Branch retinal vein occlusion: treatment modalities: an update of the literature

Non-steroidal intravitreal injection for noninfectious uveitic cystoid macular edema: Systematic review and meta-analysis

PURPOSE

To systematically review the published manuscripts on the non-steroidal intravitreal injection for treatment of noninfectious uveitic cystoid macular edema (CME).

METHODS

The PubMed, Scopus, and Web of Science, Science Direct, ProQuest, Cochrane Library, ProQuest, Embase, Clinical Key, and Springer were searched for relevant articles published until May 2022. The random-effects models were used to estimate the mean difference (MD) and 95% confidence interval (CI) for postoperative central macular thickness (CMT) and visual acuity (VA) changes. VA was transformed into the logarithm of the minimum angle of resolution (LogMAR). Meta-regression was conducted for adjusting the effects of potential confounders.

RESULTS

A total of 17 relevant studies (258 eyes) were included in this meta-analysis. A significant improvement was observed in CMT in the last follow up (350.89 ± 108.43) compared to the baseline (452.3 ± 112.67) (Log MD = 1.82, 95% CI = 1.62, 2.02; I2 = 57.7%; P = 0.002). Additionally, VA also significantly improved in the last follow up (0.56 ± 0.29) compared to the baseline (0.75 ± 0.3) (Exponential MD = 0.82, 95% CI = 0.69, 0.95; I2 = 0.0%; P = 0.98). The subgroups analyzed included ten studies on anti-vascular endothelial growth factors (VEGF), three studies on infliximab, two studies on methotrexate (MTX), and two studies on diclofenac. All subgroups showed a significant improvement in both CMT and VA at the last follow-up (P < 0.05).

CONCLUSION

Non-steroidal intravitreal injection including bevacizumab, ranibizumab, infliximab, MTX and diclofenac appears to be an effective treatment option for noninfectious uveitic CME.

VITRECTOMY FOR VITREOUS HEMORRHAGE ASSOCIATED WITH RETINAL VEIN OCCLUSION: Visual Outcomes, Prognostic Factors, and Sequelae

PURPOSE

To report the outcomes of pars plana vitrectomy for vitreous hemorrhage (VH) associated with retinal vein occlusion and to identify prognostic indicators.

METHODS

Interventional, retrospective consecutive case series between 2015 and 2021.

RESULTS

The study included 138 eyes of 138 patients (64 female and 74 male); 81 patients had branch retinal vein occlusion and 57 had central retinal vein occlusion. The mean age was 69.8 years. The mean duration between the diagnosis of VH and surgery was 79.6 ± 115.3 (range, 1-572) days. The mean follow-up was 27.2 months. The logarithm of the minimum angle of resolution visual acuity significantly improved from 1.95 ± 0.72 (Snellen equivalent, 20/1782) to 0.99 ± 0.87 (20/195) at 6 months and to 1.06 ± 0.96 (20/230) at the final visit (both P < 0.001). The visual acuity at 6 months improved by three or more lines in 103 eyes (75%). Postoperative complications during follow-up included recurrent VH in 16 eyes (12%) (of which 8 eyes underwent reoperations), rhegmatogenous retinal detachment in six eyes (4%), and new neovascular glaucoma in three eyes (2%). Worse final visual acuity was significantly associated with older age ( P = 0.007), concurrent neovascular glaucoma ( P < 0.001), central retinal vein occlusion ( P < 0.001), worse preoperative visual acuity ( P < 0.001), postoperative new neovascular glaucoma ( P = 0.021), and postoperative retinal detachment ( P < 0.001). The duration of VH was not associated with visual outcomes ( P = 0.684). Preoperative antivascular endothelial growth factor injections and tamponade did not prevent postoperative recurrent VH.

CONCLUSION

Pars plana vitrectomy is effective for VH associated with retinal vein occlusion, regardless of the duration of hemorrhage. However, pre-existing risk factors and postoperative sequelae may limit visual recovery.

Yellow Subthreshold Micropulse Laser in Retinal Diseases: An In-Depth Analysis and Review of the Literature

Yellow subthreshold micropulse laser (YSML) is a retinal laser capable of inducing a biologic response without causing thermal damage to the targeted tissue. The 577-nm YSML is delivered to the retina abiding by different protocols in which wavelength, power, duration, spot size and number of spots can be properly set to achieve the most effective and safe treatment response in various chorioretinal disorders. The ultrashort trains of power modulate the activation of the retinal pigment epithelium cells and intraretinal cells, such as Müller cells, causing no visible retinal scars. Subthreshold energy delivered by YSML stimulates the production of the heat-shock proteins, highly conserved molecules that protect cells against any sort of stress by blocking apoptotic and inflammatory pathways that cause cell damage. YSML treatment allows resorption of the subretinal fluid in central serous chorioretinopathy and intraretinal fluid in various conditions including diabetic macular edema, postoperative cystoid macular edema and other miscellaneous conditions. YSML also seems to modulate the development and progression of reticular pseudodrusen in dry age-related macular degeneration. The aim of this review is to discuss and summarize the safety and efficacy of YSML treatment in retinal diseases.

