阈值和阈值前期早产儿视网膜病变儿童视网膜电图观察

目的用全视野闪光视网膜电图（F-ERG）评价既往患阈值或阈值前期早产儿视网膜病变（ROP）JL童的视网膜功能。方法用F-ERG检查34例（68眼）既往有早产儿童,患阈值或阈值前期ROP者24例（48眼）,出生年龄体重匹配的未患ROP者10例（20眼）。统计分析两组儿童暗视和明视各反应a波、b波潜伏期和振幅的差异。结果ROP组较对照组暗视视杆反应和最大混合反应a波、b波潜伏期延长,振幅降低,差异有统计学意义,P〈O．05。ROP组与对照组明视视锥反应a波、b波振幅和潜伏期无明显差别,P〉0．05。结论阈值或阈值前期ROP视网膜功能受到影响,以视杆细胞的功能降低为主。F-ERG是评价早产儿视网膜功能有效检测手段。     

阈值期和阈值前期早产儿视网膜病变的远期视网膜电图特征

目的 观察阈值期和阈值前期早产儿视网膜病变（ROP）的远期视网膜电图特征。方法 诊断为阈值期或阈值前期ROP的24例患儿48只眼（ROP组）纳入研究。选择出生年龄、体重与之匹配的未发生ROP的早产儿10例20只眼为对照组。经过湖南省儿童医院医学伦理委员会批准并取得所有受检者父母的知情同意后,所有受检儿行全视野闪光视网膜电图（F-ERG）检查,记录视杆反应、最大混合反应以及视锥反应。结果 与对照组比较,ROP组患儿的视杆反应b波潜伏期明显延长,差异有统计学意义（t=5.643,P＜0.05）;振幅明显降低,差异也有统计学意义（t=7.068,P＜0.05）。与对照组比较,ROP组患儿的最大混合反应a、b波潜伏期均延长,差异有统计学意义（t=3.099、2.886,P＜0.05）;振幅均降低,差异也有统计学意义（t=5.614、2.850,P＜0.05）。与对照组比较,ROP组患儿的视锥细胞反应a、b波潜伏期（t=0.819、0.948）及振幅（t=0.904、0.850）无明显变化,差异均无统计学意义（P＞0.05）。结论 阈值期和阈值前期ROP患儿远期视网膜视杆反应b波及最大混合反应a、b波潜伏期延长,振幅降低;视锥反应a、b波无明显变化。     

早产儿健康眼出生时视网膜电图特点

目的 了解早产儿出生时视网膜功能发育程度，比较早产儿和足月 产婴儿出生时视 网膜功能发育的异同。 方法 健康无眼病的早产儿10例10只眼和足月产 婴儿20例20只眼，随 机选取1只眼在出生后1周内进行闪光视网膜电图（FERG）检测，记录视杆细胞反应、视锥细 胞反应、最大混合反应，振荡电位（OPs）及30 Hz闪烁光反应。 结果 与足月产 婴儿比较，早产儿出生时视杆细胞反应潜伏期明显延长 (t=3.216，P=0.003)，振幅明显降低(t=6.050，P=0.000），差异有统计学意义；最大反应a、b波潜伏期差异无 统计学意义(t=0.465，P=0.650；t=1.068，P=0.295)，而振幅降低(t=6.584，P=0.000；t=6.649，P=0.000)差异有统计学意义。两组婴儿视锥细胞反应a、b波潜伏期 差异无统计学意义(t=0.077，P=0.939；t=0.935，P=0.358)，早产儿组振幅明显降 低(t=3.417，P=0.002；t=6.310，P=0.000)， 差异有统计学意义；两组间30 Hz闪烁光峰值潜伏期差异无统计学意义(t=0.968，P=0.341），早产儿组振幅明显降低（t=3.745，P=0.001），其差异有统计学意义。 两组间最大混合反应的b／a波振幅比值差异无统计学意义(t=0.215，P=0.831)。 结论 出生时早产儿视网膜的发育程度低于足月产婴儿。     

