Longitudinal evaluation of Bruch's membrane opening-minimum rim width in Chinese children: The Hong Kong Children Eye Study.

Purpose: To evaluate longitudinal changes in Bruch's membrane opening-minimum rim width (BMO-MRW) and its associated factors in school children aged 6-8 years, over 3 years, based on the Hong Kong Children Eye Study.

Methods: In this longitudinal study, 740 children received comprehensive ophthalmologic examinations at baseline and at 3-year follow-up visits. Based on their refractive status, they were divided into groups of persistent non-myopia, newly-developed myopia, and persistent myopia. Global and sectoral BMO-MRW, retinal nerve fiber layer (RNFL) thickness, BMO area, and disc area were all measured using spectral-domain optical coherence tomography (SD-OCT).

Results: The mean age of the participants at baseline was 7.71 ± 1.01 years (range 6-8 years), and 352 (47.7 %) were males. The 3-year follow-up visit revealed a significant increase in all sectors of BMO-MRW, average global BMO-MRW changed from 339.3 ± 51.7 µm to 361.3 ± 57.8 µm. Children in the persistent myopia group and newly developed myopia group showed significantly faster rates of BMO-MRW growth in all sectors compared to children of the persistent non-myopia group (all P < 0.001). In multivariable linear regression analysis, global BMO-MRW enlargement increased with larger axial length elongation (β = 0.20, P < 0.001), larger BMO area enlargement (β = 0.21, P < 0.001), and RNFL thickness thickening (β = 0.45, P < 0.001). It decreased with larger baseline BMO-MRW (β = - 0.17, P < 0.001) and larger disc area enlargement (β = - 0.29, P < 0.001).

Conclusions: Global and sectoral BMO-MRW increased over 3 years among school children aged 6-8 years, affected by larger axial elongation, larger BMO area enlargement, more marked RNFL thickening, and decrease in optic disc area.