Objective To detecte the pathogenetic mechanism of cortical deficit in persons with strabismic amblyopia by blood oxygenation level dependent-functional magnetic resonance imaging(BOLD-fMRI)． Methods The data of BOLD-fMRI of occipital visual cortex in 11 persons with strabismic amblyopia and 8 healthy ones were collected by 1．5T MRI system．The results of binocular pixel exponent in strabismic amblyopia group was compared with that in the normal group and the result of and average activation of cortical neuron in strabismic amblyopia group was analyzed.Results The binocular pixel exponent was lower in the strabismic amblyopia group(14．13％±4．55％)than that in the normal group(47．82％±5．34％)(PConclusions The reduction of cortical binocular cells and the undersampling and coding of higher-spatial-frequency components of visual stimuli may be related to the strabismic amblyopia．BOLD-fMRI may provide a new path to detecte the pathoffenetic mechanism of cortical deficit in people with strabismic amblyopia. (Chin J Ocul Fundus Dis，2004，20：19-22)
Objective To investigate the characteristic of the multifocal visual evoked potentials(MVEP)and the visual function across the visual field in anisometropic amblyopes and isometropic amblyopes. Methods MVEP from 32 anisometropic amblyopic eyes and 31 control eyes were tested. Results In anisometropic amblyopic eyes,the latencies of MVEP were significantly prolonged．The amplitudes of MVEP were significantly attenuated in the central region of the visual field,and these phenomena gradually reduced with the increase of the eccentricity． Conclusion The visual function of anisometropic amblyopic eyes is reduced more significantly in the central region than in the peripheral region of the visual field. (Chin J Ocul Fundus Dis,20000,16:27-29)
Purpose To identify the expression of alternatively spliced mRNA isoforms of the NMDA-R1 in the visual cortex of strabismic cats. Methods Two pai rs of normal and strabismic cats were used．The amblyopic cats had been made monocularly esotropic (by tenotomy) at the age of weeks，resulting in behavioral am blyopia．Animals were sacrificed about 6 months by intraperitoneal administration of Nembutal．Cryostat sections of fresh，frozen central visual cortex of the ats were cut to 20 micron thickness．A series of digoxygenin-labelled oligonucle otide probes basing on the human gene sequence were used for ISH．Control probes included sense oligonucleotides and short segment probes which were adjacent to ，but did not，span the splice junctions．A computer-assisted systematic morphometric ounting procedure was used to enumerate hybridising cells． Results The number of positive cells expressing NMDA-R1 mRNA in t he strabismic amblyopic cats was decreased，notably in layer IV of visual cortex (P＜0．0001)．The pattern of isoform expression varied between normal and strabismic amblyopic cats with decreased numbers of 1-a，1- b and 1-1 isoforms and apparently increased expression of 1-3 P ＜0．0001)，whereas no significant difference was found for the 1-2 and 1-4 isoforms (P＞0．05)． Conclusion Transcriptional inhibition of NMDA-R1 mRNA and of specifie isoforms may underlie the change in receptor expression．Alternatively，preferentialloss of neurones bearing particular NMDA-R1 isoforms and compensation with a proportional increase in cells expressing other isoforms may occurr during the critical period of visual plasticity． (Chin J Ocul Fundus Dis，2000，16：71-138)
PURPOSE: To explore the pathogenesis of anisometropic and amblyopias. METHODS:To carry out on monocular and binocular atropinized cat models during the developmental period for anisometropia and ametropia ,and measure the cytosomal sectional area and some parameters of the dendric field from the dorsal lateral geniculate nuclei (dLGN)of adult cats by using Golgi-Cox staining. RESULIS:The changes of cytosomal sectional areas and parameters about dendric fields in the dLGN of experimental cats were as following:significant differences between cells of dLGN's A1 lamina by the monocular atropinized eyes and normal ones, binocular atropinized eyea and normal ones;no significant difference between tbat driven by the monoular and binocular atropinized eyes. CONCLUSIONS:There might be resemble pathogenesis between anisomelropic and ametropic amblyopias. （Chin J Ocul Fundus Dis,1996,12:153-156）
ObjectiveTo investigate the neural mechanisms of subjects with anisometropic amblyopia using event-related potential (ERP) technology.MethodsNineteen subjects diagnosed with anisometropic amblyopia were consecutively recruited from the outpatients of the West China Hospital of Sichuan University from June 2013 to February 2014, and twenty normal subjects were recruited as control subjects. All subjects were given different orientation Gabor stimuli with three spatial frequencies (1, 2, 8 cpd) and their ERP was recorded. The differences of P3b, including amplitude and latency, were compared between amblyopic eye and fellow or control eye.ResultsAmong the three groups of amblyopic eye and fellow or control eye, there was no statistically significant difference in accuracy or response time at three spatial frequencies (P>0.05), in latency or amplitude of P3b at low spatial frequencies (1, 2 cpd) ((P>0.05), or in amplitude of P3b at high spatial frequency (8 cpd) (P>0.05). P3b latency of amblyopic eye extended at high spatial frequency (8 cpd), compared to fellow or control eye. Amblyopic eye was most significantly weakened in Brodmann area 17 at the P3b wave of each spatial frequency (1, 2, 8 cpd), and there was most significantly weakened in high spatial frequency (8 cpd).ConclusionThe P3b latency of amblyopic eye extended at high spatial frequency suggests that the cognitive function of amblyopia is impaired, at an extent, in the late visual processing stage.