应用视网膜电图评估早产儿视网膜病变退化后的视功能

目的通过闪光视网膜电图（flash electroretinogram,F-ERG）评估曾患早产儿视网膜病变（retinopathy ofprematurity,ROP）但自行消退的患儿的视功能情况,比较其与正常早产儿的异同。方法随机选择胎龄为26~36周,出生体重为990-2700g,曾患早产儿视网膜病变但自行消退的早产儿15例（30只眼）在半岁~2岁进行F-ERG检查,并选择胎龄、出生体重和检查年龄相似的正常早产儿作为对照组,对比F-ERG各波的振幅和潜伏期。结果 ROP组和正常对照组视杆反应b波潜伏期的差异有统计学意义（P〈0.05）,最大混合反应a波、b波,视锥反应a波、b波潜伏期的差异均无统计学意义;视杆反应b波,最大混合反应a波、b波,视锥反应a波、b波振幅及30Hz闪烁光及振荡电位峰值的差异均无统计学意义（P〉0.05）。结论早产儿视网膜病变退化后对患儿的视功能影响不大,因此,发现轻度的早产儿视网膜病变不必急于手术,可以密切观察其能否消退疾病进展再考虑是否手术,视杆细胞功能的损伤可考虑以后行视功能训练。     

早产儿视网膜功能的全视野闪光视网膜电图检查

目的 观察早产儿视网膜功能变化特征。方法 对78例4～5个月婴儿在口服镇静 剂熟睡后进行全视野闪光视网膜电图（ERG)检查，测量各项反应的a波和b波的振幅和隐含期 ，以评价未成熟儿的视网膜功能。78例156只眼中，健康足月产儿33例66只眼，健康早产儿2 5例50只眼，早产儿视网膜病变（ROP）患儿20例40只眼。结果 所有足 月产儿和健康早产儿 都可以记录到明显的ERG波形。足月产儿的标准混合反应b波振幅为388.7 μV，健康早产儿 的标准混合反应b波振幅为336.7 μV，分别为正常成人混合反应b波振幅的64.4％和55.6 ％。ROP患儿中，20只眼记录不到波形，其余20只眼的标准混合反应b波振幅为183.8 μV，和足月产儿相比，隐含期也显著延迟。健康早产儿的ERG振幅较足月产儿 轻度降低， 差异有统计学意义。结论 出生后视网膜还处于不断成熟发育过程中， 健康足月产儿的ER G尚未达到正常成人的水平；早产儿视网膜发育程度较足月儿慢，不论是健康早产儿还是ROP 患儿，其ERG均不及健康足月产儿。因此ERG检查是评价早产儿视网膜功能的有效方法。     

低出生体重儿的立体视觉研究

对９０例３～１０岁低体重儿和７５例同龄足月正常体重儿进行立体视锐度检查。按年龄分组比较两组立体视异常率，≤６岁的两组间立体视异常率无显著差异（Ｐ＞０．０５）；＞６岁的两组间差异有显著性（Ｐ＜０．０５），低体重儿组的立体视异常率较高。在低体重儿组中，按胎龄分成早产儿及足月小样儿两组比较立体视异常率，两组间差异有显著性（Ｐ＜０．０５），早产儿组较高。提示出生体重及胎龄对立体视的发育有一定的影响，所以应重视对低体重儿、特别是早产低体重儿的眼科随访。     

