Microaneurysms cause refractory macular edema in branch retinal vein occlusion

Association of microaneurysms with retinal vascular alterations in patients with retinal vein occlusion

OBJECTIVE

To investigate the localization, distribution, and type of central microaneurysms (MAs) and their relationship with retinal vascular alterations in patients with retinal vein occlusion (RVO).

METHODS

In this cross-sectional study, ultra-widefield color fundus photography (UWF-CF), standard and single-capture 65° widefield (WF) optical coherence tomography angiography (OCTA) were performed in consecutive patients with RVO treated at the Department of Ophthalmology and Optometry, Medical University of Vienna. UWF-CF, en face and B-Scans in 6 mm × 6 mm OCTA were examined for detection of MAs. Nonperfusion areas (NPA) and collateral vessels (CV) were evaluated on WF-OCTA, ghost vessels (GV), and tortuous vessels (TV) on UWF-CF.

RESULTS

One-hundred-and-twelve patients were included in the study, and data from 59 eyes of 59 patients with disease duration longer than 3 months, good image quality, and without relevant ocular comorbidities were eligible for statistical analysis. Fifty-six of 59 (94.9%) patients were previously treated with anti-vascular endothelial growth factor agents for macular edema, 31 of 59 (52.5%) patients presented with MAs in the central 6 mm and 60 MAs were found in total using multimodal imaging. There was no statistically significant difference in the greatest diameter of fluid-associated versus non-fluid-associated MAs (p = 0.53). Eyes with MAs were associated with CV, TV, and GV (χ2-test; p < 0.001, p = 0.0498, and p = 0.001). Median NPA was 27.3 mm2 (quartiles 1.3-62.8 mm2) in eyes with MAs and 0 mm2 (quartiles 0-36.2 mm2) in eyes without MAs (Mann-Whitney-U-test; p = 0.018).

CONCLUSION

MAs were associated with extensive NPA, the presence of CV, GV, and TV. There was no correlation between the diameter of the MA and the adjacent intraretinal fluid in our predominantly pretreated RVO study patients.

A new surgical approach for the treatment of a refractory foveal microaneurysm: A case report

Purpose

To report a case of a refractory foveal microaneurysm (MA) that was successfully treated by use of a new surgical procedure.

Observations

This study involved a 79-year-old female with an active foveal MA associated with branch retinal vein occlusion in her left eye. Despite anti-vascular endothelial growth factor treatments, the MA remained active without closure, and best-corrected visual acuity (VA) gradually decreased from 20/20 to 20/200. After our new surgical procedure was explained in detail to the patient, written informed consent was obtained from the patient and the surgery was performed. Briefly, following pars plana vitrectomy, the internal limiting membrane in her left eye was peeled and the retina of the external wall of the MA was then gently incised. The exposed MA was then directly grabbed and pulled up onto the retina using 27-gauge microforceps, and photocoagulation was performed. At 3-months postoperative, closure of the MA and improvement in the retinal findings were observed, and best-corrected VA improved to 20/67.

Conclusions and importance

We report a case of a refractory foveal MA that was successfully treated with a novel surgical technique that closed the MA, avoided thermal damage to the surrounding tissue, and resulted in improved postoperative VA.

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 best-corrected 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±109.23 µm. 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 mm2, 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) 300 µm 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.

Predictors of treatment outcomes following treat-and-extend regimen with aflibercept for branch retinal vein occlusion: post-hoc analysis of the PLATON trial

We investigated predictors of visual outcomes and injection interval in macular edema (ME) secondary to branch retinal vein occlusion (BRVO) treated with a treat-and-extend (TAE) regimen. All 48 patients in a multicenter study were followed for 52 weeks and received three monthly intravitreal aflibercept injections before the TAE regimen, with treatment intervals adjusted by 4 weeks, up to a maximum of 16 weeks. Various laboratory biomarkers and optical coherence tomography parameters were evaluated. Patients were classified into the extension failure group if they had ≥ 1 treatment interval decreased due to an increase in the central macular thickness compared to the previous visit and 18 patients were assigned to this group. In multivariate logistic analyses, presence of microaneurysms and prominent middle limiting membrane (p-MLM) sign, increased initial external limiting membrane (ELM) disruption, and higher total cholesterol were correlated with inhibiting a sustained extension in the injection interval (P = 0.015, P = 0.032, P = 0.037, P = 0.009, respectively). Therefore, in the patients with ME secondary to BRVO with these risk factors, early consideration of frequent injection may improve treatment outcome.

