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 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)
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)
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.
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）
ObjectiveTo observe the features of the full field electroretinogram (FF-ERG) in type 1 diabetes (T1D) children without diabetic retinopathy (DR). MethodsRetrospective case study. Forty-one T1D children and 25 age-matched normal controls underwent a complete ophthalmic examination, including best-corrected visual acuity, refraction, intraocular pressure, slit lamp, fundus photography, indirect ophthalmoscopy, and spectral domain optical coherence tomography to exclude DR. All FF-ERG tests were performed by an experienced technician. The ERG series includes six protocols: dark-adapted 0.01 ERG (r-b 0.01); dark-adapted 3 ERG (mix-a 3.0, mix-b 3.0); dark-adapted 10 ERG (mix-a 10.0, mix-b 10.0); dark-adapted oscillatory potentials (OPS); light-adapted 3 ERG (c-a 3.0, c-b 3.0); light-adapted 30 Hz flicker (30 Hz FP) ERG. To compare the amplitudes and implicit times of the FF-ERG between the T1D and control group children. ResultsCompared with the control subjects, the FF-ERG amplitudes decreased and the implicit times increased in T1D. Except for r-b 0.01 (t=-0.228, P > 0.05), the amplitudes of other FF-ERGs were all significantly attenuated (t=-1.664, -3.645, -4.324, -6.123, -5.846, -12.9, -14.4, -5.23; P < 0.05) in T1D children. The implicit times of mix-b 3.0, mix-b 10.0, c-b 3.0 and OP2 significantly increased (t=5.242, 2.879, 5.378, 3.506; P < 0.05). The implicit times of r-b 0.01, mix-a 3.0, mix-a 10.0, c-a 3.0 and 30Hz FP changes were not significantly (t=2.331, 1.677, 0.557, 0.84, 0.064; P > 0.05). ConclusionThe FF-ERG amplitudes decreased and implicit times increased in T1D children compared with the control normal subjects.
Objective To observe the characteristics of the full-field flash electroretinogram (F-ERG) in rats with oxygen induced retinopathy (OIR). Methods Twenty-four neonatal Sprague Dawley rats were divided into OIR group and control group. In OIR group, 12 rats were exposed to (75±2)% oxygen for 7 days and then to room air for 7 days; in control group, 12 rats were raised in room air for 14 days. At postnatal day 21, F-ERG tests were performed to examine the rod response , the maximum mixing reaction and the cone reaction. Results Compared with the control group, the b-wave amplitudes decreased (t=3.650) and the implicit times increased (t=2.410) in rod response in OIR group, the differences were statistically significant (P＜0.05); the a- and b-wave amplitudes decreased (t=3.333, 2.562) and the implicit times increased (t=2.725, 2.482) in the maximum mixing reaction in OIR group, the differences were statistically significant (P＜0.05). There was no difference between OIR and control group on a- and b-wave amplitudes (t=0.650, 0.204) and implicit times (t=0.422, 0.076) in cone response (P＞0.05). 0.001 cd.s/m2 light intensity stimulation on rats F-ERG wave almost no response. 0.010 cd.s/m2 light intensity stimulation on rats can be recorded to the rod response waveform, with the increase of light intensity, the amplitude of b-wave increases, the a-wave extraction. Conclusions F-ERG of OIR rat showed that the amplitude and sensitivity of the rod response and maximal rod-cone response was decreased. The intensity of light had effect on the OIR rod cells, and the amplitude of b- wave increased with the increase of light intensity, the a-wave extraction.
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 clinical features of acute zonal occult outer retinopathy (AZOOR).Methods Eighteen patients (18 eyes) with AZOOR were enrolled in this study. All the patients were examined for corrected visual acuity, fundus examination, visual field and electroretinography (ERG). For part of these patients, fluorescein angiography (FFA), optic coherence tomography (OCT), visual evoked potential (VEP) and multifocal ERG (mf-ERG) were performed. Clinical features were observed. Comparative analysis was performed on the electrophysiological results between affected eyes and fellow eyes. The consistency of OCT, visual field and mf-ERG results was investigated.Results The patients included three males and 15 females. All patients were unilateral involved. 16 eyes (88.9%) were myopia, two eyes (11.1%) were emmetropia. 11 eyes (61.1%) have normal fundus; single yellow-white punctuate lesion or old RPE lesion near macular were found in three eyes (16.7%); depigmented zones in temporal retina were found in four eyes (22.2%). All central visual field results were abnormal, but peripheral visual field results were normal. OCT findings included irregularity, absence or breaks of the photoreceptor inner segment/outer segment (IS/OS) junction. Amplitudes of full-field ERG were reduced in the affected eyes (t=3.516，2.689，3.103，3.517，2.999，3.309；P＜0.05), and implicit times were delayed in most responses except for rod response (t=1.023,P=0.306). Amplitudes of P100 wave of visual evoked potential were reduced statistically (t=2.04,P=0.041), but the differences of implicit times between the affected eyes and the fellow eyes were not statistically significant (t=1.687,P=0.092). Amplitude reduction of multifocal ERG existed in all affected eyes. Coincidence was found between results of OCT and mf-ERG. But abnormal zones found by central visual field did not always coincide with those by mf-ERG. Conclusions The majority of patients who develop AZOOR are young women with myopia. Most patients have normal fundus. Central visual field and electrophysiological examinations are always abnormal. Irregularity, absence or breaks of the photoreceptor IS/OS junction can be proved by OCT.
Purpose To investigate the relationship between the changes of the thickness of retina in macula and the abnormalities in multifocal electroretinog rams (mERG) in diabetic retinopathy. Methods mERG and optical coherence tomography (OCT) examination were performed in 38 patients (60 eyes) with DR (phase Ⅲ～Ⅳ). The data were processed with software SPSS and line relation analysis was done. Results The response densities of N1, P1 and N2 in central 5deg; area was significantly negative related to the thickness of neuroretina in macular fovea (correlation efficient -0.252～-0.266，Plt;0.05). The response density of N2 in central 10deg; area was also significantly negative related to the thickness of neuroretina in macular fovea (correlation efficient -0. 332，P=0.01).There was no significant relationship between the latencies of N1 in central 5deg;, 10deg; area and the thickness of macula, whereares the latenc ies of P1 and N2 in central 5deg; were negatively related to the thickness of retinal pigment epithelium in the macular fovea (correlation efficient-0.271～ - 0.322，Plt;0.05). Conclusion The changes of the thickness of neuroretina in macula may affect the local retinal function in macula, which may be revealed by the reduction of response densities in mERG in patients with diabetic retinopathy. (Chin J Ocul Fundus Dis, 2001,17:257-259)