早产儿全视野闪光视网膜电图检查

目的观察全视野闪光视网膜电图（F-ERG）在早产儿视网膜病变（ROP）中的变化及其评价早产儿视网膜功能的可行性。方法 4～12周龄早产儿84例（168眼）,其中ROP（＋）组30例,ROP（-）组54例。在睡眠状态下进行F-ERG检查,记录视杆反应、最大混合反应以及视锥反应。成人组为健康成年人15例（30眼）。F-ERG的记录遵循ISCEV2000年修订的临床视觉电生理国际标准化程序。结果 F-ERG各反应波形发生率3组比较,ROP（＋）组最低,差异均有统计学意义（视杆反应：χ2=50.710,P=0.000;最大混合反应：χ2=32.002,P=0.000;视锥反应：χ2=23.992,P=0.000）。ROP（＋）组和ROP（-）组视杆反应波形发生率低于视锥反应,差异均有统计学意义（χ2=20.306,P=0.000;χ2=12.706,P=0.000）。3组F-ERG各反应a波、b波隐含时及振幅的比较,差异均有统计学意义（视杆反应：b波隐含时F=66.405,P=0.000;b波振幅F=180.496,P=0.000。最大混合反应：a波隐含时F=9.536,P=0.000;a波振幅F=189.150,P=0.000;b波隐含时F=89.851,P=0.000;b波振幅F=278.984,P=0.000。视锥反应：a波隐含时F=37.526,P=0.000;a波振幅F=67.182,P=0.000;b波隐含时F=32.470,P=0.000;b波振幅F=145.631,P=0.000）。除视锥反应a波振幅和b波隐含时ROP（＋）组与ROP（-）组比较以及最大混合反应a波隐含时ROP（-）组与成人组比较外,ROP（＋）组余各反应a波、b波隐含时明显延长,振幅明显降低,差异均有统计学意义（P〈0.05）。结论出生后4～12周早产儿的视网膜功能仍处于发育过程中,视杆细胞较视锥细胞成熟晚;而ROP对其视网膜功能有一定的影响,且主要影响视杆细胞功能,其影响与病变程度有关。F-ERG可以作为评价早产儿视网膜功能的检测手段之一。     

溶血卵磷脂酰基转移酶1自发突变小鼠视网膜组织和闪光视网膜电图改变

目的 观察溶血卵磷脂酰基转移酶1（LPCAT1）自发突变小鼠视网膜组织和闪光视网膜电图（F-ERG）改变情况。方法 Lpcat1基因自发突变纯合子的rd11新生小鼠60只（实验组）和与之同龄的野生型C57BL/6J小鼠60只（对照组）纳入实验。采用免疫荧光法检测两组小鼠视网膜组织中LPCAT1的表达情况。出生后3、6、9 d和2、4、6、8周,行视网膜石蜡切片观察视网膜显微结构;行全视野F-ERG检测,记录暗视杆体反应和明视锥体反应。结果 实验组小鼠视网膜组织中LPCAT1呈阴性表达;对照组小鼠视网膜组织中LPCAT1呈阳性表达,主要分布于视网膜光感受器内节,神经节细胞层可见少量表达。光学显微镜观察发现,实验组小鼠于出生后9 d左右视网膜外核层已基本形成,其光感受器细胞核层数随年龄增长而逐渐减少。对照组小鼠视网膜显微结构正常。F-ERG检测结果 显示,实验组小鼠出生后2、4周暗视杆体系统反应存在,呈降低趋势,出生后6~8周暗视杆体系统反应消失;对照组小鼠各时间点暗视杆体系统反应正常。出生后2周,实验组和对照组小鼠b波振幅分别为（72.8±15.6）、（105.2±21.1） μV,实验组较对照组降低,但差异无统计学意义（t=-2.760,P=0.025）。出生后4周,实验组和对照组小鼠b波振幅分别为（20.6±6.4）、（231.8±32.0） μV,实验组较对照组明显降低,差异有统计学意义（t=-14.471,P=0.000）。实验组小鼠出生后2、4、6周明视锥体系统反应存在,呈降低趋势,出生后8周明视锥体系统反应消失;对照组小鼠各时间点明视锥体系统反应正常。出生后2、4周,实验组小鼠b波振幅分别为（46.8±7.2）、（78.0±8.2） μV;对照组小鼠b波振幅分别为（42.8±6.4）、（91.4±9.4） μV。两组比较,差异均无统计学意义（t=0.930、-2.401,P=0.379、0.043）。出生后6周,实验组和对照组小鼠b波振幅分别为（17.2±2.0）、（116.2±12.9） μV,实验组较对照组明显降低,差异有统计学意义（t=-17.008,P=0.000）。结论 LPCAT1自发突变小鼠视网膜外层光感受器细胞核层数随年龄增长而逐渐减少,F-ERG暗视杆体和明视锥体反应异常。     