MACULAR SENSITIVITY CHANGE AFTER COMPLEMENTARY LASER THERAPY AFTER RANIBIZUMAB INTRAVITREAL INJECTION IN BRANCH RETINAL VEIN OCCLUSION

PURPOSE

We examined the effect of ranibizumab with or without laser photocoagulation on retinal sensitivity in eyes with branch retinal vein occlusion.

METHODS

Prospective randomized control study. Thirty patients with branch retinal vein occlusion received intravitreal injection of ranibizumab in a monthly pro re nata regimen. Fifteen patients received ranibizumab monotherapy alone (monotherapy group). The remaining 15 patients received rescue laser therapy at 3 or 9 months (combined group). The retinal sensitivity was measured at 32 points within central 8°, and the average of the main occlusion side among the 16 upper or 16 lower points was defined as the affected area sensitivity.

RESULTS

In comparing the monotherapy group and the combined group, the number of injections during the 12 months was 5.4 versus 4.9, the change in retinal thickness ( µ m) was -254 versus -197, the ETDRS letters of improvement was +18.3 versus +19.6, and the change in the affected area sensitivity (dB) was +7.1 versus +4.6. At 12 months, all these results were significantly improved compared with their respective baselines, but none of the differences between the two groups reached statistical significance.

CONCLUSION

Retinal sensitivity at 12 months improved in both the monotherapy group and the combined group. The additional laser did not reduce the number of injections or further improve visual acuity nor did it affect retinal sensitivity.

Update on Retinal Vein Occlusion

Retinal vein occlusion represents the second leading cause of retinal vascular disorders, with a uniform sex distribution worldwide. A thorough evaluation of cardiovascular risk factors is required to correct possible comorbidities. The diagnosis and management of retinal vein occlusion have changed tremendously in the last 30 years, but the assessment of retinal ischemia at baseline and during follow-up examinations remains crucial. New imaging techniques have shed light on the pathophysiology of the disease and laser treatment, once the only therapeutic option, is now only one of the possible approaches with antivascular endothelial growth factors and steroid injections being preferred in most cases. Nowadays long-term outcomes are better than those achievable 20 years ago and yet, many new therapeutic options are under development, including new intravitreal drugs and gene therapy. Despite this, some cases still develop sight-threatening complications deserving a more aggressive (sometimes surgical) approach. The purpose of this comprehensive review is to reappraise some old but still valid concepts and to integrate them with new research and clinical data. The work will provide an overview of the disease's pathophysiology, natural history, and clinical features along with a detailed discussion on the advantages of multimodal imaging and of the different treatment strategies with the aim of providing retina specialists with the most updated knowledge in the field.

Healing rate of macular edema secondary to branch retinal vein occlusion in two years after initiation of intravitreal ranibizumab later combined with other treatment as needed and characteristics of refractory cases

PURPOSE

To investigate the 2-year healing rate of macular edema (ME) secondary to branch retinal vein occlusion (BRVO) treated initially with intravitreal ranibizumab (IVR) and later combined with other treatment as needed, and the characteristics of refractory cases.

METHODS

130 patients (130 eyes) with BRVO-ME who received IVR initially were studied. Anti-vascular endothelial growth factor drug was additionally administered when ME relapsed or persisted. Photocoagulation was performed when the non-perfusion area (NPA) was ≥5 disc diameter (DD), and/or when ME relapsed due to microaneurysm. Patients were classified into a healed group [ME resolved in <2 years or mild ME remained without best-corrected visual acuity (BCVA) loss for ≥6 months] or refractory group (ME persisted for ≥2 years).

RESULTS

110 eyes were classified into the healed group, and 20 eyes into the refractory group. The healed group and refractory group had, respectively, mean follow-up periods of 21.2 and 37.4 months, and frequencies of NPA ≥5 DD of 55.5 and 25.0% (p = 0.015). In the healed group, mean BCVA (logMAR) improved significantly compared to baseline in all the periods until 24 months after treatment initiation and at the last visit (p<0.001). In the refractory group, mean BCVA improved significantly compared to baseline until 12 months after treatment initiation (p<0.05 for all periods), but was not significantly different at 18 or 24 months or at the last visit.

CONCLUSION

In patients with BRVO-ME treated initially with IVR and later given additional treatments as needed, the healing rate was 84.6%. In eyes that healed within 2 years, BCVA improved relative to baseline throughout 24 months and at the last visit. In refractory eyes, BCVA improved only until 12 months, and thereafter deteriorated to baseline level at the last examination.

