Intelligent diagnosis of retinal vein occlusion based on color fundus photographs

AIM:To develop an artificial intelligence(AI)diagnosis model based on deep learning(DL)algorithm to diagnose different types of retinal vein occlusion(RVO)by recognizing color fundus photographs(CFPs).METHODS:Totally 914 CFPs of healthy people and patients with RVO were collected as experimental data sets,and used to train,verify and test the diagnostic model of RVO.All the images were divided into four categories[normal,central retinal vein occlusion(CRVO),branch retinal vein occlusion(BRVO),and macular retinal vein occlusion(MRVO)]by three fundus disease experts.Swin Transformer was used to build the RVO diagnosis model,and different types of RVO diagnosis experiments were conducted.The model’s performance was compared to that of the experts.RESULTS:The accuracy of the model in the diagnosis of normal,CRVO,BRVO,and MRVO reached 1.000,0.978,0.957,and 0.978;the specificity reached 1.000,0.986,0.982,and 0.976;the sensitivity reached 1.000,0.955,0.917,and 1.000;the F1-Sore reached 1.000,0.9550.943,and 0.887 respectively.In addition,the area under curve of normal,CRVO,BRVO,and MRVO diagnosed by the diagnostic model were 1.000,0.900,0.959 and 0.970,respectively.The diagnostic results were highly consistent with those of fundus disease experts,and the diagnostic performance was superior.CONCLUSION:The diagnostic model developed in this study can well diagnose different types of RVO,effectively relieve the work pressure of clinicians,and provide help for the follow-up clinical diagnosis and treatment of RVO patients.

Comparison of efficacy of conbercept,aflibercept,and ranibizumab ophthalmic injection in the treatment of macular edema caused by retinal vein occlusion:a Meta-analysis

AIM:To evaluate and compare the anatomical and functional outcomes and negative effects of the three anti-vascular endothelial growth factor(VEGF)drugs in the treatment of macular edema(ME)due to retinal vein occlusion(RVO)based on the evidence pooled from current clinical trials and observational studies.METHODS:A systematic literature search was conducted on nine online databases from inception until April 30,2022.The main endpoints were best corrected visual acuity(BCVA),central macular thickness(CMT),and adverse events(AEs).Cumulative Meta-analysis was conducted to synthesize the outcomes of the drugs.The retrieved data were analyzed using Stata software(version 12.0).RESULTS:A total of 20 studies comprising 1674 eyes met the inclusion criteria to the Meta-analysis.It was observed that conbercept and aflibercept had better visual acuity effects compared with ranibizumab at 1mo[weight mean difference(WMD)=-0.03,P=0.001;WMD=-0.05,P=0.019],but the effects were not different from that of ranibizumab at 6mo.Moreover,there was not statistically significant dif ference in the propor tion of patients gaining≥15 letters at 12-24mo between aflibercept and ranibizumab[odds ratio(OR)=1.16,P=0.427].Conbercept had higher mean CMT change effects at 1mo(WMD=-14.43,P=0.014)and 6mo(WMD=-35.63,P≤0.001)compared with ranibizumab.Meanwhile,the mean CMT change effects at 1mo(WMD=-10.14,P=0.170),6mo(WMD=-26.98,P=0.140)and 12-24mo(WMD=-12.34,P=0.071)were comparable among the groups.Similarly,AEs were not significantly different among the treatments(OR=0.75,P=0.305;OR=1.04,P=0.89).The stability of effect size of mean BCVA and CMT improved with the increase in sample size.Aflibercept and conbercept required fewer injections compared with ranibizumab.CONCLUSION:This is the first study to evaluate the efficacy and AEs of intravitreal administration of conbercept,ranibizumab,and aflibercept in the treatment of RVOME.Intravitreal aflibercept or conbercept results in better mean change in vision and CMT reduction compared with ranibizumab.Conbercept can be considered to be a promising and innovative drug with good anti-VEGF effects.

