Detection and identification of mirror-image letter pairs in central and peripheral vision.
Vision Res
; 36(2): 331-7, 1996 Jan.
Article
em En
| MEDLINE
| ID: mdl-8594832
ABSTRACT
Reading performance is poorer in the peripheral than in the central visual field, even after size-scaling to compensate for differences in visual acuity at the different eccentricities. Since several studies have indicated that the peripheral retina is deficient with respect to spatial phase discrimination, we compared the psychometric functions for detection (D) and identification (I) of size-scaled, mirror-symmetric letters (i.e. letters differing in the phase spectra of their odd symmetric components) at three inferior field eccentricities (0, 4, and 7.5 deg) using a two-alternative, temporal, forced-choice procedure and retinal image stabilization to control retinal locus. Each subject's data were fit with Weibull functions and tested for goodness-of-fit under several hypotheses. This analysis revealed that while the psychometric functions were of constant shape across eccentricity for the respective tasks, they showed statistically significant variations in the D/I threshold ratios. However, these variations were so small that poorer reading outside the fovea is unlikely to be due to reduced letter discriminability that might occur secondary to a loss of peripheral field phase sensitivity.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Leitura
/
Campos Visuais
Tipo de estudo:
Diagnostic_studies
Limite:
Adult
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
Vision Res
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Estados Unidos