Abstract
Purpose :
Visual motion is a fundamental feature of the human visual system. It allows for figure-ground segmentation, depth perception and the recognition of kinematic events. Previously published work has shown that when visual stimuli is set in motion, it greatly improves interpretability even under conditions of reduced visual acuity. The importance of motion perception lead us to probe global motion sensitivity in children experiencing prolonged periods of visual deprivation due to the presence of bilateral congenital cataracts. Furthermore, we sought to understand how this sensitivity changed once vision was achieved and assessed performance at multiple time points post-operatively. Under Project Prakash, we collected data from nineteen participants who underwent cataract surgery after years of significant visual impairments.
Methods :
The stimuli consisted of limited life-time kinematograms. Each trial consisted of a two-second video of dots moving at a speed of 18° s-1. The field of view was 20 degrees by 20 degrees of visual angle and contained 300 black dots against a white background in each frame. A certain percentage of the dots moved either upwards or downwards, while the remainder of the dots moved in random directions. A staircase was used to determine the subject coherence threshold.
Results :
The data revealed three notable findings regarding global motion perception in children treated for curable blindness. First, despite a prolonged period of blindness early in life, their sensitivity to global motion was not impaired when compared to age-matched control subjects. Additionally, while some children were unable to perform the task pre-operatively, all children demonstrated a stable performance when tested at multiple post-operative time points. Lastly, while improvements in visual acuity were observed longitudinally, this did not translate to better global motion sensitivity.
Conclusions :
These results highlight the importance of global motion perception especially under conditions of prolonged visual deprivation. Significantly, sensitivity to global motion remains intact despite cloudy vision. This has implications for utilizing our motion perception capabilities to make sense of visual information even under conditions of reduced visual acuity, and also for facilitating visual recovery after sight onset.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.