Comparison of widefield swept-source optical coherence tomography angiography with ultra-widefield fluorescein angiography for the evaluation of lesions in retinal vein occlusion

Background

To compare widefield swept-source optical coherence tomography angiography (SS-OCTA) with ultra-widefield fundus fluorescein angiography (UWF-FA) for detecting retinal vein occlusion (RVO) lesions.

Methods

Thirty-four eyes of 32 patients with treatment-naïve RVO were enrolled at Peking University People’s Hospital from September 2021 to March 2022. Patients were imaged with a UWF-FA (200°) and a widefield SS-OCTA using 24 × 20 mm scan single capture. Quantitative assessments of RVO lesions such as foveal avascular zone (FAZ) area and perimeter, non-perfusion areas (NPA), number of microaneurysms (MAs), capillary changes and collateral vessels were performed.

Results

The measurement of FAZ area and perimeter were comparable between SS-OCTA and UWF-FA (0.373 (range, 0.277–0.48) mm2 vs. 0.370 (range, 0.277–0.48) mm2, P = 0.818 and 2.480 (range, 2.011–2.998) vs. 2.330 (range, 2.027–2.807) mm, P = 0.536, respectively). Intraclass correlation coefficients (ICCs) of FAZ area and perimeter between SS-OCTA and UWF-FA was high (0.999, [0.997–0.999] and 0.996 [0.991–0.996], respectively), suggesting good agreement. The mean NPA area was larger on SS-OCTA than that on UWF-FA (89.977 ± 78.805 mm2vs. 87.944 ± 77.444 mm2, P = 0.037). The ICC of NPA area was also high (0.999, [0.999–1.000]). The median of total MA count was less on SS-OCTA than on UWF-FA (7 (range, 0–19) vs.12 (range, 0–23), P < 0.001). Agreement in detecting MAs between SS-OCTA and UWF-FA was found to be good (ICC = 0.920, [0.555–0.974]).The total capillary changes and collateral vessels count were less on UWF-FA than SS-OCTA (11 ± 9 vs 6 ± 7, P < 0.001 and 4 (range, 0–6) vs 0 (range, 0–0), P < 0.001, respectively). Agreement in detecting capillary changes and collateral vessels between OCTA and UWF-FA was found to be fair (ICC = 0.733, [0.081–0.905] and 0.564, [0.039–0.805], respectively).

Conclusion

Compared with UWF-FA, widefield SS-OCTA was found comparable or even superior in detecting FAZ, NPA, capillary changes and collateral vessels except MAs in RVO. Widefield SS-OCTA may offer a more efficient alternative to FA for diagnosis and monitoring RVO.

Which Explanatory Variables Contribute to the Classification of Good Visual Acuity over Time in Patients with Branch Retinal Vein Occlusion with Macular Edema Using Machine Learning?

This study’s goal is to determine the accuracy of a linear classifier that predicts the prognosis of patients with macular edema (ME) due to a branch retinal vein occlusion during the maintenance phase of antivascular endothelial growth factor (anti-VEGF) therapy. The classifier was created using the clinical information and optical coherence tomographic (OCT) findings obtained up to the time of the first resolution of ME. In total, 66 eyes of 66 patients received an initial intravitreal injection of anti-VEGF followed by repeated injections with the pro re nata (PRN) regimen for 12 months. The patients were divided into two groups: those with and those without good vision during the PRN phase. The mean AUC of the classifier was 0.93, and the coefficients of the explanatory variables were: best-corrected visual acuity (BCVA) at baseline was 0.66, BCVA at first resolution of ME was 0.51, age was 0.21, the average brightness of the ellipsoid zone (EZ) was −0.12, the intactness of the external limiting membrane (ELM) was −0.14, the average brightness of the ELM was −0.17, the brightness value of EZ was −0.17, the area of the outer segments of the photoreceptors was −0.20, and the intactness of the EZ was −0.24. This algorithm predicted the prognosis over time for individual patients during the PRN phase.

Estimating ranibizumab injection numbers and visual acuity at 12 months based on 2-month data on branch retinal vein occlusion treatment

Anti-vascular endothelial growth factor treatment for macular edema secondary to branch retinal vein occlusion generally provides good visual acuity (VA) improvement but may require repeated injections for years. To reduce the number of patients who suffer from avoidable VA loss caused by treatment drop-out, providing prospects of the correlation between expected vision improvement and required number of injections at the early stages of treatment may be helpful. In this post hoc analysis of the phase IV, randomized, open-label ZIPANGU study, we investigated the correlation between the data from Month 2 and Month 12 in terms of VA and required ranibizumab injection numbers. Fifty-nine patients were evaluated (ranibizumab monotherapy, 29; combination therapy, 30). In the monotherapy group, patients who received 1 and 3 injections by Month 2 received a mean total of 2.8 and 8.3 injections during the year, respectively. Data from the combination group were similar. The correlation coefficients for VA scores at Months 2 and 12 were 0.60 and 0.51 for the monotherapy and combination groups, respectively (both p < 0.01). Based on VA and injection numbers at Month 2 of treatment, physicians could provide rough prospects on patients’ expected final VA and required number of injections.

