摘要:

SummaryTo answer the questions, (1) Which cells in the visual system are responsible for high visual acuity and (2) Does the function of the cells which provide high visual acuity develop postnatally; single cell studies have been made in the retina, lateral geniculate nucleus (LGN) and visual cortex of cats of different ages. Sustained‐X retinal ganglion cells in the area centralis (the equivalent retinal position to the human fovea) set the upper limit of visual acuity. The cellular acuity develops postnatally until it reaches the adult level at 3–4 months‐of‐age. The improvement of acuity is associated with an increase in the strength of the inhibitory surround mechanism of the receptive field of sustained cells in the area centralis. The maturation of cellular acuity coincides with maturation of retinal and LGN synaptic organisation and of optic nerve myel

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00141.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryCells in the parietal association area of stumptail monkeys did not respond to visual stimuli after binocular early deprivation. Although the monkeys responded to stimuli in the visual cortex, behaviourally they were blind. The importance of encouraging babies and infants to use all residual vision is stressed, so that the representation of visual input in the brain does not become permanently overtaken by other modalities

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00142.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryA range of methods has been developed, which can be used both to investigate the course of normal visual development and to assess clinical vision problems in infants. The behavioural ‘preferential looking’ method has been used to test acuity and contrast sensitivity in infants aged between 1–6 months and shows a rapid improvement in acuity (from 6/180 to 6/60) between I and 3 months. We have made monocular assessments and found, in most infants, similar acuity for each eye but somewhat better binocular acuity. A tracking test is under development for measurements in older infants and we have used an operant procedure with 3‐year‐olds which shows adult acuity at this age, These results have been extended to the newborn by measuring the amplitude of visual evoked potentials to patterned stimuli, indicating an acuity of approximately 6/180. The infants' refractive state has been studied by means of ‘photorefraction’. Many infants under 1 year are astigmatic but this has decreased to adult levels of incidence by 2 years. Infants of 6 months and older accurately accommodate over the adult range; younger infants accommodate appropriately for distances closer than 75 cm. Neural development rather than accommodative error appears to be the principal factor in limiting infants' acuity. A development of this technique may provide an effective means of refractive screening in

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00143.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryWithin the first week of life visual tracking and pattern differentiation were tested in 34 out of 47 premature infants born between 28–34 weeks of gestation. Positive results were achieved from 30 weeks onwards. Pattern differentiation was tested as soon as infants could be taken out of the incubator. Preference could be observed from 31 weeks post‐conceptional age. Both functions showed comparable maturation to full‐term controls by 34 weeks gest

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00144.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryThe development of the binocular reflexes during the first 6 months of life was studied in 38 normal infants. Preliminary results indicate that the following reflex is well established by 2 months, convergence by 3 months and the corrective fusion reflex by the age of 5 months.

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00145.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryDefects of the neuromotor system of the eye were found to occur in 80% of 70 visually impaired children. The influence of such defects on the developing visual acuity is discussed. Early and intensified treatment is suggested to minimize negative effects and promote visual development.

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00146.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryThe part played by vision in learning to interpret both speech and environmental sounds and to localize the latter is discussed in the light of observations of the development of sighted and of blind babies. Subsequently, some suggestions of guidance strategies based on these observations, are put forward to help visually handicapped babies acquire localization skills. Preliminary experience using these techniques has been promising and they are being further developed and researched at The Wolfson Centre in London.

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00147.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryThe VER was studied in normal children aged 4–11 years and in 71 amblyopic children at Moorfields Eye Hospital. Changes in the VER in amblyopia are best observed with 20% contrast and small square sizes. The better eye of untreated amblyopia has a normal time‐to‐peak for P1of the cortical response, while that of the amblyopic eye is delayed, the more so with poor binocular vision in partial agreement with our previous findings. We found with a high degree of significance that occlusion therapy renders the VER from the amblyopic eye more ‘normal’ but causes considerable delay in the VER from the covered eye, even though its visual acuity does not change. At the end of occlusion, these changes are usually reversible although not always completely in patients who have had prolonged

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00148.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryThe authors assessed visual functions in 10 children after operations for congenital glaucoma. All the children had had one or more operations previously and it was found that the visual development of the child was affected.

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00149.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryA sample of 583 Yugoslav urban children aged between 3 and 7 years, was tested for refraction. It was found that hypermetropia decreased between the ages of 3 and 6. but increased in the seventh year confirming other studies in this area.

ISSN:0305-1862    

DOI:10.1111/j.1365-2214.1979.tb00150.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY