Long-term outcomes of vitrectomy with or without arteriovenous sheathotomy in branch retinal vein occlusion

Ocular microcirculation changes, measured with laser speckle flowgraphy and optical coherence tomography angiography, in branch retinal vein occlusion with macular edema treated by ranibizumab

PURPOSE

This study searched for early predictive vascular biomarkers for visual outcomes in eyes with macular edema caused by branch retinal vein occlusion (BRVOME).

METHODS

Twenty-four eyes of 24 subjects with BRVOME were treated with the intravitreal injection of ranibizumab (IVR) for at least 6 months. We measured mean blur rate (MBR) in the optic nerve head (ONH) and vessel density (VD) in the macula with laser speckle flowgraphy and optical coherence tomography angiography, respectively.

RESULTS

Six-month post-IVR best-corrected visual acuity (BCVA) was correlated positively with age, pre-IVR BCVA, 1-month post-IVR BCVA, 3-month post-IVR BCVA and pre-IVR systolic blood pressure (P < 0.001, P < 0.001, P < 0.001, P < 0.001 and P = 0.02, respectively) and negatively with pre-IVR overall MBR, 1-month post-IVR overall MBR, 6-month post-IVR overall MBR, 3-month post-IVR deep retinal capillary plexus (DCP) VD and 6-month post-IVR DCP VD (P = 0.03, P = 0.03, P = 0.02, P = 0.01 and P = 0.005, respectively). Furthermore, a multiple regression analysis showed that pre-IVR overall MBR (β =  - 0.67, P = 0.009) was among independent prognostic factors predicting 6-month post-IVR BCVA. Six-month post-IVR DCP VD was also correlated with overall MBR at all time points.

CONCLUSION

ONH blood flow may be a pre-IVR biomarker of both visual outcomes and post-IVR deep macular microcirculation in eyes with BRVOME.

A systematic review of real-world evidence of the management of macular oedema secondary to branch retinal vein occlusion

This review assessed the real-world evidence of the management of macular oedema secondary to branch retinal vein occlusion (BRVO). A meta-analysis of 2530 eyes from 48 real-world studies of therapies for macular oedema secondary to BRVO was conducted. Baseline characteristics, visual, anatomical and safety outcomes were recorded. The weighted mean and weighted estimates from random-effects models were calculated for visual acuity (VA) and central subfield thickness (CST) changes at 6, 12 and 24 months. Primary outcome was change in VA (logMAR letters) at 12 months. Study quality was assessed using the quality appraisal checklist for case series developed by Institute of Health Economics. The mean baseline VA for the pooled data was 54.0 (51.5, 56.5) letters and the mean baseline CST was 501.3 (483.5, 519.1) µm. The random-effects estimate for mean (95% CI) change in VA was 14.6 (12.5, 16.7) letters at 12 months (n = 1727). The random-effects estimate for mean (95% CI) change in CST was -181.7 (-230.7, -132.7) µm at 12 months (n = 1325). The quality of studies varied considerably. Ocular and systemic adverse events were discussed in 79% and 42% of treatment arms respectively, with possible under-reporting. Visual and anatomical gains achieved in the real-world for anti-VEGF therapy were not as impressive as seminal RCTs, possibly due to reduced injection frequency in the real world and differences in baseline characteristics. There is an urgent need for consensus on the minimum efficacy, treatment burden and safety data to collect to strengthen the real-world evidence base.

Angiographic Risk Features of Branch Retinal Vein Occlusion Onset as Determined by Optical Coherence Tomography Angiography

Purpose

Examine associations between the vasculature at arteriovenous (AV) crossings and the onset of branch retinal vein occlusion (BRVO).

Methods

We included 78 patients with major BRVO, 35 patients with macular BRVO, and 110 controls without BRVO and determined the vessel positions at AV crossings, where the first- or second-order branches of the retinal veins associate, using a viewing angle of 12 × 12 mm² in optical coherence tomography angiography (OCTA).

Results

We reviewed 1349 and 1276 AV crossings in BRVO patients and control subjects, respectively. The proportions of venous overcrossing were 26.5%, 28.6%, and 26.8% at non-causative crossings in BRVO eyes, non-BRVO fellow eyes, and unaffected control eyes, respectively; however, the rate of venous overcrossings at the causative crossings was 45.1%. In OCTA analyses, we divided the branches into macular- or non-macular veins. The rate of venous overcrossing was 52.5% at causative crossings in major BRVO but was 28.6% in macular BRVO. Odds ratios for whether venous overcrossing was a risk factor for BRVO were 3.09 (95% confidence interval [CI], 1.96–4.88) and 0.94 (95% CI, 0.44–2.00) for non-macular veins and macular veins, respectively. The patients with major BRVO caused by venous overcrossing were younger than patients for whom the cause was arterial overcrossing (P < 0.001). The onset of macular BRVO did not differ between crossing patterns at causative crossings (P = 0.60).

Conclusions

In eyes with BRVO, venous overcrossing was a common angiographic feature at causative crossings and might be a risk factor for major BRVO onset.

Guidelines for the Management of Retinal Vein Occlusion by the European Society of Retina Specialists (EURETINA)

The high prevalence of cardiovascular disease particularly in the elderly population is associated with retinal vascular disease. Retinal vein occlusions represent severe disturbances of the hypoxia-sensitive neurosensory retina. Acute and excessive leakage leads to the diagnostic hallmarks of retinal hemorrhage and edema with substantial retinal thickening. Advanced diagnostic tools such as OCT angiography allow to evaluate retinal ischemia and identify the risk for late complications and will soon reach clinical routine besides fluorescein angiography. Accordingly, the duration of non-perfusion is a crucial prognostic factor requiring timely therapeutic intervention. With immediate inhibition of vascular leakage, anti-VEGF substances excel as treatment of choice. Multiple clinical trials with optimal potential for functional benefit or a lesser regenerative spectrum have evaluated aflibercept, ranibizumab, and bevacizumab. As retinal vein occlusion is a chronic disease, long-term monitoring should be individualized to combine maintenance with practicability. While steroids may be considered in patients with systemic cardiovascular risk, surgery remains advisable only for very few patients. Destructive laser treatment is an option if reliable monitoring is not feasible. Ophthalmologists are also advised to perform a basic systemic workup to recognize systemic concomitants. The current edition of the EURETINA guidelines highlights the state-of-the-art recommendations based on the literature and expert opinions in retinal vein occlusion.