早产儿和足月产婴儿视网膜电图比较

目的了解早产儿视网膜功能发育程度。方法选取健康无眼病早产儿和足月产婴儿各25例进行闪光视网膜电图(ERG)检测，记录视杆细胞反应、视锥细胞反应及最大混合反应。对比分析两组婴儿的ERG各波反应的潜伏期、振幅以及最大反应b／a波振幅比值。结果与足月产婴儿比较，早产儿视杆细胞反应潜伏期延长（t=11.007，P=0.000），差异具有统计学意义，而振幅没有明显改变（t=1.836，P=0.069）；最大反应a、b波潜伏期延长(t=2.44，P=0.010;t=10.800，P=0.000)，而振幅降低(t=5.804，P=0.000; t=5.809，P=0.000)，差异具有统计学意义。两组婴儿视锥细胞反应除b波振幅无明显差异外（t=0.486，P=0.628），a波潜伏期（t=4.444，P=0.000）和振幅（t=3.819，P=0.000）及b波潜伏期（t=2.850，P=0.005）差异具有统计学意义。两组间最大混合反应的b／a波振幅比值没有明显差异（t=1.142，P=0.256）。结论早产儿视网膜发育程度较足月产婴儿稍低。(中华眼底病杂志,2005,21:285-287)     

正常婴儿的闪光视网膜电图特性

目的：探讨4至5个月龄正常婴儿视网膜功能特性。方法：选取正常4个月龄婴儿17例(34只眼)、5个月龄婴儿13例(26只眼)和正常成年对照39例（78只眼)进行闪光视网膜电图（electroretinogram,ERG)检测，记录视杆细胞反应、视锥细胞反应及最大混合反应。对比分析两个婴儿组的ERG各个反应的b波振幅及潜伏期，并与正常成人组作比较。结果：两个正常婴儿组ERG各个反应的b波振幅和潜伏期与正常成人组相比都有非常显著差异，婴儿组的振幅低、潜伏期长。两个正常婴儿组之间相比，视锥反应有显著性差异，5个月龄组振幅较高，潜伏期较短；而视杆反应和最大混合反应无显著性差异。4个月和5个月龄婴儿组的视杆反应b波平均振幅分别为正常成人38．9％和36．7％，而视锥反应b波的平均振幅分别为正常成人的62．6％和71．5％。结论：在4至5个月龄期，婴儿ERG的各个反应都没达到正常成年人水平。视锥细胞反应与视杆细胞反应相比，在4至5个月龄期，增长得更快，发育得更成熟。     

Comparison of electroretinographic responses between two different age groups of adult Dark Agouti rats

AIM: To describe and compare the differences in electroretinographic responses between two different age groups of adult Dark Agouti (DA) rats and to better understand the effect of age on retinal histology and function.METHODS: The electroretinographic responses of two different age groups of adult DA rats were compared. Animals were divided into younger adult DA rats 10-12wk (n=8) and older adult DA rats 17-19wk (n=8). Full field electroretinography (ERG) was recorded simultaneously from both eyes after dark adaption and light adaption and parameters including the positive scotopic threshold response (pSTR), negative scotopic threshold response (nSTR), scotopic a-wave, b-wave, photopic a-wave, b-wave and photopic negative response (PhNR) were compared between groups.RESULTS: The older adult rats displayed lower stimulation thresholds of the STRs (pSTR and nSTR) and higher amplitudes of pSTR, scotopic a-wave and b-wave, photopic b-wave and PhNR amplitudes, with shorter implicit times. Photopic a-wave amplitudes were however higher in the younger adult rats.CONCLUSION:In summary, for the rod system, photoreceptor, bipolar cell and RGC activity was enhanced in the older adult rats. For the cone system, RGC and bipolar cell activity was enhanced, while photoreceptor activity was depressed in the older adult rats. Such age-related selective modification of retinal cell function needs to be considered when conducting ophthalmic research in adult rats.     

