Title: Two-Photon Microperimetry: A media opacity-independent retinal function assay

Wei, A.; Mehta, U. V.; Palczewska, G.; Palma, A. M.; Hussey, V. M.; Hoffmann, L. E.; Diep, A.; Nguyen, K.; Le, B.; Chang, S. Y.-S.; Browne, A. W.

doi:10.1101/2020.06.27.175315

bioRxiv · 10.1101/2020.06.27.175315

Title: Two-Photon Microperimetry: A media opacity-independent retinal function assay

Wei, A.·Mehta, U. V.·Palczewska, G.·Palma, A. M.·Hussey, V. M.·Hoffmann, L. E.·Diep, A.·Nguyen, K.·Le, B.·Chang, S. Y.-S.·Browne, A. W.

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Abstract

Humans perceive light in the visible portion of electromagnetic radiation. However, visible light is scattered and attenuated by optical media opacities. Because all conventional visual function tests rely on visible light, test results are reduced in patients with optical media opacities like corneal scars, cataracts, and vitreous hemorrhages. Infrared (IR) light has greater penetrance through tissue than visible light. Two-photon IR visual stimulation, a recently pioneered technology, should enable testing of retinal visual function and produce results that are less susceptible to media opacities. The effects of simulated media opacities on visual performance in young healthy volunteers and the change in visual function in healthy phakic patients of two age ranges (20-40 and 60-80-year-old) were studied using conventional testing and 2-photon infrared visual stimulation. All subjects completed visual function testing using cone contrast threshold (CCT) testing, conventional microperimetry, visible light microperimetry from a novel device (2PM-Vis), and infrared 2-photon microperimetry (2PM-IR). Retinal sensitivity measured by 2PM-IR demonstrated lower variability than all other devices relying on visible spectrum stimuli. Retinal sensitivity decreased proportionally with the transmittance of light through each filter. CCT scores and retinal sensitivity decreased with age in all testing modalities. Visible spectrum testing modalities demonstrated larger test result differences between young and old patient cohorts; this difference was inversely proportional to the wavelength of the visual function test. 2PM-IR mitigates media opacities which may mask small differences in retinal sensitivity when tested with conventional visual function testing devices.Competing Interest StatementGrazyna Palczewska has a conflict of interest in this study, as she is an employee of Polgenix, Inc.View Full Text

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Wei, A., Mehta, U. V., Palczewska, G., Palma, A. M., Hussey, V. M., Hoffmann, L. E., Diep, A., Nguyen, K., Le, B., Chang, S. Y.-S., Browne, A. W.. 2020-06-28. Title: Two-Photon Microperimetry: A media opacity-independent retinal function assay. https://doi.org/10.1101/2020.06.27.175315

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