Abstract
Purpose :
Cross-sectional assessment of connective tissue changes by high-resolution surface coil orbital MRI was performed in Indian subjects to establish age specific normative data in this group and aid trans-ethnic comparison with Caucasian subjects, where these changes have now been found to be causal for the genesis of the “sagging eye syndrome” (SES), a small-angle mechanical strabismus associated with symptomatic diplopia.
Methods :
52 orbits of 27 adult non-strabismic subjects in the age group between 18-40 years (Group A, n=18 subjects (36 orbits), average age=25±5.6 years, M:F::10:8), 41-60 years (Group B, n=05 subjects (10 orbits), average age=46.4±4.7 years, M:F::2:3) and >60 years (Group C, n=04 subjects (08 orbits), average age=74±6.3 years, M:F::3:1) were imaged by high-resolution fast spin echo T2 weighted (T2FSE) surface coil MRI sequences with the subject fixating at a central target (1.5T, Siemens Symphony). 2 mm thick quasi-coronal image planes perpendicular to the orbital axis were analysed for extra-ocular muscle (EOM) pulley locations, EOM cross-sections and LR-SR band length while quasi-sagittal and axial planes were used to analyse rectus EOM length, all by Image J software as per published norms.
Results :
The average LR-SR band length was 8.6±2.2 mm in Group A, 10.5±2.7 mm in Group B and 15.5±2.4 mm in Group C. The inter-group differences were significant at p≤0.05 with the Group A versus Group B difference being 0.03, Group B versus Group C difference being 0.001 and the Group C versus Group A being 2.65785E-09 (Figure 1).
Conclusions :
Age-related connective tissue changes in non-strabismic Indian subjects were similar to those observed in Caucasian subjects. This may translate as the basis of strabismus due to SES in this ethnic group.
This is a 2021 ARVO Annual Meeting abstract.