title: Stiles-Crawford effect of the first kind: assessment of photoreceptor alignments following dark patching.
abstract: Properties of presumed mechanisms controlling photoreceptor alignments are partially defined. A phototropic mechanism normally dominates alignment, but do modest changes in orientations occur with dark patching? Here, new photopic Stiles-Crawford (SCE-I) determinations were made before patching (pre-patch), just after 8-days of dark-patching (post-patch), and 3 days after patch removal (recovery test). We tested at 0, 11 and 22 degrees in the temporal retina of both eyes. Ten eyes of adult subjects were tested. SCE-I peak positions and Stile's parameter 'rho' were assessed. Dark-patching effects were small. Observations revealed meaningful corrective alignment overshoots with recovery in the light. Results suggest (1) the presence of multiple weak mechanisms affecting receptor alignments in the dark; (2) the phototropic mechanism to be dominant in the light; (3) the need for multiple test loci to be sampled in such studies, and (4) small changes in the SCE-I in the pupil plane can reflect meaningful events occurring at the retina.
authors.affiliation: School of Optometry (Mail Code 2020), University of California at Berkeley, Berkeley, CA 94720-2020, USA.
authors.forename: M
authors.initials: M
authors.lastname: Kono
authors.forename: J M
authors.initials: JM
authors.lastname: Enoch
authors.forename: E
authors.initials: E
authors.lastname: Strada
authors.forename: P
authors.initials: P
authors.lastname: Shih
authors.forename: R
authors.initials: R
authors.lastname: Srinivasan
authors.forename: V
authors.initials: V
authors.lastname: Lakshminarayanan
authors.forename: W
authors.initials: W
authors.lastname: Susilasate
authors.forename: A
authors.initials: A
authors.lastname: Graham
mesh_terms: D000221:Adaptation, Ocular / Q000502:physiology*; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008432:Mathematical Computing; D009949:Orientation / Q000502:physiology*; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*