Objective To explore the correlation between retinal extracellular edema and vitreous contraction in rabbits. Methods Seventeen pigmented rabbit models with retinal vein occlusion (RVO)was set up by laser photocoagulation. Retinal vascularity area was pathologically examined 1 month later.The vitreous gellength under the gravity condition and the percentage of its weight in the rabbits with extraeellular edema was observed. The mechanisms were investigated by Western immunoblotting of type II collagen.Results Extracellular edema was found in 13 experimental eyes 1 month after the formation of RVO (76.5~) with contracted vitreous gel and released watery liquid, and the a component of type II collagen was cross-linked together to form high-molecular-weight components of 1] and 7, which weakened the stability of collagen net structure.Conclusions Vitreous contraction and retinal extracellular edemawere correlated. The main reason may be the cross-links of vitreous collagen that damages the stability of collagen structure. (Chin J Ocul Fundus Dis，2004，20：2-32)
Objective To analyze the pathogenesis of cystoid macular edema (CME) secondary to exudative age-related macular degeneration (AMD). Methods From October 2000 to December 2003, OCT images of 171 eyes of 140 patients with exudative AMD were evaluated. The CNV types were classified according to its location (above or below the RPE), and the correlation between the types of CNV and the development of CME were analyzed. Results Of the 171 eyes with AMD, 89 eyes (52.0%) had CME, and 82 eyes (48.0%) had no CME. Among the 89 eyes with CME, 76 eyes (85.4% ) had an active CNV lesion, and 13 eyes (14.6%) had a disciform scar. Among the 82 eyes without CME, 69 eyes (84.1%) had an active CNV lesion, and 13 eyes (15.9 %) had a disciform scar. In the 76 eyes with both CME and active CNV, 75 eyes (9 8.7%) had a subretinal CNV, which included 61 eyes (80.3%)with a combined CNV complex and 14 eyes (18.4%) with a Gass 2 type CNV, only 1 eye (1.3%) had a Gass 1 type CNV. Whereas, in the 69 eyes with active CNV but without CME, 57 eyes (82.6%) had a Gass 1 type CNV, only 12 eyes (17.4%) had a subretinal CNV. There was a significant difference in the incidence of subretinal CNV between eyes with or without CME (χ2=99.5838, P=0.0000). Conclusions CME formation was highly corre lated with the invasion of CNV into the subretinal space. Subretinal CNV might be the direct cause of CME secondary to exudative AMD.(Chin J Ocul Fundus Dis，2004，20：299-302)
Objective To observe the efficiency and safety of a single intravi treal injection of Bevacizumab (Avastin) in patients with diabetic macular edema. Methods Prospective, open label study of 18 eyes of 18 patients with diabetic macular edema which was diagnosed by examination of regular inspection, fundus fluorescein angiography(FFA) and optic coherence tomography(OCT). The patients without general or partial surgery contraindications, aged from 34-75 years with a mean age of 54plusmn;11 years. The best corrected visual acuity of logMAR was 1.023plusmn;0.45 and the retinal thickness of macular foveal was 486 mu;m before the treatment. The eyes have intravitreal injection with Bevacizumab at dose 1.5 mg (0. 06 ml). After the treatment, the follow-up period ranging from 12 to 20 weeks (m e an 16plusmn;4 weeks). The changes of visual acuity, intraocular pressure, OCT and FFA before and after the treatment were observed and analyzed. Results All 18 patients had a mean logMAR BCVA of 1.023plusmn;0.45 at baseline and at the follow-up weeks 1, 4, 12, the mean logMAR BCVA was significantly improved as 0.864plusmn;0.48 （P=0.001）, 0.739plusmn;0.51 (P=0.003), 0.792plusmn;0.50 (P=0.015) respectively, and the differences are statistically significant compared with before. Sixteen eyes (88.9%) had a improved or stable visual acuity, the BCVA increased 2 lines (0.2 logMAR vision) or better in 10 eyes (55.6%) and decreased in 2 eyes at 12 weeks after injection. OCT demonstrated that retinal thickness of macular foveal decreased from 486 mu;m to 413 mu;m at 4 weeks, decreased to 383mu;m at 12 weeks（P=0.002， P=0.001）, and the differences are statistically significant compared with before. There are remarkable resolution of central retinal edema in 13 eyes (72.2%) at 12 weeks after the injection. No local or systemic adverse events were observed in any patients. Conclusions The preliminary result in our observati on showed that int ravitreal injection of Bevacizumab therapy was well tolerated with a significant improvement in BCVA and decrease in macular edema for patients with diabetic macular edema. A randomly controlled multicenter clinical trial is necessary. (Chin J Ocul Fundus Dis,2008,24:172-175)
OBJECTIVE:To evaluate the therapeutic effect of acetazolamide treatment on chronic cystoid macular edema (CME). METHODS:Thirty-seven patients (40 eyes)with documented chronic CME of various causes were prospectively treated for 4-week periods with acetazolamide or a placebo in a randomised,crossover study that compared their effects on the reduction of macular edema and improvement of visual functions. Central retinal artery(CRA) blood flow was determined using Doppler velocimetry and vessel diameter measurement using computerised digital image analysis of monochromatic fundus photographs on 10 patients (12 eyes)with CME pre-and post-administration of acetazolamide. RESULTS:More than half the patients showed a response to acetazolamide with partial or complete resolution of. edema. Thirty eyes had improved in visual acuity in the treated patients. Statistically significant improvement were seen in 10deg; thresholds of visual field and ERG b wave amplitude. No improvement was seen when the patients received placebo. There were significant increase of blood flow velocity in CRA and retinal vessels diameter after acetazolamide were administered 3 hours later in CME patients (Plt;0.05). CONCLUSION: Acetazolamide could be of value in reducing the degree of edema and improving visual function to chronic CME. The improvement on retinal circulation might be a major cause to limit the CME. （Chin J Ocul Fundus Dis,1997,13: 89-92）
