Grid Laser Research Articles

Resolution of refractory macular edema because of branch retinal vein occlusion after ozurdex implantation.

To report a case of a woman with a branch vein occlusion and macular edema refractory to grid laser, intravitreal bevacizumab, pars plana vitrectomy with sheathotomy of the arteriovenous branch site, and intravitreal triamcinolone, who had complete resolution of fluid after injection of a dexamethasone intravitreal implant (DEX implant, Ozurdex; Allergan, Inc, Irvine, CA). A 75-year-old woman with a branch vein occlusion and macular edema was treated with grid laser, intravitreal bevacizumab, pars plana vitrectomy with sheathotomy, and intravitreal triamcinolone. Neither edema nor vision improved. She was treated with an Ozurdex intravitreal implant. One month after Ozurdex intravitreal implantation, the patient's visual acuity and edema had improved dramatically. The macula remained flat until 5 months after injection when the edema returned and a second Ozurdex was injected. One month later, the macular edema was significantly less and visual acuity had improved to 20/50 with pinhole. Ozurdex may be effective in reducing macular edema because of a branch retinal vein occlusion in eyes refractory to multiple other treatments.

Combined Intravitreal Bevacizumab and Grid Laser Photocoagulation for Macular Edema Secondary to Branch Retinal Vein Occlusion

To evaluate long-term efficacy of intravitreal bevacizumab (IVB) versus combined IVB and macular grid laser photocoagulation for the treatment of macular edema secondary to branch retinal vein occlusion (BRVO). In this prospective study, 18 eyes were randomized into 2 groups according to treatment: Group 1 (9 eyes) underwent IVB at baseline, at month 1, and at month 2; Group 2 (9 eyes) underwent same IVB protocol combined with macular grid laser photocoagulation. Macular edema and visual acuity represented the endpoints of the study. IVB reinjections were performed in both groups if recurrent macular edema was diagnosed. Spectral domain optical coherence tomography examination as well as visual acuity examination were performed during follow-up. Statistical evaluation was performed for a matched-pair analysis. In Group 1, median baseline central retinal thickness (CRT) decreased from 420 µm (95% confidence interval 355.6-484.4) to 323 µm (261.44-384.56) at month 12 (p=0.06); median baseline BCVA improved from 0.7 logMAR (0.54-0.86) to 0.4 logMAR (0.29-0.51) at month 12 (p<0.01). In Group 2, baseline CRT decreased from 386 µm (353.91-418.09) to 238 µm (200.58-275.42) at month 12 (p<0.01); median BCVA improved from 0.6 logMAR (0.45-0.75) to 0.2 logMAR (0.12-0.28) at month 12 (p<0.01). A statistically significant difference (p=0.03) was found regarding the median number of injections (Group 1: 4±1.1; Group 2: 3±0.4). Both treatment modalities appeared effective to control BRVO-induced macular edema. In the combined-treatment Group, we observed a lower number of reinjections during follow-up, suggesting the efficacy of grid laser photocoagulation to reduce the number of intravitreal injections and maintain short- and long-term results of the therapy.

Intravitreal injection of bevacizumab combined with macular grid laser photocoagulation for macular edema in branch retinal vein occlusion

To evaluate the effects of combined therapy of intravitreal injections of bevacizumab (IVB) and additional macular grid laser photocoagulation for recurrent macular edema in branch retinal vein occlusion (BRVO). This was a retrospective interventional case series in which 44 eyes of 44 patients with macular edema due to BRVO were studied. The mean follow-up term was 77.2 ± 12.4 weeks. All patients underwent IVB as a primary therapy. After two to three IVB, 19 of the 44 eyes (43.2%) underwent laser photocoagulation in the macular edema area to prevent the recurrence of the edema. In the other 25 eyes (56.8%), macular edema was successfully treated with IVB only. Visual acuity and central macular thickness (CMT) were examined during the follow-up. The mean visual acuity and the mean CMT in both groups improved significantly after the IVB. Following macular grid laser photocoagulation for recurrent macular edema, the mean visual acuity was maintained for 24 weeks, however, the mean CMT increased significantly after 12 weeks. Additional grid laser photocoagulation for recurrent macular edema in BRVO after IVB maintained mean visual acuity with limited effects on the further recurrence of macular edema.