Long-term outcomes of anti-VEGF treatment with 5+PRN regimen for macular edema due to central retinal vein occlusion

AIM:To assess the long-term outcomes of treating macular edema(ME)associated with central retinal vein occlusion(CRVO)with a regimen of“5+pro re nata(PRN)”.METHODS:This retrospective study included 27 eyes of 27 patients with ME associated with non-ischemic CRVO(non-iCRVO group,n=15)and ischemic CRVO(iCRVO group,n=12).The eyes were treated with five consecutive intravitreal injections of conbercept or ranibizumab,followed by reinjections as needed or PRN.Retinal laser photocoagulation or intravitreal dexamethasone implants(DEX)were implemented in both groups when necessary.The best-corrected visual acuity(BCVA,logMAR)and central retinal thickness(CRT)were recorded at baseline,at 1,2,3,4,5,6,and 12mo,and at the final visit.The efficacy rates of BCVA and CRT before and after treatment were calculated.The number of injections at each visit and the incidence of adverse events were also recorded.RESULTS:The patients,aged 59.4±15.1y,were followed up for 24.7±8.8mo(range:15-42mo).After treatment,BCVA improved significantly from 1.04±0.56 logMAR at baseline to 0.59±0.36 logMAR(P=0.038)at the final visit in all patients.Both the non-iCRVO and the iCRVO groups achieved improved BCVA compared to the baseline at all visit points,but there was no statistical significance(P=0.197 and 0.33,respectively).The mean CRT was statistically reduced compared to baseline at all visit points in all the eyes and in both groups(all P<0.001).The apparent effective rate was 22.22% for BCVA and 37.04% for CRT after the first injection,48.15%for BCVA and 62.96% for CRT after 5 consecutive injections,and 74.08% for BCVA and 100% for CRT at the end of follow up.The average number of injections in all patients was 9.0±2.4 at 12mo and 14.9±8.1 finally with no statistical significance between both groups(P>0.05).Laser treatment was applied to all eyes in the iCRVO group,while only 5 patients in the noniCRVO group.Six patients in the non-iCRVO group and 3 patients in the iCRVO group had a drug switch.DEX was applied to 4 eyes in the non-iCRVO group and 5 eyes in the iCRVO group.CONCLUSION:The 5+PRN anti-vascular endothelial growth factor(VEGF)regimen is found to be safe and effective for both iCRVO and non-iCRVO,especially in the iCRVO group.The best regimen for such patients needs to be further investigated.Adjuvant laser therapy and DEX are necessary in some cases.

Differential analysis of aqueous humor cytokine levels in patients with macular edema secondary to diabetic retinopathy or retinal vein occlusion

AIM:To evaluate the difference and the correlation between the concentrations of cytokines in the aqueous humor of eyes with macular edema secondary to diabetic retinopathy(DR)or retinal vein occlusion(RVO).METHODS:This is a retrospective case control study.The aqueous humor samples were collected during intravitreal injection of anti-vascular endothelial growth factor(VEGF)for patients diagnosed with macular edema secondary to DR(DME)or RVO(RVO-ME)at Xijing Hospital from August 2021 to July 2022.Meanwhile,aqueous humor samples during vitrectomy from patients with idiopathic macular hole(IMH)were also collected and served as controls.The aqueous humor concentrations of VEGF,platelet-derived factor(PDGF),interleukin(IL)-6,IL-8,IL-18,tumor necrosis factor-α(TNF-α)and monocyte chemoattractant protein 1(MCP-1)were measured with Human Premixed Multi-Analyte Kit(Luminex).The difference of the aqueous cytokines and the correlation between the two diseases were analyzed.RESULTS:A total of 40 eyes of 38 patients were enrolled in the study,including 13 eyes of 11 DME patients(DME group),16 eyes of 16 RVO-ME patients(RVO-ME group)and 11 eyes of 11 IMH patients(control group).The VEGF,PDGF,IL-6,IL-8,and MCP-1 levels of the aqueous humor were higher in both DME and RVO-ME groups compared with the control group(all P<0.05),the levels of TNF-αwas higher in the DME group than in the control group(P<0.05).The VEGF,IL-6,MCP-1,and TNF-αlevels in the aqueous humor were significantly higher in the DR group than those in the RVO group(all P<0.05).Correlation analyses revealed that there were complex positive correlations between IL-6,IL-8,IL-18,MCP-1,and TNF-αlevels in the aqueous humor of eyes with two diseases.CONCLUSION:Although ischemic and inflammatory factors are similarly involved in the pathogenesis of DME and RVO-ME,the roles of these factors are more significant or more likely to be activated in DR patients,suggesting different treatment strategies should be considered for the two diseases.