早产儿视网膜病变激光光凝治疗后视网膜功能发育状况观察

目的 观察早产儿视网膜病变(ROP)患儿视网膜激光光凝治疗后的视网膜功能发育状况.方法 对30例患阈值期ROP并成功接受视网膜激光光凝治疗的早产儿(病例组)和30例无ROP早产儿(对照组)进行闪光视网膜电图(F-ERG)检查,记录视杆细胞反应、视锥细胞反应、最大混合反应及振荡电位.结果 与对照组比较,病例组视杆细胞反应...     

Functional changes in rod and cone pathways after photoreceptor loss in light-damaged rats

PURPOSE: To determine the functional changes in the rod and cone pathways after photoreceptor loss by continuous light exposure. METHODS: Fifty-four male Sprague-Dawley rats were exposed to diffuse fluorescent light of 2000 lux for 24 or 48 hr. Two weeks after the light exposure, full-field scotopic and photopic electroretinograms (ERGs) were elicited by different stimulus intensities with a maximum luminance of 0.84 log cd-s/m2. The amplitudes of the a- and b-waves of the scotopic ERGs and the b-wave of the photopic ERGs were measured. The animals were sacrificed after the ERG recordings, and the number of surviving rod and cone nuclei in the outer nuclear layer was counted. RESULTS: The logarithm (log) of the amplitudes of the maximum rod a-wave (rod Va(max)) and b-wave (rod Vb(max)) was reduced monotonically with a decrease in the rod nucleus counts (p < 0.0001). The regression line for the rod Va(max) decrease was significantly steeper than that for the rod Vb(max) (p < 0.005). The maximum b-wave amplitudes of the photopic ERGs (cone Vb(max)) were significantly correlated with the number of cone nuclei in a log-linear fashion. The slopes of the regression lines for the rod Vb(max) and cone Vb(max) were 0.0067 and 0.0140, respectively, which indicates that the amplitude of the cone b-wave was more severely affected than that of the rod b-waves by light-induced photoreceptor degeneration (p < 0.005). CONCLUSIONS: The amplitudes of the rod and cone ERGs were correlated with rod and cone nuclei counts in a log-linear fashion in light-damaged rats. The functional loss from the photoreceptor death had a greater effect on the cone pathway than on the rod pathway when the retinal function was assessed by the b-wave.     

Quantitative relationship of the scotopic and photopic ERG to photoreceptor cell loss in light damaged rats

In order to use the ERG to track the effects of potential photoreceptor rescue treatments, we have compared retinal histology to the ERG in light damage. Male albino CD rats (40) were purchased at 7 weeks of age and reared in 50 lx cyclic light until 8 week old. They were exposed to a range of light intensities using white fluorescent light (1000, 1500, 2000, 2500 or 3000 lx) for 24 or 48 hr (n = 5 per group). Controls remained in dim cyclic light. Seven days after exposure, dark and light adapted ERGs were recorded from threshold up to 200 cd m-2 using 50 ms Ganzfeld white light stimuli. The STR, and scotopic and photopic b-wave thresholds and amplitudes were measured. After recording the ERG, the eyes were removed from the animals in each of the five 48 hr light exposed groups and control group for histological measurements. These included: (1) outer nuclear layer width in rod photoreceptor cell number (cell count) and micrometers, and (2) outer + inner segment layer width along the vertical meridian in the inferior retina. The product of cell count and outer + inner segment length was calculated. All histological measures showed a statistically significant linear relationship to light exposure intensity (P < 0.0001): r2 = 0.94 (cell count), 0.90 (outer nuclear layer width), 0.77 (outer + inner segment length). The log of the scotopic b-wave threshold and log amplitude showed a significant linear correlation to all histological parameters (P < 0.0001) and there was no significant difference between b-wave threshold and amplitude for any one of the histology measures used. However, overall, log b-wave threshold was significantly better correlated to histology P < 0.02. Only log b-wave amplitude showed a significant increase in variability in light damaged retinas (P < 0.02). The b-wave threshold intensity increased 0.33 log cd m-2 and the maximum amplitude decreased 0.23 log microV with each 10% decrease in cell number in the outer nuclear layer. The sensitivity of the scotopic threshold response, which originates from third order neurons, changed much more slowly with cell loss, than did the b-wave (P < 0.0005) and was well fit by a linear relationship to cell loss. The increase in photopic b-wave threshold was not significant for a cell loss of less than 70-80%. Neither the photopic or scotopic b-wave could be reliably recorded with more than 80% cell loss, but the scotopic threshold response remained. Both the scotopic and photopic ERG showed similar waveform changes near the threshold, including loss of the positive going b-wave and the predominance of a negative going response. Outer nuclear layer cell counts in this study showed the same relationship to log b-wave threshold elevation, as has been previously shown for whole retinal rhodopsin content in light damage, indicating that regional histology measurements can be good indicators of overall cell survival. Both the b-wave threshold and amplitude can be reliably used to track photoreceptor cell loss due to the damaging effects of constant light, but the scotopic threshold response may be more useful in severe damage.     