Comparison of Grid Laser, Intravitreal Triamcinolone, and Intravitreal Bevacizumab in the Treatment of Diffuse Diabetic Macular Edema

Purpose: To compare the effects of grid laser (GL), intravitreal bevacizumab (IVB), and intravitreal triamcinolone acetonide (IVTA) in diffuse diabetic macular edema (DDME). Procedures: One hundred and twenty-six patients (126 eyes) treated with GL (modified grid), IVTA (4 mg), and IVB (1.25 mg) injections, matched for best corrected visual acuity (BCVA) and OCT-based central macular thickness at presentation, were enrolled. Primary outcome measure was change in best corrected logMAR visual acuity at 1-year follow-up. Results: Rates of visual stabilization (within ±0.2 logMAR of baseline BCVA) (71.4, 83.3, 78.6%, respectively) were not different between the groups (p = 0.41) at 12-month follow-up. Higher rates of anatomical and functional success, however, were evident in IVB and IVTA groups within 6 months of treatment (p < 0.05 for both). No severe adverse effects except higher intraocular pressure (10 mm Hg from baseline) in one third (14 eyes) of the IVTA cases, who required trabeculectomy in 2 (4.8%) eyes, were observed. Conclusions: Intraocular injections may give favorable results within the first 6 months, and after 6 months, GL results seem to be more favorable in the treatment of treatment-naïve, acute, nonischemic, and center-involving DDME.

Treatment of macular edema in vein occlusion

AbstractPurpose Recent multicenter trials provided us with interesting results of macular edema linked to vein occlusion. Until now, the standard of care treatment of macular edema due to branch vein occlusion remained grid laser in contrast with central vein occlusion where the absence of treatment was still recommended. ,Methods SCORE, GENEVA, BRAVO and CRUISE studies recently provided us with the following results: SCORE study found triamcinolone to be interesting to treat macular edema due to central vein occlusion but not from branch occlusion. GENEVA study assessed the effect of a delivery system of dexamethasone to treat macular edema due to venous occlusion whatever the clinical form with an improvement of visual acuity. CRUISE and BRAVO studies assessed the effect of ranubizumab which was found to improve the visual acuity of macular edema due to either central or branch vein occlusions. GALLILEO and COPERNICUS reported recent results with another antiangiogenic agents with interesting results but still unpublished.Results At this stage, to treat macula edema in vein occlusion, we have to consider the characteristics of the patients to decide which treatment should be used: lens status, increased ocular pressure, delay before treatment of the disease, clinical form of vein occlusion as well as the predictable acceptance of repeated injections by the patients.Conclusion There is an urgent need for comparative studies but these studies should consider separately branch and central vein occlusions. Commercial interest

Retinal Vein Occlusion

AbstractMacular edema is a major complication of both ischemic and non ischemic Retinal vein occlusions (RVO). Fluorescein angiography (FA) is the most effective method to determine the presence of macular cystoid edema (CME), its extension, persistence, regression, the degree of ischemia (perfused or non‐perfused RVO). Spectral domain OCT (SD‐OCT) helps to quantify the changes in retinal thickness, the amount of CME, the presence of sub retinal fluid accumulation and precise analysis of the outer retinal layers, useful as a guide for treatment. According to the recent results of the SCORE Trial, Grid Laser photocoagulation remains the reference treatment for macular edema due to branch retinal vein occlusion (BRVO) but not recommended in Central RVO Recent prospective randomized trials strongly suggest an anti‐edematous effect of intravitreal steroids (particularly dexamethasone in a slow release device) and intravitreal anti‐VEGF drugs, that may at least temporarily reduce foveal edema and improve visual function. Surgical treatment modalities have been reported for RVOs with a positive action of vitrectomy; the combination with intravitreal steroids and/or tissue plasminogen activator could permit a more rapid and lasting action. Taking into consideration the recent advances in diagnostic tools and management options, recent European practical recommendations and Guidelines, prepared by a collaborative group of retina specialists, are presented to provide the ophthalmologists with guidelines for the clinical approach of RVO.