Arteriovenous crossing associated with branch retinal vein occlusion

Branch retinal vein occlusion (BRVO) is defined as the focal occlusion of a first or second-order branch of retinal vein, which occurs most frequently at an arteriovenous (AV) crossing. Direct ophthalmoscopy, color fundus photography, and fluorescein angiography facilitate observation of AV crossings parallel to the retinal plane. Optical coherence tomography (OCT), with its high-depth resolution, enables observation of retinal lesions perpendicular to the retinal plane. OCT angiography (OCTA) provides depth-resolved images of the retinal vasculature by segmenting three-dimensional data. In this review, we discuss novel findings related to affected AV crossings associated with BRVO obtained via OCT and OCTA. The high-depth resolution of OCT or OCTA is useful for observation of the narrowed vein and determination of the vessel position of the affected AV crossing. Studies using OCT and OCTA have shown that BRVO caused by a venous overcrossing is more prevalent than previously reported, and that venous narrowing was significantly greater in instances caused by a venous overcrossing than in those caused by an arterial overcrossing. Moreover, OCTA also revealed that the retinal nonperfusion area size was larger in eyes with BRVO caused by a venous overcrossing than in those with BRVO caused by an arterial overcrossing. This contrasts with earlier findings obtained by conventional imaging modalities predating OCT, which showed that an arterial overcrossing was more common than a venous overcrossing at the causative venous occlusion site in eyes with BRVO. This review discusses these findings and their significance in the study of AV crossing associated with BRVO.

Vitrectomy for macular edema due to retinal vein occlusion

Purpose: To determine the long-term outcomes of vitrectomy for the macular edema associated with a retinal vein occlusion (RVO).

Methods: This was a retrospective, consecutive, interventional case series. The intraoperative procedures included internal limiting membrane peeling, arteriovenous sheathotomy, radial optic neurotomy, and intravitreal triamcinolone acetonide injection at the end of the surgery. The main outcome was the best-corrected visual acuity (BCVA).

Results: Eight hundred and fifty-four eyes of 854 patients were studied. The eyes consisted of 602 with branch RVO (BRVO), 74 with hemi-central RVO (hemi-CRVO), 87 with nonischemic central retinal vein occlusion (CRVO), and 91 with ischemic CRVO. The mean follow-up period was 68.6 months with a range of 12 to 262 months. The mean BCVA was significantly improved at the final visit (P<0.0001 to 0.0016). The final BCVA improved in 74.4% of the BRVO eyes, in 58.1% of the hemi-CRVO eyes, in 57.4% of the nonischemic CRVO eyes, and in 51.6% of the ischemic CRVO eyes. Multiple regression analysis showed there was no significant relationship between the intraoperative combined procedures and the final BCVA.

Conclusions: The results indicate that the type of RVO is significantly associated with the final BCVA, and vitrectomy is a treatment option to improve and maintain BCVA for a long term.

Long-term outcomes of intravitreous bevacizumab or tissue plasminogen activator or vitrectomy for macular edema due to branch retinal vein occlusion

Purpose

The purpose of this study was to determine the long-term outcomes of intravitreal bevacizumab (IVB) or intravitreal tissue plasminogen activator (tPA) or vitrectomy for macular edema associated with a branch retinal vein occlusion (BRVO).

Methods

This was a retrospective, interventional case series. Forty-one patients received a single 1.25 mg of IVB injection and followed by pro re nata protocol, 71 patients received a single intravitreal tPA, and 116 patients underwent phacovitrectomy with intraocular lens implantation.

Results

The baseline characteristics and follow-up periods were not significantly different among the three groups. The mean follow-up period was 55.5 months with a range of 12-160 months. Sixteen patients (39.0%) in the IVB group, 24 patients (33.8%) in the tPA group, and two patients (1.7%) in the vitrectomy group underwent additional surgeries during the follow-up period. The best-corrected visual acuity (BCVA) significantly improved in all groups at 1 year after the initial treatment (all, P<0.0001) and at the final visit (all, P<0.0001). The differences in the BCVA between the three groups were not significant at all times after the initial treatment.

Conclusion

The three groups led to similar long-term good visual outcomes. However, additional surgeries were performed in more than 30% of patients in the IVB and tPA groups.

Recent advances in understanding and managing retinal vein occlusions

Retinal vein occlusions are the second most common form of retinal vascular disease. Previously, laser treatment for branch retinal vein occlusion and intravitreal triamcinolone acetonide for central retinal vein occlusion were the standard of care. Recent studies have demonstrated that anti-vascular endothelial growth factor (anti-VEGF) agents have a superior safety and efficacy profile for the treatment of both branch and central retinal vein occlusions. The use of wide-field fluorescein angiography has also allowed better visualization of the retinal periphery. Despite the better documentation of retinal non-perfusion, laser photocoagulation to the areas of non-perfusion does not seem to result in a reduction of macular edema or reduction in treatment burden and has been relegated to patients who develop rubeosis or neovascularization of the retina. More recently, several studies have demonstrated the use of a long-acting dexamethasone implant administered intravitreally or triamcinolone administered in the suprachoroidal space as a viable approach to treat retinal vein occlusion.

Towards Robot-Assisted Retinal Vein Cannulation: A Motorized Force-Sensing Microneedle Integrated with a Handheld Micromanipulator †

Retinal vein cannulation is a technically demanding surgical procedure where therapeutic agents are injected into the retinal veins to treat occlusions. The clinical feasibility of this approach has been largely limited by the technical challenges associated with performing the procedure. Among the challenges to successful vein cannulation are identifying the moment of venous puncture, achieving cannulation of the micro-vessel, and maintaining cannulation throughout drug delivery. Recent advances in medical robotics and sensing of tool-tissue interaction forces have the potential to address each of these challenges as well as to prevent tissue trauma, minimize complications, diminish surgeon effort, and ultimately promote successful retinal vein cannulation. In this paper, we develop an assistive system combining a handheld micromanipulator, called "Micron", with a force-sensing microneedle. Using this system, we examine two distinct methods of precisely detecting the instant of venous puncture. This is based on measured tool-tissue interaction forces and also the tracked position of the needle tip. In addition to the existing tremor canceling function of Micron, a new control method is implemented to actively compensate unintended movements of the operator, and to keep the cannulation device securely inside the vein following cannulation. To demonstrate the capabilities and performance of our uniquely upgraded system, we present a multi-user artificial phantom study with subjects from three different surgical skill levels. Results show that our puncture detection algorithm, when combined with the active positive holding feature enables sustained cannulation which is most evident in smaller veins. Notable is that the active holding function significantly attenuates tool motion in the vein, thereby reduces the trauma during cannulation.

Structural and functional assessment after intravitreal injection of ranibizumab in diabetic macular edema

PURPOSE

To evaluate structure and function improvement in central retina by optical coherence tomography (OCT) and multifocal electroretinography (mf-ERG) in diabetic macular edema (DME) patients after intravitreal injection of ranibizumab (IVR) treatment.

METHODS

Twenty-seven eyes in 27 patients with DME received three consecutive monthly injections of IVR (0.05 ml, 10 mg/ml) and as needed thereafter. The clinical parameters of best-corrected visual acuity (BCVA), central foveal thickness (CFT) and mf-ERG were monitored for 6 months before and after IVR. The findings at baseline, 1, 3 and 6 months were analyzed. Correlation and regression analyses were performed on BCVA, CFT, mf-ERG amplitude and implicit time of the N1 and P1 waves.

