The Stiles-Crawford effect of the first kind (SCE-I) was measured on both emmetropic and myopic subjects at six different retinal locations. The results revealed a number of significant discrepancies in receptor alignment between the groups of different refractive errors. In myopic subjects, the receptors in the nasal retina (i.e. between the fovea and the optic nerve head) were found to be aligned nasally towards the optic nerve head, whereas the receptors in the temporal retina were aligned towards the centre of the exit pupil. In emmetropic subjects, the receptors across the retina were finely tuned towards the centre of the exit pupil. The magnitude of the receptor displacement in myopic subjects was found to be directly associated with the length of the eyeball. 相似文献
We studied amplitude of the wave N200 of the motion-onset VEP by varying the side length of a square stimulation field between 0.5 and 7 degrees. A significant increase in amplitude was obtained between 0.5 and 1 degree of side length in central stimulation and between 0.5 and 5 degrees in 10-degree peripheral stimulation. Variations of spatial frequency between 0.34 and 6.8 c/deg did not modify the amplitude size, ie, no tuning effect could be found. The results of simultaneous and separate stimulation of foveal and parafoveal regions support the observation that the stimulation field size is a minor influence. Features of motion-sensitive cortical neurons, such as those found in monkeys, could account for this behavior. 相似文献
目的:探讨波及黄斑区的孔源性视网膜脱离(RRD)行巩膜扣带手术前后黄斑区三维光学相干断层扫描图像(3D-OCT)特征,分析其与视力的相关性。方法:回顾性系列病例,30例30眼波及黄斑区的RRD行巩膜扣带术治疗的临床资料,在术后2d,2wk,1、3、6mo随诊时双眼均行3D-OCT检查,观察椭圆体带(EZ)、外界膜(ELM)、黄斑区视网膜下液高度(SRFH)、黄斑中心凹视网膜厚度(CRT)的变化,分析其与术后最佳矫正视力(BCVA)的关系。结果:术前,术后2d,2wk,1、3、6mo SRFH、CRT、BCVA均有差异(P<0.01),术后SRFH、CRT都有不同程度降低,术后BCVA都有不同程度升高,组内两两对比:除SRFH(2wk vs 1mo,P>0.05)、CRT(2d vs 2wk,P>0.05)、BCVA(2d vs术前,2wk vs术前,P>0.05)无统计学意义外,其余各项间的比较均有统计学意义(P<0.05)。EZ、ELM形态可分为:A:EZ和ELM均连续(EZ+ELM+),9眼;B:EZ断裂和ELM连续(EZ-ELM+),7眼;C:EZ连续和ELM断裂:EZ+ELM-,6眼;D:EZ和ELM均断裂(EZ-ELM-),8眼,术后6mo上述4种类型的BCVA分别为0.15±0.04、0.50±0.06、0.54±0.05、0.59±0.09(F=87.210,P<0.05),两两比较:除C vs B和C vs D差异无统计学意义(P>0.05)外,其余各组间的比较差异均有统计学意义(P<0.05)。术后2d的SRF发生率为87%,术后6mo仍有46.6%患者存在持续性SRF。术后CRT与术后SRFH具有正相关关系。结论:巩膜扣带术后黄斑微结构呈动态改变,SRF影响可能表现为BCVA延迟恢复,随着SRF缓慢吸收,CRT逐渐降低,BCVA逐渐升高;ELM或EZ连续提示有较好的BCVA,而ELM断裂可能提示视觉质量更差。 相似文献
PurposeTo refine estimates of macular soft drusen abundance in eyes with age-related macular degeneration (AMD) and evaluate hypotheses about drusen biogenesis, we investigated topographic distribution and growth rates of drusen by optical coherence tomography (OCT). We compared results to retinal features with similar topographies (cone density and macular pigment) in healthy eyes.MethodsIn a prospective study, distribution and growth rates of soft drusen in eyes with AMD were identified by human observers in OCT volumes and analyzed with computer-assistance. Published histologic data for macular cone densities (n = 12 eyes) and in vivo macular pigment optical density (MPOD) measurements in older adults with unremarkable maculae (n = 31; 62 paired eyes, averaged) were revisited. All values were normalized to Early Treatment Diabetic Retinopathy Study (ETDRS) subfield areas.ResultsSixty-two eyes of 44 patients were imaged for periods up to 78 months. Soft drusen volume per unit volume at baseline is 24.6-fold and 2.3-fold higher in the central ETDRS subfield than in outer and inner rings, respectively, and grows most prominently there. Corresponding ratios (central versus inner and central versus outer) for cone density in donor eyes is 13.3-fold and 5.1-fold and for MPOD, 24.6 and 23.9-fold, and 3.6 and 3.6-fold.ConclusionsNormalized soft drusen volume in AMD eyes as assessed by OCT is ≥ 20-fold higher in central ETDRS subfields than in outer rings, paralleling MPOD distribution in healthy eyes. Data on drusen volume support this metric for AMD risk assessment and clinical trial outcome measure. Alignment of different data modalities support the ETDRS grid for standardizing retinal topography in mechanistic studies of drusen biogenesis. 相似文献