Intravitreal Bevacizumab Associated with Grid Laser Photocoagulation in Macular Edema Secondary to Branch Retinal Vein Occlusion

To evaluate intravitreal bevacizumab (IVB) combined with grid laser photocoagulation in macular edema (ME) secondary to branch retinal vein occlusion (BRVO). Eight eyes (8 patients) with ME associated with BRVO with at least 3 months of evolution since symptom onset were included. All subjects underwent measurement of best-corrected visual acuity (BCVA) and imaging with spectral domain optical coherence tomography (SD-OCT) at baseline and 1, 3, 6, and 12 months. Intravitreal bevacizumab was administered at baseline and macular grid laser photocoagulation 1 month later. During follow-up, additional IVB was administered based on physician discretion if persistent or recurrent intraretinal fluid (cysts) was observed on SD-OCT. The mean BCVA and SD-OCT central subfield thickness (CST) values were determined at each time point. Fisher exact test was performed to assess differences between baseline and post-treatment BCVA and SD-OCT measurements. The mean baseline BCVA was 0.28±0.14 (mean±SD), and the mean CST was 479±137 µm. The mean BCVAs at 1, 3, 6, and 12 months were 0.47±0.18 (p=0.031), 0.56±0.50 (p=0.031), 0.65±0.60 (p=0.008), and 0.66±0.65 (p=0.016), respectively. The mean CST values at 1, 3, 6, and 12 months were 295±60 µm (p=0.008), 333±114 µm (p=0.070), 339±80 µm (p=0.008), and 335±109 µm (p=0.008). A mean 2.13 injections were administered; the second injection was administered a mean of 2.71 months after baseline. Combined treatment with IVB and macular grid photocoagulation provided good results and may be considered as an alternative therapy for ME in BRVO. Further studies are needed to assess these preliminary results.

Innovations thérapeutiques dans les pathologies vasculaires et néovasculaires hors DMLA

Recent multicenter randomized studies about persistent macular edema in venous occlusions provided us with interesting results. Until now, the standard of care treatment of macular edema due to branch vein occlusion remained grid laser in contrast with central vein occlusion where the absence of treatment was still recommended. Score, Geneva, Bravo and Cruise studies recently provided us with the following results. Score study found triamcinolone to be interesting to treat macular edema due to central vein occlusion but not from branch occlusion. Geneva study assessed the effect of a delivery system of dexamethasone to treat macular edema due to venous occlusion whatever the clinical form with an improvement of visual acuity. Cruise and Bravo studies assessed the effect of ranubizumab, which was found to improve the visual acuity of macular edema due to either central or branch vein occlusions. At this stage we need comparative studies to precise the indication of these different approaches that remain perhaps complementary of laser treatment.

Microstructural changes following inadvertent multi-spot laser photocoagulation of the fovea

