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.
Objective:To observe the effect of beta;estradiol on gluta mate concentration in rabbitsprime; retinae injured by ischemic reperfusion.
Methods:Twenty r abbits ware randomly divided into two groups, the control group and the treatmen t group, with 10 rabbits in each group. Before examined by binocular flash elect roretinography (FERG), retinal ischemic reperfusion (RIR) model was induced in t h e right eyes of all the rabbits by increasing intraocular pressure to 120 mm Hg for 60 minutes; the left eyes were as the control eyes. The rabbits were hypoder mically injected with beta;estradiol (0.1 mg/kg) in treatment group and with phys i ological saline in the control group 2 hours before ischemia. The results of FER G of the right eyes in both of the 2 groups 0, 4, 8, and 24 hours after reperfus ion were record respectively and were compared with the results of FERG before r eperfusion. The retina tissue was collected after the last time of FERG. The con c entration of glutamate was detected by Hitachi L8800 amino acid analyzer.
Results:In the right eyes in both of the 2 groups, the result of F ERG showed a beeli ne just after reperfusion. There was no significant difference of awave amplit u de between the 2 groups (t=1.357, 0.798, 0.835; Pgt;0.05); the b wave amplitudes i n experimental group were much higher than those in the control group (t=4.447, 2.188, 3.106; Plt;0.01). The concentration of glutamate in retina was (0.265plusmn;0.014) g/L in the right eyes and (0.207plusmn;0.013) g/L in the left eyes in the control group, and (0.231plusmn;0.007) g/L in the right eyes and (0.203plusmn;0 .014) g/L in the le ft eyes in the treatment group; the difference between the 2 groups was signific ant (F=50.807, P=0.000). There was statistical difference between righ t and left eyes both in the 2 groups and the significant difference of the right eyes betw een the two groups was also found (P=0.000); there was no statistical diffe rence of the left eyes between the 2 groups (P＝0.505).
Conclusion:beta;-estradiol may prevent the increase of the concentration of glutamate in retina induced by RIR to protect retinal tissue.
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.
ObjectiveTo observe the preliminary clinical application value of the handheld non-mydriatic visual electrophysiological diagnostic system RETeval in screening for diabetic retinopathy (DR).MethodsRetrospective clinical study. Fifty-eight patients with type 2 diabetes mellitus and 16 normal subjects who were admitted to Wuhan General Hospital of the PLA from November 2017 to May 2018 were enrolled in this study. All patients had not received any ophthalmologic treatment. All patients were examined by the default “DR assessment protocol” model of the RETeval device, and the “DR score” were measured by the system. The FFA results were used as the gold standard, and the DR was graded according to the international DR grading standard established in 2002. Patients were divided into vision threatening DR (VTDR) positive group and VTDR (?) group, DR (+) group and DR (?) group. Two independent sample t tests was used to compare the implicit time, amplitude, and pupil area ratio between eyes of different groups. Spearman correlation analysis was used to analyze the relationship between “DR score” and DR severity. The receiver operating characteristic area under the curve (AUC) assesses the sensitivity and specificity of RETeval in detecting DR and VTDR. The threshold of sensitivity and specificity was determined by using the maximum Youden index as a standard.ResultsThe AUC of DR was 0.936, the sensitivity was 81%, the specificity was 92%; the AUC of VTDR was 0.976, the sensitivity was 96% and the specificity was 70%. Compared with DR (?) group, the implicit time of DR (+) group was delayed and the amplitude and pupil area were decreased (t=－13.43, 5.49, 6.09; P=0.000, 0.000, 0.000). Compared with VTDR (?) group, the implicit time of VTDR (+) group was delayed and the amplitude and pupil area were decreased (t=－11.05, 7.46, 5.73; P=0.000, 0.000, 0.000). The “DR score” was significantly correlated with the severity of DR (r=0.89, P＜0.05).ConclusionsThe “DR score” measured by the RETeval instrument has a high degree of specificity and sensitivity in the diagnosis of DR and VTDR. It is highly correlated with the severity of DR.
