Objective To explore the effect of ischemia-reperfusion injury on the retinal functions of rats. Methods Seventy Wistar rats were selected, 20 of which were selected randomly and divided into two groups (control group and single-irrigated group). The rats were anesthetized and their anterior chambers of the right eyes were cannulated with a 7-gauge needle connected to a reservoir containing ringers balanced salt solution, which was maintained at the same level o f the eye for 1 hour. After that, ERG was recorded in both eyes of all rats. All the left rats were divided randomly into 10 groups and they were treated as the single-irrigated group. Retinal ischemia was induced by raising the reservoir to a height of 150 mm Hg. One hour later except the single ischemia group, all o f t he groups resumed perfusion after 3,6,12,and 24 hours and 3,5,7,14,and 21 days s eparately. ERG was recorded in both eyes of all rats.Results There was no difference in the results of ERG between left and right eyes in either the control group or the single-irrigated group. All the waves of ERG vanished in the single-ischemia group after 1 hour. In the ischemia-reperfusion groups, the waves of ERG partly recovered and the amplitude reduced persistently and progressively.Conclusion Ischemia-reperfusion injury may affect the function of the retina persistently and progressively. (Chin J Ocul Fundus Dis，2003，19：201-268)
Objective To observe the retinal function of infa nts with retinopat hy of prematurity (ROP). Methods A total of 78 infants (156 ey es) aged from 4-5 months underwent full-field flash electroretinogram (ERG) examination. The am p litude and implicit time of a-and b-wave of ERG were detected to evaluate the i nfants' retinal function. Seventy-eight infants (156 eyes) included 33 healthy a nd full-term infants (66 eyes), 25 healthy premature children (50 eyes), and 20 infants (40 eyes) with ROP. Results Obvious ERG waveforms were recorded in all the fullterm and healthy premature children. Amplitude of combined b-wave wa s 388.7 mu;V in full-term infants and 336.7 mu;V in healthy premature children, whi c h was 64.4% and 55.6% of that of the healthy adults respectively. In infants wit h ROP, ERG was nonrecordable in 20 eyes (50％); amplitude of combined b-wave was 183.8 mu;V in the other 20, whose implicit time delayed obviously compared with that of fullterm infants. The amplitude of ERG of healthy premature infants de c reased significantly compared with that of the full-term infants. Conclusions Retina keeps growing after birth. ERG of healthy full-term chi ldren is not as developed as those of adults. The progress of retinal maturation in infants with ROP is slower than that in the full-term infants. ERG examination is an effecti ve method in evaluating retinal function of infants with ROP.
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 the clinical application value of multifocal oscillatory potentials (MOPs) in retinal vein occlusion (RVO). Methods MOPs were tested using VERIS 4.0 visual evoked response imaging system for 19 cases (19 eyes) of RVO，among them 8 cases of central retinal vein occlusion (CRVO) and 11 cases of branch retinal vein occlusion (BRVO). Twenty normal subjects were as normal control group. The stimulative visual angles subtended ±26.6°horizontally and ±22.1°vertically. The filter setting was bandpass 100～1000 Hz. The retinal responses from 103 hexagons were recorded in 4 min (8 segments). Results In normal control group, OP-1, OP-2 and OP-3 were recorded during 37 ms for first order and 47 ms for second order first slice in whole test field and 5 ring retinal regions, the oscillatory wave shapes of second order were clearer than those of first order. In RVO groups, 91.6% latencies of OP-1, OP-2 and OP-3 were delayed, and 70.8% amplitudes of OP-1, OP-2 and OP-3 were reduced. The delay of the latencies and the decrease of the amplitude in CRVO were more markedly than those in BRVO. Conclusion MOPs can be effectively and quantitatively used to evaluate the retinal function of the different location in RVO. (Chin J Ocul Fundus Dis,2002,18:20-22)
ObjectiveTo observe the electroretinogram (ERG) photopic negative response (PhNR) of idiopathic macular hole (IMH) in stage 2 by vitrectomy with or without internal limiting membrane peeling (ILMP).MethodsTwenty-three stage 2 IMH patients (23 eyes) were enrolled in this prospective study. All patients received the best corrected visual acuity (BCVA), optical coherence tomography and flash-ERG examinations. The patients were randomly divided into group A (11 eyes, vitrectomy) and B (12 eyes, vitrectomy with ILMP). There was no significant difference in BCVA (t=0.96, P=0.350), diameter of macular hole (MH) (t=3.21, P=0.580) and the PhNR amplitude (t=0.98, P=0.353) in group A and B. All patients underwent 25G vitrectomy, ILMP was carried out in group B. The follow-up time was 3 to 6 months, with the mean follow-up time of 4.3 months. BCVA, MH closure rate and PhNR amplitude in group A and B were analyzed before and after surgery.ResultsThree months after surgery, 10 eyes (90.9%) gained MH closure but 1 eye (9.1%) failed in group A. In group B, 12 eyes (100.0%) gained MH closure. There was no significant difference in MH closure rate between the two groups (P=0.462). The mean BCVA of group A and B was 0.69±0.24 and 0.65±0.22, there was no significant difference between the two groups (t=0.49, P=0.722). The amplitude of PhNR in group A was (36.6±7.4) μV, which was lower than the pre-surgery PhNR, but the difference was not significant (t=0.73, P=0.472). The amplitude of PhNR in group B was (27.1±12.4) μV, which was lower than that the pre-surgery PhNR, and the difference was significant (t =3.56, P =0.002). The difference of PhNR amplitude in group A and B was statistically significant (t=2.17, P=0.042).ConclusionCompared with non-ILMP, vitrectomy combined with ILMP will significantly reduce the PhNR amplitude of IMH in stage 2.
