[PS-2.20] Central and peripheral visual function in Developmental Dyslexia

de Araújo Vilhena, D. 1, 2, 3 , Reis Guimarães, M. 1 , Queiroz Guimarães, R. 1 & Vieira Pinheiro, &. M. . 1, 2

1 Laboratory of Applied Research in Neuroscience of Vision (LAPAN), Eye Hospital of Minas Gerais - Dr. Ricardo Guimarães, Belo Horizonte, Minas Gerais, Brazil.
2 Laboratory of Cognitive Processes (LabCog), Graduate Program on Psychology: Cognition and Behavior, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
3 Faculty of Psychology and Education Science, University of Porto, Porto, Portugal.

This study analyzed the central and peripheral visual function in a group with Developmental Dyslexia (DD). We retrospectively reviewed the records of patients with formal diagnosis of DD (n = 74; age range = 7-51; M age = 14.9, SD = 7.7 years; 74% male; 39% left-handed) and compared to a typically developing Control Group, matched for age, gender and handedness (n = 74; age range = 7-51; M age = 15.8, SD = 7.7 years; 74% male; 39% left-handed). Participants with DD reported more symptoms of visual reading difficulty, visual reading discomfort, and more text-related visual distortions, compared to control (p<0.05). For the central visual function, DD patients had worse monocular and binocular visual acuity (p<0.05); stereopsis (p=0.012); and lateral phorias (p=0.046). Concerning eye-movement recorded while reading texts (Visagraph-III), DD had a significantly worse number of Fixations, Regressions, Span of Recognition, and Reading Rate (p<0.05). For the peripheral visual function, DD had a decreased sensitivity on detection of the frequency doubling illusion (FDT, p=0.0001). In conclusion, DD presented worse scores both on central and peripheral visual function than the matched-Control Group. These findings suggest that both parvo as well as magnocellular visual pathways are directly involved in proficient reading.

Funding: This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (Capes) - Finance Code 001.