ObjectiveTo evaluate the changes in subfoveal choroidal thickness (SFCT) in amblyopic eyes.MethodsA evidence-based medicine study. Chinese and English as search terms for amblyopia and choroid was used to search literature in Wanfang, CNKI, and PubMed of National Library of Medicine. Incomplete or irrelevant literature and review literature were excluded. The literature was meta-analyzed using STATA 15.0. The weighted mean difference (WMD) and 95% confidence interval (CI) were selected as the estimated value of effect size, and subgroup analysis and sensitivity analysis were used to detect the source of heterogeneity.ResultsAccording to the search strategy, 75 articles were initially retrieved, and 15 articles were finally included for meta-analysis. A total of 650 patients with amblyopia, aged 3 to 65 years old, were included. The enhanced depth imaging technology of spectral domain optical coherence tomography was used to measure SFCT. The results of meta analysis showed that SFCT of amblyopic eyes was more effective than the contralateral eye (WMD=18.89 μm, 95% CI 14.81-22.98 μm, P＜0.001) and normal eyes were thicken (WMD=39.49 μm, 95% CI 33.88-45.09 μm, P＜0.001). There was no statistically significant difference in SFCT between anisometropic and strabismic amblyopia eyes (WMD=－5.03 μm, 95% CI －19.50-9.44 μm, P=0.495).ConclusionsThe SFCT of amblyopic eyes in amblyopic patients is thicker than that of the contralateral eye and normal eyes. There is no difference in SFCT between anisometropia and strabismus amblyopia.
Amblyopia is a visual development deficit caused by abnormal visual experience in early life, mainly manifesting as defected visual acuity and binocular visual impairment, which is considered to reflect abnormal development of the brain rather than organic lesions of the eye. Previous studies have reported abnormal spontaneous brain activity in patients with amblyopia. However, the location of abnormal spontaneous activity in patients with amblyopia and the association between abnormal brain function activity and clinical deficits remain unclear. The purpose of this study is to analyze spontaneous brain functional activity abnormalities in patients with amblyopia and their associations with clinical defects using resting-state functional magnetic resonance imaging (fMRI) data. In this study, 31 patients with amblyopia and 31 healthy controls were enrolled for resting-state fMRI scanning. The results showed that spontaneous activity in the right angular gyrus, left posterior cerebellum, and left cingulate gyrus were significantly lower in patients with amblyopia than in controls, and spontaneous activity in the right middle temporal gyrus was significantly higher in patients with amblyopia. In addition, the spontaneous activity of the left cerebellum in patients with amblyopia was negatively associated with the best-corrected visual acuity of the amblyopic eye, and the spontaneous activity of the right middle temporal gyrus was positively associated with the stereoacuity. This study found that adult patients with amblyopia showed abnormal spontaneous activity in the angular gyrus, cerebellum, middle temporal gyrus, and cingulate gyrus. Furthermore, the functional abnormalities in the cerebellum and middle temporal gyrus may be associated with visual acuity defects and stereopsis deficiency in patients with amblyopia. These findings help explain the neural mechanism of amblyopia, thus promoting the improvement of the treatment strategy for amblyopia.