RESULTS

IVR significantly improved visual acuity from the beginning of the treatment (P < 0.05). There were significant decreases in the CFT compared with the baseline after IVR (P < 0.05). The mean amplitude of P1 and N1 in the central ring at all examinations increased significantly compared with the baseline (P < 0.05). The mean P1 and N1 implicit times in the central ring were shortened, but not significantly (P > 0.05). There were significant correlations of BCVA with CFT, P1 and N1 amplitudes in the central retina (P < 0.05).

CONCLUSION

In addition to the improvement in BCVA and the reduction in CFT, IVR improved macular retinal function, as assessed by mf-ERG, in diabetic eyes. The combination of OCT and mf-ERG for macular evaluation may better assess DME.

Therapies for Macular Edema Associated with Branch Retinal Vein Occlusion: A Report by the American Academy of Ophthalmology

PURPOSE

To evaluate the available evidence on the ocular safety and efficacy of current therapeutic alternatives for the management of macular edema (ME) secondary to branch retinal vein occlusion (BRVO).

METHODS

Literature searches were last conducted on January 31, 2017, in PubMed with no date restrictions and limited to articles published in English, and in the Cochrane Database without language limitations. The searches yielded 321 citations, of which 109 were reviewed in full text and 27 were deemed appropriate for inclusion in this assessment. The panel methodologist assigned ratings to the selected studies according to the level of evidence.

RESULTS

Level I evidence was identified in 10 articles that addressed anti-vascular endothelial growth factor (VEGF) pharmacotherapies for ME, including intravitreal bevacizumab (5), aflibercept (2), and ranibizumab (4). Level I evidence was identified in 6 studies that examined intravitreal corticosteroids, including triamcinolone (4) and the dexamethasone implant (2). Level I evidence also was available for the role of macular grid laser photocoagulation (7) and scatter peripheral laser surgery (1). The inclusion of level II and level III studies was limited given the preponderance of level I studies. The number of studies on combination therapy is limited.

CONCLUSIONS

Current level I evidence suggests that intravitreal pharmacotherapy with anti-VEGF agents is effective and safe for ME secondary to BRVO. Prolonged delay in treatment is associated with less improvement in visual acuity (VA). Level I evidence also indicates that intravitreal corticosteroids are effective and safe for the management of ME associated with BRVO; however, corticosteroids are associated with increased potential ocular side effects (e.g., elevated intraocular pressure, cataracts). Laser photocoagulation remains a safe and effective therapy, but VA results lag behind the results for anti-VEGF therapies.

New Developments in the Classification, Pathogenesis, Risk Factors, Natural History, and Treatment of Branch Retinal Vein Occlusion

For years, branch retinal vein occlusion is still a controversial disease in many aspects. An increasing amount of data is available regarding classification, pathogenesis, risk factors, natural history, and therapy of branch retinal vein occlusion. Some of the conclusions may even change our impression of branch retinal vein occlusion. It will be beneficial for our doctors to get a deeper understanding of this disease and improve the treatment skills. The aims of this review is to collect the information above and report new ideas especially from the past a few years.

Five-year outcomes of pars plana vitrectomy for macular edema associated with branch retinal vein occlusion

Purpose

Long-term outcomes of pars plana vitrectomy (PPV) for macular edema (ME) associated with branch retinal vein occlusion (BRVO) have been previously reported, but the studies did not report the number of additional treatments after surgery. During 5 years of follow-up, we therefore investigated the efficacy and safety of PPV for BRVO and evaluated the incidence of additional treatments.

Methods

We retrospectively reviewed the medical records of 25 eyes of 24 patients who underwent PPV for ME associated with BRVO and were followed up for at least 5 years. Best-corrected visual acuity was measured, and foveal thickness was assessed by optical coherence tomography. Additional treatments were also investigated.

Results

The logarithm of the minimal angle of resolution (logMAR) improved from 0.53±0.23 at baseline to 0.16±0.25 at 5 years (P<0.0001). The foveal thickness decreased from 535±222 µm at baseline to 205±143 µm at 5 years (P<0.0001). For the eyes with residual ME, the following additional treatments were performed within 5 years of follow-up: sub-Tenon injection of triamcinolone acetonide in two eyes, intravitreal injection of bevacizumab in three eyes, grid laser photocoagulation in one eye, and direct photocoagulation of macroaneurysm in one eye. Additional surgeries were performed in two eyes: for one eye, phacoemulsification extraction of the ocular lens and intraocular lens implantation were performed because of cataract progression, and for the other eye, additional PPV was done for postoperative retinal detachment.

Conclusion

PPV was effective for resolution of ME associated with BRVO and improved visual acuity with a small number of additional treatments during long-term follow-up.

Impaired Retinal Perfusion Resulting From Vitreoretinal Traction: A Mechanism of Retinal Vascular Insufficiency

BACKGROUND AND OBJECTIVE

To demonstrate vitreoretinal traction as a mechanism of abnormal retinal vascular perfusion.

PATIENTS AND METHODS

Retrospective report of three cases demonstrating vitreoretinal traction concurrent with abnormal retinal perfusion. Subjects were retrospectively identified based on clinical records from two tertiary care retina subspecialty practices. All subjects underwent complete ophthalmic examination and ancillary testing as necessary for their standard clinical care. Vascular perfusion was assessed by one or more methods, including wide-field fluorescein angiography and optical coherence tomography angiography (OCTA). Vitreoretinal traction was assessed by clinical examination; intraoperative surgical observations; and fundus imaging, including wide-field, red-free, and color images as well as OCT.

RESULTS

Three cases are shown in which vitreoretinal traction was clearly documented and correlated with abnormal retinal vascular perfusion. Abnormal vascular perfusion correlated with the distribution of vessels affected by vitreoretinal traction in all cases. Vascular perfusion normalized in all cases after surgery was used to relieve vitreoretinal traction.

CONCLUSION

The authors demonstrate that vitreoretinal traction can alter retinal vascular perfusion in a reversible fashion. These results suggest that there can be a direct mechanical effect of vitreous traction on retinal vascular perfusion. Further advances in wide-field imaging, wide-field OCT, and OCTA will help better evaluate this cause of retinal vascular insufficiency.

Robotic Assisted Cannulation of Occluded Retinal Veins

PURPOSE

To develop a methodology for cannulating porcine retinal venules using a robotic assistive arm after inducing a retinal vein occlusion using the photosensitizer rose bengal.

METHODOLOGY

Retinal vein occlusions proximal to the first vascular branch point were induced following intravenous injection of rose bengal by exposure to 532nm laser light delivered by slit-lamp or endolaser probe. Retinal veins were cannulated by positioning a glass catheter tip using a robotically controlled micromanipulator above venules with an outer diameter of 80μm or more and performing a preset piercing maneuver, controlled robotically. The ability of a balanced salt (BSS) solution to remove an occlusion by repeat distention of the retinal vein was also assessed.