Dear Editor, Laser photocoagulation of the fovea is historically an accidental and sight-threatening complication rarely reported during routine treatment [1]. We present a case of inadvertent foveal laser photocoagulation during multi-spot Pascal macular grid laser. A 66-year-old woman presented with left branch retinal vein occlusion and non-resolving cystoid macular oedema (Fig. 1), and underwent macular laser treatment. Vision was 6/18, with an artificial fellow eye. The patient was comfortable during initial laser titration stages, using single-spot 10ms 100μm burns, (power 125mW;fluence 16 Joules/cm). Modified Pascal grid laser involved multispot arrays applied to the macula. During delivery of the first multi-spot array, the patient’s head moved suddenly away from the slit-lamp due to anxiety from the light flashes produced. Laser burns were inadvertently scattered across the foveal zone (Fig.1). Immediately postlaser, vision was 6/19. Routine fundus autofluorescence (AF) and OCT identified misdirected parafoveal burns, with a single burn overlying the anatomical fovea (Fig. 2). At day 3, vision was stable despite increased central retinal thickness (Fig. 1). Burns showed initial hyper-autofluorescence on serial AF, and the intraretinal hyper-reflectivity slowly resolved (Fig. 2) [2]. At 6 months, the anatomical foveal burn showed restoration of the inner and outer segment junction of the photoreceptors (Fig. 2). Vision was 6/9 and with barely-visible foveal burns (Fig. 1). Retrospective review of our laser logbook documented 3,932 Pascal laser procedures between 11 December 2006 and April 1 2011. Institutional Pascal auditing has not reported any operational or laser-related adverse events [3]. The prevalence of inadvertent foveal photocoagulation complication following Pascal is 0.025% (1/3,932) in our institution. The Pascal photocoagulator has safety mechanisms in place [4]. The inner row of Pascal spots is delivered in 132ms, theoretically below patients’ reaction time. Lowfluence 10–30ms pulse duration Pascal can minimize scarring [2, 5]. The foveal 10ms burns healed over time, with photoreceptor infilling and minimal retinal pigment epithelium damage [6]. After this case, we routinely advise patients pre-laser application about multi-spot Pascal light flashes. In borderline cases, single-spot laser strategies are recommended. Despite a potentially sight-threatening adverse event such as foveal photocoagulation, a pattern-spot laser system application of low fluence 10ms burns may not lead to long-term microstructural alterations on FD-OCT or visual complications. Funding support None

Template matching for improved accuracy in molecular tagging velocimetry

In 2D molecular tagging velocimetry (MTV), tags are written into a fluid flow with a laser grid and imaged at discrete times. These images are analyzed to calculate Lagrangian displacement vectors, often by direct cross correlation. The cross correlation method is inherited from particle imaging velocimetry, where the correlated images contain a random pattern of particles. A template matching method is presented here which takes advantage of the known geometry of laser written tag grids in MTV to achieve better accuracy. Grid intersections are explicitly located in each image by correlation with a template with several linear and rotational degrees of freedom. The template is a continuous mathematical function, so the correlation may be optimized at arbitrary sub-pixel resolution. The template is smooth at the spatial scale of the image noise, so random error is substantially suppressed. Under typical experimental conditions at low imaging resolution, displacement uncertainty is reduced by a factor of 5 compared to the direct cross correlation method. Due to the rotational degrees of freedom, displacement uncertainty is insensitive to highly deformed grids, thus permitting longer delay times and increasing the relative accuracy and dynamic range of the measurement. In addition, measured rotational displacements yield velocity gradients which improve the fidelity of interpolated velocity maps.

Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation.

To assess the quantitative and morphological changes of the macula in response to macular grid laser for diabetic macular oedema (DMO) using optical coherence tomography (OCT). Cirrus OCT macular cube scans of 30 eyes of 25 patients were retrospectively analysed before and 4 months after macular grid laser for diffuse DMO. The oedema was quantified and response evaluated in the nine early-treatment diabetic retinopathy study (ETDRS) zones of the macula. Post-laser OCT changes were compared with the baseline features, including morphology patterns, changes in both logarithmic transformed (logOCT) and standardised average macular thickness (AMT), total macular volume, number of parafoveal quadrants involved, and the presence of intact 3rd hyper-reflective band (HRB). The rate of change of retinal thickness in response to laser was maximum in the central (8.17%) and perifoveal inferior quadrants (0.04%). Diffuse retinal thickening on OCT responded best to treatment. The AMT of 300-350 μm had the worst response (+0.94%). Eyes with less than four quadrants of oedema showed good response. Disrupted HRB was associated with poor visual gain (-0.33 ETDRS letters). The topographic location of oedema on the retinal map and the morphological patterns of the oedema on OCT are useful predictors of treatment response in diffuse DMO.

