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 evaluate the variability of four parameters of multi-focal electroretinogram (mERG) a-wave amplitude, b-wave amplitude, awave latent period, b-wave latent period. Methods Sixty normal eyes of 46 volunteers were divided into 3 groups of different ages. RETIscan 3-12 system was used to carry out mERG examination. The stimulus matrix of 61 hexagonal elements spanning the central 24deg;of the visual field. These hexons were scaled with eccentricity and divide d into 5 rings. First-order kernel was selected. Results The variability of four parameters of mERG was great. The variability of b-wave latent period was the smallest, its coefficient of variatian was 4.52%～15.62%；that of a-wave latent period held the second place:10.29%~48.67%；that of b-wave amplitude was greater:25.92%~76.11%；that of a-wave amplitude was the greatest:43.82%~88.23%. The results of three groups showed that b-wave amplitude of ring 1 had the smallest variability. Conclusions The variability of latent period is smaller than that of amplitude; the variability of b-wave was smaller than that of a-wave. The longer the centrifugal distance, the lower the amplitude density of a-wave and b-wave. Physiological and anatomical factors might be important for the variability of parameters of multi-focal electroretinogram. (Chin J Ocul Fundus Dis, 2001,17:277-279)
OBJECTIVE:To investigate the value of psychophysical testing for the macular function in the diegnosis of diabetic retinopathy(DR). METHODS:To compare the testing results of macular light sensitivity and pattern visual evoked potential(P-VEP)of 30 eyes of 15 normal person with those of 82 eyes of 41 diabetic patients(27 eyes without DR,55 eyes with simple type DR ). RESULTS:The macular light sensitivity of diabetic patients is much lower than that of normal Control group(plt;0.05). In the diabetic group, 62.19% is abnormal in macular light sensitivity, 69.51% in P-VEP. CONCLUSION: Testing of macular light sensitivit y is helpful in finding of diabetic retinopathy and early deterioration of macular visual function in diabetics. （Chin J Ocul Fundus Dis,1996,12: 223-224）
Objective To explore the connection between the melanin content of retinal pigment epithelial (RPE) cells and the function of photoreceptors, and the function of melanin on retinal light damage. Methods Agematched old dopachrome tautomerase knockout (DCT-/-) mice and wildtype mice were collected as the DCT-/- group and wildtype group, with 20 mice in each group. Baseline electroretinograms (ERG) in accordance with the international standards for the clinical electrophysiology were performed on all the mice, and the max ERG was recorded. Two mice were randomly selected in each group and were executed，and the removal eyeballs were as the control. The remaining 18 mice in each group were exposed to cold fluorescent light with the quantity of electricity of 20 W for 36 hours with a circle of 12 hours light12 hours dark12 hours light, which was repeated continuously for three times. The light intensity was (5000plusmn;356) lx. Six days after the light illumination, ERG were performed again and the results were recorded. Cervical dislocation methods were used to executed 2 mice which were chosen randomly in each group, and the eyeballs were removed. The tissue sections were observed under the optical and electron microscope.Results The results of ERG showed that the amplitude of a and b wave was lower in DCT-/- group than that in wildtype group before and after light injury （a wave before light injury: t=-7.13，Plt;0.01；b wave before light injury: t=-4.414，Plt;0.01；a wave after light injury: t=-10.162，Plt;0.01；b waveafter light injury: t=-6.772，Plt;0.01）. The decrease of amplitude of a and b wave was much obvious in DCT-/- group than that in wildtype group （a wave:t=4.975,Plt;0.01；b wave:t=2.908,Plt;0.01）. After the light injury, retinal edema and thinning were found in DCT-/- group which wasobvious than that in wildtype group; the photoreceptor layers and melanin were more seriously affected in DCT-/- group than that in wild-type group.Conclusions After the light illumination, the melanin of RPE cells reduces and the function of photoreceptors decreases, which suggests that melanin may play an protective role in the light injury.