Optical coherence tomography angiography for macular microvessels in ischemic branch retinal vein occlusion treated with conbercept:predictive factors for the prognosis

AIM:To evaluate the predicative factors of visual prognosis using optical coherence tomography angiography(OCTA)in ischemic branch retinal vein occlusion(BRVO)patients with macular edema(ME)after anti-vascular endothelial growth factor(VEGF)treatment.METHODS:In this retrospective analysis,data from 60 patients(60 eyes)with a definite diagnosis of ischemic BRVO with ME by fundus fluorescein angiography(FFA)were studied.The eyes with ME according to spectral domain optical coherence tomography(SD-OCT)underwent intravitreal conbercept(IVC)and 3+pro re nata(PRN)regimen.The injection times were recorded.Two weeks after injection,fundus laser photocoagulation was performed in the non-perfusion area of the retina.The patients were followed up once a month for 6mo.The bestcorrected visual acuity(BCVA),foveal avascular zone(FAZ),and A-circularity index(AI),at 6mo and the baseline were compared.RESULTS:All patients showed significant improvement in BCVA from 0.82±0.32 to 0.39±0.11 logMAR(P<0.001).The mean central macular thickness(CMT)significantly decreased from 476.22±163.54 to 298.66±109.23μm.Both the FAZ area and AI at 6mo were significantly higher than those at the baseline:the FAZ area increased(0.38±0.02 vs 0.39±0.02 mm^(2),P<0.05);the AI increased(1.27±0.02 vs 1.31±0.01,P=0.000).The baseline BCVA showed a significantly positive correlation with the baseline FAZ area,FAZ perimeter(PERIM)and AI,final visual gain(FVG)and injection times,respectively(P<0.001).FVG showed a significantly negative correlation with the FAZ area,PERIM,AI and injection times,but a significantly positive correlation with vessel densities(VDs)300μm area around FAZ(FD-300;P<0.001).Injection times was positively correlated with the baseline FAZ area,and AI,but inversely correlated with the baseline FD-300(P<0.001).However macular ischemia was noted in 5 cases during follow-up.CONCLUSION:Using OCTA to observe macular ischemia and quantify parameters can better predict the final visual prognosis of patients before treatment.The changes in FAZ parameters may influence the visual prognosis and injection times.

Central Retinal Vein Occlusion in Healthy Young Adults Following COVID-19 Vaccination: Case Series

Our aim is to report 4 cases of central retinal vein occlusion following COVID-19 vaccine administration. In this case series, 4 patients between 23-32 years of age presented to us with unilateral central retinal vein occlusion after 2-15 days of getting vaccinated against COVID-19. One patient was a known case of hypertension and 1 was hypothyroid. All the patients had disc swelling, flame shaped haemorrhages, dilated and tortuous blood vessels in the retina. One patient had cystoid macular edema and was treated with intravitreal ranibizumab. As there were no positive systemic risk factors or incidents, COVID-19 vaccines might have an association with the central retinal vein occlusion in these cases. .

Effect of a novel tyrosine kinase inhibitor nintedanib on bFGF and VEGF concentrations in a rabbit retinal vein occlusion model

AIM:To evaluate whether a novel tyrosine kinase inhibitor nintedanib could inhibit basic fibroblast growth factor(bFGF)and vascular endothelial growth factor(VEGF)simultaneously for retinal vascular disease in vivo.METHODS:After a laser induced rabbit retinal vein occlusion(RVO)model was made,0.5 mg of nintedanib was injected intravitreally in the left eye on the third day while the right eye was as a control.Intracameral samples were taken on the day before laser treatment and days 1,3,7,14,21,and 28 after treatment.Enzyme-linked immunosorbent assay(ELISA)was used to test the bFGF and VEGF-A concentrations in the aqueous humor.RESULTS:Both bFGF and VEGF-A rose significantly on the third day after laser treatment in both eyes.In the control eye the bFGF concentration peaked on the 14th day while the VEGF-A concentration dropped rapidly soon after the third day.After nintadanib injection in the study eye,both bFGF and VEGF-A showed a significant reduction on the 4th day(7th day after laser treatment)when compared to the control eye,and kept on low level in the following several weeks.CONCLUSION:Intravitreal injection of nintedanib can inhibit the expression of bFGF and VEGF in the process of RVO model to a certain extent,which is expected to become a new method for the treatment of retinal vascular diseases or fibrotic diseases.

