Unintended wavefront aberration changes associated with the re-blocking of scleral lenses

This study quantifies the unintended changes in wavefront aberrations within a sample of commercial scleral lenses due to the re-blocking step in the patch-cutting method for manufacturing wavefront-guided scleral lenses. The wavefront aberrations for a sample of 15 sphero-cylindrical scleral lenses were measured (Measurement 1) using a wavefront sensor. The lenses were mounted (re-blocked) onto a lens mount, removed (de-blocked) from the lens mount, and again measured (Measurement 2). The lenses were measured a third time (Measurement 3) after a period of storage. The difference in wavefront aberrations between Measurements 1 and 2 served as a treatment condition, and the difference between Measurements 2 and 3 served as a control condition. This study demonstrated that re-blocking of commercial scleral lenses induces small but measurable changes in the aberration structure of the lenses that may be important once aberrations from all steps in the method are considered.