Comparative Evaluation of Pan Anti-VEGF with Selective Anti-VEGF with Laser for Diabetic Macular Edema in Indian Eyes: A Randomized Prospective Study

Background: To evaluate intravitreal 0.5 mg ranibizumab plus laser with 0.3 mg pegaptanib plus laser with focal/ grid laser alone for treatment of diabetic macular edema (DME) Methods: A total of 45 study eyes with DME involving the fovea and visual acuity (VA) of 20/32 or worse were randomized into three groups, ranibizumab 0.5 mg + prompt laser (Group 1), pegaptanib sodium 0.3 mg + prompt laser (Group 2) and laser alone (Group 3) with 15 eyes in each study arm. Retreatment was based on optical coherence tomography measurements and VA changes. Results: The mean VA change (± standard deviation) at 1 year in Groups 1, 2 and 3 were 10.4±2.1, 7.6±2.3 and 2±2.7 letters (p<0.001) respectively on a standardized ETDRS chart. There was no significant difference between the VA gain between Group 1 and 2 at 1 year (p=0.189) however significant difference existed between Groups 1 and 2 when compared to Group 3 (p=0.0001). Conclusions: Ranibizumab and Pegaptanib with prompt focal/grid laser proved to be more effective than prompt focal/grid laser alone in treatment of center involved DME. There was no statistical difference in the visual gain achieved in the two intravitreal groups.

Long-term effect of early intervention with single intravitreal injection of bevacizumab followed by panretinal and macular grid photocoagulation in central retinal vein occlusion (CRVO) with macular edema: A pilot study

To evaluate the effect of single-dose intravitreal bevacizumab followed by panretinal and macular grid laser, early in the course of central retinal vein occlusion (CRVO). It is a prospective, non-randomized, interventional study of nine eyes of nine patients with <10 days origin of CRVO who received 2.5 mg (0.1 ml) intravitreal bevacizumab, followed 3 weeks later by panretinal and macular grid photocoagulation. Its effect on visual acuity and anatomical features of CRVO were studied. Nine eyes of nine patients (male : female = 8 : 1, mean age 54 years), with <10 days (average 2.67 days) onset of CRVO, received intravitreal bevacizumab within 7 days of presentation (average 3.1 days) followed 3 weeks later by panretinal with macular grid laser. Presenting mean baseline visual acuity was 20/320 (1.2 logarithm of the minimum angle of resolution (LOGMAR) units). All the patients showed rapid improvement in the form of rapid clearance of retinal hemorrhages, decreased optic disc swelling and venous dilation, and tortuosity. Mean final visual acuity was 20/63 (0.5 LOGMAR units). No patient showed conversion from non-ischemic to ischaemic CRVO, recurrence of macular edema, and disc collateral formation. Early intravitreal bevacizumab followed by panretinal and macular grid laser may provide visually and anatomically favourable results in a case of CRVO. It may also obviate the need for repeated injection. It requires a large randomized study to substantiate the results.

Intravitreal bevacizumab for macular edema due to branch retinal vein occlusion: 12-month results

Purpose:To present the functional and anatomic changes after intravitreal bevacizumab in eyes with macular edema (ME) due to branch retinal vein occlusion (BRVO).Design:The study was a retrospective study.Materials and methods:The study included 31 patients with ME due to BRVO. We compared the examination findings of patients with ME before and after intravitreal bevacizumab therapy at 12 months. The study included patients who had macular edema secondary to BRVO treated with bevacizumab. The therapy was started in the first week after occlusion. The initial therapy was three intravitreal bevacizumab injections at monthly intervals with 1.25/0.05 mL bevacizumab. Patients with a baseline visual acuity less than 0.5 (logarithm of the minimum angle of resolution [logMAR] 0.30), central macular thickness (CMT) more than 290 μm, and no neovascularization were included. Patients with diabetes mellitus or a history of intravitreal triamcinolone or grid laser photocoagulation therapy or ischemic BRVO were excluded. The retreatment criteria were as follows: increased CMT more than 100 μm combined with a loss of visual acuity of five or more letters. The statistical analysis of this study was carried out by paired samples t-test (SPSS). A P value of less than 0.05 was considered to be statistically significant.Results:This retrospective study included 33 eyes of 31 patients (20 women, 11 men; mean age was 55.30 ± 9.62 years (range 36–75 years). Patients received a mean of 5.3 injections during 12 months of follow-up. The best corrected visual acuity increased from 0.66 ± 0.20 (logMAR) at baseline to 0.22 ± 0.13 (logMAR) (t = 15.42; P < 0.001) at month 12. The CMT decreased from 494.15 ± 104.16 μm at baseline to 261.79 ± 45.36 μm at month 12 (− 232.36 ± 109.98 μm); P < 0.001). No bevacizumab-related systemic or ocular adverse effects following intravitreal drug injections were observed. The majority of patients required reinjection(s) treatment for ME (84.9%).Conclusion:Intravitreal therapy using bevacizumab appears to be an effective primary treatment option for ME due to BRVO. No serious ophthalmologic or systemic side effects were observed for intravitreal bevacizumab therapy. The main disadvantage of bevacizumab therapy is the requirement of multiple injections in order to maintain visual and anatomic improvements.

