Metrics of the normal anterior sclera: imaging with optical coherence tomography

Background: To investigate anterior scleral thickness in a cohort of healthy subjects using enhanced depth imaging anterior segment optical coherence tomography. Methods: Observational case series. The mean scleral thickness in the inferonasal, inferotemporal, superotemporal, and superonasal quadrant was measured 2mm from the scleral spur on optical coherence tomography in healthy volunteers. Results: Fifty-three eyes of 53 Caucasian patients (25 male and 28 female) with an average age of 48.6years (range: 18 to 92years) were analysed. The mean scleral thickness was 571μm (SD 84μm) in the inferonasal quadrant, 511μm (SD 80μm) in the inferotemporal quadrant, 475 (SD 81μm) in the superotemporal, and 463 (SD 64μm) in the superonasal quadrant. The mean scleral thickness was significantly different between quadrants (p < 0.0001, repeated measures one-way ANOVA). The association between average scleral thickness and age was statistically significant (p < 0.0001, Pearson r = 0.704). Conclusions: Enhanced depth imaging optical coherence tomography revealed the detailed anatomy of the anterior sclera and enabled non-invasive measurements of scleral thickness in a non-contact approach. The anterior scleral thickness varies significantly between quadrants, resembling the spiral of Tillaux. An association of increasing scleral thickness with age was found