Deep-learning classifier with ultrawide-field fundus ophthalmoscopy for detecting branch retinal vein occlusion

AIM: To investigate and compare the efficacy of two machine-learning technologies with deep-learning(DL) and support vector machine(SVM) for the detection of branch retinal vein occlusion(BRVO) using ultrawide-field fundus images. METHODS: This study included 237 images from 236 patients with BRVO with a mean±standard deviation of age 66.3±10.6 y and 229 images from 176 non-BRVO healthy subjects with a mean age of 64.9±9.4 y. Training was conducted using a deep convolutional neural network using ultrawide-field fundus images to construct the DL model. The sensitivity, specificity, positive predictive value(PPV), negative predictive value(NPV) and area under the curve(AUC) were calculated to compare the diagnostic abilities of the DL and SVM models. RESULTS: For the DL model, the sensitivity, specificity, PPV, NPV and AUC for diagnosing BRVO was 94.0%(95%CI: 93.8%-98.8%), 97.0%(95%CI: 89.7%-96.4%), 96.5%(95%CI: 94.3%-98.7%), 93.2%(95%CI: 90.5%-96.0%) and 0.976(95%CI: 0.960-0.993), respectively. In contrast, for the SVM model, these values were 80.5%(95%CI: 77.8%-87.9%), 84.3%(95%CI: 75.8%-86.1%), 83.5%(95%CI: 78.4%-88.6%), 75.2%(95%CI: 72.1%-78.3%) and 0.857(95%CI: 0.811-0.903), respectively. The DL model outperformed the SVM model in all the aforementioned parameters(P<0.001). CONCLUSION: These results indicate that the combination of the DL model and ultrawide-field fundus ophthalmoscopy may distinguish between healthy and BRVO eyes with a high level of accuracy. The proposed combination may be used for automatically diagnosing BRVO in patients residing in remote areas lacking access to an ophthalmic medical center.

Microvascular changes after conbercept therapy in central retinal vein occlusion analyzed by optical coherence tomography angiography

AIM: To investigate microvascular changes in eyes with central retinal vein occlusion(CRVO) complicated by macular edema before and after intravitreal conbercept injection and evaluate correlations between these changes and best-corrected visual acuity(BCVA) and retinal thickness. METHODS: Twenty-eight eyes of 28 patients with macular edema caused by CRVO were included in this retrospective study. All patients received a single intravitreal conbercept injection to treat macular edema. BCVA and the results of optical coherence tomography angiography(OCTA) automatic measurements of the vessel density in the superficial(SCP) and deep retinal capillary plexus(DCP), the foveal avascular zone(FAZ) area, the FAZ perimeter(PERIM), the vessel density within a 300-μm wide ring surrounding the FAZ(FD-300), the acircularity index(AI), the choriocapillaris flow area, and retinal thickness were recorded before and at one month after treatment and compared with the results observed in age-and sexmatched healthy subjects. RESULTS: The vessel density in the SCP and DCP, the FD-300, and the flow area of the choriocapillaris were allsignificantly lower in CRVO eyes than in healthy eyes, while the AI and retinal thickness were significantly higher(all P<0.05). After treatment, retinal thickness was significantly decreased, and the mean BCVA had markedly improved from 20/167 to 20/65(P=0.0092). The flow area of the choriocapillaris was also significantly improved, which may result from the reduction of shadowing effect caused by the attenuation of macular edema. However, there were no significant changes in SCP and DCP vessel density after treatment. The flow area of the choriocapillaris at baseline was negatively correlated with retinal thickness.CONCLUSION: OCTA enables the non-invasive, layerspecific and quantitative assessment of microvascular changes both before and after treatment, and can therefore be used as a valuable imaging tool for the evaluation of the follow-up in CRVO patients.

Therapeutic potential of intravitreal pharmacotherapy in retinal vein occlusion

Retinal vein occlusion (RVO) is the most common visually disabling disease affecting the retina after diabetic retinopathy. Although the disease entity has long been known, its management is still controversial. Macular edema is the main reason for decreased visual acuity (VA) in this retinal vascular disorder. Recently the vitreous cavity has increasingly been used as a reservoir of drugs for the direct treatment of macular edema through intravitreal injection route. The most widely injected drugs so far have been triamcinolone acetonide (TA) and bevacizumab. The objective of this review is to evaluate the evidence and discuss the rationale behind the recent suggestions that intravitreal pharmacotherapy by corticosteroids and anti-vascular endothelial growth factors may be useful in the treatment of retinal vein occlusion.