RESULTS

Cannulation using the preset piercing program was successful in 9 of 9 eyes. Piercing using the micromanipulator under manual control was successful in only 24 of 52 attempts, with several attempts leading to double piercing. The best location for cannulation was directly proximal to the occlusion. Infusion of BSS did not result in the resolution of the occlusion.

CONCLUSION

Cannulation of venules using a robotic microassistive arm can be achieved with consistency, provided the piercing is robotically driven. The model appears robust enough to allow testing of therapeutic strategies aimed at eliminating a retinal vein thrombus and its evolution over time.

RETINAL VEIN OCCLUSIONS, FROM BASICS TO THE LATEST TREATMENT

PURPOSE

To review the pathophysiology, diagnosis, and updated treatments of retinal vein occlusions (RVOs).

METHODS

A review of the literature was performed, focusing on the epidemiology, pathophysiology, diagnosis, and treatments (including both medical and surgical treatments) of RVO. Based on this review, a comprehensive overview was provided regarding the topic of RVO and focused on recent treatment updates.

RESULTS

Retinal vein occlusions have an age- and sex-standardized prevalence of 5.20 per 1,000 for any RVO, 4.42 per 1,000 for branch RVO, 0.80 per 1,000 for central RVO. Worldwide, an estimated 16.4 million adults are affected by RVOs, with 2.5 million affected by central RVO and 13.9 million affected by branch RVO. Retinal vein occlusion is recognized as an important cause of blindness and the diagnostic approaches and treatment options for RVO are reviewed and reported. The current treatment options including medical treatments (bevacizumab, ranibizumab, aflibercept, triamcinolone, and dexamethasone implants) and surgical alternatives were reviewed and reported with summaries on the corresponding strength of evidence.

CONCLUSION

Despite the understanding of this disease entity, challenges persist in the long-term treatment of RVO-related complications and visual loss. This review provided a detailed summary on the rationality and efficacy of recently developed treatment regimes and evaluated the potential benefit of combination therapy.

Multifocal Electroretinogram in Diabetic Macular Edema; Correlation with Visual Acuity and Optical Coherence Tomography

Purpose:

To evaluate multifocal electroretinogram (mfERG) changes in eyes with diabetic macular edema (DME) and investigate any possible correlation with optical coherence tomography (OCT) features and visual acuity (VA).

Methods:

Twenty-nine right eyes of 29 subjects with DME due to non-proliferative diabetic retinopathy and 30 eyes of 30 normal subjects were evaluated. All patients underwent a complete ophthalmic examination. Sixty-one scaled hexagon mfERG responses were recorded. Components of the first order kernel of N1, N2, and P1 in five concentric rings centered on the fovea, were measured in both groups. Correlation and regression analyses were performed among VA, central macular thickness (CMT) based on OCT, mfERG amplitude, and latency of the N1, N2 and P1 waves.

Results:

Significant differences were observed in all mfERG parameters in five-ring regions of the retina between eyes with DME versus controls (P < 0.05). There were significant correlations among VA with N2 (P = 0,001, b = 0.73) and P1 amplitudes (P = 0.001, b = −0.84) in the central macular area, and there was a borderline association between VA and CMT (P = 0.042, b = 0.392).

Conclusion:

Amplitudes of mfERG components (N1, P1, and N2) are significantly reduced and their latencies are delayed in eyes with DME indicating functional impairment in the outer retina. The mfERG total amplitude was significantly correlated with VA even more than CMT, therefore the combined use of OCT and mfERG for macular evaluation may better evaluate visual status in DME patients.

Experimental Application of Piezoelectric Actuator-Driven Pulsed Water Jets in Retinal Vascular Surgery

PURPOSE

To report on the effectiveness and safety of an ophthalmic piezoelectric actuator-driven pulsed water jet (ADPJ) system adapted for intraocular use.

METHODS

First, we determined the highest ADPJ flow rate that did not cause an unsafe rise in intraoperative intraocular pressure (IOP) in rabbits (n = 4). Next, we determined the most effective ADPJ frequency (in hertz) at that flow rate. Finally, we visualized the ADPJ stream, measured its pressure, and determined the minimum voltage and distance between the ADPJ needle and retinal veins to induce intravenous displacement of the blood column (DBC) through massage of the outer retinal vessels (n = 3) while not causing retinal tearing or hemorrhage.

RESULTS

We found that a 0.05 mL/min ADPJ flow rate caused IOP to rise above 40 mm Hg after 1 minute, but that at 0.025 mL/min, IOP stayed below 40 mm Hg even after 3 minutes. Moreover, we found that a 0.025 mL/min ADPJ stream was stable at a pulse frequency of 10 Hz and that at this flow rate/frequency the ADPJ pressure was closely correlated with the applied voltage (P < 0.001, r² = 0.9991). The minimum voltage and distance to achieve intravenous DBC without causing retinal tearing or hemorrhage were 40 V and 0.5 mm, respectively.

CONCLUSIONS

With an appropriate flow rate and surgical time, ADPJ successfully induced massage of the retinal vessels and intravenous DBC while maintaining safe IOP and not causing retinal complications.

TRANSLATIONAL RELEVANCE

The ADPJ system has promise as a safe and minimally invasive instrument for the intraocular surgical treatment of human retinal vascular diseases.

Pathogenesis, prevention, diagnosis and management of retinal vein occlusion

Retinal vein occlusion (RVO) is the second vascular retinal cause of visual loss and defined by the occlusion of a retinal vein. It is divided into branch retinal vein occlusion or central retinal vein occlusion, depending on the location of occlusion. RVO has severe medical, financial and social implications on the patients. The diagnosis of the disease is easier nowadays with the use of spectral domain optical coherence tomography and fluorescein angiography. The treatment options for RVO have changed dramatically over the past few years with the introduction of the intravitreal injections of dexamethasone (Ozurdex), bevacizumab (Avastin), ranibizumab (Lucentis) and aflibercept (EYLEA), along with the panretinal laser photocoagulation, abandoning former treatment modalities and surgical solution. This manuscript is a review of current literature about RVO with emphasize on the pathophysiology, risk factors and prevention, diagnosis and sub-group categorization and treatments including medical and surgical. Since no official guidelines are available for the treatment of RVO patients, and considering the latest developments in the treatment options, and the variety of follow-up and treatment modalities, this manuscript aims to provide tools and knowledge to guide the physician in treating RVO patients, based on the latest publications from the literature and on several of the patients characteristics.

Role of inflammation in previously untreated macular edema with branch retinal vein occlusion

BACKGROUND

The association of inflammatory factors and the aqueous flare value with macular edema in branch retinal vein occlusion (BRVO) patients remains unclear. The relationship between the aqueous flare value and the vitreous fluid levels of vascular endothelial growth factor (VEGF), interleukin (IL)-6, monocyte chemotactic protein (MCP)-1, soluble intercellular adhesion molecule 1 (sICAM-1), and soluble VEGF receptor-2 (sVEGFR-2) was evaluated to investigate the role of inflammation in BRVO associated with macular edema. Aqueous flare values and the vitreous levels of VEGF, IL-6, MCP-1, sICAM-1, and sVEGFR-2 were compared between previously untreated patients with BRVO and patients with macular hole (MH).