Objective To observe the changes of visual acuity、multifocal electroretinogram (mfERG) and optical coherence tomogram（OCT）before and after successful idiopathic macular hole (IMH) surgery, and evaluate the efficiency of the IMH surgery. Methods A total of 28 eyes of 28 patients with IMH who underwent vitrectomy during February 2001 and May 2002 in our hospital were collected. visual acuity, mfERG, and OCT were examined preoperatively and 1, 3, 6, and 12 months postoperatively, respectively. The results were analyzed statistically compared with 33 eyes in control group. Results (1) OCT showed that 27 eyes (96.43%) had anatomic closure of the macular hole 1 month after the surgery without recurrence in 12 months. Just 1 eye (3.57%) failed in the closure within 1 year. (2) The visual acuity was much higher in the eyes 1 year after surgery, especially within 6 months postoperatively, than that before the vitrectomy（P＜0.01）. (3) Before the operation, the mfERG topographies of IMH eyes seem like volcanoes becase the response densities of wave P1 of ring 1 and ring 2 were lower than control group while the other three rings kept in normal. The central peaks of mfERG topographies reappeared little by little during 1 year after the surgery, and the response densities of wave P1 of ring 1 and ring 2 were higher than before, which was still lower than the control group（P＜0.05）. (4) The thickness of neuroepithelial layer (NEL) of fovea measured by OCT of 27 eyes with anatomic closure was no longer varied and kept lower than control group throughout the follow-up time （P＜0.05）. (5) One year after the operation, there were positive correlations among visual acuity, mfERG and NEL（P＜0.05）. Conclusions Vitrectomy is useful for IMH, which could be evaluated by visual acuity mfERG and OCT efficiently. The three factors had consistency. (Chin J Ocul Fundus Dis，2004，20：221-225)
Objective To investigate the early effects of intervention with tanakan on retinal function in diabetic retinopathy(DR) after laser photocoagulation. Methods Prospective random controlled study was performed on 60 Patients (60 eyes) from 23 to 69 years old with DR(phase Ⅲ～Ⅳ). The multifocal electroretinograms (MERG) were tested with VERIS Ⅳ before, the 3rd day and the 7th day after photocoagulation. Results No significant differences were found in the latencies and response densities of N1,P1 and N2 between the two groups before photocoagulation. Compared with that before photocoagulation, three days after photocoagulation the latencies in tanakan group had no significant change. The response densities of N1,P1 and N2 reduced and the changes were much smaller than that in control. Three days after photocoagulation, the response densities of P1 and N2 in the central macula 5°area were much higher and the latencies of P1 and N2 were significantly shorter than that in control group. There were no significant differences in the response densities in the 7th day and the differences in the latencies between two groups still existed. Conclusion Tanakan may be effective in preventing the retina from damage of retinal photocoagulation in some degree in DR. (Chin J Ocul Fundus Dis, 2002, 18: 208-211)
ObjectiveTo evaluate the characteristics of electroretinagram (EGR) in children with history of pre-threshold or threshold retinopathy of prematurity (ROP). MethodsA total of 24 children (48 eyes) with history of pre-threshold ROP or threshold ROP received F-ERG examination.Ten age and body weight-matched children with a history of premature birth (20 eyes) but without ROP were recruited as control group. The rod response, maximal rod-cone response and cone response of F-ERG were recorded respectively following the International Standard Protocal of ISCEV (2000 version).The latency and amplitude of a-wave and b-wave of various responses were analyzed. The trial was approved by the Ethic Committee of Hunan Children's Hospital and informed consent was obtained from the parents of patients prior to any medical procedure. ResultsThere was significant difference between ROP and control group in rod response,the latency was longer (t=5.643,P<0.05) and the amplitude was lower in ROP group(t=7.068,P<0.05).In maximal rod-cone response both in a and b wave, the latency wave was longer(t=3.099, 2.886;P<0.05) and the amplitude was lower(t=5.614, 2.850;P<0.05) in ROP group. But there is no difference between ROP and control group in cone response latency(t=0.819, 0.948)and amplitude(t=0.904, 0.850). ConclusionERG in ROP children with history of pre-threshold or threshold ROP is abnormal, which mainly in rod response,but the cone response remains normal.
Objective To explore the changes of multifocal electroret inogram (mERG) before and after retinal detachment surgery and its clinical significance. Methods Eighteen patients suffered from rhegmatogen ous retinal detachment underwent mERG before and after surgery using VERIS ScienceTM 4.0. The mERG at different area was compared between preoperative and postope rative surgery. Results Preoperatively, the latencies of a wave and b wave in detached area were statistically longer than in attached area (t=4.541 and 6.784, Plt;0.01). The amplitude densities of a wave and b wave were statistically smaller in detached area than in attached area (t=3.680 and 4.257, Plt;0.01). Postoperatively, the amplitude densities of a wave and b wave at fovea, macula, perimacular area and whole tested area significantly improved. Statistical difference was found before and after surgery, but no statistical difference was found in the latencies of a wave and b wave. The amplitude densities of a wave and b wave in the preoperative detached area were statistically larger after surgery than before surgery (Plt;0.05). Conclusions After retinal detachment surgery, the responses of mERG improve to some degree. mERG was a promising tool to evaluate the recovery of retinal function after surgery . The amplitude densities are more sensitive than the latencies to evaluation of retinal function. (Chin J Ocul Fundus Dis, 2001,17:264-267)
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)