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)
ObjectiveTo evaluate the efficacy and security of intravitreous injection with triamcinolone acetonide (TA) for macular edema.MethodsA total of 41 eyes in 37 patients with macular edema who measured up were collected, including 21 eyes of 21 cases in retinal vein occlusion (RVO) group, 17 eyes of 13 cases in diabetic retinopathy (DR) group, and 3 eyes of 3 cases in the other-causes group. Before the treatment, the average visual acuity was 0.07, 0.06, and 0.08 in the 3 groups respectively, and the mean thickness of macular fovea detected by optic coherence tomography (OCT) was (974±394) and (873±213) in RVO and DR group, respectively. Intravitreous injection with 0.1 ml TA (40 mg/ml) was performed on each patient. The average follow-up duration was 8 months after the treatment. The visual acuity, intraocular pressure (IOP), changes of lens and ocular fundus, and retinal thichness at macular area before and after the treatment was observed and compared.ResultsAll eyes except one had improved visual acuity. The mean visual acuity improved to 0.25, 0.20, and 0.35 in the 3 groups respectively 6 months after the treatment. Alleviated or reducing macular edema was found in all of the patients. The average retinal thickness at macular fovea was (173±41) and (204±76) in RVO and DR group respectively 1 month after the treatment, which had statistical significance compared with that before the treatment (t =8.323, 6.842; P＜0.01). The intraocular pressure was ＞21 mm Hg (1 mm Hg = 0.133 kPa) in 6 eyes (14.6%), which mostly happened 1 week to 2 months after the injection, and was controlled to normal level after partially treated with βreceptor retarder. The cataract developed in 1 eye, and another patient with macular edema after vitrectomy due to diabetes had macular hole 2 months after the injection. There were 2 eyes underwent intravitreous injection with 0.1 ml TA 4-5 months after the first treatment due to the recurrence of macular edema in RVO and DR group respectively.ConclusionsIntravitreous injection with TA is a promising therapeutic method for macular edema that fails to respond to conventional treatment. Transient elevation of ocular pressure is the most common side effect. Further study is needed to assess the long-term efficacy and safety. (Chin J Ocul Fundus Dis, 2005,21:209-212)
Objective To explore the relationship between the classification of diabetic macular edema（DME）and the stages of the diabetic retinopathy (DR) , the diabetic duration and the visual loss.Methods Retrospectively analyzed the clinical data of fundus fluorescein angiography (FFA) and other related information of 1521 patients who were diagnosed as DR. Classified DR according to national standard of the diagnosis and classification of DR, and classified DME according to the standard made by the early treatment diabetic retinopathy study research group of United States. The occurrence of DME in DR in each stage and the relationships between DME and the disease course and the vision were analyzed.Results In 1521 patients, 791 eyes in 468 patients had DME ( 30.77%), including 361 eyes (45.64%) with focal DME and 430 eyes (54.36%) with diffuse DME. The occurrence of DME was 1.13% in I-stage DR, 7.84%in II-stage DR, 41.98% in III-stage DR, and 48.93% in IV-stage DR. Focal and diffuse DME usually occurred at the III and IV stage of DR respectively, with 178 eyes (22.51%) with focal macular edema at the III stage of DR, and 249 eyes (31.48%) with diffuse DME at the IV-stage of DR. Patients with DME were hardly found at the V and VI stage of DR because of retinal proliferation and vitreous hemorrhage or other complications which made the condition of macula region blurred. The visual acuity of diffuse DME was worse than focal DME. DME often occurred within 10 years in the diabetic duration, and its severity and incidence increased year by year.Conclusions DME is the main cause of visual impairment of DR. The incidence of DME increased as the course of the DR prolonged. Along with the development of retinopathy, the incidence of DME increased, and the severity of DME aggravated, but the development of DME and its classification can not be brought into definite correspondence or unification with the classification of DR, hence the typing of DME in another individual classification in DR is of course necessary. (Chin J Ocul Fundus Dis，2003，19：83-86)