METHODS

Vitreous samples were obtained from 45 patients during vitreoretinal surgery (28 patients with BRVO and 17 with MH), and the levels of VEGF, IL-6, MCP-1, sICAM-1, and sVEGFR-2 were measured by enzyme-linked immunosorbent assay. Retinal ischemia was evaluated by measuring the area of capillary non-perfusion using fluorescein angiography and the Scion Image program. Aqueous flare values were measured with a laser flare meter and macular edema was examined by optical coherence tomography.

RESULTS

The median aqueous flare value was significantly higher in the BRVO group (12.1 photon counts/ms) than in the MH group (4.5 photon counts/ms, P < 0.001). There were significant correlations between the aqueous flare value and the vitreous levels of VEGF, IL-6, MCP-1, and sICAM-1 in the BRVO group (ρ = 0.54, P = 0.005; ρ = 0.56, P = 0.004; ρ = 0.52, P = 0.006; and ρ = 0.47, P = 0.015, respectively). The aqueous flare value was also significantly correlated with the foveal thickness in the BRVO group (ρ = 0.40, P = 0.037).

CONCLUSIONS

Inflammation may induce an increase of vascular permeability and disrupt the blood-aqueous barrier via release of inflammatory factors (VEGF, IL-6, MCP-1, and sICAM-1) in BRVO patients with macular edema.

Matched control study of visual outcomes after arteriovenous sheathotomy for branch retinal vein occlusion

Background

The purpose of this study was to evaluate visual outcomes of arteriovenous sheathotomy for macular edema due to branch retinal vein occlusion (BRVO).

Methods

The medical records of 45 eyes from 45 patients who had undergone vitrectomy surgery with arteriovenous sheathotomy for BRVO were studied. Forty-five eyes of 45 patients with a BRVO but without intervention were studied as the control group. The best-corrected visual acuity and central macular thickness were compared between the two groups at baseline and at 1, 3, 6, and 12 months postoperatively.

Results

Improvement of best-corrected visual acuity was 0.42 logarithm of the minimum angle of resolution (logMAR) units in the sheathotomy group and 0.22 logMAR units in the control group (P=0.007). The mean postoperative central macular thickness was significantly thinner in the sheathotomy group at 1 month (P=0.01), but not at 3, 6, and 12 months (P=0.75, P=0.81, and P=0.46, respectively). Improvement of best-corrected visual acuity at 12 months was significantly correlated with baseline best-corrected visual acuity, age, duration of symptoms, and sheathotomy (P<0.05).

Conclusion

Arteriovenous sheathotomy for BRVO improves best-corrected visual acuity significantly more than the natural course of the BRVO disease process.

Association of electroretinogram and morphological findings in central retinal vein occlusion with macular edema

The objective of this study was to evaluate the relations among electroretinogram (ERG) parameters (cone a-wave, cone b-wave, and 30 Hz flicker), retinal thickness, and retinal volume in 16 patients with central retinal vein occlusion and macular edema. The amplitude and implicit time of the ERG parameters were extracted from the ERG traces. Retinal thickness and volume were measured by optical coherence tomography in nine macular subfields. Then the correlations among ERG parameters and morphological parameters were analyzed. The cone b-wave and 30 Hz flicker implicit time were correlated with retinal thickness and volume in seven out of nine subfields, excluding the temporal subfields. In addition, the amplitude of the cone b-wave was correlated with retinal thickness and volume in the nasal inner and nasal outer subfields. These findings suggest that retinal thickness and volume may be associated with outer and inner retinal function in central retinal vein occlusion patients.

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

BACKGROUND

Retinal vein occlusion is the second most common retinal vascular disorder after diabetic retinopathy and is considered to be an important cause of visual loss. In this review, our purpose is to update the literature about the treatment alternatives for branch retinal vein occlusion.

METHODS

Eligible papers were identified by a comprehensive literature search of PubMed, using the terms "branch retinal vein occlusion," "therapy," "intervention," "treatment," "vitrectomy," "sheathotomy," "laser," "anti-VEGF," "pegaptanib," "bevacizumab," "ranibizumab," "triamcinolone," "dexamethasone," "corticosteroids," "non-steroids," "diclofenac," "hemodilution," "fibrinolysis," "tPA," and "BRVO." Additional papers were also selected from reference lists of papers identified by the electronic database search.

RESULTS

Treatment modalities were analyzed.

CONCLUSIONS

There are several treatment modalities for branch retinal vein occlusion and specifically for its complications, such as macular edema, vitreous hemorrhage, retinal neovascularization, and retinal detachment, including anti-aggregative therapy and fibrinolysis, isovolemic hemodilution, vitrectomy with or without sheathotomy, peripheral scatter and macular grid retinal laser therapy, non-steroid agents, intravitreal steroids, and intravitreal anti-vascular endothelial growth factors (anti-VEGFs).

Vitreomacular adhesion and neovascular age-related macular degeneration

We explore the hypothesis that vitreomacular adhesion (VMA) and vitreomacular traction (VMT) play a role in the pathogenesis and clinical course of neovascular ("wet") age-related macular degeneration (AMD). Several biological theories are offered to explain this possible association, including direct tractional force, altered vitreous oxygenation, altered diffusion coefficients of intravitreal molecules, and alterations in the pharmacokinetics of intravitreal drugs. Release of VMT may improve the clinical course of neovascular AMD, and a few case series suggest that vitrectomy can lead to both a functional and anatomic improvement. A large, randomized, controlled clinical trial is underway, investigating pharmacologic release of VMA in eyes with neovascular AMD.

Effects of Vitrectomy on Recurrent Macular Edema due to Branch Retinal Vein Occlusion after Intravitreal Injection of Bevacizumab

Purpose. To evaluate the effects of pars plana vitrectomy (PPV) on recurrent macular edema due to branch retinal vein occlusion (BRVO) after intravitreal injections of bevacizumab (IVB). Methods. This retrospective study included 22 eyes of 22 patients who underwent single or multiple IVB injections for macular edema due to BRVO and showed a recurrence of macular edema. All patients then underwent PPV and were followed up for more than 6 months after the surgery with examinations of best corrected visual acuity (BCVA) and optical coherence tomography (OCT). OCT parameters were central macular thickness (CMT) and average retinal thickness in a 1-mm-diameter circular region at the fovea (MRT). Results. Mean BCVA, CRT, and MRT were significantly improved from the baseline after PPV. Greater improvement of BCVA, CRT, and MRT was obtained after 1 month of IVB than after 6 months of PPV. No eyes showed worsening of macular edema after the surgery. Conclusion. PPV improved BCVA and recurrent macular edema due to BRVO, but PPV that was less effective than IVB had been in the same patients. PPV may be one of the treatment options for recurrent macular edema due to BRVO after IVB.

