Yap Tiong Peng, Luu Chi D, Suttle Catherine M, Chia Audrey, Boon Mei Ying
School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW, Australia.
Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia; Department of Surgery (Ophthalmology), The University of Melbourne, Parkville, Victoria, Australia.
Vision Res. 2024 Sep;222:108439. doi: 10.1016/j.visres.2024.108439. Epub 2024 Jun 18.
It is important to understand the development of meridional anisotropies in neurotypical children since those with poor visual development, such as amblyopia, can have different patterns of meridional anisotropies. While the oblique effect is usually observed in adults, neurotypical children who have normal 20/20 visual acuity tend to demonstrate a horizontal effect electrophysiologically. In this longitudinal study, orientation-specific visual evoked potentials (osVEPs) and psychophysical grating acuity were used to investigate the changes in the meridional anisotropies in children aged 3.8 to 9.2 years over two visits averaging four months apart. While it was hypothesized that the electrophysiological horizontal effect may shift towards an oblique effect, it was found that the electrophysiological horizontal effect persisted to be present in response to the suprathreshold moderate contrast 4 cycles-per-degree grating stimuli. Psychophysical grating acuity, however, demonstrated an oblique effect when assessed binocularly. In addition, a significant effect of visit, representing an increase in the average age over this period, was observed in the average osVEP C3 amplitudes (4.5 μV) and psychophysical grating acuity (0.28 octaves or approximately 1-line on the logMAR chart). These findings are relevant when evaluating amblyopia treatments and interventions, as it confirms the necessity to take into account of the effect of normal maturation and learning effects when evaluating young children. Special attention should also be given to children with early-onset myopia and high astigmatism even when their visual acuity is 20/20 as the electrophysiological findings are suggestive of poor visual development, which warrants further investigation.
了解正常儿童子午线各向异性的发展很重要，因为那些视觉发育不良的儿童，如弱视儿童，可能有不同的子午线各向异性模式。虽然成年人通常会观察到倾斜效应，但视力正常（20/20）的正常儿童在电生理上往往表现出水平效应。在这项纵向研究中，使用定向特异性视觉诱发电位（osVEP）和心理物理学光栅视力来研究3.8至9.2岁儿童在平均相隔四个月的两次就诊期间子午线各向异性的变化。虽然假设电生理水平效应可能会向倾斜效应转变，但研究发现，在阈上中等对比度4周/度光栅刺激下，电生理水平效应仍然存在。然而，当双眼评估时，心理物理学光栅视力表现出倾斜效应。此外，在平均osVEP C3振幅（4.5 μV）和心理物理学光栅视力（0.28倍频程或在对数MAR图表上约1行）中观察到就诊的显著影响，这代表在此期间平均年龄的增加。这些发现与评估弱视治疗和干预措施相关，因为它证实了在评估幼儿时考虑正常成熟和学习效应的必要性。即使视力为20/20，对于早发性近视和高度散光的儿童也应给予特别关注，因为电生理结果表明视觉发育不良，这值得进一步研究。
