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.
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.
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.
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 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 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．
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.
Objectives To observe the clinical characteristics of Leber congenital amaurosis (LCA) and analyze the features to differentiate LCA from other similar disorders.Methods Prospective study of 15 LCA patients which include 10 males and 5 females, aged from 2 to 31 years with the mean age 13.6 years. Medical history, family history, perinatal conditions, as well as complete ocular evaluations were well documented. Among the subjects, 12 patients underwent optometry check, 10 patients underwent ERG and 8 patients had OCT testing. Results All of the patients had nystagmus and sluggish pupillary reflex. The visual acuity distributed from light perception to 0.1. Fivepatients (33.3%) were presented with photophobia, while 7 patients (46.7%) had nyctalopia. Among 12 cases underwent refraction examination, 6 patients (50%) had spherical equivalent of ge;+5D；1 patient（8.3%）had spherical equivalent of ge;+5D; 2 patients (16.7%) had bilateral mild to moderate hyperopia；1 patient (8.3%) had one emmertropic eye and one mild myopic eye; 2 patients (16.7%) had moderate to high myopia. Eight patients (53.3%) had enophthalmus,4 patients (26.7%) had oculodigital sign. All of the 10 patients underwent ERG showed extinguished waveform. Under OCT assesement, 7 patients had decreased fovea thickness; 1 patient had increased fovea thickness, complicated by epiretinal membrane; mild abnormality of microstructure of the retina with diminished and disrupted IS/OS hyperreflectivity were found in 2 cases；while more pronounced disarrangement of the retinal layers were found in 6 cases，inner layers were better reserved in all patients.Conclusions Severe visual impairment or blindness, nystagmus, pupillary reflex, extinguished ERG and hyperopia are main clinical characteristics of LCA.
Objective To observe the changes of visual acuity and multifocal electroretinogram （mfERG）before and after pars plana vitrectomy (PPV) combined with internal limiting membrane（ILM）peeling with ICG on idiopathic macular hole surgery. Methods The clinical data of 19 patients (19 eyes) with idiopathic macular hole（IMH） who had undergone PPV combined with ILM peeling assisted by 0.25% ICG from Zhongshan Ophthalmic Center were retrospectively analyzed. The closure of macular holes was confirmed by OCT two months after surgery. VERIS Science 4.9 visual evoked response image system was used to record the amplitude density of P1 waves according to six concentric rings before and two,six,twelve months after surgery, meanwhile compared and analyzed best corrected visual acuity（BCVA）before and after surgery. Results The results of OCT showed that 16 eyes (84.21%) had anatomic closure of the macular hole two months after the surgery while three eyes (15.79%) failed in the closure. The BCVA after surgery improved significantly which was more obvious at the second month (F=6.389，Plt;0.05). Compared with before surgery, the responses were depressed severely in P1 wave amplitude densities in six rings, the differences were statistically significant (t=6.140，Plt;0.05). Conclusion The postoperative BCVA of IMH patients improved but the amplitude densities of P1 wave depressed compared with before surgery.
Objective To measure the macular function of the fellow eye in patients with unilateral retinal vein occlusion (RVO). Methods A total of 24 cases of unilateral RVO were diagnosed by fundus fluorescein angiography (FFA), and multifocal ERG (mfERG) was recorded by RETI scan. The mfERG data of 24 fellow eyes of those RVO patients, and 18 normal control eyes were analyzed and compared. The parameters included the amplitude density, latency of the P1 and N1 wave in 6 concentric circles and 4 quadrants of the mfERG graphics. Results The amplitude densities of P1 and N1 wave in first and second concentric circles of RVO fellow eyes were significantly lower than normal eyes (t=4.520, 2.147; P＜0.05). There was no significant difference (P＞0.05) of P1/N1 latency in any concentric circles or quadrants between RVO fellow eyes and normal eyes. Conclusion The central fovea of the RVO fellow eyes was functionally impaired.