Contrast sensitivity in children

We have used a spatial two-alternative, forced-choice staircase technique to measure contrast sensitivities for sinusoidally modulated gratings. Subjects, all of whom were untrained observers, consisted of children of ages 2–16 yr and adults. Our testing method was completely successful with children who were over 3.5 yr but failed with those below 2.5 yr. Mean contrast sensitivities of the youngest group from which data were obtained (2.5–4.5 yr) were 0.35 log units lower than those of adults. However, there was very little difference between these two groups in the middle range of spatial frequencies tested. A gradual increase with age of contrast sensitivities was found up to about 8 yr. This change is probably due to a combination of neural development and non-visual factors.     

Triethyltin decreases maximal electroshock seizure severity in adult rats

Acute and subacute treatment of adult rats with triethyltin bromide (TET) caused dose-dependent and time-dependent decreases in maximal electroshock seizure (MES) severity. This decrease in excitability was characterized by both a decrease in the percentage of animals exhibiting a maximal seizure and a corresponding decrease in the extension durations and an increase in the flexion durations. Acutely treated rats received (ip) 0, 1, or 5 mg/kg TET while subacutely exposed (po) received 0, 1, 5, or 10 ppm TET in the drinking water for 10 days. Experiments were designed so that the total consumed dose of TET, on a milligram per kilogram basis, equaled that in the acute experiment. No alterations in body weight were observed in either experiment. Acutely, the onset of action of TET was detectable within 0.5 hr. For the 1 mg/kg group, the effect peaked between 4 and 24 hr and completely recovered by 72 to 96 hr. For the 5 mg/kg group, the marked effect peaked at 4 hr, however, no recovery was observed. Subacute exposure for 1 to 2 days produced marked decreases in MES severity which were still present in the 5- and 10-ppm groups 14 days after cessation of exposure. Comparison of the onset and recovery data in the acute and subacute experiments revealed a close correspondence in similarly dosed rats. Comparison with other MES data from our laboratory revealed that adult rats were more sensitive to TET than adult mice or developing rats. Additionally, the MES test was able to detect subtle functional alterations in the central nervous system at lower doses of TET than previously reported neurobehavioral evaluation procedures.     

三维仿真技术在眼视光教学中应用的研究进展

The three-dimensional simulation technology refers to the technology which can use the computer technology to generate a realistic virtual environment with visual, hearing, touch, taste, and other perception. Users can have interaction with entity in the virtual environment. With its very vivid virtual reality （VR） technology, 3D simulation technology has gained more and more attention and provided a new development platform for ophthalmology and optometry teaching. This paper mainly introduced teaching the present development situation and the specific application of the 3D simulation model, 3D animation technology, virtual reality technology in optometry and ophthalmology.     

眼视光专业眼科学基础教学改革中的几点体会

在眼视光专业专科层次的教学中,根据高职高专人才培养要求,我们打破常规将眼科学基础安排在第一学年第一学期,精心组织教学,采取一系列教学模式,如调动学生的学习积极性,理论联系实际,多媒体和板书结合,多途径进行社会实践等,以临床实践需要为动力推动基础医学理论教学,建立科学合理的、适应现代眼科学基础发展趋势的授课体系,在学生中获得了较满意的效果。     

