Retinal arterial and vein occlusion: is surgery ever indicated?

PURPOSE OF REVIEW: To highlight the recent progression in surgical treatments for central retinal vein occlusion (CRVO) and central retinal artery occlusion (CRAO). RECENT FINDINGS: Anti-VEGF treatment, accepted as a primary treatment for CRVO, is unable to effectively treat all types of the diseases. Regarding CRAO, there are not any accepted therapies available. There have however been recent innovations in surgery, such as utilizing robotics-assisted tools in cannulation procedures for central retinal artery occlusion, or micro-cystotomy for refractory macular edema resulting from ischemic CRVO. SUMMARY: Refractory macular edema due to CRVO can be treated with aspiration of the fluid found inside the large cysts often seen in edema. The success rate of micro-cystotomy has been reported at 78% in eyes with refractory macular edema. Recent studies have shown that cannulation with tissue plasminogen activator (tPA) is effective for eyes with CRAO due to thrombus.Recent cannulation or micro-cystotomy procedures can be enhanced with the use of robotic tools which allow us to perform this difficult procedure more easily. Newly developed technology, and consequent developments in surgical procedures, will allow us to deal with unmet needs for retinal vessel occlusive diseases.

Case series of branch retinal vein occlusion secondary to rhegmatogenous retinal detachment and its surgical management.

BACKGROUND: To review cases of branch retinal vein occlusion (BRVO) secondary to rhegmatogenous retinal detachment (RRD) and its surgical management and presume their mechanism. METHODS: Medical records of patients who underwent surgery for RRD between 2015 and 2019 at a single tertiary care center were retrospectively reviewed. New BRVO secondary to RRD or its surgical procedure was diagnosed based on the fundus examination and its clinical course. RESULTS: A total of 734 RRD surgeries were performed for five years, and six cases of new BRVOs were noticed in the first year after surgery (incidence was 0.68%: six cases of BRVO / 734 cases of surgical RRD); five cases occurred after vitrectomy, and one occurred after scleral buckling. In three cases, retinal veins were presumed to already be partially occluded related due to a kink of the retinal vein seen before surgery. In the other three cases, the retinal veins were presumed to have incurred damage during vitrectomy. CONCLUSION: In the present cohort, RRD or its related procedures caused BRVO within a year of surgery at an incidence of 0.68%. The proposed mechanisms are kinks of the retinal vein on the detached retina and damage to the retinal vein during vitrectomy.

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.

Minimal surgery for tractional retinal detachment secondary to branch retinal vein occlusion: a case report.

BACKGROUND: Tractional retinal detachment secondary to retinal vein occlusion is a complex entity that can be extremely difficult to manage due to an intricate association of the retinal tissue with the fibrovascular proliferation, making vitreous dissection an extraordinarily difficult procedure. Minimal surgery without endo-tamponade can reduce recovery time and avoid complications of surgery, which in some cases can lead to blindness and even phthisis. CASE PRESENTATION: A 64-year-old Indian woman presented with progressive worsening of vision (right eye) due to fovea involving tractional retinal detachment secondary to supero-temporal branch retinal vein occlusion. After anterior, core and peripheral vitrectomy, the epicenter of the fibrous bridge causing foveal split was identified and released. The corrected distance visual acuity improved from 6/60 pre-operatively to 6/12 post-operatively. At the 5-year follow-up, the patient remains stable both anatomically and visually. CONCLUSIONS: This case illustrates how careful identification of the epicenter of traction helps maximize visual gain in patients with minimal risk of iatrogenic retinal tears and eliminates the need for endo-tamponade with either gas or silicone oil. Minimal surgery for tractional detachment provides excellent visual gains with minimal risks in select cases.

Force and Velocity Based Puncture Detection in Robot Assisted Retinal Vein Cannulation: In-Vivo Study.

OBJECTIVE: Retinal vein cannulation is a technically demanding surgical procedure and its feasibility may rely on using advanced surgical robots equipped with force-sensing microneedles. Reliable detection of the moment of venous puncture is important, to either alert or prevent the clinician from double puncturing the vessel and damaging the retinal surface beneath. This paper reports the first in-vivo retinal vein cannulation trial on rabbit eyes, using sensorized metal needles, and investigates puncture detection. METHODS: We utilized total of four indices including two previously demonstrated ones and two new indices, based on the velocity and force of the needle tip and the correlation between the needle-tissue and tool-sclera interaction forces. We also studied the effect of detection timespan on the performance of detecting actual punctures. RESULTS: The new indices, when used in conjunction with the previous algorithm, improved the detection rate form 75% to 92%, but slightly increased the number of false detections from 37 to 43. Increasing the detection window improved the detection performance, at the cost of adding to the delay. CONCLUSION: The current algorithm can supplement the surgeons' visual feedback and surgical judgment. To achieve automatic puncture detection, more measurements and further analysis are required. Subsequent in-vivo studies in other animals, such as pigs with their more human like eye anatomy, are required, before clinical trials. SIGNIFICANCE: The study provides promising results and the criteria developed may serve as guidelines for further investigation into puncture detection in in-vivo retinal vein cannulation.

