Objective To investigate the early influences of laser photocoagulation on retinal function in diabetic retinopathy(DR)． Methods The multifocal electroretinograms (MERG) of 30 eyes with DR (phase Ⅲ～Ⅳ) were tested with visual evoked response image system IV b efore,and the 3rd day and the 7th day after laser photocoagulation． Results Three days after photocoagulation, the latency of N1 prolonged in the central macula 5deg; area and superionasal quadrant．Th e response densities of N1,P1 and N2 markedly reduced, and most significant changes occurred in the central macula 5deg; area and then in the central 10deg;area． There were also differences in the changes of the amplitude of N1 and P1 in diff erent quadrants ．The changes of visual acuity were positively related to the de crease of amplitudes of N1,P1 and N2 in the macula． Conclusion The reduction of response densities in MERG reveals functional damage in diabetic retina occurring early after photocoagulation．The functional damage in macula induced indirectly by photocoagulation may explain the reduction of visual acuity after panretinal photocoagulation in some degree． (Chin J Ocul Fundus Dis, 2001,17:181-183)
PURPOSE:To investigate the effect of the retinal ganglion cell on the origin of the scotopic threshold response(STR)of the cat and human electroretinogram. METHODS:An optic atrophy model was established in cats with retinal photocoagulation around the optic disc. The STR and flash visual evoked potentials(FVEP)were recorded from 18 cases(24 eyes)of normal human,6 cases of the optic atrophy patients,6 cases of normal cats and 4 cases of retinal photocoagulating cats in 4, 8 and 16 weeks after retinal photocoagulation. In addition,ganglion cells were observated in 8 and 16 weeks after retinal photocoagulation using light and electron microscopes. RESULTS :The pathologic changes after retinal photocoagulation verify secondary atrophy of ganglion cells. STR was normal and FVEP was not recorded in cats of retinal photocoagulation and patients with optic atrophy. CONCLUSION :Retinal ganglion cell loss does not abolish the cat and human STR.There is no effect of ganglion cell on the origin of STR. （Chin J Ocul Fundus Dis,1997,13: 215-218 ）
Objective To study and compare the clinical efficacy between intravitreal conbercept injection and (or) macular grid pattern photocoagulation in treating macular edema secondary to non-ischemic branch retinal vein occlusion (BRVO). Methods Ninety eyes of 90 patients diagnosed as macular edema secondary to non-ischemic BRVO were enrolled in this study. Forty-eight patients (48 eyes) were male and 42 patients (42 eyes) were female. The average age was (51.25±12.24) years and the course was 5–17 days. All patients were given best corrected visual acuity (BCVA), intraocular pressure, slit lamp with preset lens, fluorescence fundus angiography (FFA) and optic coherent tomography (OCT) examination. The patients were divided into conbercept and laser group (group Ⅰ), laser group (group Ⅱ) and conbercept group (group Ⅲ), with 30 eyes in each group. The BCVA and central macular thickness (CMT) in the three groups at baseline were statistically no difference (F=0.072, 0.286;P=0.930, 0.752). Patients in group Ⅰ received intravitreal injection of 0.05 ml of 10.00 mg/ml conbercept solution (conbercept 0.5 mg), and macular grid pattern photocoagulation 3 days later. Group Ⅱ patients were given macular grid pattern photocoagulation. Times of injection between group Ⅰ and Ⅲ, laser energy between group Ⅰ and Ⅱ, changes of BCVA and CMT among 3 groups at 1 week, 1 month, 3 months and 6 months after treatment were compared. Results Patients in group Ⅰ and Ⅲ had received conbercept injections (1.20±0.41) and (2.23±1.04) times respectively, and 6 eyes (group Ⅰ) and 22 eyes (group Ⅲ) received 2-4 times re-injections. The difference of injection times between two groups was significant (P＜0.001). Patients in group Ⅱ had received photocoagulation (1.43±0.63) times, 9 eyes had received twice photocoagulation and 2 eyes had received 3 times of photocoagulation. The average laser energy was (96.05±2.34) μV in group Ⅰ and (117.41±6.85) μV in group Ⅱ, the difference was statistical significant (P=0.003). BCVA improved in all three groups at last follow-up. However, the final visual acuity in group Ⅰ and group Ⅲ were better than in group Ⅱ (t=4.607, –4.603;P＜0.001) and there is no statistical significant difference between group Ⅲ and group Ⅰ (t=–0.802,P=0.429). The mean CMT reduced in all three groups after treating for 1 week and 1 month, comparing that before treatment (t=–11.855, –10.620, –10.254;P＜0.001). There was no statistical difference of CMT between group Ⅰand Ⅲ at each follow up (t=0.404, 1.723, –1.819, –1.755;P=0.689, 0.096, 0.079, 0.900). CMT reduction in group Ⅰ was more than that in group Ⅱ at 1 week and 1 month after treatments (t=–4.621, –3.230;P＜0.001, 0.003). The CMT in group Ⅲ at 3 month after treatment had increased slightly comparing that at 1 month, but the difference was not statistically significant (t=1.995,P=0.056). All patients had no treatment-related complications, such as endophthalmitis, rubeosis iridis and retinal detachment. Conclusions Intravitreal conbercept injection combined with macular grid pattern photocoagulation is better than macular grid pattern photocoagulation alone in treating macular edema secondary to non-ischemic BRVO. Combined therapy also reduced injection times comparing to treatment using conbercept injection without laser photocoagulation.
Objective To investigate the effect of micropulse di ode laser treatment on the retina in Brown-Norway rats (BN Rats). Methods 130 eyes of BN rats received irradiance of different powers of micr opulse diode laser with 810nm wavelength through a contact lens. Fundus color photography and fundus fluorescein angiography (FFA) were performed on day 1, 3, 7, 14 and 28 days after treatment. Animals were sacrificed on 1, 3, 7, 14 and 28 days separately for historical study. The expression of heat shock protein-70 (HSP-70) in the retina was observed with immunohistochemistry. Cell apoptosis of retina tissue was examined by TdT mediated dUTP nick end labeling (TUNEL). Results (1) No change was found in no visible reaction laser spots by light microscope. High duty cycles with threshold and suprathreshold en ergies can produce severe damage even to the inner nuclear layer. (2) HSP-70 ex pression was markedly increased in the inner nuclear layer at 1d after micropulse diode laser. This increase in HSP-70 expression peaked at day 3 whereafter a decline near to normal at 2 weeks was detected. (3) Apoptosis was detected mainl y in retinal pigment epithelium, outer nuclear layer, inner nuclear layer and ev en choroid by TUNEL after micropulse diode laser treatment. The TUNEL-positive cells increased with the laser power. Maximum TUNEL-positive cells could be seen at day 3 after treatment. Conclusions The retinal injury has positive relationship with laser energy. The thermal damage is confined to the RPE and spare the neurosensory retina when using threshold power (50mW) with 50% duty-cycle and supra-threshold power with high duty-cycle (100mW，5%～15%). The hyper expression of HSP-70 and apoptosis mechanism may play an important role in the tissue repair process. (Chin J Ocul Fundus Dis,2008,24:122-126)