Direct Photocoagulation for Treating Microaneurysms with Hyperreflective Ring in Eyes with Refractory Macular Edema Associated with Branch Retinal Vein Occlusion

Microaneurysms (MAs) with hyperreflective rings are sometimes detected in eyes with refractory macular edema (ME) associated with branch retinal vein occlusion (BRVO) for more than 12 months after onset when examined using optical coherence tomography (OCT). We proposed that these MAs could result in refractory ME secondary to BRVO and hypothesized that OCT-guided direct photocoagulation of MAs could result in a reduction in refractory ME. Eleven eyes (from eleven different patients) with refractory ME associated with BRVO for more than 12 months following initial treatment were included. The mean number of MAs in each eye at baseline was 3.5 ± 2.0 (range, 1–8). The mean central subfield thickness, central macular volume, and parafoveal macular volume significantly decreased 6 months following initial direct photocoagulation when compared with those at baseline (baseline = 378.7 ± 61.8 μm, post-treatment = 304.2 ± 66.7 μm, p = 0.0005; baseline = 0.3 ± 0.049 mm³, post-treatment = 0.24 ± 0.053 mm³, p = 0.001; and baseline = 2.5 ± 0.14 mm³, post-treatment = 2.28 ± 0.15 mm³, p = 0.001, respectively). Moreover, the mean best-corrected visual acuity significantly improved 6 months following initial direct photocoagulation when compared with that at baseline (baseline = 0.096 ± 0.2 logarithm of the minimum angle of resolution (logMAR), post-treatment = 0.0077 ± 0.14 logMAR, p = 0.031). Direct photocoagulation could be suggested as a treatment option for refractory ME associated with BRVO in MAs with a hyperreflective ring on OCT.

Vascular abnormalities may progress in branch vein occlusion despite resolution of macular edema

Progression of vascular abnormalities was assessed between resolved and persistent macular edema (ME) in branch retinal vein occlusion. Progression was more common in eyes with resolved ME, suggesting that resolved ME may not signify stability.

Classification of good visual acuity over time in patients with branch retinal vein occlusion with macular edema using support vector machine

PURPOSE

To identify the eyes with macular edema (ME) due to a branch retinal vein occlusion (BRVO) that have good visual acuity during the continuous anti-vascular endothelial growth factor (anti-VEGF) treatment based on the patients' clinical information and optical coherence tomography (OCT) images by using machine learning.

METHODS

Sixty-six eyes of 66 patients received 1 anti-VEGF injection followed by repeated injections in the pro re nata (PRN) regimen for 12 months. The patients were divided into two groups: those with and those without good vision during the 1-year experimental period. Handcraft features were defined from the OCT images at the time of the first resolution of the ME. Variables with a significant difference between the groups were used as explanatory variables. A classifier was created with handcrafted features based on a support vector machine (SVM) that adjusted parameters for increasing maximal precision.

RESULTS

The age, best-corrected visual acuity (BCVA) at the baseline, BCVA at the first resolution of the ME, integrity and reflectivity of the external limiting membrane (ELM), the ellipsoid zone (EZ), and area of the outer segments of the photoreceptors were selected as explanatory variables. The classification performance was 0.806 for accuracy, 0.768 for precision, 0.772 for recall, and 0.752 for the F-measure.

CONCLUSION

The use of the SVM of the patient's clinical information and OCT images can be helpful for determining the prognosis of the BCVA during continued pro re nata anti-VEGF treatment in eyes with ME associated with BRVO.

Microaneurysm density in residual oedema after anti-vascular endothelial growth factor therapy for diabetic macular oedema

PURPOSE

To investigate the relationship between microaneurysm (MA) density and residual oedema after intravitreal injection of an anti-vascular endothelial growth factor agent for the treatment of diabetic macular oedema (DMO).

