Perception of first-order grating acuity and second-order spatial contrast sensitivity in anisometropia amblyopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To study the perception of first-order grating acuity and second-order spatial contrast sensitivity in patients with monocular anisometropia amblyopia.METHODS:A total of 715 children(715 eyes)diagnosed as monocular anisometropia amblyopia in our hospital from January 2018 to December 2022 were collected as amblyopia group, and 745 children(745 eyes)with normal corrected visual acuity were collected. The best corrected visual acuity(BCVA), first-order grating acuity and/or second-order spatial contrast sensitivity were measured, repectively. The perception ability of amblyopia patients to first-order grating acuity and second-order spatial contrast sensitivity were analyzed.RESULTS:There were significant differences between amblyopia group and normal control group in the perception of first-order grating acuity(11.58±6.10 vs. 20.27±3.47, P<0.001)and second-order spatial contrast sensitivity(0.33±0.16 vs 0.12±0.04, P<0.001). And there were significant differences between mild-to-moderate amblyopia and severe amblyopia patients in first-order grating acuity(12.10±6.23 vs. 8.13±3.70, P<0.001)and second-order spatial contrast sensitivity(0.32±0.16 vs. 0.37±0.17, P<0.05).CONCLUSION: The first-order and second-order visual pathway of the cerebral cortex in children with monocular anisometropia amblyopia have different degrees of damage. The injury of severe amblyopia is more serious than that of mild-to-moderate amblyopia.

Vernier But Not Grating Acuity Contributes to an Early Stage of Visual Word Processing / 神经科学通报·英文版

The process of reading words depends heavily on efficient visual skills, including analyzing and decomposing basic visual features. Surprisingly, previous reading-related studies have almost exclusively focused on gross aspects of visual skills, while only very few have investigated the role of finer skills. The present study filled this gap and examined the relations of two finer visual skills measured by grating acuity (the ability to resolve periodic luminance variations across space) and Vernier acuity (the ability to detect/discriminate relative locations of features) to Chinese character-processing as measured by character form-matching and lexical decision tasks in skilled adult readers. The results showed that Vernier acuity was significantly correlated with performance in character form-matching but not visual symbol form-matching, while no correlation was found between grating acuity and character processing. Interestingly, we found no correlation of the two visual skills with lexical decision performance. These findings provide for the first time empirical evidence that the finer visual skills, particularly as reflected in Vernier acuity, may directly contribute to an early stage of hierarchical word processing.

The Effect of Diffusion Blur on Central and Peripheral Vision in Normal Adults

Diffusion blur, caused by liquid crystal windows, reduces contrast sensitivity and luminance, so visual acuity is decreased. Moreover, the windows' optical characteristics are similar to those of the cataractous lens. We measured the effect of liquid crystal window on central and peripheral visual acuity using Snellen and grating visual acuity charts. The subjects were 10 normal adults, therefore 20 eyes. We measured the voltage of the liquid crystal window at which the subjects could read the visual acuity chart through the liquid crystal window. In central vision, visual acuity was overestimated according to the Snellen chart, when compared to the results measured by those grating chart. But in peripheral vision, there were no differences between the two visual acuity charts. These results suggested that grating acuity has some limitations when used as a visual acuity test for cataractous patient. The ability of liquid crystal windows to cause diffusion blur suggests they could be used for foUowup observation in treatment of amblyopia or macular diseases.