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)
Objective To icompare the effects of indocyanine green angiography(ICGA) on ganzfeld Electroretinogram(ERG). Methods ICGA was performed used the Topcon 50IA retina camera, Ganzfeld ERG was recorded by Neuropack Ⅱ evoked response recorder. The Ganzfeld ERG was recorded before and after ICGA in 20 cases (38 e yes) with different diseases , Ganzfeld ERG was recorded according to the ISCEV standard recommendations. Results ICGA did neither affect Ganzfeld ERG a-wave and b-wave latency nor amplitudes of dark adaptation, maximum response and light adaptation.(Pgt;0.05). Conclusion ICGA using the Topcon 50IA could be performed prior to the recording of the Ganzfeld ERG. (Chin J Ocul Fundus Dis, 2001,17:284-285)
Objective To analyze the protective effects of heat-shock response on the retinae of the rats after retinal ischemic reperfusion injury.Method Twenty Wistar rats (20 eyes) were divided into 4 groups: intracameral perfusion group (group P), intracameral perfusion after quercetin injection group (group P+Q), intracameral perfusion after heat shock group (group P+H), and in tracameral perfusion after quercetin injection and heat shock group (group P+Q+H ). According to the standard program established by International Society for Clinical Visual Electrophysiology, we recorded the results of the dark-adapted electroretinogram (D-ERG ),oscillatory potentials (OPs),and light-adapted ERG (L-ERG) of the rats with intraocular hypertension after induced by heat shock response. The expressions of HSP 70 of the rats in all groups were observed by Western blotting.Results The expression of HSP 70 of the rats in group P+H was the highest in all groups, but the expressions of HSP70 in group P+Q and P+Q+H were inhibited significantly. The amplitudes of a and b wave of ERG and O2 wave of OPs decreased, and the delitescence of them were delayed significantly in rats after intracameral perfusion. The amplitude of b wave of D-ERG and O2 wave of OPs in group P+H were higher than which in group P. Zero hour after perfusion, the amplitudes of all waves in group P+H increased significantly (Plt;0.05). Twenty-four hours after perfusion, the retinal functional resumption of the rats in group P+H was better than which in group P. In group P+Q and P+Q+H, the delitescences of all waves of ERG and O2 wave of OPs were the longest and the amplitudes were the lowest, and some waves even disappeared.Conclusions The heat-shock response may improve the recovery ability of the retinal cells after injury of ischemic reperfusion.(Chin J Ocul Fundus Dis，2003，19：117-120)
Objective To explore significance of multifocal ERG(MERG) in evaluating visual function in patients with retinal detachment(RD). Methods MERG was tested using VERIS 4.0 visual evoked response imaging system for 21 patients with retinal detachment (22 eyes) and 36 normal subjects (42 eyes). The stimulative visual angles subtendedplusmn;26.6deg;horizontally and plusmn;22.1deg;vertically. Burian-Allen contact lens electrode was used to record the responses from 103 retinal locations in 8 min (16 segments). Results The latencies of a wave and b wave at the 4 quadrans, macular area and extra-macular area in RD group were significantly delayed and their amplitudes markedly decreased comparing with normal group (Plt;0.01). The amplitude densities of b wave at detached area, attached area in RD eyes and at the retina in normal eyes were (3.44plusmn;2.85), (6.34plusmn;3.31),(21.32plusmn;6.48) nV/deg2 respectively. There was statistically significant difference among them (Plt;0.05). Conclusion MERG can evaluate objectively and quantitatively the visual function at macular area, posterior polar detached area and attached area in RD. (Chin J Ocul Fundus Dis,2000,16:244-247)
Objective To study the response of the retinal neuronal adaptive system to changes of background illumination (BG) by measuring the oscillatory potentials (OPs) and the a- and b-waves of the electroretinogram (ERG) in different BG illuminations. Methods The a- and b-wave and the digitally filtered OPs were simultaneously recorded from Wistar Fu rats aged from 25 to 29 days during dark adaptation (DA) and during 6~8 minutes of BG illuminations at four levels increased successively by steps of two log units, i.e., ldquo;low scotopicrdquo; level of 1.43times;10-6cd/m2, ldquo;high scotopicrdquo; of 1.43times;10-4cd/m2 , ldquo;low mesopicrdquo; of 1.43times;10-2cd/m2 and ldquo;high mesopicrdquo; of 1.43times;10-2cd/m2. Full field stimulus flashes of 75 msec duration and 1.43times;10-2cd/m2intensity was delivered at an interval of 1 minute. Results Five OP wavelets were recorded in DA and during scotopic BG illuminations. The number of wavelets was reduced to three as the eyes were exposed to mesopic BG levels. However, the sum of OPs amplitudes (SOPs) increased as the BG was intensified, except at ldquo;high mesopicrdquo; level, by which a significant decrease of SOPs occurred. The amplitudes of the a-and b-waves remained unchanged at the two scotopic BG and decreased as the BG intensity increased to mesopic levels. Conclusion The response of retinal neural adaptive system of the Albino rat to changes of BG light is more sensitive and robust than the slow components of the ERG. The enhancement of the oscillatory responses at ldquo;low mesopicrdquo; illumination level suggests that using proper BG light may be conducive to reducing the variation of OPs. (Chin J Ocul Fundus Dis, 2001,17:286-288)