Objective To investigate the effects of Hep-A and Hep-B on vascular endothelial growth factor (VEGF)-induced breakdown of blood-retinal barrier. Methods The mice were subcutaneously injected vehicle, Hep-A or Hep-B 10 mg/kg twice a day for 5 days. Then, 1 μl of 10-6mol/L VEGF were intravitreous injected. After 6 hours, 13.7×104Bq/g3H-mannital were injected intraperitoneally. The mice were sacrificed and the retinas, lungs, kidneys were removed and examined for radioactivity. The result were analyzed using SPSS software to calculate and compare retina/lung and etina/kidney leakage ratio among groups of different treatment. Result The retina/lung and retina/kidney leakage ratio were 0.38±0.04 and 0.21±0.03 respectively in normal mice; increased significantly to 1.05±0.11 and 0.46±0.04 respectively in model mice, both Plt;0.01 compared to those in normal mice; decreased to 0.59±0.06 and 0.32±0.03 respectively in mice treated with Hep-A, both Plt;0.01 compared to those in model mice; decreased 0.54±0.04 and 0.35±0.03 in mice treated with Hep-B,both Plt;0.01 compared to those in model mice. Conclusion Hep-A and Hep-B can significantly reduce VEGF-induced breakdown of blood-retinal barrier in mice. Chin J Ocul Fundus Dis，2004，20：352-354)
Objective To determine the effect of posterior vitreous detachment on the prognosis of branch retinal vein occlusion (BRVO). Methods One hundred and sixteen patients (116 eyes) with BRVO who underwent vitreous examination were retrospectively studied.The relati onship of vitreous conditions to posterior segment neovascularization and macular edema was statistically investigated. Results In 40 ischemic cases,12 of 25 eyes (48.0%) with no posterior vitreous detachme nt (PVD) or partial PVD developed retinal or optic disc neovascularization ,or both,but only one of the 15 eyes (6.7%) with complete PVD developed neovasculariz ation during a mean follow-up period of 10.7plusmn;2.2 months (Plt;0.05) . Diffuse macular edema was found in 45 eyes (38.8%).The incidence o f macular edema was significantly higher in eyes with vitreomacular attachment (51.5%) than in those with vitreomacular separation (22.0%) (Plt;0.01). Conclusion It was suggest ed that compl ete PVD may play a role in protecting eyes with BRVO from posterior segment neov ascularization and macular edema. (Chin J Ocul Fundus Dis, 2001,17:2-4)
Objective To observe the short-term effect of changing the sequence of PRP and MLP on the pre-proliferative or proliferative diabetic retinopathy patients with clinical significant macular edema (CSEM). Methods Sixty-three consecutive pre-proliferative or proliferative diabetic retinopathy outpatients (103 eyes) with clinical significant macular edema were selected and divided into two groups: 54 eyes in patients of group A accepted MLP one month prior to PRP and 49 eyes in patients of group B accepted the photocoagulative therapies in a contrary sequence. All the patients were followed up for 3 to 13 months and visual acuity. Light sensitivity of 5deg;macular threshold, and FFA were performed pre- and post-photocoagution. Results The improvement of visual acuity was found to be better in group A than that of group B (Plt;0.01) 2 months after the therapy, since then, there was no significant defference (Pgt;0.05) in both groups. Three and 4 months after the treatment, there was no significant difference in change of light sensitivity of 5deg;macular threshold in both groups. The macular leakages of 59 eyes, 32 ingroup A and 27 in group B, were well controlled. Conclusion Among the pre-proliferative or proliferative diabetic retinopathy patients with CSEM, visual acuity of those who accept MLP prior to PRP more rapidly than those who accept contrary sequence of photocoagulation, but the changing of therapeutic sequence might have no dramatic influence on light sensilivity of 5deg;macular threshold. (Chin J Ocul Fundus Dis,2000,16:150-152)
Objective To expolre the factors which affect the size of diabetic,macular fobeal avascss scular zone(FAZ). Methods Making ten years of duration of diabetes a limit,79 nonproliferative and early proliferative diabetic patients were divided into 2 groups.Diabetic retinopathy severity level was diveided into 4 stages,and the macular edema was subdivided into focal、diffuse and cystoid according to fluorescein leakage of foveomacular region.All patients were measured FAZ with Heidelberg scanning laser fluoresceion angiography system and then compaired the size of FAZ of patients with different duration of diabetes、diabetic retinopathy severity level and macular edema status.The results were performed analysis of variance and t test. ResultsThe study shown the size of FAZ was not directly related to the duration of diabetes(t=1.3854,Pgt;0.1);There were significant differences about the size of FAZ of patients with different diabetic retinopathy severity level(F=7.6251,P＜0.01)and macular edema status(F=5.4369,P＜0.01)． Conclusion The size of FAZ was significantly increased in diabetic patients.It was enlarged with the development of diabetic retinopathy severity level,but it was not related to duration of diabetes. (Chin J Ocul Fundus Dis,2000,16:155-156)