September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Characterization of two-photon vision by measurements of sensitivity threshold
Author Affiliations & Notes
  • Katarzyna Komar
    Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
  • Grazyna Palczewska
    Department of Medical Devices, Polgenix, Inc, Cleveland, Ohio, United States
  • Jianye Zhang
    Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
  • Maciej Nowakowski
    Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
  • Zhiqian Dong
    Department of Medical Devices, Polgenix, Inc, Cleveland, Ohio, United States
  • Krzysztof Palczewski
    Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
  • Maciej Wojtkowski
    Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
  • Footnotes
    Commercial Relationships   Katarzyna Komar, None; Grazyna Palczewska, Polgenix Inc (E); Jianye Zhang, None; Maciej Nowakowski, None; Zhiqian Dong, Polgenix Inc (E); Krzysztof Palczewski, Polgenix Inc (C), US patent 8,346,345 and 7,706,863 (P); Maciej Wojtkowski, None
  • Footnotes
    Support  This work was supported by TEAM project of Foundation of Polish Science
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 196. doi:
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      Katarzyna Komar, Grazyna Palczewska, Jianye Zhang, Maciej Nowakowski, Zhiqian Dong, Krzysztof Palczewski, Maciej Wojtkowski; Characterization of two-photon vision by measurements of sensitivity threshold. Invest. Ophthalmol. Vis. Sci. 2016;57(12):196.

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      © 2017 Association for Research in Vision and Ophthalmology.

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Abstract

Purpose : Pulsed infrared light (IR) causes visual sensation in humans, with a color perception corresponding to light of roughly half the wavelength. The authors previously identified this phenomenon as two photon isomerization of visual pigments. In this contribution, we present an improved laboratory set-up, and data from IR psychophysical measurements in human subjects.

Methods : The improved set-up, Fig. 1, allows for the measurement of sensitivity threshold via the use of visible and IR light. Additionally, this novel set-up is equipped with the capability to measure recovery of light sensitivity after variable visible light bleaching.
Light from a pulsed laser (1045nm) is split into two beams where one is routed through the crystal for second harmonic generation (SHG) at 522.5nm. Both, IR or visible light beams are directed into the dark adapted subject’s eye pupil after reflecting off the pair of galvo-scanners. The subject can adjust the beam power by operating a gradient filter with a computer mouse. The bleaching LED diode (530nm) was providing a uniform illumination of the subject’s retina.
Retinoid content in Abca/ Rdh8/ mouse eyes at defined time-point after bleaching was quantified by high performance liquid chromatography (HPLC).
All tests in human subjects were conducted in compliance with ANSI Z136.1:2014 and/or EN 60825−1:2014. The study was approved by the Ethics Committee of the Collegium Medicum NCU.

Results : Mean sensitivity threshold for IR beam was 24±6 µW for 10 volunteers aged 30-42 years old – Fig.2. The threshold from the same group for visible light had large variation: 1.5 fW-25 pW, confirming that measurements of visual threshold with IR provide more consistent results. Our result indicate that compared to previous reports in BALB/c mice, recovery of retinyl esters and visual chromophore after bleaching are delayed in mouse models of Stargardt disease.

Conclusions : IR and visible light induced vision processes can now be easily compared using the same setup. Bleaching optical train allows for measuring the recovery time curves for two-photon vision. Retinoids measurement in mice supports measurements in humans by providing a way of tracking visual system kinetics trends on the molecular level.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

Fig.1. Set-up for sensitivity measurements.

Fig.1. Set-up for sensitivity measurements.

 

Fig.2. Sensitivity threshold results from humans.

Fig.2. Sensitivity threshold results from humans.

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