Three-dimensional characterization of developing and adult ocular vasculature in mice using in toto clearing

The ocular vasculature is critically involved in many blinding diseases and is also a popular research model for the exploration of developmental and pathological angiogenesis. The development of ocular vessels is a complex, finely orchestrated sequence of events, involving spatial and temporal coordination of hyaloid, choroidal and retinal networks. Comprehensive studies of the tridimensional dynamics of microvascular remodeling are limited by the fact that preserving the spatial disposition of ocular vascular networks is cumbersome using classical histological procedures. Here, we demonstrate that light-sheet fluorescence microscopy (LFSM) of cleared mouse eyes followed by extensive virtual dissection offers a solution to this problem. To the best of our knowledge, this is the first 3D quantification of the evolution of the hyaloid vasculature and of post-occlusive venous remodeling together with the characterization of spatial distribution of various cell populations in ocular compartments, including the vitreous. These techniques will prove interesting to obtain other insights in scientific questions addressing organ-wide cell interactions.

Repeatability of Optical Coherence Tomography Angiography Measurements in Patients with Retinal Vein Occlusion

PURPOSE

To analyze the repeatability of vessel density (VD) measurements and manual foveal avascular zone (FAZ) measurements using optical coherence tomography angiography (OCTA) in patients with retinal vein occlusion (RVO) without macular edema.

METHODS

The study population consisted of patients with RVO and central macular thickness <300 μm. For each subject, measurements were performed twice with a 5-minute interval. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were calculated to analyze the repeatability of results obtained with the OCTA device. To identify factors related to repeatability, we performed Pearson correlation analyses based on the CV of potential factors.

RESULTS

A total of 48 eyes were included in the study. The ICCs of the VDs in superficial capillary plexus (SCP) and the deep capillary plexus (DCP) were 0.748 and 0.665, respectively, and the CVs of the VDs in SCP and DCP were 9.1% and 12.6%, respectively. The ICCs associated with the FAZ of the superficial layer (SFAZ) and that of the deep layer (DFAZ) were 0.965 and 0.956, respectively, and the CV of the SFAZ and DFAZ were 8.8% and 9.7%, respectively. From Pearson correlation analyses, OCTA quality was significantly correlated with the CV of the VDs of SCP and DCP. However, there were no variables that were significantly correlated with the CV of SFAZ and DFAZ, including OCTA quality.

CONCLUSIONS

VD measurements in the SCP layer using OCTA exhibited good repeatability, and VD measurements in the DCP layer exhibited relatively low repeatability compared to that of SCP layer measurements in patients with RVO without macular edema after treatment with bevacizumab. Manual measurement of the FAZ area in both SCP and DCP layers resulted in good repeatability. In addition, the repeatability of VD measurements in SCP and DCP layers was correlated with OCTA image quality.

Histopathological Changes of the Retina After Nd: YAG Laser Thrombolysis in Branch Retinal Vein Occlusion: An Experimental Study

Introduction: The efficacy of many therapeutics techniques for treatment of branch retinal vein occlusion (BRVO) has been the subject of many investigations. The aim of the present work is to evaluate the transluminal Nd: YAG laser thrombolysis as a new therapeutic approach used for treatment of BRVO in rabbits as an experimental model. Methods: Four rabbits were considered as a control (n=8 eyes); occlusion of the branch retinal veins was performed by using a dye enhancing thrombus formation in right eyes of 10 rabbits (n=10 eyes). Thrombi in the retinal veins were induced by intravenous injection of rose bengal solution as a photosensitizer immediately before the argon laser application with a power of 1200 mW, a spot size of 100 µm, and a duration of 20 ms. One week later, transluminal Nd: YAG laser thrombolysis (30 mJ, 3 pulses/4 ns) was employed to the site of occluded veins, until the thrombi were partially or completely shattered. The rabbits were followed up after 4 days, 1 week and 2 weeks for slit lamp fundus examination and the treated retinas were isolated for histopathological examination. Results: Argon laser photothrombosis induced complete BRVO with some vitreous hemorrhage, destruction, and necrosis in the surrounding retinal layers. Moreover, one week later, Nd: YAG laser thrombolysis showed complete venous flow, minimal vitreous hemorrhage, reperfused retina, complete veins improvement. Follow up after 2 weeks revealed more improvement of all retinal layers. Conclusion: Treatment with transluminal Nd: YAG laser thrombolysis represented a novel therapeutic modality in BRVO.

