In vivo anterior scleral morphometry, axial length and myopia

Purpose: To in-vivo quantify differences in anterior scleral shape between myopes and emmetropes and relate them with axial length and refractive power.

Methods: Forty-two participants (84 eyes) were included in this study. Twenty-five participants were categorised as emmetropes and seventeen participants were categorised as myopes. The refractive state was measured monocularly using a closed window autorefractometer. Axial length was acquired using an optical biometer and topographical data was obtained using a non-contact corneo-scleral topographer. Anterior scleral asymmetry was calculated from 3-dimensional data using a custom-made algorithm and further correlated to axial length and refractive power. Right and left eyes were analysed independently.

Results: The anterior scleral shape was highly correlated with axial length (OS and OD: R = 0.76, p < 0.001) and moderately correlated with refractive power (OS: R = 0.48, OD: R = 0.53, both p < 0.01). The more myopic the eye, the less asymmetric the anterior sclera.

Conclusions: Both axial length and refractive power are well correlated with the anterior scleral shape. The refractive state of each patient should therefore be taken into consideration when analysing scleral shape when planning certain treatments or surgeries and when fitting scleral contact lenses.