Myopes experience greater contrast adaptation during reading

Colm McGonigle; Ian van der Linde; Shahina Pardhan; Stephen A Engel; Edward A H Mallen; Peter M Allen

doi:10.1016/j.visres.2016.01.001

Myopes experience greater contrast adaptation during reading

Vision Res. 2016 Apr:121:1-9. doi: 10.1016/j.visres.2016.01.001. Epub 2016 Feb 3.

Authors

Colm McGonigle¹, Ian van der Linde², Shahina Pardhan³, Stephen A Engel⁴, Edward A H Mallen⁵, Peter M Allen⁶

Affiliations

¹ Department of Vision and Hearing Sciences, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK; Vision and Eye Research Unit (VERU), Postgraduate Medical Institute, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK.
² Vision and Eye Research Unit (VERU), Postgraduate Medical Institute, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK; Department of Computing and Technology, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK.
³ Vision and Eye Research Unit (VERU), Postgraduate Medical Institute, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK.
⁴ Department of Psychology, University of Minnesota, 75 E River Rd, MN 55455, USA.
⁵ School of Optometry and Vision Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP, UK.
⁶ Department of Vision and Hearing Sciences, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK; Vision and Eye Research Unit (VERU), Postgraduate Medical Institute, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK. Electronic address: peter.allen@anglia.ac.uk.

PMID: 26804636
DOI: 10.1016/j.visres.2016.01.001

Abstract

In this study, we investigated whether reading influences contrast adaptation differently in young adult emmetropic and myopic participants at the spatial frequencies created by text rows and character strokes. Pre-adaptation contrast sensitivity was measured for test gratings with spatial frequencies of 1cdeg(-1) and 4cdeg(-1), presented horizontally and vertically. Participants then adapted to reading text corresponding to the horizontal "row frequency" of text (1cdeg(-1)), and vertical "stroke frequency" of the characters (4cdeg(-1)) for 180s. Following this, post-adaptation contrast sensitivity was measured. Twenty young adults (10 myopes, 10 emmetropes) optimally corrected for the viewing distance participated. There was a significant reduction in logCS post-text adaptation (relative to pre-adaptation logCS) at the row frequency (1cdeg(-1) horizontal) but not at the stroke frequency (4cdeg(-1) vertical). logCS changes due to adaptation at 1cdeg(-1) horizontal were significant in both emmetropes and myopes. Comparing the two refractive groups, myopic participants showed significantly greater adaptation compared to emmetropic participants. Reading text on a screen induces contrast adaptation in young adult observers. Myopic participants were found to exhibit greater contrast adaptation than emmetropes at the spatial frequency corresponding to the text row frequency. No contrast adaptation was observed at the text stroke frequency in either participant group. The greater contrast adaptation experienced by myopes after reading warrants further investigation to better understand the relationship between near work and myopia development.

Keywords: Contrast adaptation; Myopia; Near work; Spatial frequency.

MeSH terms

Adaptation, Ocular / physiology*
Adult
Contrast Sensitivity / physiology*
Emmetropia / physiology
Female
Humans
Male
Myopia / physiopathology*
Reading*
Young Adult