Retinal vessel oxygen saturation in healthy subjects and early branch retinal vein occlusion

AIM： To measure the retinal oxygen saturation in healthy subjects and early branch retinal vein occlusion（BRVO） in Chinese population.METHODS： The retinal vessel oxygen saturation of the healthy subjects and BRVO patients were measured by a noninvasive retinal oximeter（Oxymap ehf.,Reykjavik,Iceland）.RESULTS： The study included 22 patients with unilateral BRVO（mean age： 55.1±8.8y） in the study group and 91 healthy participants（mean age： 37.5±14.0y） in the control group.In the healthy individuals,mean arterial and venous oxygen saturation were significantly（P〈0.001）higher in the superior nasal quadrant（98.5%±10.1%and 57.3%±8.7%,respectively） than in the inferior nasal quadrant（94.2%±9.0% and 54.1%±9.6%,respectively）,followed by the superior temporal quadrant（89.1%±10.1%and 51.9%±8.9%,respectively） and the inferior temporal quadrant（86.4%±9.4% and 46.6%±9.6%,respectively）.In patients with ischemic BRVO,arterial oxymetric values were significantly higher and venous measurements significantly lower for the affected vessel（107.5%±9.7% and46.4%±14.2%,respectively） than the unaffected vessel in the same eye（99.2%±12.2% and 55.5%±7.9%,respectively）and as compared to the vessel in the unaffected fellow eye（93.1%±6.9% and 55.7%±6.8%）（P=0.005 and P=0.02,respectively）.In the patients with non-ischemic BRVO,mean venous oxygen saturation was lower in the affected vein（39.8%±12.2%） than in the unaffected vessels of the same eye（50.8%±10.5%） and in the fellow eye（58.21%±5.7%）（P=0.03）.Mean arterial oxygen saturation did not differ significantly（P=0.42） between all three groups.CONCLUSION： In patients with BRVO,the venous oxygen saturation in the affected vessels is decreased potentially due to decreased blood velocity and flow.Interestingly,thearterial oxygen saturation in eyes with ischemic BRVO is increased in the affected arteries.

Comparison of one and three initial monthly intravitreal ranibizumab injection in patients with macular edema secondary to branch retinal vein occlusion

AIM： To compare three initial monthly intravitreal ranibizumab（IVR） injections followed by pro re nata（PRN） dosing with one initial monthly IVR injections followed by PRN dosing for macular edema（ME） secondary to branch retinal vein occlusion（BRVO）.METHODS： Forty-two eyes of 42 patients who had IVR injections for BRVO were retrospectively studied. Eighteen eyes received 1 initial IVR injection（1＋PRN group） and 24 eyes received 3 monthly IVR injections（3＋PRN）. At 1, 3, 6 and 12mo; spectral-domain optical coherence tomography（SD-OCT） was performed. Central macular thickness（CMT）, the integrity of the external limiting membrane（ELM）, the presence of subretinal fluid, cyst size, the presence of inner segment/outer segment（IS/OS） defect were determined.RESULTS： At baseline the mean CMT was 521.3±153.2 μm in the 3＋PRN group while it was 438.1±162.4 μm in 1＋PRN group. At the final visit, mean CMT was 278.3±87.8 μm in the 3＋PRN group and 285.2±74.2 μm in the 1＋PRN group（P=0.079）. The changes in CMT over the entire study period were also comparable in both groups（243±160 μm in the 3＋PRN group, and 152.9±175.3 μm in the 1＋PRN group; P=0.090）. At baseline, best-corrected visual acuity（BCVA） was 0.92±0.60 logarithm of the minimal angle of resolution（logMAR） in the 3＋PRN group, while it was 0.72±0.46 logMAR in the 1＋PRN group. Final BCVA was 0.42±0.55 logMAR in the 3＋PRN group and 0.38±0.50 logMAR in the 1＋PRN group（P=0.979）. Additionally, the BCVA changes from baseline to final visit were not significantly different（-0.50±0.45 logMAR in the 3＋PRN group, and-0.33±0.39 logMAR in the 1＋PRN group; P=0.255）.CONCLUSION： No significant differences in the anatomical or functional results are found between 3＋PRN and 1＋PRN regimens in the patients receiving ranibizumab for ME secondary to BRVO. Intact IS/OS and baseline BCVA are good predictor of the visual gain, while baseline CMT is a good predictor of the anatomical gain.

