Pupil size following dark adaptation in patients with retinitis pigmentosa

Pupil size following dark adaptation in patients with retinitis pigmentosa

Autor Berezovsky, Adriana Autor UNIFESP Google Scholar
Salomão, Solange Rios Autor UNIFESP Google Scholar
Birch, D. G. Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
Retina Fdn SW
Resumo According to the equivalent light hypothesis, molecular defects in the photoreceptor lead to a continuous activation of the photoreceptor cascade in a manner equivalent to real light. the consequences in diseases such as retinitis pigmentosa (RP) are as disruptive to the cells as real light. Two forms of the equivalent light hypothesis can be distinguished: strong - mutations in rhodopsin or other cascade proteins in some forms of RP continuously excite the visual phototransduction cascade, weak - disruption of outer segments in all patients with RP eliminates circulating dark current and blocks neurotransmitter release in a manner similar to real light. Both forms of the equivalent light hypothesis predict that pupils of patients with RP will be constricted like those of normal subjects in the light. the purpose of this study was to test the equivalent light hypothesis by determining whether steady-state pupil diameter following full dark adaptation is abnormally small in any of a sample of patients with RP. Thirty-five patients with RP and 15 normal subjects were tested. Direct steady-state pupillometric measures were obtained from one eye in a full-field dome after 45 min of dark adaptation by videotaping the pupil with an infrared camera. Mean pupil diameter in the dark was comparable (t = -0.15. P = 0.88) between patients with RP (6.85 +/- 0.58 min) and normal subjects (6.82 +/- 0.76 mm). the results of the present study are clearly counter to the prediction of the second (weaker) form of the equivalent light hypothesis.
Palavra-chave pupil
retina
retinitis pigmentosa
Idioma Inglês
Data de publicação 2001-08-01
Publicado em Brazilian Journal of Medical and Biological Research. São Paulo: Assoc Bras Divulg Cientifica, v. 34, n. 8, p. 1037-1040, 2001.
ISSN 0100-879X (Sherpa/Romeo, fator de impacto)
Publicador Assoc Bras Divulg Cientifica
Extensão 1037-1040
Fonte http://dx.doi.org/10.1590/S0100-879X2001000800010
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000170731800010
SciELO S0100-879X2001000800010 (estatísticas na SciELO)
Endereço permanente http://repositorio.unifesp.br/handle/11600/26597

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