Evaluation of ultrasound-assisted thrombolysis using custom liposomes in a model of retinal vein occlusion

PURPOSE

To study the potential efficacy of ultrasound (US) assisted by custom liposome (CLP) destruction as an innovative thrombolytic tool for the treatment of retinal vein occlusion (RVO).

METHODS

Experimental RVO was induced in the right eyes of 40 rabbits using laser photothrombosis; the US experiment took place 48 hours later. Rabbits were randomly divided into four equal groups: US+CLP group, US+saline group, CLP+sham US group, and no treatment group. The latter three groups acted as controls. Fundus fluorescein angiography and Doppler US were used to evaluate retinal blood flow.

RESULTS

CLP-assisted US thrombolysis resulted in restoration of flow in seven rabbits (70%). None of the control groups showed significant restoration of retinal venous blood flow.

CONCLUSIONS

US-assisted thrombolysis using liposomes resulted in a statistically significant reperfusion of retinal vessels in the rabbit experimental model of RVO. This approach might be promising in the treatment of RVO in humans. Further studies are needed to evaluate this approach in patients with RVO. Ultrasound assisted thrombolysis can be an innovative tool in management of retinal vein occlusion.

Three treatments for macular edema because of branch retinal vein occlusion: intravitreous bevacizumab or tissue plasminogen activator, and vitrectomy

PURPOSE

To evaluate the effectiveness of intravitreous bevacizumab (Avastin), intravitreous tissue plasminogen activator, and vitrectomy for the macular edema secondary to branch retinal vein occlusion.

METHODS

Retrospective, interventional case series. We studied 228 eyes of 228 patients. Forty-one eyes received 1.25 mg of intravitreous bevacizumab, 71 eyes received tissue plasminogen activator, and 116 eyes underwent vitrectomy. A reinjection of 1.25 mg of bevacizumab was based on the morphologic and functional findings. The main outcome measures were the best-corrected visual acuity and optical coherence tomography-determined foveal thickness.

RESULTS

The mean postoperative follow-up period was 32.2 months with a range of 12 months to 69 months. The mean number of intravitreous bevacizumab was 2.8 with a range of 1 to 5. The mean best-corrected visual acuity and foveal thickness significantly improved after all 3 treatments, and the differences in the best-corrected visual acuity between the 3 groups were not significant at 12 months. Fourteen eyes (34%) in the intravitreous bevacizumab group and 21 eyes (30%) in the tissue plasminogen activator group required additional surgeries.

CONCLUSION

The 3 treatments appear to provide similar visual outcomes at 12 months. However, in some eyes treated with intravitreous bevacizumab or tissue plasminogen activator, additional surgeries were required, and a longer follow-up period was required to determine the final outcome.

Inflammatory factors in major and macular branch retinal vein occlusion

Concentrations of inflammatory factors were measured in 40 patients with macular edema due to major branch retinal vein occlusion (BRVO) or macular BRVO who were treated by pars plana vitrectomy. Vitreous fluid levels of vascular endothelial growth factor (VEGF), soluble intercellular adhesion molecule-1 (sICAM-1), and pigment epithelium-derived factor (PEDF) were determined. Visual acuity and central macular thickness were significantly improved at 6 months in both groups. Vitreous fluid levels of VEGF and sICAM-1 were higher in the major BRVO group than the macular BRVO group, while the PEDF level was lower in the major group than the macular group. The mean visual acuity and central macular thickness at 6 months were not significantly different between the macular and major groups. In conclusion, patients with major BRVO had higher vitreous levels of inflammatory factors and lower vitreous levels of anti-inflammatory PEDF. Accordingly, regulating inflammatory factors might be more important in major BRVO than macular BRVO.

Treatment of macular edema due to branch retinal vein occlusion with single or multiple intravitreal injections of bevacizumab

PURPOSE

We examined the predictive factors for final visual acuity (VA) with macular edema of branch retinal vein occlusion (BRVO) treated by intravitreal injection of bevacizumab (IVB) and examined the differences between patients without recurrent macular edema due to BRVO after a single IVB and patients treated with multiple IVB because of recurrent macular edema.

METHODS

In this retrospective study, 37 eyes of 37 patients with BRVO were treated with IVB and followed up for more than 24 weeks. Eighteen eyes showed no recurrence of macular edema after a single IVB (single IVB group). The remaining 19 eyes showed recurrent macular edema and underwent multiple IVB (multiple IVB group). VA and morphologic parameters of optical coherence tomography were examined.

RESULTS

Mean VA, central retinal thickness, and mean retinal thickness in a circular region of 1-mm diameter at the fovea improved significantly with IVB treatment in both groups. Final VA was correlated with baseline VA and integrity grade of the photoreceptor inner and outer segment (IS/OS) line beneath the fovea.

CONCLUSION

Baseline VA and IS/OS line grade at 4 weeks may be predictive factors for final VA.

Rebound of macular edema after intravitreal bevacizumab therapy in eyes with macular edema secondary to branch retinal vein occlusion

PURPOSE

To determine the incidence of rebound macular edema after intravitreal bevacizumab in eyes with macular edema secondary to branch retinal vein occlusion and to identify the pretreatment factors that were significantly associated with the rebound.

METHODS

The changes in the foveal thickness after the intravitreal bevacizumab (1.25 mg/0.05 mL) were studied in 65 eyes of 65 patients with macular edema secondary to branch retinal vein occlusion. A rebound of macular edema was defined as a ≥110% increase in the foveal thickness or a foveal thickness ratio of ≥110% (foveal thickness at the recurrence/foveal thickness at the baseline × 100). Multivariate logistic regression analyses and subgroup analyses were performed to determine which pretreatment factors were associated with the rebound.

RESULTS

Seven of 65 eyes (10.8%) showed a rebound (≥110% of baseline thickness). Subgroup analyses showed that a thinner pretreatment fovea and a shorter interval between symptom onset to the initiation of the intravitreal bevacizumab were significantly associated with a rebound of macular edema (P < 0.01). The interval from symptoms onset to the initiation of treatment was <8 weeks in all 7 eyes with a rebound macular edema.

CONCLUSION

These results suggest that a rebound of macular edema in eyes with branch retinal vein occlusion was more likely to occur when the intravitreal bevacizumab therapy is initiated before the macular edema reaches the maximum level. Rebound of macular edema may be effectively avoided by waiting at least 8 weeks after the onset of symptoms to begin the intravitreal bevacizumab.

Management of retinal vein occlusion--consensus document

Retinal vein occlusion (RVO) can have severe consequences for the people affected by the disease, including visual loss with costly social repercussions. Currently, there is no European consensus with regard to the management of RVO. Following a careful review of the medical literature as well as the data from several clinical trials, a collaborative group of retina specialists put forth practical recommendations based on the best available scientific evidence for the clinical approach to RVO. Taking into consideration the recent advances in diagnostic tools and management options, the present document aims to provide the European ophthalmologists with guidelines for clinical practice to the benefit of their patients.