Intravitreal injection of bevacizumab alone or with triamcinolone acetonide for treatment of macular edema caused by central retinal vein occlusion

AIM: To compare the efficacy and safety of intravitreal bevacizumab alone versus bevacizumab combined with triamcinolone acetonide in eyes with macular edema caused by central retinal vein occlusion (CRVO) in Chinese patients. METHODS: Seventy-five eyes of 75 patients were enrolled in this prospective, randomized, consecutive study. Thirty-six patients in group 1 were treated with an intravitreal injection of bevacizumab (1.25mg/0.05mL), and 39 patients in group 2 were treated with intravitreal bevacizumab (1.25mg/0.05mL) combined with triamcinolone acetonide (2mg/0.05mL). The main outcomes of the mean best corrected visual acuity (BCVA), central retinal thickness (CRT), and intraocular pressure (IOP) were measured. RESULTS: In group 1, the mean BCVA improved from 37.78 +/- 6.14 (baseline) to 48.06 +/- 3.86, 46.48 +/- 4.77 and 44.18 +/- 5.78 at four, six and twelve weeks post-injection, respectively (P<0.01, P=0.03, P=0.04). In group 2, the mean BCVA improved from 35.92 +/- 6.20 (baseline) to 50.69 +/- 4.22, 48.76 +/- 5.59 and 45.70 +/- 6.56 at the same time points (P<0.01 each). However, there was no significant differences in the mean BCVA (F=0.043, P=0.836) and CRT (F=0.374, P=0.544) between these two groups. During the follow-up, five patients in group 1 and six patients in group 2 with high IOP were controlled with anti-glaucoma drugs. CONCLUSION: Intravitreal injection of bevacizumab alone or combined with triamcinolone acetonide has a short beneficial effect in Chinese patients with macular edema caused by CRVO, but there is no significant difference between the two groups.

Intravitreal anti-VEGF agents, oral glucocorticoids, and laser photocoagulation combination therapy for macular edema secondary to retinal vein occlusion: preliminary report

AIM： To evaluate the efficacy and safety of combined anti-vascular endothelial growth factor （VEGF） agents, oral glucocorticoid, and laser photocoagulation therapy for macular edema （ME） secondary to retinal vein occlusion （RVO）. METHODS： This study included 16 eyes of 16 patients with RVO-associated ME. Patients were initially treated with oral prednisone and an intravitreal anti-VEGF agent. Two weeks later, patients underwent standard laser photocoagulation. Best-corrected visual acuity （BCVA）, central retinal thickness （CRT）, and retinal vessel oxygenation were examined over 12mo. RESULTS： Patients received 1.43＋0.81 anti-VEGF injections. Mean baseline and 12-month IogMAR BCVA were 0.96±0.51 （20/178） and 0.31±0.88 （20/40）, respectively, in eyes with central retinal vein occlusion （CRVO） （P〈0.00）, and 1.02±0.45 （201209） and 0.60±0.49 （20/80）, respectively, in eyes with branch retinal vein occlusion （BRVO） （P〈0.00）. At 12mo, CRT had significantly decreased in eyes with CRVO （P〈0.00） and BRVO （P〈0.00）. Venous oxygen saturation had significantly increased in eyes with CRVO （P〈0.00） and BRVO （P〈0.00）. No examined parameters were significantly different between the 2 RVO groups. No serious adverse effects occurred. CONCLUSION： Anti-VEGF, glucocorticoid, and photocoagulation combination therapy improves visual outcome, prolongs therapeutic effect, and reduces the number of intravitreal injections in eyes with RVO- associated ME.