INTRAOPERATIVE THREE-DIMENSIONAL FLUORESCEIN ANGIOGRAPHY-GUIDED PARS PLANA VITRECTOMY FOR BRANCH RETINAL VEIN OCCLUSION.

PURPOSE: To show surgical results of the intraoperative 3D fluorescein angiography-guided pars plana vitrectomy for branch retinal vein occlusion with vitreous hemorrhage and neovascularization elsewhere. METHODS: The NGENUITY 3D visualization system was used for the digital-assisted vitrectomy. Three-dimensional fluorescein angiography-guided pars plana vitrectomy was performed in three patients with branch retinal vein occlusion with vitreous hemorrhage and neovascularization elsewhere. RESULTS: In all eyes, the scatter retinal photocoagulations for a nonperfusion area, depicted as hypofluorescein, and the segmentation and delamination of the perivascular fibrovascular proliferative membrane, depicted as hyperfluorescein, could be safely performed on the same screen while implementing intraoperative 3D fluorescein angiography. CONCLUSION: Three-dimensional fluorescein angiography-guided pars plana vitrectomy, a novel approach that fully uses the advantages of digital-assisted vitrectomy, can be one of the useful techniques for the treatment of branch retinal vein occlusion with vitreous hemorrhage and neovascularization elsewhere.

Assessment of pupillary light reflex using dynamic pupillometry in laser-treated eyes with retinal vein occlusion.

PURPOSE: This study aims to evaluate the pupillary light reflex measured with dynamic pupillometry in patients who underwent retinal laser photocoagulation due to unilateral retinal vein occlusion (RVO). METHODS: A total of 48 patients with unilateral RVO were included in the study. Thirty-four patients had undergone retinal laser photocoagulation while the remaining 14 patients that did not undergo laser treatment were observed for control purposes. Of the laser-treated eyes, 14 eyes (41.2%) had central RVO (CRVO) and 20 eyes (58.8%) had branch RVO (BRVO). Among the 14 patients with RVO without laser treatment, nine eyes (64.3%) had CRVO and five eyes (35.7%) had BRVO. Pupillary light reflexes were assessed with dynamic pupillometry (MonPackOne®; Metrovision, France). The parameters of the eyes with RVO were compared with that of fellow healthy eyes. RESULTS: Mean patient age was 65.8 ± 10.4 years and median time after photocoagulation was 25.5 months. Eyes that received laser photocoagulation had lower pupil contraction amplitude (p = 0.037), prolonged contraction latency (p = 0.027), slower contraction velocity (p = 0.043), and slower dilation velocity (p < 0.001) compared to healthy fellow eyes. Subgroup analysis revealed that eyes with CRVO had lower contraction amplitude (p = 0.013) and slower dilation velocity (p = 0.003), and eyes with BRVO had slower dilation velocity (p = 0.003). Non-laser-treated eyes with RVO revealed no significant difference in any of the pupillary light reflex parameters compared to fellow eyes. CONCLUSION: Laser-treated eyes with RVO demonstrated changes in pupillary light reflex parameters including reduced contraction amplitude, prolonged contraction latency, and slower contraction and dilation velocities measured with dynamic pupillometry.

Endovascular surgery in the field of ophthalmology.

