certain conditions, such as during accommodation. However, today it is possible to overcome these technical limitations with non-contact commercially available instruments, such as scleral profilometers, that cover the corneo-scleral area far beyond the limbus up to 20 mm in diameter, opening a new branch of possibilities. In particular, it has been proved that the Eye Surface profiler (ESP) provides excellent levels of accuracy for the central area of 8 mm diameter. This error increases with the radial distance.14 Our preliminary experience with ESP showed changes in the shape within measurements from a particular subject but not in the corneal shape. Those changes could have been an artefact produced as a consequence of the increasing error variability in the peripheral area of the measurements or physiological changes that could happen as a consequence of the subject’s accommodation while focusing at the internal target of the instrument. The hypothesis of this work is that accommodation might cause changes in the scleral shape. Beyond proving this hypothesis, this work aims to quantify those changes and ascertain whether they depend on age (accommodative ability) and refractive power. METHODOLOGY Subjects Participants in this included twenty two, healthy adult subjects (13 females, 9 males) aged between 19 and 84 (mean ± SD age: 39 ± 20 years). The study was approved by The University of Manchester Human Research Ethics Committee and adhered to the tenets of the Declaration of Helsinki. All subjects gave written informed consent to participate after the nature and possible consequences of the study were explained. All participants were free of ocular disease, had no anisometropia (i.e., had < 1.00 D difference in spherical equivalents between the eyes), had less
certain conditions, such as during accommodation. However, today it is possible to overcome these technical limitations with non-contact commercially available instruments, such as profilometers, that cover the corneo-scleral area far beyond the limbus up to 20 mm in diameter, opening a new branch of possibilities. In particular, it has been proved that the Eye Surface profiler (ESP) provides excellent levels of accuracy for the central area of 8 mm diameter. This error increases with the radial distance.14 Our preliminary experience with ESP showed changes in the scleral shape within measurements from a particular subject but not in the corneal shape. Those changes could have been an artefact produced as a consequence of the increasing error variability in the peripheral area of the measurements or physiological changes that could happen as a consequence of the subject’s accommodation while focusing at the internal target of the instrument. The hypothesis of this work is that accommodation might cause changes in the scleral shape. Beyond proving this hypothesis, this work aims to quantify those changes and ascertain whether they depend on age (accommodative ability) and refractive power. METHODOLOGY Subjects Participants in this included twenty two, healthy adult subjects (13 females, 9 males) aged between 19 and 84 (mean ± SD age: 39 ± 20 years). The study was approved by The University of Manchester Human Research Ethics Committee and adhered to the tenets of the Declaration of Helsinki. All subjects gave written informed consent to participate after the nature and possible consequences of the study were explained. All participants were free of ocular disease, had no anisometropia (i.e., had < 1.00 D difference in spherical equivalents between the eyes), had less