Establishing an experimental rat model of photo-dynamically-induced retinal vein occlusion using erythrosin B

AIM:To develop a reliable,reproducible rat model of retinal vein occlusion(RVO)with a novel photosensitizer(erythrosin B)and study the cellular responses in the retina.METHODS:Central and branch RVOs were created in adult male rats via photochemically-induced ischemia.Retinal changes were monitored via color fundus photography and fluorescein angiography at 1 and 3h,and 1,4,7,14,and 21d after irradiation.Tissue slices were evaluated histopathologically.Retinal ganglion cell survival at different times after RVO induction was quantified by nuclear density count.Retinal thickness was also observed.RESULTS:For all rats in both the central and branch RVO groups,blood flow ceased immediately after laser irradiation and retinal edema was evident at one hour.The retinal detachment rate was 100%at 3h and developed into bullous retinal detachment within 24h.Retinal hemorrhages were not observed until 24h.Clearance of the occluded veins at 7d was observed by fluorescein angiography.Disease manifestation in the central RVO eyes was more severe than in the branch RVO group.A remarkable reduction in the ganglion cell count and retinal thickness was observed in the central RVO group by 21d,whereas moderate changes occurred in the branch RVO group.CONCLUSION:Rat RVO created by photochemicallyinduced ischemia using erythrosin B is a reproducible and reliable animal model for mimicking the key features of human RVO.However,considering the 100%rate ofretinal detachment,this animal model is more suitable for studying RVO with chronic retinal detachment.

Effects of two different doses of intravitreal bevacizumab on subfoveal choroidal thickness and retinal vessel diameter in branch retinal vein occlusion

AIM： To investigate the effects of two different doses of intravitreal bevacizumab on subfoveal choroidal thickness （SFChT） and retinal vessel diameter in patients with branch retinal vein occlusion. METHODS： An interventional, restrospective study of 41 eyes of 41 patients who had completed 12mo of follow-up, divided into group 1 （1.25 mg of bevacizumab, 21 eyes of 21 patients） and group 2 （2.5 mg of bevacizumab, 20 eyes of 21 patients）. Complete ophthalmic examination, fluorescein angiography, enhanced depth imaging optical coherence tomography and measurement of retinal vessel diameter with IVAN software were performed at baseline and follow-up. RESULTS： The SFChT changed from 279.1 （165-431） μm at baseline to 277.0 （149-413） μm at 12mo in group 1 （P= 0.086）, and from 301.4 （212-483） μm to 300.3 （199-514） μm in group 2 （P=0.076）. The central retinal arteriolar equivalent （CRAE） changed from 128.8 ±11.2 μm at baseline to 134.5±8.4 μm at 12mo in group 1, and from 134.6±9.0 μm to 131.4±12.7 μm in group 2 （P =0.767）. The central retinal venular equivalent （CRVE） changed from 204.1±24.4 μm at baseline to 196.3±28.2 μm at 12mo in group 1, and from 205.8±16.3 μm to 194.8±18.2 μm in group 2 （P=0.019）. The mean central macular thickness （P〈0.05） and average best-corrected visual acuity （BCVA; P〈0.05） improved in both groups CONCLUSION： Changes in the SFChT are not statistically significant and not different according to the doses of bevacizumab. The CRAE did not show significant change, however, the CRVE showed significant decrease regardless of the dose.

Choroidal thickness measurements with optical coherence tomography in branch retinal vein occlusion

AIM： To evaluate central macular thickness（CMT） and mean choroidal thickness（MCT） in eyes with branch retinal vein occlusion（BRVO）, before and after ranibizumab treatment using spectral domain-optical coherence tomography（SD-OCT）.·METHODS： Forty-two patients with unilateral BRVO and macular edema were included in this study. There were 25 men and 17 women. Using SD-OCT, choroidal thickness was measured at 500 μm intervals up to 1500μm temporal and nasal to the fovea. MCT was calculated based on the average of the 7 locations. All the eyes with BRVO were treated with intravitreal ranibizumab（0.5 mg/0.05 m L）. Comparisons between the BRVO and fellow eyes were analyzed using Mann-Whitney U test. Preinjection and post-injection measurements were analyzed using Wilcoxon test and repeated measure analysis.· RESULTS： At baseline, there was a significant difference between the BRVO and fellow eyes in MCT[BRVO eyes 245（165-330） μm, fellow eyes 229（157-327） μm]and CMT [BRVO eyes 463（266-899） μm, fellow eyes 235（148-378） μm（P =0.041, 0.0001, respectively）]. Following treatment, CMT [295（141-558） μm] and MCT [229（157-329） μm] decreased significantly compared to the baseline measurements（P =0.001, 0.006, respectively）.Also BCVA（log MAR） improved significantly（P=0.0001） in the BRVO eyes following treatment. After treatment CMT[BRVO eyes 295（141-558） μm, fellow eyes 234（157-351） μm]and MCT [BRVO eyes 229（157-329） μm, fellow eyes 233（162-286） μm] values did not reveal any significant difference in BRVO eyes and fellow eyes（P=0.051, 0.824,respectively）.· CONCLUSION： In eyes with BRVO, CMT and MCT values are greater than the fellow eyes, and decrease significantly following ranibizumab injection.

