Development of global visual processing: From the retina to the perceptive field

Abstract

Young children exhibit poorer visual performance than adults due to immaturity of the fovea and of the fundamental processing of visual functions such as masking and crowding. Recent studies suggest that masking and crowding are closely related to the size of the fundamental processing unit—the perceptive field (PF). However, while it is known that the retina and basic visual functions develop throughout childhood, it is not clear whether and how changes in the size of the PF affect masking and crowding. Furthermore, no retinal and perceptual development data have been collected from the same cohort and time. Here we explored the developmental process of the PF and the basic visual functions. Psychophysical and imaging methods were used to test visual functions and foveal changes in participants ranging from 3–17 years old. Lateral masking, crowding and contrast sensitivity were tested using computerized tasks. Foveal measurements were obtained from spectral-domain optical coherence tomography (OCT). The children patterns below 6 years exhibited high crowding, while the expected facilitation was found only at a larger target-flanker distance than required for children above 6 years, who exhibited the typical adult. Foveal thickness and macular volume for the children below 6 years were significantly lower than for the older group. Significant correlation was found for contrast sensitivity, foveal thickness and macular volume with age and between contrast sensitivity and foveal thickness. Our data suggest that the developmental processes at the retina and visual cortex occur in the same age range. Thus, in parallel to maturation of the PF, which enables reduction in crowding, foveal development contributes to increasing contrast sensitivity.

Binocular fusion disorders impair basic visual processing

“…No binocular advantage of the threshold elevations was found, confirming recent findings that sometimes two eyes are not better than one in cases of contextual modulations 76 , 77 , 79 . In light of our results, and since (1) both crowding and masking are dependent on the perceptual field size 48 , 59 , 102 , 112 and (2) crowding is similar to lateral interactions in certain spatial and temporal conditions 48 , we suggest that heterophoria could affect the symmetry of the perceptive field as well as the crowding effect—a hypothesis that deserves further investigation.…”

“…It was suggested that the suppressive zone is indicative of the perceptive field size (the perceptive field is the psychophysical analog to the classical receptive field in the visual cortex, for a review, see 48 , 105 , 106 ). Recently, it was shown that the binocular perceptive field size decreases with development, reaching an adult’s size in up to 5–6 years 59 ; however, these findings did not determine whether the perceptive field size would be different between the horizontal and the vertical meridian in general, and in heterophoria, in particular.…”

“…The response to a local element in a contour is modulated by lateral, suppressive, or facilitative inputs, similar to the mechanisms found in collinear facilitation 57 . This suggests that collinear facilitation is the process responsible for grouping 55 , 58 and for contour integration 27 , 59 , 60 of elements. Both mechanisms are involved in object recognition in visual perception, although some studies suggest that the collinear facilitation and contour integration mechanisms do not share the same sites 29 .…”

Extended perceptive field revealed in humans with binocular fusion disorders

“…The estimated size of the PF in this method is in agreement with previous studies using different methods. This method is used to estimate the development of collinear facilitation in children; it is related to the PF’s size 57 ; hence, it is the method that we chose for estimating the PF’s size in this study. We compared the estimation of the PF obtained using two types of lateral masking paradigms: the classic LM featuring flankers with an equal phase to the target, and the LM used by Zenger and Sagi 49 featuring opposite-phase flankers.…”

“…However, the PF’s size can also be modified by perceptual learning 70 – 72 or by its development. Recently, it was shown that the binocular perceptive field size decreases with development, reaching an adult’s size in up to 5–6 years 57 . In amblyopia, a pathology resulting from the absence of correlated binocular vision experience during the critical period at about 6 years old, it was shown that the PF’s size was greater than in neurotypical subjects, regardless of the amblyopia type (anisometropic or strabismic) 73 , 74 .…”