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)
ObjectiveTo observe the full-field ERG (ff-ERG) characteristics of patients with acute regional occult outer retinopathy (AZOOR).MethodsA retrospective observational study. From June 2017 to June 2019, 62 eyes of 42 patients (AZOOR group) who were diagnosed with AZOOR in the Department of Ophthalmology of West China Hospital of Sichuan University were included in the study. All patients had no obvious localized disease on the fundus. Among 62 eyes, BCVA of 16 eyes were＜0.1, BCVA of 27 eyes were ≤0.5, and BCVA of 19 eyes were＞0.5. From June 2018 to January 2019, 40 normal volunteers (80 eyes) who attended the outpatient clinic of West China Hospital of Sichuan University and passed detailed ophthalmological examination to exclude all eye diseases including refractive errors were selected as the normal control group. All the examined eyes were tested with ff-ERG using the German Roland visual electrophysiological inspection system. The peak times and amplitudes of the waveforms induced by each response of dark adaptation 0.01 ERG, dark adaptation 3.0 ERG, dark adaptation 3.0 ERG, light adaptation 3.0 ERG, and light adaptation 30 Hz flicker ERG were recorded, respectively. The peak time and amplitude of each ff-ERG response between the two groups were compared by independent sample t test. The peak time and amplitude of each ff-ERG response between different BCVA eyes in the AZOOR group were compared by variance test.ResultsCompared with the normal control group, 0.01 ERG b wave of the dark adaptation of AZOOR group (t=3.601, －6.120), 3.0 ERG a wave and b wave of dark adaptation (t=2.627, －4.263, 3.719, －5.866), 3.0 Oscillation potential P2 wave of dark adaptation (t=－6.625), 3.0 ERG a wave and b wave of bright adaptation (t=3.762, －3.612, 3.648, －3.739) and 30 Hz flicker ERG P wave of bright adaptation (t=－3.832), all peak time of those were significantly delayed, the amplitude decreased, and the difference was statistically significant (P＜0.05). Comparison of different BCVA eyes in the AZOOR group showed that 0.01 ERG b wave amplitude of dark adaptation (F=3.950), 3.0 ERG a peak and b wave amplitude of dark adaptation (F=4.408, 4.876), oscillation potential P2 wave amplitude of dark adaptation (F=4.295), 3.0 ERG b wave amplitude of bright adaptation (F=4.344) and 30 Hz flicker ERG P wave amplitude of bright adaptation (F=4.483) of differences were statistically significant (P＜0.05). There was no statistically significant difference in waveform peak time and amplitude of the other reactions (P＞0.05). Pairwise comparison results showed that, compared with those with 0.1≤BCVA≤0.5 and BCVA＞0.5, those with BCVA＜0.1 dark adaptation to 0.01 ERG b wave, dark adaptation 3.0 ERG b wave, dark adaptation oscillation potential P2 wave, and light adaptation 3.0 ERG b wave and light adaptation 30 Hz scintillation ERG P wave amplitude were significantly reduced, and dark adaptation to 3.0 ERG a peak was significantly delayed, the difference was statistically significant (P＜0.05).ConclusionsThe ff-ERG of patients with AZOOR show delayed peak time and decreased amplitude of each response. The worse BCVA are accompanied by the more obvious decrease of each response amplitude of ff-ERG.
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 investigate the degree of retinal development in preterm infants.MethodsFlash electroretinography (ERG) was performed on 25 healthy preterm infants and 25 full-term ones, and the response of rod cells and cone cells and maximal mixed responses were recorded. The delitescence and amplitudes of a-and b-waves and the ratio of amplitudes of b-/a-wave of maximal responses were analyzed. ResultsCompared with the full-term infants, The delitescence of responses of rod cells in preterm infants was statistically longer（t=11.007，P=0.000）but without any significant changes of amplitudes （t=1.836，P=0.069）; statistically longer delitescence (t=2.44, P=0.010; t=10.800, P=0.000) and lower amplitude (t=5804，P=0.000; t=5.809,P=0.000) of a-and b-wave of maximal response were found in preterm infants group. In the response of cone cells, there were significant differences of the delitescence （t=4.444，P=0.000）and amplitude （t=3.819，P=0.000）of a-wave and delitescence of b-wave（t=2.850，P=0.005） between the two groups, and no statistical difference of amplitude of b-wave （t=0.486，P=0.628） between the two groups. The ratio of amplitudes of b-/a-wave of the maximal mixed response was not significantly different between the two groups （t=1.142，P=0.256）.ConclusionsThe development of retinal function is slower in preterm infants than that in full-term ones.(Chin J Ocul Fundus Dis, 2005,21:285-287)
Objective To investigate the changes of multifocal electroretinogram (mf-ERG) in type 2 diabetes without clinically apparent retinopathy. Methods Eighteen type 2 diabetes patients (32 eyes) without clinically observed retinopathy and 14 normal control eyes received mfERG examination. Results The latency of P1 wave in the ring one, ring two and ring three of diabetes were (48.47±2.33), (31.19±15.53), (15.67±5.73) ms respectively, which had significantly statistical difference with the normal control eyes (t=5.145，2.376，2.276；P＜0.05). The amplitude density of P1 wave of temporal retina in diabetes patients was (9.07±2.19) nV/deg2,which was significant different （t=-3.468,P＜0.05） with the normal control eyes (14.13±2.76) nV/deg2. Conclusion The latency of mf-ERG P1 wave is delayed, and the amplitude density of P1 wave of temporal retina is declined in type 2 diabetes patients without clinically apparent retinopathy.
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.