Comparison of intravitreal bevacizumab with intravitreal triamcinolone acetonide for treatment of cystoid macular edema secondary to retinal vein occlusion : a Meta-analysis

AIMTo compare the effects of intravitreal injection of bevacizumab (IVB) with intravitreal triamcinolone acetonide (IVTA) on the treatment of cystoid macular edema (CME) secondary to retinal vein occlusion (RVO).METHODSA literature search was conducted using PubMed, the Cochrane Central Register of Controlled Trials, Web of Science and the Chinese Biomedical Database. The comparison was divided into two groups, group 1 conducted comparison in branch RVO (BRVO) or central RVO (CRVO), group 2 conducted comparison in ischemic-RVO or nonischemic-RVO. Pooled mean differences (MDs) for changes in visual acuity (VA), central macular thickness (CMT) and intraocular pressure (IOP) were calculated in groups at 4, 12 and 24wk after treatment respectively.RESULTSEight studies comparing the efficacy of IVB with IVTA were included in the Meta-analysis. In group 1, in BRVO, significant difference was shown on the comparison of CMT at 24wk (MD, -45.66; 95% CI, -76.03 to -15.28; P=0.003), IVB was effective on BRVO for at least 24wk; no significant differences were found in the comparison of VA at each time points (P&#x0003e;0.05 respectively). In CRVO, no significant differences were found in the comparison of VA or CMT between IVB and IVTA at each time points (P&#x0003e;0.05, respectively). In group 2, in ischemic-RVO, significant differences were shown in the comparison of VA (MD, -0.28; 95% CI, -0.42 to -0.14; P&#x0003c;0.0001) and CMT (MD, -86.50; 95% CI, -151.18 to -22.43; P=0.008) at 24wk; In nonischemic-RVO, no significant differences were demonstrated in the comparison of VA or CMT between IVB and IVTA at each time points (P&#x0003e;0.05, respectively). The occurrence of high IOP was much lower in IVB group.CONCLUSIONThis Meta-analysis suggested that IVB was effective in decreasing CMT in BRVO for at least 24wk, IVB is more effective on improving VA and reducing CMT in ischemic-RVO. IVB is more promising on RVO than IVTA.

Comparison of intravitreal ranibizumab and bevacizumab for the treatment of macular edema secondary to retinal vein occlusion

AIMTo compare the efficacy of ranibizumab and bevacizumab for macular edema due to retinal vein occlusion (RVO).

Ocular hypertension in patients with central/hemicentral retinal vein occlusions： cumulative prevalence and management

AIM： To prospectively evaluate the cumulative prevalence and the management of ocular hypertension（OH） in patients with unilateral acute central/hemicentral retinal vein occlusions（C/HCRVOs） over the course of 3 y. METHODS： The study included 57 patients with unilateral acute C/HCRVOs. All patients underwent a comprehensive ophthalmological examination of both eyes. OH associated with C/HCRVO in patients showing a score 〉5% for the risk of conversion to primary open angle glaucoma（POAG） was treated with OH medication. The treatment aimed for a decrease in intraocular pressure（IOP） to 〈21 mm Hg with a 〉22% reduction from the initial values. The cumulative prevalence of OH and the effectiveness of treatment assessed by the cumulative prevalence of conversion from OH to POAG, were estimated. RESULTS： Fifteen patients had OH associated with C/HCRVOs, the cumulative prevalence of OH was 29.4%（95% confidence interval, 16.9-41.9）. The mean value of the risk score of OH conversion to POAG for the 5 subsequent years was 11.7%±5.4%. The IOP significantly decreased from 25.67±2.16 mm Hg to 18.73±2.96 mm Hg. None of the OH patients converted to POAG during the follow-up period. CONCLUSION： The increased cumulative prevalence of OH in C/HCRVO patients indicates that OH is a risk factor for the appearance of venous occlusion. Patients with OH associated with C/HCRVO must be considered to be at high risk for conversion to POAG. Treatment with OH medications prevented conversion to POAG during the 3-year follow-up.