Ranibizumab versus aflibercept for macular edema due to central retinal vein occlusion: 18-month results in real-life data

PURPOSE

The objective of this study was to compare the anatomical and functional outcomes of ranibizumab versus aflibercept for the treatment of macular edema due to central retinal vein occlusion (CRVO) in routine clinical practice.

METHODS

Participants in this observational study included 62 treatment-naïve patients with CRVO who received intravitreal injections of either ranibizumab or aflibercept. The demographic data, best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) characteristics were evaluated at baseline and at months 1, 2, 3, 6, 12 and 18 post-treatment.

RESULTS

At month 18, the mean BCVA of ranibizumab-treated eyes increased 7.9 letters, compared to 7.4 letters for eyes receiving aflibercept, with a similar number of injections. There was no statistically significant difference between the two groups in letters or in central subfield thickness at month 18. At the end of the follow-up, 50% of patients in the ranibizumab group and 42.9% in the aflibercept group showed complete resolution of macular edema.

CONCLUSIONS

Ranibizumab and aflibercept demonstrated similar anatomical and functional outcomes over 18-month follow-up in patients with macular edema due to CRVO, with a similar number of injections.

Different effect of serotonin on intracellular calcium ion dynamics in the smooth muscle cells between rat posterior ciliary artery and vorticose vein

5-hydroxytriptamine (5-HT: serotonin) is an important transmitter that causes vessel constriction, although few studies have examined the effect of 5-HT on venous smooth muscles. The intracellular Ca(2+) concentration ([Ca(2+)]i) plays an essential role in stimulus-response coupling in numerous tissue/cells including vascular smooth muscle cells. The present study was performed to examine whether differences between arteries and veins in the response to 5-HT can be detected under confocal microscope with respect to [Ca(2+)]i dynamics. In posterior ciliary arteries of rats, 5-HT induced a [Ca(2+)]i increase. The 5-HT-induced responses were caused by both Ca(2+) influx and mobilization. Agonist and antagonist experiments revealed that arterial smooth muscles possess 5-HT1a, 1b, 2 (Gprotein-coupled type) and 5-HT3 (ion channel type) receptors, and that 5-HT2 in particular plays a major role in these responses. For vorticose veins, the 5-HT-induced responses were also caused by both Ca(2+) influx and mobilization. However, the cAMP dependent pathway (5-HT4-7) was found to be significant in vasocontraction with respect to 5-HT in these vessels. Thus, Ca(2+) mobilization was induced by 5-HT2 and 5-HT4-7 in a vessel-dependent manner, whereas Ca(2+) influx universally was induced by 5-HT3. These results indicate that the posterior ciliary arteries and vorticose veins in the same tissue might differ greatly in their responses to stimulus.

Intravitreal Diclofenac in the Treatment of Macular Edema Due to Branch Retinal Vein Occlusion

BACKGROUND AND OBJECTIVE

To evaluate the effect of a single dose of intravitreal diclofenac on macular edema (ME) due to branch retinal vein occlusion (BRVO).

PATIENTS AND METHODS

In this prospective, interventional case series, 15 eyes with BRVO and ME with central macular thickness (CMT) greater than 250 µm on spectral-domain optical coherence tomography (SD-OCT) were enrolled. All patients were given 0.05 mg/0.1 mL of intravitreal diclofenac under aseptic conditions and followed up for 3 months with respect to best-corrected visual acuity (BCVA), intraocular pressure (IOP), fundus fluorescein angiography, and CMT measured on OCT.

RESULTS

The mean visual acuity improved from 0.115 ± 0.03 preoperatively to 0.356 ± 0.29 at 3 months (P = .002). Mean line improvement was 2.2 ± 1.6. Mean preoperative CMT decreased from 453.2 µm ± 55.3 µm to 340.47 µm ± 101 µm at 3 months postoperatively (P = .001). The mean preoperative IOP was 16.4 mm Hg ± 1.59 mm Hg, whereas the mean postoperative IOP was 16.6 mm Hg ± 1.58 mm Hg (P = .08). None of the 12 phakic eyes showed evidence of cataract progression.

CONCLUSION

Intravitreal diclofenac is safe and effective in improving BCVA and decreasing CMT in patients with BRVO and ME.

Peripheral retinal non-perfusion and treatment response in branch retinal vein occlusion

AIM

To evaluate the association between the size of peripheral retinal non-perfusion and the number of intravitreal ranibizumab injections in patients with treatment-naive branch retinal vein occlusion (BRVO) and macular edema.

METHODS

A total of 53 patients with treatment-naive BRVO and macular edema were included. Each patient underwent a full ophthalmologic examination including optical coherence tomography (OCT) imaging and ultra wide-field fluorescein angiography (UWFA). Monthly intravitreal ranibizumab injections were applied according to the recommendations of the German Ophthalmological Society. Two independent, masked graders quantified the areas of peripheral retinal non-perfusion.