Autosomal dominant retinitis pigmentosa: a log quotient analysis of the photopic and scotopic b-wave amplitude.

The relationship of the photopic and the scotopic b-wave amplitudes of the electroretinogram was studied in 85 normal subjects and 25 patients with autosomal dominant retinitis pigmentosa, in which one amplitude was at least 20 microvolts. The log quotient of their b-wave amplitudes--that is log of the photopic b-wave amplitude divided by the scotopic b-wave amplitude--was considered to represent the activity of cones relative to rods. The log quotient values had a normal gaussian distribution in the normal control eyes, while they formed two groups in the patients with autosomal dominant retinitis pigmentosa. In the first group (type 1), the scotopic b-wave was non-recordable while the photopic b-wave amplitude was larger than 20 microvolts in all cases, indicating that the log quotient is larger than 0.5 and that the rod system is much more severely affected than the cone system. The second group (type 2) had a log quotient smaller than 0.5 and its distribution almost overlapped the normal one, indicating more symmetrical damage in the cone and rod systems. The mean final rod threshold at 45 minutes for type 1 was significantly higher than that for type 2. The log quotient proved to be a useful index for analysing the cone and rod involvement and consequently provides a better understanding of autosomal dominant retinitis pigmentosa.     

Postnatal retinal development as measured by the electroretinogram in premature infants

Light-adapted and dark-adapted electroretinograms were obtained in 27 premature infants who were screened for retinopathy of prematurity shortly after birth. Thirteen showed no retinopathy and 13 had mild to moderate retinopathy, which ranged from stage I, zone III (International Classification) to stage III, zone II. Measurements were made during the first 16 months of life. The configuration of the waveforms under both photopic and scotopic conditions changed during this period showing increased amplitudes of both the a- and the b-waves. A scotopic intensity series was performed and the b-wave amplitudes and implicit times were measured. The b-wave amplitude data were averaged for three adult control subjects, for infants without retinopathy of prematurity measured at 3–4 and at 6–7 months and for infants with retinopathy of prematurity measured at 3–4 and at 6–7 months. The Naka-Rushton function was fitted to the average data. The Rmax increased from 3 to 6 months and from 6 months to adulthood, and the Isat values decreased over this age range. The b-wave implicit times were within normal range in the 6-month data. There was no difference in Rmax or Isat for infants with and without ROP.     

Absolute and relative sensitivity of the scotopic system of rat: electroretinography and behavior

The goal of the present study was to relate the dark and light-adapted flash sensitivity of the scotopic threshold response (STR) and rod b-wave of the electroretinogram (ERG) to behaviorally measured rod increment threshold responses. Small amplitudes of the dark-adapted STR and b-wave, the latter after application of NMDA, were found to increase in proportion to flash intensity. The value obtained for the sensitivity of the b-wave would be expected if signals from rods were summed linearly by the rod bipolar cell. The sensitivity of the STR could not be accounted for in terms of rod signal convergence as the source of this ERG component is still unknown. Increment threshold responses of rats were measured behaviorally in an operant conditioning chamber. At absolute threshold, on average I in 2400 rods were activated by the test flash. Comparison of the adaptive effects of background lights on behaviorally measured scotopic sensitivity and rod ERG sensitivity suggest that the increment threshold sensitivity of rat is regulated at three different sites in the retina.