You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
Video-Game Play Induces Plasticity in the Visual System of Adults with Amblyopia
Abstract 1:
A pilot study suggests that playing video games may enhance a range of spatial vision functions in adults with amblyopia


Title 2:
Foveal contour interactions and crowding effects at the resolution limit of the visual system.
Abstract 2:
We describe several experiments on  contour interactions and crowding effects at the resolution limit of the visual system . As test stimuli we used characters that are often employed in optometric practice for testing visual acuity : L and olt C 's , Snellen E 's , and rectangular gratings . We tested several hypotheses that have been put forward to explain  contour interaction  and  crowding effects . In Experiment 1 and Experiment 2 , L and olt C 's were the test stimuli , and bars , or L and olt C 's , or gratings served as distractors . In Experiment 1 , we showed that neither scale invariance nor spatial frequency selectivity is a characteristic of foveal crowding effects . These results allowed us to conclude that mechanisms other than lateral masking contribute to observers ' performance in ' crowded ' tasks . R. F. Hess , S. C. Dakin , and N. Kappor ( 2000 ) suggested that the spatial frequency b and most appropriate for target recognition is shifted by the surrounding bars to higher spatial frequencies that can not be resolved by observers . Our Experiment 2 rejects this hypothesis as the experimental data do not follow theoretical predictions . In Experiment 3 , we employed Snellen E 's , both as test stimuli and as distractors . The masking functions were similar to those measured in Experiment 1 when the test L and olt C was surrounded by L and olt C 's . In Experiment 4 , we extended the range of test stimuli to rectangular gratings ; same-frequency or high-frequency gratings were distractors . In this case , if the distracting gratings had r and om orientation from trial to trial , the critical spacing was twice larger than in the first three experiments . If the orientation of the distractors was fixed during the whole experiment , the critical spacing was similar to that measured in the first three experiments . We suggest that the visual system can use different mechanisms for the discrimination of different test stimuli in the presence of particular surround . Different receptive fields with different spatial characteristics can be employed . To explain why crowding effects at the resolution limit of the visual system are not scale invariant , we suggest that a range of stimuli , slightly varying in size , may all be processed by the same neural channel -- the channel with the smallest receptive fields of the visual system


Title 3:
Crowding in Children's Visual Acuity Tests—Effect of Test Design and Age
Abstract 3:
Purpose . The aim of this study was to investigate the effect of test design ( crowding ) and age on visual acuity in a sample of young children . Methods . Vision was measured in 103 children aged between 4 and 9 years using five different visual acuity tests . The tests included three crowded tests : logMAR Crowded test , the Sonksen logMAR test , and the Crowded Kay Picture test , and two single optotype tests : the Single Kay Picture and Sheridan Gardiner tests . Tests were presented in a r and om order using st and ardized instructions and a defined end-point . Results were analyzed in two age groups , younger ( 4 to 6 years ) and older ( 7 to 9 years ) . Results . In both groups , there was a significant main effect of test on acuity ( younger : F = 63.92 , dF = 4 , p < 0.001 ; older : F = 63.59 , dF = 4 , p < 0.001 ) . In the younger group , an effect of crowding was seen in all three crowded tests , but in the older group , an effect of crowding was seen only in the crowded letter tests . In both groups , mean acuity was lowest with the logMAR Crowded test , which has the closest interoptotype spacing ( 0.5 ) , slightly higher with the Sonksen test ( with interoptotype spacing of 1.0 ) and highest with the single optotype tests ( no crowding ) . More crowding was seen in the younger children . Conclusions . Our results show that maturation of line acuity is still taking place between the ages of 4 and 9 years . Measured acuity is affected by the amount of contour interaction induced by the type of optotype ( letter or picture ) and by the interoptotype separation . Another factor , probably a maturation of gaze control or selective attention is responsible for the reduction in crowding with age


Title 4:
Patterns of visual impairment associated with lesions of the preterm infant brain.
Abstract 4:
The visual function of 42 children with haemorrhagic and /or ischaemic cerebral lesions acquired before a gestational age of 35 weeks was examined and related to cranial ultrasound in the neonatal period and to MRI and neurodevelopmental status at follow-up . All 37 children with abnormal ultrasound scans and one of the five with normal ultrasound scans showed impairment of one or more aspects of visual function . While impaired acuity was more frequent among infants with MRI evidence of visual pathway damage , this was not an invariable finding . Normal or near-normal visual acuity did not preclude the presence of other functional visual deficits . The authors conclude that preterm cerebral insults may produce a variety of visual difficulties , the pattern and severity of which can not be predicted on imaging . Each child therefore requires individual assessment of multiple aspects of visual function


Title 5:
Contour Interaction Function in the Preschool Child
Abstract 5:
Contour interaction was investigated in 12 preschool children 3 to 4 years of age , and compared to the results obtained from 5 normal adults tested under an identical paradigm .  Observers viewed the display from a distance at which they could identify the location of a gap ( up or down ) in an isolated C correctly on 90 to 95 % of the trials . The isolated C and C 's with bars tangentially located at various positions above and below the test optotype were intermixed r and omly . Percent correct was plotted as a function of the angular subtense of the gap width of the test optotype . A significant decrease in performance was found when the bars were positioned at 0.71 to 1.42 times the angular subtense of the gap for both the preschool children and the adults . The results suggest that preschool children demonstrate contour interaction that is quantitatively similar to adults . Because the spacing of letters on st and ard acuity charts is typically larger than the range over which contour interaction occurs , the poorer acuity often measured with charts compared to isolated letter presentation in preschool children suggests that factors other than contour interaction ( perhaps attentional factors ) are involved
Results Children with normal vision show an extent of contour interaction over an area 1.5–3 × as large as that seen in adults NV .
The magnitude of contour interaction normally ranges between 1–2 lines on an acuity chart and this magnitude is even larger when stimuli are arranged in a circular configuration .
Adults with congenital nystagmus ( CN ) show interaction areas that are 2 × larger than those seen adults with NV .
The magnitude of the crowding effect is also 2 × as large in individuals with CN as in individuals with NV .
This is the first systematic review to compare crowding ratios and it shows that charts with 50 % interoptotype spacing were most sensitive to capture crowding effects .
The groups that showed the largest crowding effects were individuals with CN , VI adults with central scotomas and children with CVI .
Perceptual Learning seems to be a promising technique to reduce excessive foveal crowding effects