Human scotopic dark adaptation: Comparison of recoveries of psychophysical threshold and ERG b-wave sensitivity.
J Vis
; 11(8)2011 Jul 06.
Article
em En
| MEDLINE
| ID: mdl-21733908
ABSTRACT
We have compared the time course of dark adaptation of the human scotopic visual system, measured psychophysically and from the b-wave of the electroretinogram (ERG), for bleaches ranging from a few percent to near total. We also measured light adaptation, in order to apply a "Crawford transformation" to convert the raw measurements of dark adaptation into equivalent background intensities. For both the "psychophysical threshold equivalent" intensity and the "ERG b-wave sensitivity equivalent" intensity, the equivalent background declined over much of its range with an "S2" component, though with somewhat different slopes of -0.36 (psychophysical) and -0.22 (ERG) log(10) unit min(-1), respectively. In addition, the magnitude of the equivalent background was approximately 1 log(10) unit lower in the psychophysical experiments than in the ERG experiments. Despite these differences, the two approaches extract a common time course for the decline in level of free opsin following moderately large bleaches. We conclude that the recovery of psychophysical scotopic visual threshold over the S2 region reflects events that are present by the stage of the first synapse of rod vision, stemming ultimately from the presence of unregenerated opsin in the rod outer segments.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Psicofísica
/
Limiar Sensorial
/
Percepção Visual
/
Recuperação de Função Fisiológica
/
Adaptação à Escuridão
/
Eletrorretinografia
Tipo de estudo:
Diagnostic_studies
Limite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
J Vis
Assunto da revista:
OFTALMOLOGIA
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Austrália