[SERV clinical practice guidelines: management of retinal vein occlusion. Sociedad Española de Retina y Vitreo]

PURPOSE

A guidelines for the management of retinal vein occlusion is presented. This is necessary because at this moment several therapeutic alternatives have been developed although their role is not yet sufficiently defined.

METHODS

Review of the literature for evidence published up to date. Relevant literature was identified and the level of evidence graded. Evidence was then assessed for consistency, applicability and clinical impact. The information was contrasted with those guides published in other countries.

RESULTS

Taking into account the different options of treatment that are currently used, several modes of action are suggested. The role of the various complementary examinations are discussed and it is recommended that criteria for the treatment are based on clinical, angiographic, and tomographic findings.

CONCLUSIONS

Although there is no overall consensus, these guidelines promote a good standard of clinical practise and provide an update of the management of retinal vein occlusion.

Retinal vein occlusions: The potential impact of a dysregulation of the retinal veins

A retinal vein occlusion (RVO) is a sight threatening disease. It can be divided into central vein occlusion and branch retinal vein occlusion. The pathogenesis of the condition remains to be solved. Mechanical compression of the vessel wall or thrombotic occlusion of the vessel lumen, sometimes combined with rheological disorders, are often assumed pathomechanisms. Accordingly, the therapy relies either on mechanical decompression, lyses of thrombi or improvement of rheology. A number of observations however, such as the relationship of RVO to atherosclerotic risk factors, spontaneous reversibility particularly in young patients, rest flow observed in angiography, occlusion despite anticoagulation or thrombocytopenia and finally the positive effect of anti-VEGF therapy are not explained by the present pathogenetic concept. As a new concept we propose a local venous constriction induced by vasoconstrictive molecules diffusing from neighbouring diseased arteries and/or from other neighbouring (hypoxic) tissues. Recognizing these postulated conditions might lead to an earlier identification of impending vein occlusions as well as to a treatment more tailored to the risk factor constellation of the particular patient.

Long-term study of vascular perfusion effects following arteriovenous sheathotomy for branch retinal vein occlusion

PURPOSE

To evaluate the perfusion effects and long-term visual outcome of pars plana vitrectomy (PPV) combined with arteriovenous sheathotomy (AVS) with or without triamcinolone for nonischaemic branch retinal vein occlusion (NI-BRVO).

METHODS

Prospective, interventional case series of eight patients with NI-BRVO and haemorrhagic macular oedema. Patients underwent PPV and AVS (n = 5), or PPV, AVS and intravitreal triamcinolone (IVT, n = 3). A masked grading technique assessed fundus photographs and fluorescein angiography (FFA) following surgery. Scanning laser ophthalmoscopy/optical coherence tomography (SLO/OCT) evaluated macular oedema and outer retinal architecture. Main outcomes examined included visual acuity (VA), retinal reperfusion, collateral vessel regression, vascular dilatation, cystoid macular oedema (CMO), and ocular neovascularization.

RESULTS

Seven of eight patients underwent uncomplicated surgery, with increased intraretinal perfusion and reduced engorgement of distal retinal veins. The mean pre-logMAR VA was 0.8 (SD 0.17) and did not improve significantly after surgery (post-logMAR 0.6, SD 0.38; p = 0.11, paired t-test). SLO/OCT showed persistent CMO in four patients, and subfoveal thinning of the photoreceptor layer. Collateral vessels disappeared at the blockage site post-AVS in 7/8 eyes, and this was associated with improved retinal perfusion. Six of eight patients developed epiretinal membrane. No patients developed ocular neovascularization. The average follow-up was 34.5 months.

CONCLUSIONS

PPV with AVS is a safe procedure, and adjunctive IVT had no additional effects on vascular perfusion. Successful decompressive surgery was followed by disappearance of collateral vessels at the BRVO blockage site and was a clinical marker for intravascular reperfusion. Long-term epiretinal gliosis and subfoveal photoreceptor atrophy limited functional and visual recovery.

A randomized trial comparing the efficacy and safety of intravitreal triamcinolone with standard care to treat vision loss associated with macular Edema secondary to branch retinal vein occlusion: the Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) study report 6

OBJECTIVE

To compare the efficacy and safety of 1-mg and 4-mg doses of preservative-free intravitreal triamcinolone with standard care (grid photocoagulation in eyes without dense macular hemorrhage and deferral of photocoagulation until hemorrhage clears in eyes with dense macular hemorrhage) for eyes with vision loss associated with macular edema secondary to branch retinal vein occlusion (BRVO).

METHODS

Multicenter, randomized clinical trial of 411 participants. Main Outcome Measure Gain in visual acuity letter score of 15 or more from baseline to month 12.

RESULTS

Twenty-nine percent, 26%, and 27% of participants achieved the primary outcome in the standard care, 1-mg, and 4-mg groups, respectively. None of the pairwise comparisons between the 3 groups was statistically significant at month 12. The rates of elevated intraocular pressure and cataract were similar for the standard care and 1-mg groups, but higher in the 4-mg group.

CONCLUSIONS

There was no difference identified in visual acuity at 12 months for the standard care group compared with the triamcinolone groups; however, rates of adverse events (particularly elevated intraocular pressure and cataract) were highest in the 4-mg group. Application to Clinical Practice Grid photocoagulation as applied in the SCORE Study remains the standard care for patients with vision loss associated with macular edema secondary to BRVO who have characteristics similar to participants in the SCORE-BRVO trial. Grid photocoagulation should remain the benchmark against which other treatments are compared in clinical trials for eyes with vision loss associated with macular edema secondary to BRVO. Trial Registration clinicaltrials.gov Identifier: NCT00105027.

