Objective To evaluate the variability of four parameters of multi-focal electroretinogram (mERG) a-wave amplitude, b-wave amplitude, awave latent period, b-wave latent period. Methods Sixty normal eyes of 46 volunteers were divided into 3 groups of different ages. RETIscan 3-12 system was used to carry out mERG examination. The stimulus matrix of 61 hexagonal elements spanning the central 24deg;of the visual field. These hexons were scaled with eccentricity and divide d into 5 rings. First-order kernel was selected. Results The variability of four parameters of mERG was great. The variability of b-wave latent period was the smallest, its coefficient of variatian was 4.52%～15.62%；that of a-wave latent period held the second place:10.29%~48.67%；that of b-wave amplitude was greater:25.92%~76.11%；that of a-wave amplitude was the greatest:43.82%~88.23%. The results of three groups showed that b-wave amplitude of ring 1 had the smallest variability. Conclusions The variability of latent period is smaller than that of amplitude; the variability of b-wave was smaller than that of a-wave. The longer the centrifugal distance, the lower the amplitude density of a-wave and b-wave. Physiological and anatomical factors might be important for the variability of parameters of multi-focal electroretinogram. (Chin J Ocul Fundus Dis, 2001,17:277-279)
Objective To investigate the early influences of laser photocoagulation on retinal function in diabetic retinopathy(DR)． Methods The multifocal electroretinograms (MERG) of 30 eyes with DR (phase Ⅲ～Ⅳ) were tested with visual evoked response image system IV b efore,and the 3rd day and the 7th day after laser photocoagulation． Results Three days after photocoagulation, the latency of N1 prolonged in the central macula 5deg; area and superionasal quadrant．Th e response densities of N1,P1 and N2 markedly reduced, and most significant changes occurred in the central macula 5deg; area and then in the central 10deg;area． There were also differences in the changes of the amplitude of N1 and P1 in diff erent quadrants ．The changes of visual acuity were positively related to the de crease of amplitudes of N1,P1 and N2 in the macula． Conclusion The reduction of response densities in MERG reveals functional damage in diabetic retina occurring early after photocoagulation．The functional damage in macula induced indirectly by photocoagulation may explain the reduction of visual acuity after panretinal photocoagulation in some degree． (Chin J Ocul Fundus Dis, 2001,17:181-183)
PURPOSE:To investigate the effect of the retinal ganglion cell on the origin of the scotopic threshold response(STR)of the cat and human electroretinogram. METHODS:An optic atrophy model was established in cats with retinal photocoagulation around the optic disc. The STR and flash visual evoked potentials(FVEP)were recorded from 18 cases(24 eyes)of normal human,6 cases of the optic atrophy patients,6 cases of normal cats and 4 cases of retinal photocoagulating cats in 4, 8 and 16 weeks after retinal photocoagulation. In addition,ganglion cells were observated in 8 and 16 weeks after retinal photocoagulation using light and electron microscopes. RESULTS :The pathologic changes after retinal photocoagulation verify secondary atrophy of ganglion cells. STR was normal and FVEP was not recorded in cats of retinal photocoagulation and patients with optic atrophy. CONCLUSION :Retinal ganglion cell loss does not abolish the cat and human STR.There is no effect of ganglion cell on the origin of STR. （Chin J Ocul Fundus Dis,1997,13: 215-218 ）
Objective To measure and compare the difference between the normal control and retinoschisis with multifocal electroretinography. Methods Nineteen cases (21 eyes) of normal control and 8 cases (15 eyes) of inherited retinoschisis were measured with VERIS ScienceTM 4.0.Three cases (6 eyes) of inherited retinoschisis were tested with Ganzfeld ERG. Results There was statistically significant difference of average response density and latencies in all 6 ring retinal regions between the normal control and retinoschisis. The topography of multifocal ERG showed that multifocal amplitude decreased with disappearing or decreasing of central peak amplitude in patients with retinoschisis. The P1/N1ratio of the multifocal ERG average response densities in 6 ring retinal regions was different from the b/a ratio of the Ganzfeld ERG. Conclusion Each of the multifoca l ERG and Ganzfeld ERG has its advantage in the diagnosis of the retinoschisis. (Chin J Ocul Fundus Dis, 2001,17:268-270)
