SFCT and ST measurements in different areas showed significant differences between the affected eye, contralateral eye in BRVO patients (P<0.05). In comparison between BRVO-affected eyes and control eyes, there were no statistically significant differences in age and axial length between the two groups (P>0.05). However, significant differences were observed in SFCT and temporal, nasal, superior, and inferior ST between the two groups (P<0.05). When comparing SFCT and ST between BRVO-affected eyes with and without macular edema, no statistically significant differences were found (t=-1.10, 0.45, -1.30, -0.30, 1.00; P=0.28, 0.66, 0.21, 0.77, 0.33). Correlation analysis indicated a significant positive correlation between SFCT and temporal ST in BRVO patients (r=0.288, P=0.049), while no correlation was found between SFCT and nasal, superior, and inferior ST (P>0.05). Conclusion: In BRVO patients, both SFCT and ST increase, and there is a significant correlation between SFCT and the ST at the site of vascular occlusion.