豚鼠的条栅视力检测设备的制作及其条栅视力的测定

目的 通过豚鼠视动反应来测量分析其条栅视力.方法 实验研究.根据视动性头部震颤反应的原理,豚鼠被单独放置在直径为130 cm的转鼓中央,转鼓内壁贴有可以更换空间频率和对比度的方波条栅.测量之前在豚鼠头部贴一小纸板,上面印有两个小白点,自行编写的测量软件通过追踪小白点的运动来记录头部的追随运动.两个小白点之间的相对位置关系被定义为头转动的角速度,而头转动的角速度与鼓转动的角速度的比值定义为"头部运动反应率".取相同年龄不同屈光状态(+9.70～-15.00 D)的豚鼠11只,比较其对0.6周/度和2.4周/度的条栅的反应;取相同屈光状态,不同年龄(1～3月龄)的豚鼠17只,测量其对不同级别条栅的反应;取相同年龄相同屈光度的豚鼠3只,在不同环境照度(10、30和350 cd/m2)下测量其对级别为0.6周/度而对比度不同(25%、50%和100%)的条栅的视动性反应.不同年龄段豚鼠各级条栅视力的比较用单因素方差分析;各种环境照度下不同对比度条栅之间的视动性反应的比较,以及不同屈光度组别豚鼠的视力比较,均用非参数检验中的Kruskal-Wallis检验法.结果 自制视力仪可以在豚鼠双眼开放状态下有效而快速的测量其单眼视力;而且可以敏感的检测出不同屈光不正豚鼠的视力差别;不同月龄豚鼠,随年龄增加,对各条栅的视动反应逐渐明显稳定,年龄小的豚鼠(1月龄)与较年龄大的豚鼠(2,3月龄)的视动性头部追随运动反应明显低,差异有统计学意义(F=35.73,P＜0.001).2月龄豚鼠,测试其0.6周/度空间频率的条栅,对于三个不同对比度的条栅,其视动性反应的最大斜率均出现在照明度为30 cd/m2时,分别为0.70±0.10(25%)、0.94±0.16(50%)和0.95±0.20(100%).在3种照明度下,对对比度为100%的条栅的头部视动性反应率最大,分别为0.81±0.25(10 cd/m2)、0.95±0.20(30 cd/m2)、0.80±0.09(350 cd/m2).结论 高度近视性屈光不正的豚鼠的视力低于远视性屈光不正的豚鼠;随年龄增加,豚鼠的头部视动性反应逐渐明显并稳定;同一级别条栅对比度下,豚鼠的最大视动反应出现在照明度为30 cd/m2左右.总而言之,豚鼠的空间视力随近视程度增加而减少,随年龄和环境照度的增加而增加.     

视力资料统计学处理的几个基本问题

目前采用的各种视力表均存在着不同的缺陷,由此造成眼科医师评估视力资料的困难。多数问题表现在对眼科临床科研中统计学分析方法的应用方面。不同的视力表中视力与视角间的数量关系不同,随之视力和视角的资料类型也不同,进而采用的统计学方法也不同。只有弄清上述问题,才能正确理解视力资料并进行合理的处理。（中华跟科杂志,2007,43：484-488）     

Immediate and long-term alterations in maximal electroshock seizure responsiveness in rats neonatally exposed to triethyltin bromide

Neonatal rats were injected (sc) with 0, 0.25, 0.5, 1.0, 2.5, or 5.0 mg/kg triethyltin bromide (TET) in a 2% ethanol vehicle on Days 0, 5, 10, 15, and 20 postnatally. TET-exposed neonates exhibited a dose-dependent delay in the ontogenetic appearance of both the clonic and tonic maximal electroshock seizure (MES) responses which were apparent up to Day 45, as evaluated by the MES grade distributions and the durations of the individual phases of the MES. In marked contrast, adult rats (exposed to TET only as neonates) exhibited long-term increases in MES severity, as evaluated by the durations of the individual phases of the MES. At 75 days of age, a time when the 1.0 mg/kg developmentally TET-treated group exhibited an increased seizure severity, a single challenge dose of 1.0 mg/kg TET (ip) produced a proportional decrease in MES severity in both developmentally treated and control rats. No changes in preweaning or postweaning body weight were observed in the animals in the 0.25, 0.5, 1.0, or 2.5 mg/kg groups. A 30% decrease in weaning weight and an approximate 15% decrease in postweaning weight were observed in the 5.0 mg/kg group. These seizure results demonstrate that developmental exposure to TET produces immediate and long-term alterations in central nervous system functioning, which are of an opposite character. Interestingly, we have previously shown that developmental lead exposure produces a similar developmental/adult dichotomy of effects with regard to the MES severity; however, the two patterns are reversed (D. A. Fox, S. R. Overmann, and D. E. Woolley (1979). Neurotoxicology1, 149–170).