ObjectiveTo investigate the effects of Krüppel-like factor 7 (KLF7) on the survival of retinal ganglion cells (RGCs) and electroretinogram (ERG) after retinal ischemia-reperfusion (RIR) injury in mice.MethodsA total of 126 male C57BL/6J mice were randomly divided into normal group, RIR group, normal-KLF7 group, normal-green fluorescent protein (GFP) group, RIR-KLF7 group and RIR-GFP group. At the age of 8 weeks, mice of normal-KLF7 group and RIR-KLF7 group were intravitreally injected 1ul of 1.0×1012 vg/ml adeno-associated virus overexpressing KLF7 (AAV2-KLF7-GFP). Mice of normal-GFP group and RIR-GFP group were injected adeno-associated virus of AAV2-GFP with the same titer. At the age of 11 weeks, RIR injury was induced in mice of RIR group, RIR-KLF7 group and RIR-GFP group, and intraocular pressure was measured. Retinal cryosections were used to access the efficacy of virus transfection 4 weeks after AAV2-KLF7-GFP transfer. 7 days after RIR injury, RGCs’ survival rate was observed and quantified by immunofluorescent staining. ERG was performed to observe the differences in amplitudes and incubation period of scotopic ERG a-, b-wave, oscillatory potentials (Ops), photopic negative responses (PhNR). Optomotor response was performed to observe the differences of visual acuity. Expression of KLF7 was detected by western blot 4 weeks after AAV2-KLF7-GFP transfer.ResultsCompared with normal group, RGCs’ survival rates, amplitudes of ERG a-, b-wave, Ops, PhNR and visual acuity of mice in RIR group were decreased, and the differences were statistically significant (t=12.860, 7.157, 5.735, 8.953, 4.744, 9.887; P＜0.05). With the increase of light intensity, the amplitudes of scotopic ERG a- and b-wave were gradually increased while the incubation period was gradually shortened. Compared with RIR group, RGCs’ survival rates, amplitudes of ERG a-, b-wave, Ops, PhNR and visual acuity of mice in RIR-KLF7 group were increased, and the differences were statistically significant (t=6.350, 3.253, 3.695, 5.825, 5.325, 4.591; P＜0.05). Protein level of KLF7 was up-regulated in normal-KLF7 group than those in normal group, and the difference was statistically significant (t=4.105, P＜0.01).ConclusionOverexpression of KLF7 can improve RGCs’ survival rates and preserve the electrophysiological function.
Objective To measure the macular function of the fellow eye in patients with unilateral retinal vein occlusion (RVO). Methods A total of 24 cases of unilateral RVO were diagnosed by fundus fluorescein angiography (FFA), and multifocal ERG (mfERG) was recorded by RETI scan. The mfERG data of 24 fellow eyes of those RVO patients, and 18 normal control eyes were analyzed and compared. The parameters included the amplitude density, latency of the P1 and N1 wave in 6 concentric circles and 4 quadrants of the mfERG graphics. Results The amplitude densities of P1 and N1 wave in first and second concentric circles of RVO fellow eyes were significantly lower than normal eyes (t=4.520, 2.147; P＜0.05). There was no significant difference (P＞0.05) of P1/N1 latency in any concentric circles or quadrants between RVO fellow eyes and normal eyes. Conclusion The central fovea of the RVO fellow eyes was functionally impaired.
ObjectiveTo evaluate Micron Ⅳ retinal imaging system in three mouse models of retinal diseases. MethodsMouse models of oxygen induced retinopathy (OIR) model (OIR group), N-methyl-N nitrosourea (MNU) model (MNU group) and N-methyl-D-aspartate (NMDA) model (NMDA group) were induced in 24 healthy male C57BL/6J mice. Fundus photograph, fundus fluorescein angiography (FFA) and optical coherence tomography (OCT) and electroretinogram (ERG) were used to evaluate these mice. All the imaging examinations were performed by Micron Ⅳ retinal imaging system. ResultsOIR mice showed tortuous and dilated retinal vessels in fundus photograph, neovascularization plexus and vascular leakage in FFA, and epiretinal fibrovascular tissue and tortuous expansion vascular vessels in OCT. MNU mice showed wax yellow optic disk without retinal pigmentary changes, slight thinning of retinal blood vessels in FFA, and normal structure and thickness in OCT. The a-wave amplitudes of the maximum mixed response decreased significantly, and were (15.38±4.36) μV and (13.78±5.52) μV at 2 or 3 days of modeling, respectively. NMDA mice showed a pale retina with vasospasm. ERG revealed that there was no obvious change in latency of a- and b-wave, but significantly decreased amplitude of b-wave at 12 hours and 24 hours after modeling with (72.28±7.18) μV and (65.35±9.18) μV, respectively. ConclusionMicron Ⅳ retinal imaging system is a real-time, non-invasive tool to study the retinal structure and function in animal models of retinal diseases.