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Visual Development (visual + development)
Selected AbstractsVisual Development, Diagnosis, and Treatment of the Pediatric PatientCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 5 2007Article first published online: 9 AUG 200 No abstract is available for this article. [source] Visual development in preterm infantsDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 4 2005Ashima Madan MD First page of article [source] Multiple sensitive periods in human visual development: Evidence from visually deprived childrenDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2005Terri L. Lewis Abstract Psychophysical studies of children deprived of early visual experience by dense cataracts indicate that there are multiple sensitive periods during which experience can influence visual development. We note three sensitive periods within acuity, each with different developmental time courses: the period of visually-driven normal development, the sensitive period for damage, and the sensitive period for recovery. Moreover, there are different sensitive periods for different aspects of vision. Relative to the period of visually driven normal development, the sensitive period for damage is surprisingly long for acuity, peripheral vision, and asymmetry of optokinetic nystagmus, but surprisingly short for global motion. A comparison of results from unilaterally versus bilaterally deprived children provides insights into the complex nature of interactions between the eyes during normal visual development. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 46: 163,183, 2005. [source] The key role of electrophysiology in the diagnosis of visually impaired childrenACTA OPHTHALMOLOGICA, Issue 6 2006Maria Van Genderen Abstract. Purpose:, To describe the outcome of specialized electrophysiology in visually impaired children. Methods:, We carried out a retrospective evaluation of 340 electrophysiological examinations performed in 298 children over a 3-year period (2001,2003), with regard to demographic data, referral pattern, degree of compliance, and diagnostic results. Electrophysiology was performed without sedation or anaesthesia. In electroretinograms, DTL electrodes were used in combination with online selection of responses. Visual evoked potentials testing was performed with seven active occipital electrodes. Results:, The mean age of the children was 7 ± 5 years; 72 (24%) of the children were mentally as well as visually impaired. Main reasons for referral were suspected posterior segment disease, abnormal visual development, unexplained low vision, high myopia, and suspected albinism. Compliance was good in 302/340 (88%), partial in 24/340 (7%), and absent in 14/340 (4%) of the examinations. Of the 326 successful procedures, 215 (66%) showed abnormal results. Tapetoretinal dystrophy (22%), opticopathy (16%), congenital stationary night blindness (13%), and cone dystrophy (11%) were the most frequently established diagnoses. Albinism was confirmed in 14 of 24 suspected patients; additionally, unsuspected misrouting was found in six. In 26 (9%) of the patients, a previously established diagnosis was changed. Conclusions:, In a specialized setting, electrophysiological examinations can be performed successfully in visually impaired children. The results are essential for the final ophthalmological diagnosis and have important consequences for rehabilitation. [source] Effects of binocular form deprivation on the excitatory post-synaptic currents mediated by N-methyl-D-aspartate receptors in rat visual cortexCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2004Wei Qin MD Abstract Purpose:,To investigate the effects of binocular form deprivation (BFD) on the excitatory post-synaptic currents (EPSCs) mediated by the N-methyl-D-aspartate (NMDA) receptor (NMDA-EPSCs), and the proportion of NMDA-EPSCs relative to glutamate receptor currents (glutamate-EPSCs) in rat visual cortex. Methods:,Binocular form deprivation was achieved by suturing the eyelids of Wistar rats at postnatal day (PD) 14, before eye-opening. Visual cortical slices (300 µm) were prepared from normal and BFD Wistar rats aged PD 14, 21 and 28. Recordings were obtained in slices from layer II to IV using the whole-cell patch-clamp technique. Glutamate-EPSCs were isolated in the presence of bicuculline methiodide (20 µmol/L) in the bathing medium, and NMDA-EPSCs were isolated with a combination of bicuculline methiodide (20 µmol/L) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 20 µmol/L). In addition, D,L-2-amino-5-phosphonovalerate (AP-5, 20 µmol/L) was applied to study the NMDA-only mediated currents. For each cell, the ratio of peak NMDA to glutamate EPSCs was calculated. Results:,During visual development, the decay time constant of NMDA-EPSCs became shorter after eye-opening in normal rats (F = 5.949, P <0.05; PD 28 vs PD 14, P = 0.027), but not in rats with BFD (P > 0.05). The weighted time constant of NMDA-EPSCs in the visual cortex became shorter after the rats' eyes were opened in the normal group (F2,37 = 4.727, P = 0.015; PD 28 vs PD 14, P = 0.035), but not in the BFD group (P > 0.05). However, the rise time constant and peak value of NMDA-EPSCs showed no significant changes in normal and BFD groups (P > 0.05). The ratio of NMDA-EPSCs to glutamate-EPSCs became gradually smaller with age in the normal rats (F = 4.661, P < 0.05; PD 28 vs PD 14, P = 0.025), but not in the BFD group (P > 0.05). Conclusions:,These studies reveal that the proportion of NMDA-EPSCs relative to glutamate-EPSCs and the decay time constant of NMDA-EPSCs are influenced by BFD. These changes may reflect important experience-dependent modifications of neuronal synapses in visual cortex. [source] | ||||||||||