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)
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 assess the effects of 670nm LED (lightemitting diode) to protect the photoreceptor from the lightinduced damage in a rat model. Methods 32 SD rats were randomly assigned to one of eight groups: untreated control group, the LEDtreated control group, three groups of lightinduced damage，and three groups of lightinduced damage treated with LED. Lightinduced damage result from exposing to constant light for 3 hours of different illuminations of 900，1800 and 2700 lx, respectively. The LED treatment (50 mW) was delivered for 30 minutes at 3 hours before the light damage and 0，24 and 48 hours after the light damage. Retinal function and morphology were measured by electroretinogram (ERG) and histopathology assay. Results The illumination of 900 lx for 3 hours did not damage the rat retina. The illumination of 1800 lx for 3 hours resulted in thinner ONL and no OS and IS. The ratio of damaged area/total retinal area was 048plusmn;012， the damaged thickness of ONL/normal ONL (L5 ) was 039plusmn;007，and the amplitude of ERG b wave was (431plusmn;120) mu;V. With the LED treatment the ratio of damaged area decreased (M6=017plusmn;0.12, P5/6=0.002), and the ratio of the damaged thickness of ONL also decreased (L6=0.22plusmn;0.09, P5/6lt;0.01), and the amplitude of ERG b wave increased to (1011plusmn;83) mu;V（P5/6lt;0.001）. The illumination of 2700 lx for 3 hours caused severed damage to the rat retina and the LED could not protect them significantly. Conclusions 670 nm LED treatment has an evident protective effect on retinal cells against light-induced damage, which may be a simple and effective therapy to prevent or to delay agerelated macular degeneration.
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 investigate the degree of retinal developmen t in pret erm infants and compare the electroretinograms between preterm and fullterm in fants. Methods Flash electroretinogram (ERG) were obtained wit h contact lens el ectrodes in one eye from ten preterm infants (10 eyes) and twenty full-term inf a nts (20 eyes) in seven days after birth. The rod cell, cone cell, maximal combi nation, oscillatory potentials, and 30 Hz flicker responses were recorded. Results Compared with the full-term infants, the implicit time of rod cell respon s e (t=3.216，P=0.003) was longer and the amplitudes were lower (t=6.0 50，P=0.000) in the preterm infants; the difference of implicit time of maximal response was not significant (t=0.465，P=0.650; t=1.068，P=0.295), while th e amplitudes dec reased (t=6.584, P=0.000; t=6.649, P=0.000). The a- and b-wav e implicit time of cone response was not differed much between the two groups (t=0.077, P=0.939; t=0.935,P=0.358); the amplitudes was obvious lower in preterm group (t =3 .417，P=0.002；t=6.310，P=0.000); the difference of implicit t ime of 30 Hz flic ker betw een the two groups was not significant (t=3.745，P=0.001). The difference of b/a value of maximal combination response was not obvious between the two groups ( t=0.215, P=0.831). Conclusions The development of retinal function is slower in preterm infants than that in full-term ones．
One eye each in 3 groups of 12 pigmented rabbits after bilateral vitrectomy received 0.5mg, 1mg or 2mg triamcinolone acetonide (TA), respectively. The fellow eye received only balance saline solution as control. Ophthalmoscopy and electroretinography were performed during 1 day to 38 days after vitrectomy and drug injection. Light and electronmicroscopic studies were done on the 28th day. The particles of drug were visible on day 28 in all TA-treated eyes. Administration of 0. 5rug and 1mg TA did not result in different changes in ERG b-wave amplitudes compared with those in control eyes(P＞0. 05). There were significant elevations of ERG b-wave in 2mg TA eyes compared to the control eyes(Plt;0.05), Both ligbt and electronmicroscopy of the retina in these groups were almost normal. The results showed no Toxielties in TA treated eye up to 2mg after vitrectomy. This offers the experimental evidence as a baseline for combining TA with vitrectomy to reduce recurrence of proliferative vitreoretinopathy. （Chin J Ocul Fundus Dis,1996,12: 105- 107）
Objective To observe the changes of the multifocal electr oretinograph (mf-ERG) in commotio retinae. Methods The affected eyes (traumatic group) and the fellow eyes (control group) of 31 patients with unilateral commotio retinae were examined by RETI scan 3.15 system. The responses of 61 retinal regions were recorded, and the average amplitude densities of the N1 (the first negative) wave and P1 (the first positive) wave in different regions of retinal were analyzed. Results The average amplitude densities of 1-4 rings in N1wave and 1-5 rings in P1wave were much lower in traumatic group than those in the control. Conclusions The average amplitude densities of N1wave and P1wave of mf-ERG in retin al affected regions decreases markedly in eyes with commotio retina; mf-ERG may provide the quantificational and orientational detection for the visual ability of the eyes with commotio retinae.(Chin J Ocul Fundus Dis，2004，20：226-228)
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)
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.
Purpose To measure and compare the difference of multifocal electroretinogram in normal subjects and patients with age-related macular degeneration. Methods Seventeen cases(20 eyes)of normal subjects,7 cases(10 eyes)of dry form AMD(age-related macular degeneration),8 cases(8 eyes)of wet-form AMD and 11 cases(11 eyes)of idiopathic macular hole(IMH)were tested with VERIS SciencesTM 4.0 made by EDI company of America.The latencies and average response densities of 6 ring retinal regions in normal subjects were compared with those in various types of age-related maculopathies. Results The N1 and P1 wave latencies of all 6 rings in wet-form AMD and the N1 wave latencies of 3～6 rings in dry-form AMD were delayed statistically.The N1 and P1 wave average response densities of 1～4 rings in and the P1 wave average response densities of 1-6 rings wet-form AMD and the N 1 wave average response densities of 1～5 and the P1 wave average response densties of 1-6 rings in dry-form AMD were decreased statistically.The N1 and P1 wave average response densities of 1～2 and the P1 wave average esponse densities of 1～3 rings were decrease statistically in IMH. Conclusion Multifocal electroretinogram can be used to quantitate the visual function of the affected location in age-related macular degeneration. (Chin J Ocul Fundus Dis,2000,16:224-226)