METHODS

Patients with DMO were divided into those with residual oedema (RO) and those with no residual oedema (NRO) by the presence and absence of oedema at 1 month after intravitreal injection of either aflibercept or ranibizumab. We then compared MA density, best corrected visual acuity (BCVA), central retinal thickness (CRT) and size of the severely thickened area, as indicated by a white area (WA) on optical coherence tomography.

RESULTS

We examined 48 eyes in the RO group and 25 eyes in the NRO group (n = 73). In both groups, the CRT and WA size significantly decreased and BCVA improved at 1 month and thereafter. CRT was significantly higher and BCVA was poor in the RO group at 1 and 3 months, while WA size was larger at 1, 3 and 6 months compared with the NRO group (p < 0.05). The number of injections in the RO group (3.62 ± 1.75) was larger than the NRO group (1.89 ± 0.97; p < 0.0001). At 1 and 6 months, the MA density in the area with persistent oedema was significantly higher than in the area with improved oedema (1 month: p = 0.0001, 6 months: p = 0.029).

CONCLUSION

High MA density and extensive swelling may be characteristic of RO following treatment for DMO with intravitreal injection of either aflibercept or ranibizumab.

Subfoveal Choroidal Thickness and Treatment Outcomes of Intravitreal Aflibercept for Branch Retinal Vein Occlusion

We aimed to investigate the relationship between subfoveal choroidal thickness (SCT) and treatment outcomes of intravitreal aflibercept (IVA) for macular edema (ME) due to branch retinal vein occlusion (BRVO). We retrospectively evaluated 46 patients with treatment-naive BRVO-ME who underwent IVA treatment between March 2016 and February 2017. There was no significant difference in visual acuity within 6 months (0.29 ± 0.20 vs. 0.27 ± 0.19, p = 0.338), the mean central foveal thickness improvement (332.0 ± 162.2 μm vs. 303.9 ± 166.6 μm, p = 0.492), and the mean number of IVA injections (1.7 ± 0.7 vs. 1.6 ± 0.7 times, p = 0.658) between the SCT thickened (n = 26 patients, 26 eyes) and SCT non-thickened groups (n = 20 patients, 20 eyes). The rate of ME recurrence was significantly lower in the SCT decreased group (6/17 eyes (35.2%) vs. 19/30 eyes (63.3%); p = 0.038). In conclusion, pretreatment choroidal thickening does not affect the therapeutic effect of IVA for BRVO, but ME recurrence was lower in cases of treatment-related choroidal thinning. Thus, changes in SCT may be a therapeutic indicator of IVA for acute BRVO.

Twenty-Four Month Results of Intravitreal Ranibizumab for Macular Edema after Branch Retinal Vein Occlusion: Visual Outcomes and Resolution of Macular Edema

Purpose: To report 24-month results after one intravitreal ranibizumab (IVR) injection followed by pro re nata (PRN) dosing for macular edema (ME) after branch retinal vein occlusion (BRVO).Methods: Eyes with BRVO met the followings were included: 77 letters or less best-corrected visual acuity (BCVA) (Early Treatment Diabetic Retinopathy Study [ETDRS] score) and central retinal thickness (CRT) of 250 µm or more. IVR injection was performed followed by a PRN regimen. The retreatment criteria included visual loss of five or more ETDRS letters compared with the previous visit, 250 µm or more of CRT, or presence of residual or recurrent ME including the parafoveal lesions. The primary outcome measures were the BCVA changes at month 12 and month 24 from baseline, and the secondary outcomes were changes in CRT, resolution of ME, the number of IVR injections, and changes of nonperfused areas (NPAs).Results: Twenty eyes of 20 patients (5 men, 15 women; mean age, 68.2 years) were enrolled. The mean BCVAs (ETDRS letters) at baseline, month 12, and month 24 were 62.0, 80.2, and 80.9, respectively. The mean ETDRS letters gains were 18.3 and 19.0 at month 12 and month 24, respectively. The percentages of patients with Snellen equivalent BCVAs of 20/20 or better at month 12 and month 24 were 75% and 70%, respectively. The mean CRTs at baseline, month 12, and month 24 were 480, 252, and 272 μm, respectively. Forty percent of all eyes had complete resolution of ME. The mean number of IVR injections was 8.3 times, which gradually decreased over time. The NPA change in either Zone 1 or Zone 2 was not significant during the follow-up. No adverse side effects were observed.Conclusion: IVR injection followed by a PRN regimen provided pretty good visual outcomes at month 24.