In this article, we provide an overview of the current perspectives on endovascular surgery in ophthalmology, including a description of the various approaches, recent clinical results and future prospects. Experimental studies of endovascular surgery in ophthalmology started in the 1980s; since then, a considerable amount of research has been done to develop the procedure for clinical use. During the past two decades endovascular surgery has been performed on eyes with retinal vascular disorders, including central retinal vein occlusion and central retinal artery occlusion. The first endovascular surgery on human eyes was performed in 1998 on a patient with central retinal vein occlusion (CRVO). The most recent techniques used in retinal endovascular surgery involve manual injection of liquid agents such as tissue plasminogen activator into major retinal vessels using a 47 or 48-gauge micro-needle. New technology using a bimanual procedure and digitally assisted vitrectomy systems enables surgeons to perform this delicate procedure more effectively. Recent results reported from a number of researchers corroborate the effectiveness of the procedure. Endovascular surgery is one of the latest techniques in the field of ophthalmology and has garnered significant interest from vitreoretinal surgeons. However, it is also at the limit of what surgeons are able to accomplish with manual precision. There is still much to learn and improve to maximize the potential of this approach. The combination of skills as a surgeon, sound science, objective clinical evidence and cutting edge technology will lead to improvements in this field.

Outcome of Intravitreal Dexamethasone Implant Use in Uveitic Eyes Undergoing Pars Plana Vitrectomy Surgery.

Purpose: To report the outcomes in eyes with noninfectious uveitis receiving dexamethasone implant at the time of pars plana vitrectomy (PPV).Methods: Retrospective analysis of visual acuity (VA), intraocular pressure (IOP), vitreous haze score (VHS), and central subfield thickness (CST) at baseline and follow-up visits.Results: Fourteen eyes received dexamethasone implant at the time of PPV. The CST was improved from 469 ± 182 µm at baseline to 320 ± 60 at 6 months (p = .0112) and 295 ± 46 at 12 months (p = .0728). Vitritis only recurred in 2 eyes at 6 months (18.2%) and 1 eye at 12 months (14.3%). The probability of VA improvement of ≥0.3 logMAR was 57% at 6 months and 66% at 12 months. Therapy for IOP rise was initiated in 6 eyes (42.9%).Conclusions: Local delivery of dexamethasone implant with PPV is a feasible method to counteract postoperative inflammation and macular thickening.

Predictive values of initial semi-quantitative assessment of relative afferent pupillary defect for neovascularization in central retinal vein occlusion.

PURPOSE: To measure the predictive values of relative afferent pupillary defect (RAPD) assessed semi-quantitatively, and visual acuity (VA) at onset of central retinal vein occlusion (CRVO), for neovascularization. METHODS: Retrospective analysis of the TROXHEMO trial that included patients with CRVO within 30 days after the onset. Inclusion criteria were as follows: semi-quantitative RAPD assessment at diagnosis and/or at one month. RAPD was 'severe' if ≥ 0.9 log. Exclusion criteria were as follows: prophylactic panretinal photocoagulation (PRP) before neovascularization. RESULTS: Among the 119 patients enrolled in the main centre, 101 were analysed. 26 had a neovascular complication during the twelve months of follow-up: rubeosis (19), glaucoma (7) and posterior neovascularization (15). The mean time to onset of a neovascular complication was 4.7 months (1 to 12, median 3 months). All the patients who had a neovascular complication had RAPD at first examination or at one month (negative predictive value (NPV) = 100%) but the positive predictive value (PPV) was low (31%, 95% CI [21%; 42%]). The association 'severe RAPD or VA < 35 letters (ETDRS) at inclusion or at one month' was the best compromise between PPV (53%, [39%; 68%]) and NPV (96%, [92%; 100%]). CONCLUSION: To predict neovascularization, RAPD should be routinely evaluated with filters: the risk of neovascular complication is (a) almost nil if there is no RAPD, (b) very low if there is no severe RAPD and if VA is higher than 35 letters, and (c) higher than 50% if RAPD is ≥ 0.9 log or if VA is less than 35 letters.

[Selective panretinal laser photocoagulation in ischemic central retinal vein occlusion]. / Selektivnaya panretinal'naya lazernaya koagulyatsiya pri ishemicheskikh okklyuziyakh tsentral'noi veny setchatki.

