Anterior scleral thickness and shape changes with different levels of simulated convergence.

Abstract Purpose Convergence plays a fundamental role in the performance of near visual tasks. We measured the effect of two levels of convergence on anterior scleral thickness and shape in emmetropes, low to moderate myopes and high myopes. Methods Forty-five healthy young adults aged between 18 and 35 years including 15 emmetropes, 15 low/moderate myopes, and 15 high myopes were recruited. Anterior segment optical coherence tomography and eye surface profilometry were used to evaluate the anterior scleral thickness (nasal only, n = 42) and shape (n = 40), before and during two visual tasks involving 9° and 18° convergence, in those participants with complete and reliable data. Results Convergence led to a thickening of the total anterior eye wall (5.9 ± 1.4 μm) and forward movement (10 ± 2 μm) of the nasal anterior scleral surface (both p  Conclusion During convergence, the biomechanical forces acting on the eye lead to nasal anterior scleral thickening and forward movement of the nasal scleral surface.