Multimodal Imaging of Microvascular Abnormalities in Retinal Vein Occlusion

The technologies of ocular imaging modalities such as optical coherence tomography (OCT) and OCT angiography (OCTA) have progressed remarkably. Of these in vivo imaging modalities, recently advanced OCT technology provides high-resolution images, e.g., histologic imaging, enabling anatomical analysis of each retinal layer, including the photoreceptor layers. Recently developed OCTA also visualizes the vascular networks three-dimensionally, which provides better understanding of the retinal deep capillary layer. In addition, ex vivo analysis using autologous aqueous or vitreous humor shows that inflammatory cytokine levels including vascular endothelial growth factor (VEGF) are elevated and correlated with the severity of macular edema (ME) in eyes with retinal vein occlusion (RVO). Furthermore, a combination of multiple modalities enables deeper understanding of the pathology. Regarding therapy, intravitreal injection of anti-VEGF drugs provides rapid resolution of ME and much better visual improvements than conventional treatments in eyes with RVO. Thus, the technologies of examination and treatment for managing eyes with RVO have progressed rapidly. In this paper, we review the multimodal imaging and therapeutic strategies for eyes with RVO with the hope that it provides better understanding of the pathology and leads to the development of new therapies.

Time course of collateral vessel formation after retinal vein occlusion visualized by OCTA and elucidation of factors in their formation

BACKGROUND

It is clinically recognized that collateral vessels can form after retinal vein occlusion (RVO) in some cases and these vessels can lead to spontaneous recovery of the pathological condition. In recent years, optical coherence tomography angiography (OCTA) has become a decisive clinical instrument. Unlike previous angiography tests, OCTA enables the non-invasive visualization of fundus vasculature without the need for administration of a contrast agent. However, it remains to be determined if OCTA depicts the 'true' histological status as several studies have reported artifacts in OCTA imaging.

METHODS

We generated a laser-induced mouse RVO model, and evaluated the subsequent formation of collateral vessels in order to understand the mechanisms by which collateral vessels form using OCTA imaging, as well as molecular and histological assessments.

RESULTS

We succeeded in visualizing the time course of collateral vessel formation in a mouse RVO model and confirmed the similarity in formation of collateral vessels only within the deep layer of the retina in both human and mouse. We hypothesized that sphingosine 1-phosphate receptor-1 (S1PR1) may play important roles via vascular shear stress linking vein occlusion and collateral vessel formation. Results from OCTA revealed that collateral vessels are increased in response to administration of a S1PR1 agonist in a mouse RVO model. Based on quantitative reverse transcription polymerase chain reaction (qRT-PCR), S1PR1 messenger ribonucleic acid (mRNA) levels in the whole retina peaked 6 h after photocoagulation in this model. Immunohistochemical staining of retinal flat mounts revealed that S1PR1 staining occurred along the laser-occluded blood vessels.

CONCLUSION

We observed the temporal process of collateral vessel formation in a mouse RVO model and identified the relationship between S1PR1 and shear stress as one of the factors in collateral vessel formation in RVO.

Twenty-four-month results of intravitreal aflibercept for macular edema due to branch retinal vein occlusion

PURPOSE

To investigate 24-month results of intravitreal aflibercept (IVA) for macular edema due to branch retinal vein occlusion (BRVO-ME).

STUDY DESIGN

Retrospective study.

METHODS

Subjects were treatment-naïve BRVO-ME patients at the Ophthalmology Department of Juntendo University Urayasu Hospital from November 2015 to March 2017 who received IVA treatment for 24 months. After the first injection, reinjection was performed as needed when ME had recurred or was prolonged beyond 300 μm. Data included changes in best corrected visual acuity and central foveal thickness, total number of injections, and the case background factors that required reinjection after 12 months. ME remission was defined as patients without additional injections for 6 months.

RESULTS

Forty eyes of 40 patients (64.5 ± 11.5 years), 21 men and 19 women, were included. Average best corrected visual acuity and central foveal thickness at baseline were logMAR 0.42 ± 0.21, 601.4 ± 181.3 μm, logMAR 0.08 ± 0.25, 214.6 ± 62.7 μm at 12 months, logMAR 0.02 ± 0.16, 216.6 ± 97.8 μm at 24 months, all significantly improved from baseline. The average number of injections was 2.2 ± 1.0 times in the first year and 0.4 ± 0.8 times in the second year. The rate of ME remission was 60.0% at 12 months and 87.5% at 24 months. Period between onset and injections was significantly associated with reinjection after 12 months (p =.030).

CONCLUSIONS

IVA was effective over 24 months for ME due to BRVO in many cases. Early injection treatment may reduce the need for later injections.