Objective To observe the changes of photopic negative response (PhNR) of electroretinography (ERG) in patients with retinal vein occlusion (RVO). Methods A total of 30 patients (30 eyes) with retinal vein occlusion (RVO) diagnosed by indirect ophthalmoscopy and fundus fluorescein angiography (FFA) were selected; the unaffected fellow eyes of the patients and another 25 healthy agematched individuals (50 eyes) were cllected as the normal control. All of the patients underwent the examination of visual acuity, visual field, and flashERG (FERG); the normal control ones underwent FERG. In the 30 patients with RVO, there were 14 with central RVO (CRVO) and 16 with branch RVO (BRVO). According to the disease history and results of FFA, the patients were divided into 3 time groups: lt;1 month, 1-3 months, and gt;3 months; according to the types of RVO, the patients were divided into ischemic and nonischemic group. The amplitude of PhNR and other parameters were analysed. The relationship among the amplitude of PhNR and RVO types and time course were analyzed.Results The amplitude of PhNR in the CRVO and BRVO eyes was (28.20plusmn;5.8) and (36.96plusmn;4.71) mu;V, respectively; those in the unaffected fellow and control eyes was (61.25plusmn;3.93) and (59.33plusmn;16.92) mu;V, respectively; the amplitude of PhNR was significantly smaller in the CRVO and BRVO eyes than those in the unaffected fellow or control eyes (F=10.69 and 9.80，P＜0.001; F=9.69 and 9.75，P＜0.001). The amplitude of PhNR in ischemic and nonischemic group in CRVO eyes was (22.77plusmn;15.73) and (36.63plusmn;12.91) mu;V, respectively; the difference between the two groups was significant（t=6.54, Plt;0.01）. The amplitude of PhNR in ischemic and nonischemic group in BRVO eyes was (32.39plusmn;13.22) and (46.73plusmn;10.43) mu;V, respectively; there was no significant difference between the two groups（t=2.12, Plt;0.05）. The amplitude of PhNR was (24.58plusmn;14.60) and (27.94plusmn;15.73) mu;V, respectively, in CRVO and BRVO eyes with lt; 1 month disease course; was (50.39plusmn;13.80) and (58.69plusmn;12.43) mu;V in those with 1-3 months disease course; and was (25.40plusmn;19.94) and (34.48plusmn;16.72) mu;V in those with ＞3 months diseases course. Significant difference was found between the 1-3 months group and ＞3 months group in CRVO eyes（F=4.30，Plt;0.01）. Conclusions The amplitude of PhNRs was significantly smaller in RVO eyes than those in the unaffected fellow or control eyes.The amplitude of PhNR amplitude of ischemic type was smaller than that of nonischemic type. The amplitude of PhNR has descending，ascending，and descending tendency during the disease courses.
Objective To observe the changes of electroretino gram(ERG) in temporary traumatic ocular hypotension and to detect the possiblem echanism. Method The rabbit model with ocular hypotenstion was made. At the 2nd, 4th, 8th, 16th week after trauma, the ocular tension and ERG was examined. Result Amplitude of b wave in treated group was 2.5 times as high as that in the control at the 2nd week after trauma, and then decrease to 1.5 times as high as that in the control at the 16th week. Conclution Higher amplitude of b-wave of ERG in rabbit with ocular hypotension may be related to blood circulation congestion, which might lead to accumulation of the metabolic toxin. (Chin J Ocul Fundus Dis，2004，20：189-191)
Objective To observe the changes of electrophysio logical results in rabbits with normal and injured photoreceptor due to subretinal implantation of chip. Methods Photoreceptor damage was induced by injection with NaIO3 solution in 22 out of 30 rabbits. A chip with the diameter of 3 mm made by the array composed of 90 microelectrodes photodiode and conjoint electrode was implanted into subretinal space or choroid of the right eyes of 22 rabbits with photoreceptor and 4 normal rabbits, and the left eyes were the control. The examinations of local flash-visual evoked potential (F-VEP), local flash-electroretinogram (F-ERG), full-field F-ERG and full-filed F-VEP were measured respectively.Another 4 rabbits underwent biocular extirpation for path ological examination . Results In 22 rabbits with photo-receptor damage, the amplitude of the main wave of local ERG was obviously higher in 11 eyes with chips than that in the control ones, and was also higher in 2 eyes with chips of the 4 mormal rabbits than that in the control eyes. No wave was found in an eye with retinal hole on the surface of the chip. The repeataility of main amplitude of local-VEP and full-field F-VEP is not satisfactory; no significant changes were observed between chip-implanted eyes and the control eyes examined by full-filed F-ERG. Conclusion The implanted chip may stimulate local retina and induce electrical activities after stimulated by light. (Chin J Ocul Fundus DIs, 2006, 22: 324-327)