Relationship Of Axial Length And Anterior Scleral Topography In Healthy Eyes

To investigate the relationship between axial length and corneal-scleral geometric parameters as well as the prediction ability of such parameters to predict the axial length

Optometric Clinic, University of Alicante, Alicante, Spain

Observational study including 96 healthy subjects from 96 eyes. In all of them, axial length was measured by optical biometry (IOL Master 500). Corneal curvature and scleral sagittal height parameters at 13, 14 and 15 mm were obtained automatically using corneoscleral topography (eye surface profiler; ESP). In addition, corneal and scleral sagittal heights at numerous locations (21 radii: 0–10 mm from the corneal apex at 12 angles: 0–330°) were calculated using the raw height data extracted from the ESP. The relationships between axial length and the study parameters were analysed using Pearson correlation analysis. Multiple linear regression analysis was used to obtain the equations for the prediction of axial length.

The temporal-nasal scleral asymmetry at 13-, 14-and 15-mm chord lengths was significantly correlated with axial length (r2 ≤ 0.26; p < 0.001). Significant inverse correlations were found between the temporal scleral sagittal height and axial length (r2 ≤ 0.28; p ≤ 0.02). The nasal scleral sagittal height was not associated with axial length. Three significant multiple linear regression models were fitted based on spherical equivalent, corneal radius and scleral asymmetry at 13 (r2 = 0.79; p < 0.001), 14 (r2 = 0.80; p < 0.001) and 15 (r2 = 0.80; p < 0.001) mm chord lengths.

Larger ocular globes show reduced temporal-nasal scleral asymmetry, mainly due to the lower sagittal height of the temporal sclera. Thus, the geometry of the temporal scleral may be a factor of interest during myopia progression and it use as a biomarker of myopia progression should be investigated further.