Suspended scattering particles in motion using OCT angiography in branch retinal vein occlusion disease cases with cystoid macular edema

We aimed to investigate the clinical implication of suspended scattering particles in motion (SSPiM) using optical coherence tomography angiography (OCTA) among branch retinal vein occlusion disease (BRVO) cases with macular edema (ME). Medical records of BRVO patients were reviewed. Central retinal thickness (CRT), ME type, and cyst size on optical coherence tomography images were evaluated before and after intravitreal bevacizumab injection. Nonperfusion area, SSPiM, and microvascular abnormalities in OCTA images were evaluated using a Heidelberg machine. SSPiM was identified in 24 of 56 cases. There were no differences in baseline characteristics between groups with and without SSPiM. Disease duration, disease-free duration, previous injection number, microaneurysms in the superficial vascular complex, and microaneurysms in the deep vascular complex (DVC) (p = 0.003, 0.013, 0.028, 0.003, < 0.001, respectively) differed significantly between the two groups. After multivariate logistic analysis, microaneurysms in the DVC were the only different factor between the two groups (odds ratio [OR]: 0.091; p = 0.001). Furthermore, SSPiM in the DVC (OR 10.908; p = 0.002) and nonperfusion grade (OR 0.039; p < 0.001) were significantly associated with cyst response after intravitreal injection. SSPiM may be correlated with microaneurysms in the DVC and a poor anatomical response after intravitreal injection.

Morphologic Classifications and Locations of Microaneurysms and Clinical Relevance in Branch Retinal Vein Occlusion

Purpose

To classify microaneurysms (MAs) and investigate the relationships with retinal edema in eyes with branch retinal vein occlusion (BRVO).

Study Design

Retrospective, observational, consecutive case series.

Methods

Eyes with MAs due to BRVO that underwent optical coherence tomography angiography (OCTA) were enrolled. MAs on OCTA images were morphologically classified into six types: focal bulge, saccular, fusiform, mixed (saccular/fusiform), pedunculated, and irregular. The frequency, size, location, and relationships with retinal edema also were investigated.

Results

Twenty-four eyes of 23 patients (12 men, 11 women; mean age, 68.0 years) were enrolled. A total of 244 MAs were detected on the OCTA images. The focal bulge and saccular types accounted for over 70% of all MAs. Smaller MAs such as the focal bulge or saccular type also were detected both at the edge of the nonperfused areas (NPAs) and in collateral vessels. In contrast, larger MAs such as the pedunculated or irregular types tended to form at the edges of the NPAs. Older age, the presence of MAs in the collateral vessels, and the absence of pedunculated type were independent predictive factors for retinal edema but not the MA size, or presence in the retinal deep capillary plexus. After treatment, the mean retinal thickness decreased significantly, but the mean MA size remained unchanged.

Conclusion

OCTA enables morphologic classification, three-dimensional analysis, and investigation of the longitudinal changes of MAs with noninvasive volumetric quantification, leading to a better understanding of the pathology of MAs in eyes with BRVO.

Collateral vessels on optical coherence tomography angiography in eyes with branch retinal vein occlusion

AIMS

To detect collateral vessels using optical coherence tomography angiography (OCTA) in eyes with branch retinal vein occlusion (BRVO) and to investigate the associations with visual outcomes and macular oedema.

METHODS

Eyes with macular oedema secondary to BRVO that underwent OCTA at baseline and were followed up for more than 6 months were enrolled. The presence of collaterals, whether the collaterals were leaky or not, and the associations with visual outcomes and macular oedema were investigated.

RESULTS

Twenty-eight eyes of 28 patients (8 men and 20 women; mean age, 68 years) were enrolled. Collaterals were detected in 23 eyes (82%) and already existed at the initial visit. Collaterals were more frequently detected in eyes with major BRVO or ischaemic type. One-third of the collaterals were leaky and all of the leaky collaterals had microaneurysms (MAs) inside. Macular oedema in eyes with collaterals was more quickly and frequently resolved than that in eyes without collaterals, but there were no significant differences. Collateral vessel formation did not seem to impact on visual outcomes, but the mean baseline central retinal thickness (CRT) was significantly higher in eyes with collaterals, and the mean CRT reduction at 6 months after treatments was significantly greater than in eyes without collaterals.

CONCLUSIONS

These results suggest that collateral vessels are formed at the acute phase in eyes with BRVO. In addition, the presence of collaterals might be associated with absorption of macular oedema, but MAs formed in collaterals sometimes can cause macular oedema.

