Laboratory of Applied Research in Neuroscience of Vision, Hospital de Olhos de Minas Gerais-Dr. Ricardo Guimarães, Belo Horizonte, MG, Brazil.
Arq Bras Oftalmol. 2021 Jul 14;84(5):442-448. doi: 10.5935/0004-2749.20210069. eCollection 2021.
This study aimed to verify if patients with developmental dyslexia present deficits coherent with visual magnocellular dysfunction.
Participants with confirmed diagnosis of developmental dyslexia (n=62; age range=8-25 years; mean age=13.8 years, standard deviation=3.9; 77% male) were compared to a control group with normal development, matched for age, sex, ocular dominance, visual acuity, and text comprehension. The frequency-doubling technology perimetry was used to evaluate the peripheral visual field contrast sensitivity threshold. The Visagraph III Eye-Movement Recording System was used to evaluate ocular motor skills during text reading.
The developmental dyslexia group had significantly worse contrast sensitivity in the frequency-doubling technology, with strong effect size, than the matched control group. The developmental dyslexia group had more eyes classified in the impaired range of sensitivity threshold to detect frequency-doubling illusion than the control group. Moreover, the developmental dyslexia group had poorer ocular motor skills and reading performance, revealed by a difference in ocular fixations, regressions, span recognition, reading rate, and relative efficiency between groups. A significant correlation was found between contrast sensitivity and ocular motor skills. Participants with good relative efficiency had significantly better contrast sensitivity than participants with poor relative efficiency.
The developmental dyslexia group presented a markedly worse performance in visual variables related to visual magnocellular function (i.e., frequency-doubling technology perimetry and ocular motor skills) compared with a matched control group. Professionals need to be aware of the importance of evaluating vision of individuals with developmental dyslexia beyond visual acuity and including in their assessments instruments to evaluate temporal processing, with contrast sensitivity threshold.
本研究旨在验证发展性阅读障碍患者是否存在与视觉大细胞功能障碍相关的缺陷。
将确诊为发展性阅读障碍的患者（n=62；年龄范围为 8-25 岁；平均年龄为 13.8 岁，标准差为 3.9；77%为男性）与正常发育的对照组进行比较，对照组匹配年龄、性别、优势眼、视力和文本理解。使用倍频技术视野计评估周边视觉场对比度敏感阈值。使用 Visagraph III 眼动记录系统评估阅读过程中的眼球运动技能。
发展性阅读障碍组的倍频技术对比度敏感阈值明显差于匹配对照组，具有较强的效应量。发展性阅读障碍组中，有更多的眼睛被归类为对检测倍频错觉的敏感阈值受损，而对照组则较少。此外，发展性阅读障碍组的眼球运动技能和阅读表现较差，表现在眼球注视、回扫、视距识别、阅读速度和组间相对效率方面的差异。对比敏感度和眼球运动技能之间存在显著相关性。相对效率较好的参与者的对比敏感度明显好于相对效率较差的参与者。
与匹配对照组相比，发展性阅读障碍组在与视觉大细胞功能相关的视觉变量（即倍频技术视野计和眼球运动技能）方面表现明显较差。专业人员需要意识到评估发展性阅读障碍个体视力的重要性，不仅要评估视力，还要包括评估时间处理能力的工具，包括对比敏感度阈值。