PURPOSE: To compare the effectiveness and safety of panretinal laser photocoagulation targeting far-periphery (sPRP) versus conventional panretinal laser photocoagulation (cPRP) in patients with ischemic central retinal vein occlusion (iCRVO) in terms of the degree of macular edema. MATERIAL AND METHODS: The study included eight (5 males and 3 females, mean age 59.4±17.2 years) and seven (6 males and 1 female, mean age 75.7±9.1 years) patients in sPRP and cPRP groups, respectively. iCRVO was defined as a CRVO case with baseline best corrected visual acuity (BCVA) of <0.2, central retinal thickness (CRT) of >500 µm and severe intraretinal hemorrhages. sPRP included dense photocoagulation of far-periphery over 360˚ and standard photocoagulation of the mid-periphery. Primary outcome measures were CRT and macular volume at the end of the follow-up. BCVA served as the secondary outcome measure. RESULTS: The median of the follow-up period was 9.5 months (ranged from 1.5 to 19 months). In the sPRP group, at the end of the follow-up both CRT and macular volume significantly decreased from 892.0±149.4 µm to 391.8±131.2 µm (p<0.001) and from 16.6±4.1 mm3 to 9.7±1.4 mm3, respectively (p=0.008). In the cPRP group, at the end of the follow-up CRT and macular volume changes were statistically insignificant: from 761.0±162.1 µm to 705.0±181.8 µm (p=0.46) and from 13.6± 3.2 mm3 to 11.8±1.7 mm3, respectively (p=0.38). At the end of the follow-up, cPRP group did not have changes in BCVA, while in the sPRP group BCVA increased statistically significantly from 1.45±0.6 LogMAR (≈0.06) to 1.1±0.6 LogMAR (≈0.14) (p=0.03). There were no adverse events or complications associated with laser treatment in any of the study patients. CONCLUSION: This study demonstrates the superiority of sPRP compared with cPRP for treatment of patients with iCRVO, showing that selective laser treatment of the far-periphery results in significant reduction of macular edema associated with severe retinal ischemia.

Chorioretinal Anastomosis for Central Retinal Vein Occlusion: A Review of Its Development, Technique, Complications, and Role in Management.

Treatments for central retinal vein occlusion (CRVO) have improved dramatically with the advent of intravitreal agents aimed at blocking the effects of the dominant hypoxia-induced upreglulated cytokine, which is vascular endothelial growth factor (VEGF). This cytokine breaks down the capillary endothelial barriers and is a major component of the macular edema in this condition. These treatments although impressive only address some of the sequelae of CRVO and have no effect on the underlying cause which is an obstruction to venous outflow leading to retinal blood flow stagnation and an elevation of the retinal central venous pressure (CVP). The creation of a laser-induced chorioretinal anastomosis (L-CRA) between the obstructed high pressure retinal venous circulation and the unobstructed low pressure choroidal venous circulation is a means addressing the causal pathology. The L-CRA will help lower the elevated CVP, which has been up until now an unaddressed component of the macular edema in this condition.This article reviews the preclinical and clinical development of the L-CRA and the results of the studies into its effect on the natural history of CRVO. It now can be used in combination with existing anti-VEGF treatments with the intravitreal agents addressing the component of the CRVO-induced macular edema due to the cytokine dysregulation, and the L-CRA addressing the component due to the elevated CVP and retinal venous stagnation. Improvements in laser technology have led to higher success rates in L-CRA creation and potential complications are now minimized and better controlled. The combination of L-CRA with intravitreal anti-VEGF agents offers the potential of a permanent cure with a significant reduction in the burden of therapy and improved visual outcomes in this condition.

Clinical presentation and prognostic factors affecting surgical outcomes of secondary macular holes after retinal vein occlusions.

PURPOSE: To describe clinical presentation, morphological features and surgical outcomes of macular hole (MH) secondary to retinal vein occlusion (RVO). METHOD: This prospective interventional study evaluated eight eyes with atypical MH (secondary to RVO) and data regarding medical management, pars plana vitrectomy, postoperative anatomical hole closure, visual acuity improvement, morphological features of hole were noted till the last follow-up. RESULTS: Eight eyes with full-thickness MH in an RVO eye were followed-up for a minimum period of 3 months postoperatively. Five subjects had a RVO episode which occurred more than 6 months before the onset of the recent symptoms (Group 1; 4 branch RVO and 1 central RVO), and 3 subjects had a recent onset branch RVO within 6 months (Group 2). All FTMH cases except one showed closure at the last follow-up. Visual acuity of all eyes improved from 0.91 ± 0.57 logMAR to 0.5 ± 0.3 logMAR (p = 0.093). At baseline, visual acuities of the two groups had no significant difference. Postoperatively, group 1 holes had better visual prognosis, than Group 2 holes, further substantiated by persistence of subretinal fluid in Group 2 eyes till last follow-up. Minimum hole diameter was higher in the recent RVO group, although anatomical closure was obtained in all of these eyes. Most holes had favorable morphological hole features like raised configuration with rounded edges. CONCLUSION: In the presence of favorable morphological features, secondary macular holes associated with retinal vein occlusion may show optimal outcomes after surgery. It is not clear whether acutely created holes in recent onset RVO should be operated early. Older holes may have better prognosis.

