Traction centered nasal to the optic nerve head in high myopic observers

Abstract

Measuring the Stiles-Crawford effect of the first kind (SCE-1), we determined effects of tractional strains caused by serial Opto-Kinetic Nystagmus (OKN) stimuli in myopic observers (near-sighted or short-sighted) just nasal to the optic disc. Responses were recorded in high myopes with and without myopic supertraction and in low myopes. SCE-1 was measured before, just after, and following recovery from serial OKN stimuli at 22 Temporal Visual Field (TVF). Previously, this site was identified as near the locus of greatest retinal traction in high myopic observers. Testing was photopic and within the linear portion of the Weber function. A modest increase was found in measured SCE-1 thresholds (¼ sensitivity reduced) immediately after serial OKN stimuli. SCE-1 functions were flatter; their peaks were transiently altered, and shifted in the opposite direction to OKN-induced saccades. Recovery occurred within a few minutes. Transients in photoreceptor alignments and sensitivity (triggered by OKN-return saccadic eye movements) occurred near 22 TVF in the nasal retina in all subjects measured. Differences existed between short and longer-term photoreceptor alignments.