RESULTS

Intravitreal injections improved best-corrected visual acuity (BCVA) significantly from 22.23±16.33 Early Treatment of Diabetic Retinopathy Study (ETDRS) letters to 36.23±15.19 letters (P<0.001), and mean central subfield thickness significantly reduced from 387±115 µm to 321±115 µm (P=0.01). Mean number of intravitreal ranibizumab injections was 3.61±1.56. The size of retinal non-perfusion correlated significantly with the number of intravitreal ranibizumab injections (R=0.724, P<0.001).

CONCLUSION

Peripheral retinal non-perfusion in patients with BRVO associates significantly with intravitreal ranibizumab injections in patients with BRVO and macular edema.

Experimental Branch Retinal Vein Occlusion Induces Upstream Pericyte Loss and Vascular Destabilization

Aims

Branch retinal vein occlusion (BRVO) leads to extensive vascular remodeling and is important cause of visual impairment. Although the vascular morphological changes following experimental vein occlusion have been described in a variety of models using angiography, the underlying cellular events are ill defined.

Methods and Results

We here show that laser-induced experimental BRVO in mice leads to a wave of TUNEL-positive endothelial cell (EC) apoptosis in the upstream vascular network associated with a transient edema and hemorrhages. Subsequently, we observe an induction of EC proliferation within the dilated vein and capillaries, detected by EdU incorporation, and the edema resolves. However, the pericytes of the upstream capillaries are severely reduced, which was associated with continuing EC apoptosis and proliferation. The vascular remodeling was associated with increased expression of TGFβ, TSP-1, but also FGF2 expression. Exposure of the experimental animals to hypoxia, when pericyte (PC) dropout had occurred, led to a dramatic increase in endothelial cell proliferation, confirming the vascular instability induced by the experimental BRVO.

Conclusion

Experimental BRVO leads to acute endothelial cells apoptosis and increased permeability. Subsequently the upstream vascular network remains destabilized, characterized by pericyte dropout, un-physiologically high endothelial cells turnover and sensitivity to hypoxia. These early changes might pave the way for capillary loss and subsequent chronic ischemia and edema that characterize the late stage disease.

Intravitreal Ranibizumab for Stage IV Proliferative Sickle Cell Retinopathy: A First Case Report

Purpose. To present the case of a 27-year-old male patient with stage IV proliferative sickle cell retinopathy, treated with one intravitreal injection of ranibizumab, showing regression of the neovascularization and no recurrence at the 9-month follow-up. Methods. A 27-year-old male patient presented with blurred vision and floaters in the right eye since three days. His best corrected visual acuity was 6/18. Ophthalmological examination and fluorescein angiography revealed proliferative sickle cell retinopathy stage IV with vitreous hemorrhage and sea fan neovascularization, as well as ischemic areas at the temporal periphery. Results. The patient was treated with one intravitreal injection of ranibizumab, presenting improvement in the visual acuity from 6/18 to 6/6, resolution of vitreous hemorrhage, and regression of the neovascularization. Additionally, he underwent scatter laser photocoagulation at the ischemic areas. At the 9-month follow-up there was no recurrence, while no adverse effects were noticed. Conclusions. Intravitreal ranibizumab may be a useful adjunct to laser photocoagulation in the management of proliferative sickle cell retinopathy and may permit some patients to avoid pars plana vitrectomy for vitreous hemorrhage.

Risk factors for central and branch retinal vein occlusion: a meta-analysis of published clinical data

Retinal vein occlusion (RVO) is a major cause of vision loss. Of the two main types of RVO, branch retinal vein occlusion (BRVO) is 4 to 6 times more prevalent than central retinal vein occlusion (CRVO). A basic risk factor for RVO is advancing age. Further risk factors include systemic conditions like hypertension, arteriosclerosis, diabetes mellitus, hyperlipidemia, vascular cerebral stroke, blood hyperviscosity, and thrombophilia. A strong risk factor for RVO is the metabolic syndrome (hypertension, diabetes mellitus, and hyperlipidemia). Individuals with end-organ damage caused by diabetes mellitus and hypertension have greatly increased risk for RVO. Socioeconomic status seems to be a risk factor too. American blacks are more often diagnosed with RVO than non-Hispanic whites. Females are, according to some studies, at lower risk than men. The role of thrombophilic risk factors in RVO is still controversial. Congenital thrombophilic diseases like factor V Leiden mutation, hyperhomocysteinemia and anticardiolipin antibodies increase the risk of RVO. Cigarette smoking also increases the risk of RVO as do systemic inflammatory conditions like vasculitis and Behcet disease. Ophthalmic risk factors for RVO are ocular hypertension and glaucoma, higher ocular perfusion pressure, and changes in the retinal arteries.