Structural and Functional Analyses of Retinal Ischemia in Eyes with Retinal Vein Occlusion: Relationship with Macular Edema or Microaneurysm Formation

PURPOSE

To study the structural and functional changes of retinal ischemia and investigate their association with macular edema (ME) or microaneurysm (MA) formation in eyes with retinal vein occlusion (RVO).

METHODS

Sixty eyes of 30 patients (27 eyes with branch [b]RVO, 3 with central RVO, and 30 fellow eyes) were retrospectively reviewed. Optical coherence tomography (OCT), OCT angiography (OCTA), and microperimetry were performed simultaneously to measure retinal thickness and sensitivity. The presence of ME or MA was also assessed using OCT and fluorescein angiography.

RESULTS

The mean retinal sensitivity in the nonperfused areas (NPAs) deteriorated, and this was significantly (r = -0.379, p = 0.0391*) and inversely correlated with duration from disease onset. ME and MA were unlikely to be observed around the area where the retinal sensitivity decreased. In the NPAs, the mean retinal thickness of the superficial capillary plexus (SCP) (p < 0.0001), deep capillary plexus (DCP) (p = 0.0323), and outer retina (p = 0.0008) were significantly thinner than those in the fellow eyes, respectively. Multivariate regression analysis revealed that the thicknesses of the DCP (β: 0.3107, p = 0.0007) and outer retina (β: 0.3482, p = 0.0001) were the independent correlative factors of the retinal sensitivity, but that SCP thickness was not.

CONCLUSION

Deep retinal thinning in NPAs was correlated significantly with a decreased retinal sensitivity, which might be a negative predictor of ME and MA in eyes with RVO.

Six-month results of intravitreal ranibizumab for macular edema after branch retinal vein occlusion in a single-center prospective study: visual outcomes and microaneurysm formation

Purpose

The aim of this study is to report the 6-month results after one intravitreal ranibizumab (IVR) injection followed by pro re nata dosing for macular edema (ME) after branch retinal vein occlusion.

Patients and methods

The inclusion criteria included a minimal patient age of 18 years, 20 letters or more best-corrected visual acuity (BCVA) (Early Treatment Diabetic Retinopathy Study [ETDRS] score, 77 letters or less), and central retinal thickness (CRT) of 250 microns or more. The primary outcome measure was the mean BCVA change from baseline at month 6; the secondary outcomes were mean changes in CRT, residual ME, and microaneurysm formation.

Results

Twenty patients were enrolled from March 2014 through October 2016 at Nagoya City University Hospital. The baseline mean ETDRS letters and CRT were 63.1 and 500 microns, respectively; mean time from symptom onset to initial therapy was 1.80 months; and mean ETDRS gain and CRT reduction were 15.2 letters and 230 microns, respectively. The percentages of patients with Snellen equivalent BCVAs of 20/40 (70 ETDRS letters) or better and 20/20 (85 ETDRS letters) were 90% and 15%, respectively. Residual ME and microaneurysms were observed in 85% and 35% of patients. Microaneurysm formation was associated with delayed initial therapy.

Conclusion

Prompt initiation of IVR injection provided a better visual prognosis at month 6 and suppressed the microaneurysm formation.

PREDICTORS OF REFRACTORY MACULAR EDEMA AFTER BRANCH RETINAL VEIN OCCLUSION FOLLOWING INTRAVITREAL BEVACIZUMAB

PURPOSE

To evaluate the predictors of refractory macular edema (ME) that develops despite multiple bevacizumab injections in patients with branch retinal vein occlusion (BRVO).

METHODS

A total of 107 patients who followed at least 2 years were assigned to 2 groups: a refractory group (n = 56) and a responsive group (n = 51). Baseline characteristics, treatment response at 3 months, and fluorescein angiographic findings at 6 months were compared. Then we tried to identify factors associated with refractory ME development.

RESULTS

Compared to the responsive group, the refractory group had older age, longer pre-treatment duration, and shorter occlusion distance from disk. At 3 months, the refractory group exhibited lower visual acuity, thicker central retinal thickness (CRT), and larger proportion of external limiting membrane (ELM) and outer plexiform layer disruption. After 6 months, proportion of unresolved vein occlusion, macular ischemia, number of microaneurysms, and non-perfusion areas were higher in the refractory group. Refractory ME was associated with pre-treatment duration ≥3 months, short occlusion distance from disk, thick CRT and ELM disruption at 3 months, and unresolved vein occlusion at 6 months.

CONCLUSION

If BRVO-ME patients exhibit the above-mentioned characteristics, they may have refractory ME, which should inform treatment decisions.