Childhood Lensectomy Is Associated with Static and Dynamic Reduction in Schlemm Canal Size: A Biomechanical Hypothesis of Glaucoma after Lensectomy.

Purpose: To compare Schlemm canal (SC) and trabecular meshwork (TM) in children with healthy eyes and those with and without glaucoma after lensectomy.

Design: Cross-sectional observational study.

Participants: Fifty children 4 to 16 years of age with healthy eyes and 48 children who underwent lensectomy (124 healthy and 72 postlensectomy eyes).

Methods: Anterior segment (AS) OCT (Tomey SS-1000 CASIA; Tomey, Nagoya, Japan) of the nasal iridocorneal angle at 2 levels of accommodative effort (2.5 diopters [D] and 15 D). For each parameter and state of accommodation, a random effects model was fitted to estimate differences between healthy eyes and eyes with history of lensectomy.

Main Outcome Measures: Dimensions of SC and TM and conventional AS OCT iridocorneal angle measurements.

Results: The horizontal diameter of SC and its cross-sectional area (CSA) are significantly smaller in eyes that have undergone lensectomy versus healthy eyes. Accommodative effort increases SC size in healthy eyes, but not in eyes that have undergone lensectomy.

Conclusions: Lensectomy is associated with a reduction in SC size and a loss of physiologic SC dilatation during accommodative effort, which may reflect a reduction in outflow facility and may contribute to the development of glaucoma after lensectomy.