Stiles-Crawford effect of the first kind: assessment of photoreceptor alignments following dark patching.
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.
Kono
M
M
School of Optometry (Mail Code 2020), University of California at Berkeley, Berkeley, CA 94720-2020, USA.
Enoch
J M
JM
Strada
E
E
Shih
P
P
Srinivasan
R
R
Lakshminarayanan
V
V
Susilasate
W
W
Graham
A
A
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*