Physiology of vitreous surgery

Vitreous surgery has various physiological and clinical consequences, both beneficial and harmful. Vitrectomy reduces the risk of retinal neovascularization, while increasing the risk of iris neovascularization, reduces macular edema and stimulates cataract formation. These clinical consequences may be understood with the help of classical laws of physics and physiology. The laws of Fick, Stokes-Einstein and Hagen-Poiseuille state that molecular transport by diffusion or convection is inversely related to the viscosity of the medium. When the vitreous gel is replaced with less viscous saline, the transport of all molecules, including oxygen and cytokines, is facilitated. Oxygen transport to ischemic retinal areas is improved, as is clearance of VEGF and other cytokines from these areas, thus reducing edema and neovascularization. At the same time, oxygen is transported faster down a concentration gradient from the anterior to the posterior segment, while VEGF moves in the opposite direction, making the anterior segment less oxygenated and with more VEGF, stimulating iris neovascularization. Silicone oil is the exception that proves the rule: it is more viscous than vitreous humour, re-establishes the transport barrier to oxygen and VEGF, and reduces the risk for iris neovascularization in the vitrectomized-lentectomized eye. Modern vitreous surgery involves a variety of treatment options in addition to vitrectomy itself, such as photocoagulation, anti-VEGF drugs, intravitreal steroids and release of vitreoretinal traction. A full understanding of these treatment modalities allows sensible combination of treatment options. Retinal photocoagulation has repeatedly been shown to improve retinal oxygenation, as does vitrectomy. Oxygen naturally reduces VEGF production and improves retinal hemodynamics. The VEGF-lowering effect of photocoagulation and vitrectomy can be augmented with anti-VEGF drugs and the permeability effect of VEGF reduced with corticosteroids. Starling's law explains vasogenic edema, which is controlled by osmotic and hydrostatic gradients between vessel and tissue. It explains the effect of VEGF-induced vascular permeability changes on plasma protein leakage and the osmotic gradient between vessel and tissue. At the same time, it takes into account hemodynamic changes that affect the hydrostatic gradient. This includes the influence of arterial blood pressure, and the effect oxygen (laser treatment) has in constricting retinal arterioles, increasing their resistance, and thus reducing the hydrostatic pressure in the microcirculation. Reduced capillary hydrostatic pressure and increased osmotic gradient reduce water fluxes from vessel to tissue and reduce edema. Finally, Newton's third law explains that vitreoretinal traction decreases hydrostatic tissue pressure in the retina, increases the pressure gradient between vessel and tissue, and stimulates water fluxes from vessel into tissue, leading to edema.

Long-term visual outcome of arteriovenous adventitial sheathotomy on branch retinal vein occlusion induced macular edema

Purpose

To evaluate long-term visual outcome of arteriovenous adventitial sheathotomy in BRVO-induced macular edema.

Methods

The visual outcomes of 8 patients following vitrectomy with arteriovenous adventitial sheathotomy for BVO-induced macular edema (surgery group) were retrospectively evaluated. The three year post-operative visual acuity of the surgery group was compared with that of the conservatively managed controls.

Results

All patients were followed for a minimum of 36 months. Mean BCVA (logMAR) in the surgery group changed from 1.10± 0.34 to 1.19±0.70 and to 0.80±0.36 at 12 and 36 months, respectively (p=0.959 at 12 months, p=0.018 at 36 months). In the control group, visual acuity improved from 1.15±0.43 to 0.43±0.44 and to 0.43±0.39 at 12 and 36 months, respectively (p=0.015 at 12 months, at p=0.003 at 36 months). A strong trend toward better visual acuity at 12 months and final examination was observed for controls. (surgery vs. control group, p=0.052 at 12 months, p=0.066 at 36 months).

Conclusions

Considering the favorable natural course of BVO and the unproven effect of reperfusion on macular edema, surgical efficacy of arteriovenous adventitial sheathotomy requires further evaluation.

Visual acuity and multifocal electroretinographic changes after arteriovenous crossing sheathotomy for macular edema associated with branch retinal vein occlusion

PURPOSE

To evaluate the influence of arteriovenous (AV) sheathotomy on retinal function with central multifocal electroretinography (mfERG) in eyes with macular edema secondary to branch retinal vein occlusion (BRVO).

METHODS

Fifteen patients (15 eyes) who underwent AV sheathotomy for macular edema secondary to BRVO were included in the study. Best-corrected visual acuity and mfERG responses from the most central seven hexagons were analyzed before and 6 months after the operation.

RESULTS

The mean preoperative Early Treatment Diabetic Retinopathy Study (ETDRS) score +/- SD was 34.1 +/- 12.7 letters (Snellen equivalent, 20/50) and significantly improved up to 40.5 +/- 10.9 letters (Snellen equivalent, 20/40) at 6 months after AV sheathotomy (P = 0.027, Wilcoxon signed rank test). The mean preoperative P1 amplitude +/- SD of the most central 7 hexagons was 39.30 +/- 10.86 nV/deg(2) for the affected eye versus 47.72 +/- 6.67 nV/deg(2) for the normal fellow (control) eye (P = 0.013, Mann-Whitney U test) and significantly increased up to 50.71 +/- 15.58 nV/deg at 6 months after the operation (P = 0.014, Wilcoxon signed rank test). Significant correlations between preoperative and postoperative ETDRS score and preoperative P1 amplitude were present (r = 0.929, P < 0.001; r = 0.768, P = 0.001; respectively [Spearman correlation]).

CONCLUSIONS

AV sheathotomy improved macular function and anatomical outcome as measured by ETDRS score and mfERG responses in patients with macular edema due to BRVO.

Arteriovenous crossing sheathotomy versus intravitreal triamcinolone acetonide injection for treatment of macular edema associated with branch retinal vein occlusion

PURPOSE

To compare the functional and anatomical outcomes of arteriovenous (AV) sheathotomy and intravitreal triamcinolone acetonide (IVTA) injection in the treatment of macular edema associated with branch retinal vein occlusion (BRVO).

METHODS

Forty eyes of 40 patients with macular edema secondary to BRVO were randomized into two treatment groups. A total of 20 patients received AV sheathotomy (sheathotomy group), and the second group of 20 patients was treated with IVTA (IVTA group). Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (VA) score, total macular volume measured, and foveal thickness by 3rd generation optical coherence tomography (OCT3) were evaluated as main outcome measurements.

RESULTS

The average changes in ETDRS scores, total macular volumes, and foveal thicknesses compared to baseline values, were significant 3 months and 6 months after treatment in both groups (P < 0.05, paired t-test), but only the IVTA group showed significant improvements 1 month after treatment. The between-group differences in average ETDRS score, total macular volume, and foveal thickness changes were significantly better at 1 month after treatment in the ITVA group (P = 0.026, P < 0.001, P = 0.001, respectively, Student's t-test), at which time IVTA patients had better vision and anatomical outcomes than did those in the sheathotomy group.

CONCLUSIONS

After either AV sheathotomy or IVTA treatment, patients with macular edema secondary to BRVO showed similar functional and anatomical outcomes 6 months later. When the cost and the risks of vitreoretinal surgery are considered, IVTA treatment may be a better treatment option, as the drug yields better short-term outcomes.

Use of intravitreal triamcinolone in the treatment of macular edema related to retinal vein occlusion

Objective:

To analyze the increasing trend of intravitreal triamcinolone (IVTA) use in the treatment of retinal vein occlusion-related macular edema.

Methods:

We performed MEDLINE/PUBMED searches (September 1984 - December 2007) to identify articles containing the keywords macular edema and triamcinolone. Case reports, reviews and abstracts were identified from references in the reviewed literature. This review focuses on literature published during the past 7 years with more than two-thirds of the articles that we reviewed being printed during the past 5 years. These reports analyzed the success of IVTA in the treatment of macular edema over a 12 month course of time.

Results:

The majority of studies suggested promising results for short time periods (4-6 months) after IVTA treatments. However, long term results were not encouraging.

Conclusions:

The success of IVTA therapy for short durations has been the impetus for development of sustained release devices to be used in the treatment of macular edema associated with various retinal diseases including edema related to retinal vein occlusion.