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A reinterpretation of critical flicker-frequency (CFF) data reveals key details about light adaptation and normal and abnormal visual processing.
Prog Retin Eye Res. 2021 Sep 08 [Online ahead of print]PR

Abstract

Our ability to see flicker has an upper frequency limit above which flicker is invisible, known as the "critical flicker frequency" (CFF), that typically grows with light intensity (I). The relation between CFF and I, the focus of nearly 200 years of research, is roughly logarithmic, i.e., CFF ∝ log(I)-a relation called the Ferry-Porter law. However, why this law should occur, and how it relates to the underlying physiology, have never been adequately explained. Over the past two decades we have measured CFF in normal observers and in patients with retinal gene defects. Here, we reanalyse and model our data and historical CFF data. Remarkably, CFF-versus-I functions measured under a wide range of conditions in patients and in normal observers all have broadly similar shapes when plotted in double-logarithmic coordinates, i.e., log (CFF)-versus-log(I). Thus, the entire dataset can be characterised by horizontal and vertical logarithmic shifts of a fixed-shape template. Shape invariance can be predicted by a simple model of visual processing built from a sequence of low-pass filters, subtractive feedforward stages and gain adjustment (Rider, Henning & Stockman, 2019). It depends primarily on the numbers of visual processing stages that approach their power-law region at a given intensity and a frequency-independent gain reduction at higher light levels. Counter-intuitively, the CFF-versus-I relation depends primarily on the gain of the visual response rather than its speed-a conclusion that changes our understanding and interpretation of human flicker perception. The Ferry-Porter "law" is merely an approximation of the shape-invariant template.

Authors+Show Affiliations

UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, England, UK.UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, England, UK.UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, England, UK. Electronic address: a.stockman@ucl.ac.uk.

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

34506951

Citation

Rider, Andrew T., et al. "A Reinterpretation of Critical Flicker-frequency (CFF) Data Reveals Key Details About Light Adaptation and Normal and Abnormal Visual Processing." Progress in Retinal and Eye Research, 2021, p. 101001.
Rider AT, Henning GB, Stockman A. A reinterpretation of critical flicker-frequency (CFF) data reveals key details about light adaptation and normal and abnormal visual processing. Prog Retin Eye Res. 2021.
Rider, A. T., Henning, G. B., & Stockman, A. (2021). A reinterpretation of critical flicker-frequency (CFF) data reveals key details about light adaptation and normal and abnormal visual processing. Progress in Retinal and Eye Research, 101001. https://doi.org/10.1016/j.preteyeres.2021.101001
Rider AT, Henning GB, Stockman A. A Reinterpretation of Critical Flicker-frequency (CFF) Data Reveals Key Details About Light Adaptation and Normal and Abnormal Visual Processing. Prog Retin Eye Res. 2021 Sep 8;101001. PubMed PMID: 34506951.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A reinterpretation of critical flicker-frequency (CFF) data reveals key details about light adaptation and normal and abnormal visual processing. AU - Rider,Andrew T, AU - Henning,G Bruce, AU - Stockman,Andrew, Y1 - 2021/09/08/ PY - 2021/06/02/received PY - 2021/08/25/revised PY - 2021/08/30/accepted PY - 2021/9/11/pubmed PY - 2021/9/11/medline PY - 2021/9/10/entrez KW - CFF KW - Clinical vision KW - Critical flicker fusion KW - Flicker acuity KW - GNAT2 KW - GRM6 KW - GUCA1A KW - GUCY2D KW - Gene defects KW - KCNV2 KW - LRAT KW - Light adaptation KW - Linear systems KW - Molecular loss KW - NR2E3 KW - OPA1 KW - OPN1LW KW - OPN1MW KW - RGS9 KW - RPE65 KW - Temporal processing KW - Visual psychophysics SP - 101001 EP - 101001 JF - Progress in retinal and eye research JO - Prog Retin Eye Res N2 - Our ability to see flicker has an upper frequency limit above which flicker is invisible, known as the "critical flicker frequency" (CFF), that typically grows with light intensity (I). The relation between CFF and I, the focus of nearly 200 years of research, is roughly logarithmic, i.e., CFF ∝ log(I)-a relation called the Ferry-Porter law. However, why this law should occur, and how it relates to the underlying physiology, have never been adequately explained. Over the past two decades we have measured CFF in normal observers and in patients with retinal gene defects. Here, we reanalyse and model our data and historical CFF data. Remarkably, CFF-versus-I functions measured under a wide range of conditions in patients and in normal observers all have broadly similar shapes when plotted in double-logarithmic coordinates, i.e., log (CFF)-versus-log(I). Thus, the entire dataset can be characterised by horizontal and vertical logarithmic shifts of a fixed-shape template. Shape invariance can be predicted by a simple model of visual processing built from a sequence of low-pass filters, subtractive feedforward stages and gain adjustment (Rider, Henning & Stockman, 2019). It depends primarily on the numbers of visual processing stages that approach their power-law region at a given intensity and a frequency-independent gain reduction at higher light levels. Counter-intuitively, the CFF-versus-I relation depends primarily on the gain of the visual response rather than its speed-a conclusion that changes our understanding and interpretation of human flicker perception. The Ferry-Porter "law" is merely an approximation of the shape-invariant template. SN - 1873-1635 UR - https://www.unboundmedicine.com/medline/citation/34506951/A_reinterpretation_of_critical_flicker-frequency_(CFF)_data_reveals_key_details_about_light_adaptation_and_normal_and_abnormal_visual_processing. L2 - https://linkinghub.elsevier.com/retrieve/pii/S1350-9462(21)00062-8 DB - PRIME DP - Unbound Medicine ER -
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