June 2022
Volume 63, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2022
Dynamic OFF stimulation reduces perceived saturation of red color, similarly in myopes and emmetropes
Author Affiliations & Notes
  • Frank Schaeffel
    Myopia Research Group, Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
    Section Neurobiology of the Eye, Ophthalmic Research Institute University of Tuebingen, Tuebingen, Germany
  • Barbara Swiatczak
    Myopia Research Group, Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
  • Footnotes
    Commercial Relationships   Frank Schaeffel None; Barbara Swiatczak None
  • Footnotes
    Support  Institute of Molecular and Clinical Ophthalmology Basel (IOB)
Investigative Ophthalmology & Visual Science June 2022, Vol.63, 404. doi:
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      Frank Schaeffel, Barbara Swiatczak; Dynamic OFF stimulation reduces perceived saturation of red color, similarly in myopes and emmetropes. Invest. Ophthalmol. Vis. Sci. 2022;63(7):404.

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

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Abstract

Purpose : It has previously been shown that predominant activation of OFF pathways in the retina induces choroidal thinning and transient axial eye elongation, while stimulation of ON pathways can thicken the choroid. Because the balance between ON and OFF input strength has been linked to refractive error development, we developed a novel psychophysical procedure to quantify ON vs. OFF input strength in emmetropes and myopes.

Methods : Sixteen young healthy subjects (7 males, average age: 28±3 years, average refraction: -1.0±1.9D, range: +1.6 to -5.5D) were asked to match the saturation of a red bar presented on the computer screen with the perceived saturation of red squares (RGB(255,0,0) that randomly appeared inside a dynamic ON or OFF stimulus field (Figure 1A). The field consisted of 1400 grey squares with saw–tooth shaped temporal luminance profiles that could be reversed by the user. Cycle repetition frequency was 7.5 Hz. Temporal profiles in each field were randomly phase shifted with respect to each other. Each stimulus (ON or OFF) was repeated four times in each subject in random order. Subjects were blinded regarding the type of stimulation.

Results : Dynamic OFF stimulation severely reduced perceived saturation of the red squares in 13 out of 16 subjects. They appeared darker and pale. In contrast, red squares appeared fully saturated with dynamic ON stimulation (ON: matched red pixel values 202±20; OFF: 154±11, p<0.001). Three subjects (2 emmetropes and 1 myope) did not perceive changes in red saturation between ON and OFF (gray bars, Figure 1B, left). However, no trend was observed that OFF stimulation was more effective in myopes than in emmetropes (Figure 1B, right).

Conclusions : Perceived saturation of small red squares in a field with dynamic OFF stimuli was considerably reduced, suggesting an interaction of chromatic pathways and OFF pathways. The effect was not dependent on refractive error, suggesting that ON and OFF pathways are not affected in myopic subjects. This is in line with previous findings showing that the choroid in emmetropic and myopic eyes responds similarly to reading of text with normal and inverted contrast.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Figure 1. (A) Dynamic stimulus (B) Perceived red saturation during ON and OFF dynamic stimulation in each individual subject (left) and averages (right). Error bars denote standard deviations. *p<0.001

Figure 1. (A) Dynamic stimulus (B) Perceived red saturation during ON and OFF dynamic stimulation in each individual subject (left) and averages (right). Error bars denote standard deviations. *p<0.001

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