June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
The Influence of Dark and Light Adaptation on Phosphene Thresholds Elicited with DTL Electrodes
Author Affiliations & Notes
  • renan rocha memória
    Ophthalmology, FMRP-USP, Ribeirão Preto, SP, Brazil
  • Santana José Galdino Souza
    Ophthalmology, FMRP-USP, Ribeirão Preto, SP, Brazil
  • Rodrigo Jorge
    Ophthalmology, FMRP-USP, Ribeirão Preto, SP, Brazil
  • Andre Messias
    Ophthalmology, FMRP-USP, Ribeirão Preto, SP, Brazil
  • Footnotes
    Commercial Relationships   renan memória, None; Santana José Galdino Souza, None; Rodrigo Jorge, None; Andre Messias, None
  • Footnotes
    Support  none
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 5879. doi:
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      renan rocha memória, Santana José Galdino Souza, Rodrigo Jorge, Andre Messias; The Influence of Dark and Light Adaptation on Phosphene Thresholds Elicited with DTL Electrodes. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5879.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : To investigate the influence of dark, and light adaptation using 4 different chromatic backgrounds (white; blue; red and amber), on phosphene thresholds (PT) elicited with DTL electrodes.

Methods : PT were psychophysically determined using a staircase method in 27 healthy subjects after 30 min dark adaptation, and after 5 min adaptation to 4 different full-field light backgrounds: red, amber, blue and white (in this order, all at 10 photopic cd/m2, ColorDome – Diagnosys LLC). DTL electrodes were used, and stimuli were generated (20 Hz, square waves) using an electric stimulation system (Okuvision - Germany).

Results : Mean PT found after dark-adaptation was statistically significant higher (P < 0,05) than after light-adaptation, no significant differences were found between red, amber and blue, but PT after white background adaptation was significantly lower than with the other colors. The mean PT in the dark was 316.9 ± 10.1 µA, and 190 ± 6.5 µA; 188.3 ± 8.0 µA; 185.4 ± 8.1 µA; and 170.7 ± 5.8 µA for red, amber, blue and white background respectively (Fig. 1).

Conclusions : These results suggest that the human retina requires higher electrical current to elicit visualization of phosphenes when adapted to darkness, and also, that light adaptation with a white background appear to reduce PT more than red, amber or blue backgrounds.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

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