Visual Activity Evoked by Infrared in Humans After Dark Adaptation

Study Summary

This pilot study will evaluate the visual response to infrared (IR) in humans after dark adaptation. The investigators plan to determine which wavelength and intensity the human eye is most sensitive to in healthy and color-blind participants by using a broad spectrum light source and wavelength-specific IR bandpass filters. The long-term goal of this research is to better understand the role that IR plays in visual function, and whether this can be manipulated to allow for vision in certain retinal pathologies that result from loss of photoreceptor cells. The investigators central objective is to test the electrophysiologic response to IR in the dark-adapted retinal and visual pathways. The investigator's central hypothesis is that IR evokes a visual response in humans after dark adaptation, and the characteristics of this response suggest transient receptor potential (TRP) channel involvement. The investigators rationale is that a better understanding of how IR impacts vision may allow for an alternative mechanism for vision in a number of diseases that cause blindness from the degradation or loss of function of photoreceptor cells. The investigators will test the investigator's hypothesis with the following Aims: Aim 1: Arm 1: To determine the optimal IR wavelength for visual perception in dark-adapted human participants. The investigators hypothesize that the healthy human eye will detect IR irradiation, with a maximum sensitivity at a specific wavelength. Using a broad-spectrum light source with wavelength-specific bandpass filters, the spectral range of visual perception to IR will be evaluated. Arm 2: To determine the optimal IR wavelength for visual perception in dark-adapted human participants who are colorblind. The investigators hypothesize that the colorblind human eye will detect IR irradiation, with a maximum sensitivity at a specific wavelength. Using a broad-spectrum light source with wavelength-specific bandpass filters, the spectral range of vi

Primary Outcome

We measured the minimum threshold intensities (uW) via subjective perception of near IR light (900 - 1400 nm) in 50 nm intervals. After 30 minutes of dark adaptation and over three trials, participants verbalized by saying 'yes' to the minimal intensity they could see the IR stimulus as the power source for the light was slowly increased from 0V to 12 V. The voltage was averaged for the three trials at each wavelength. Analysis of variance was used to evaluate the effect of the wavelength on the

Interventions

• OTHER Tungsten halogen light with narrow bandpass filters