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.
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.
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）
Commonly clinical visual electrophysiological detection methods include flash ERG, pattern ERG, VEP and multifocal ERG, etc. These inspection methods play an important role in disease identification and visual function judgment. However, lacking of understand the basic principles of electrophysiological testing, misunderstandings of the clinician influence the choice of examination methods or interpretation of examination results. The understanding of the basic principles of electrophysiological testing and analysis of the causes of these misunderstandings have important clinical significance in the correct application of visual electrophysiological testing technology.
Objective To observe the effect of persistent flickering stimulus on the structure and function of retina in guinea pigs during a developmentally sensitive period.Methods Twenty-four two- week-old guinea pigs were randomly divided into flicker light (FL) group and control group, with 12 guinea pigs in each group. Animals in FL group were raised under 500 Lux illumination with a duty diurnal cycle of 50% at a flash rate of 0.5 Hz. Animals in control group were reared under steady 500 Lux illumination. Light emitting diode (LED) lamps were used for lighting under a 12-hour light/12-hour dark cycle. After the collection of fundus photographs and electroretinograms recorded at week 12, eyeballs were taken out, three dimensions were measured, and histopathological changes were examined.Results Compared to control group, tessellated fundus in FL group appeared more prevalent; implicit time of ldquo;ardquo; waves were prolonged in electroretinogram; the eyeballs were increased in horizontal, vertical, axial dimensions by (0.89plusmn;0.30), (0.69plusmn;0.20) and (0.96plusmn;0.30) mm respectively, the differences between two groups were statistically significant (t=12.7,11.9,15.8;P＜0.05). The gap of sclera collagen fiber was slightly widened.The photoreceptor layer was more likely to develop a disordered outer segment, which contained deciduous disc membranes.Conclusion Persistent flickering stimulus is attended by development of excessive ocular enlargement,which could affect the retinal structure and function of photoreceptors.
ObjectiveTo observe the effect of simulated microgravity on the photopic negative response (PhNR) of full-field flash ERG in adult mice.MethodsIn an experimental study, forty-eight adult male C57BL/6J mice (48 eyes) were randomly divided into model and control groups. Model mice were further divided into three subgroups of 8 each: tail-suspended for 15 days (subgroup A), tail-suspended for 30 days (subgroup B), and tail-suspended for 30 days followed by returning to normal position for 30 days (subgroup C). The three control subgroups were similarly fixed with a harness but kept in the normal position for corresponding periods of 15, 30, and 60 days. The mice were immediately examined using ERG-PhNR, flash VEP, OCT and visually-guided behavior in vivo, and subsequently sacrificed to analyze the retinal histology in vitro. PhNR amplitude was measured from baseline to PhNR trough. N1 peak-time and N1-P1 amplitude of VEP was analyzed. The escape duration was used to quantitatively evaluate the visual function of mice. In addition, inner retinal thickness was analyzed by OCT imaging. Data were compared by the independent sample t-test.ResultsPhNR amplitude in the model subgroup A was obviously lower than the corresponding control subgroup, the difference was statistically significant (t=?3.196, P＜0.01). There was no significant difference in PhNR amplitude between the model subgroup B or C and the corresponding control subgroup (t=?1.976, 0.285; P＞0.05). There was no significant difference in FVEP N1 peak-time or N1-P1 amplitude between any of the three model subgroups and the corresponding control subgroup (P＞0.05). There was no significant difference in OCT-measured inner retinal thickness between any of the three model subgroups and the corresponding control subgroup (t=?0.461, 2.073, ?0.402; P＞0.05). The three model subgroups showed almost normal retinal structure, including the retinal ganglion cell, inner pexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, ellipsoid zone and RPE. There was no significant difference in visually-guided escape time between any of the three model subgroups and the corresponding control subgroup (t=?0.637, ?0.955, 1.297; P＞0.05).ConclusionVia tail-suspension, short-term simulated microgravity can affect the PhNR of flash ERG; however, the change is reversible and does not affect visual function of mice.