Eyes With Acute, Treatment-Naïve CRVO and Foveal Intraretinal Hemorrhage: Characteristics and Outcomes.

BACKGROUND AND OBJECTIVE: To compare outcomes in eyes with central retinal vein occlusion (CRVO) presenting with (group 1) or without (group 2) fovea-involving intraretinal hemorrhage (IRH). PATIENTS AND METHODS: Retrospective review of patients diagnosed with acute, treatment-naïve CRVO between January 2009 and July 2016. RESULTS: One hundred fifteen (39.8%) of 289 CRVO eyes had fovea-involving IRH. At baseline, eyes in group 1 had significantly worse visual acuity (VA) (1.2 ± 0.10 logMAR vs. 0.9 ± 0.06 logMAR; P = .001) and greater central subfield thickness (CST) (610.4 µm ± 35.9 µm vs. 435.0 µm + 21.6 µm; P < .001) than eyes in group 2. Final visual outcomes were comparable between groups (1.24 ± 0.09 logMAR vs. 1.02 ± 0.08 logMAR; P = .08). Group 1 received a significantly greater number of intravitreal anti-vascular endothelial growth factor injections during the first year (7.80 ± 0.40 vs. 5.20 ± 0.40; P = .001). CONCLUSIONS: Although treatment-naïve eyes with acute CRVO and fovea-involving IRH had worse VA and greater CST at presentation, the final VA was comparable to eyes without such a hemorrhage. Eyes with foveal IRH had a greater treatment burden in the first 12 months. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:752-759.].

Peripheral Microvascular Abnormalities Detected by Wide-Field Fluorescein Angiography in Eyes with Branch Retinal Vein Occlusion.

PURPOSE: To evaluate the location of microvascular abnormalities using wide-field fluorescein angiography (WFFA) and investigate the impact on visual outcome in eyes with branch retinal vein occlusion (BRVO). METHODS: Forty eyes of 39 patients (24 males and 15 females with an average age of 71 years) were retrospectively reviewed. One patient had BRVO bilaterally. WFFA was performed in all patients to evaluate perfusion status and detect microvascular abnormalities. The WFFA images were divided into 3 zones: zone 1, posterior pole; zone 2, mid-periphery; zone 3, far periphery, in order to document the presence of microvascular abnormalities. Scatter retinal photocoagulation (PC) was performed for retinal neovascularization (NV) and/or widespread nonperfused areas (NPAs). RESULTS: The incidence of microvascular abnormalities in zone 3 was significantly (p < 0.0001) less than in zones 1 and 2. The presence of larger NPAs in zone 1, but not in zone 3, was associated with the incidence of NV and vitreous hemorrhage. The presence of peripheral lesions and the application of PC did not affect the visual outcome. CONCLUSION: The presence of peripheral abnormalities or scatter PC for NPAs did not affect the visual outcome in eyes with BRVO.

Design and evaluation of a new bioelectrical impedance sensor for micro-surgery: application to retinal vein cannulation.

PURPOSE: Nowadays, millions of people suffer from retinal vein occlusion, a blind-making eye disease. No curative treatment currently exists for this vascular disorder. However, a promising treatment consists in injecting a thrombolytic drug directly inside the affected retinal vessel. Successfully puncturing miniature vessels with diameters between 50 and 400 [Formula: see text] remains a real challenge, amongst others due to human hand tremor, poor visualisation and depth perception. As a consequence, there is a significant risk of double-puncturing the targeted vessel. Sub-surfacic injection of thrombolytic agent could potentially lead to severe retinal damage. METHODS: A new bio-impedance sensor has been developed to visually display the instant of vessel puncture. The physical working principle of the sensor has been analysed, and a representative electrical model has been derived. Based on this model, the main design parameters were derived to maximise the sensor sensitivity. A detailed characterisation and experimental validation of this concept were conducted. RESULTS: Stable, repeatable and robust impedance measurements were obtained. In an experimental campaign, 35 puncture attempts on ex vivo pig eyes vessels were conducted. A confusion matrix shows a detection accuracy of 80% if there is a puncture, a double puncture or no puncture. The 20% of inaccuracy most probably comes from the limitations of the employed eye model and the experimental conditions. CONCLUSIONS: The developed bio-impedance sensor has shown great promise to help in avoiding double punctures when cannulating retinal veins. Compared to other puncture detection methods, the proposed sensor is simple and therefore potentially more affordable. Future research will include validation in an in vivo situation involving vitreoretinal surgeons.