Evidence for transient forces/strains at the optic nerve head in myopia: repeated measurements of the Stiles-Crawford Effect of the First Kind (SCE-I) over time

Probable transient changes in photoreceptor alignments, inferred from the measurements of the Stiles–Crawford effect of the first kind (SCE ‐ I), were demonstrated in myopic eyes with elongated axial length (regardless of the magnitude of refractive error) at three retinal locations; the fovea (point of fixation), and 22° and 27° in the nasal retina. The changes were much bigger at 22° and 27° in the nasal retina (which are located beyond the optic nerve head) than at the fovea. These transient effects were revealed by repeatedly testing the same retinal locations over a period of time. Time intervals between the subsequent/repeated measurements ranged from less than an hour to several months. In some locations, the changes were recorded in less than an hour. Collectively, these were very meaningful changes. Generally bigger effects were recorded in the horizontal SCE ‐ I than in the vertical SCE ‐ I.