Treatment of macular edema due to retinal vein occlusions

Retinal vein occlusion (RVO) is a prevalent retinal vascular disease, second only to diabetic retinopathy. Previously there was no treatment for central retinal vein occlusion (CRVO) and patients were simply observed for the development of severe complications, generally resulting in poor visual outcomes. The only treatment for branch vein occlusion (BRVO) was grid laser photocoagulation, which reduces edema very slowly and provides benefit in some, but not all patients. Within the past year, clinical trials have demonstrated the effects of three new pharmacologic treatments, ranibizumab, triamcinolone acetonide, and dexamethasone implants. The benefit/risk ratio is best for intraocular injections of ranibizumab, making this first-line therapy for most patients with CRVO or BRVO, while intraocular steroids are likely to play adjunctive roles. Standard care for patients with RVO has changed and will continue to evolve as results with other new agents are revealed.

Grid photocoagulation combined with intravitreal bevacizumab for recurrent macular edema associated with retinal vein occlusion

Purpose:To report the efficacy of grid photocoagulation combined with intravitreal bevacizumab (IVB) for macular edema recurring after previous IVBs associated with retinal vein occlusion (RVO).Methods:This retrospective study consisted of 19 eyes with branch retinal vein occlusion (BRVO) and nine eyes with central retinal vein occlusion (CRVO), which were treated with grid photocoagulation combined with IVB for recurrent macular edema after previous IVBs. The mean duration of total follow-up was 29.3 ± 5.8 months.Results:After this combination therapy, foveal thickness was reduced, significant with slight improvement in visual acuity (VA). At 1 month after treatment, although 25 of the 28 eyes showed complete resolution of the cystoid space, the macular edema recurred to some extent in 19 eyes. Compared with initial values, final foveal thickness was reduced significantly in both BRVO and CRVO groups (P < 0.001), but improvement in VA was significant only for eyes with BRVO (P = 0.012). The total number of IVB was 2.8 ± 0.7 for eyes with either BRVO or CRVO.Conclusion:Grid photocoagulation combined with IVB has a substantial effect on reducing recurrent macular edema associated with RVO, but the effect on visual acuity is limited.

Anti-VEGF (vascular endothelial growth factor) drugs in diabetic macular oedema

Sir, I read the article by Forte et al1 with interest. I congratulate the authors for evaluating different treatment options in diabetic macular oedema (DME). I would like to comment about the treatment of DME with intravitreal bevacizumab (IVB) alone. The half-life of IVB in the vitreous cavity of a rabbit eye has been shown to be 4.32 days.2 Most in-vivo studies have shown that IVB either plateaus or decreases macular thickness in most eyes between 3–6 weeks. This demands a need for repeat injections. According to Parravano et al,3 multiple studies have shown only short-term benefit of anti-VEGF (vascular endothelial growth factor) drugs as compared with present treatment modalities. There is no sufficient high-quality evidence from large randomized controlled trials supporting the use of either single or multiple anti-VEGF intravitreal injections to treat DME. The systemic safety of IVB is not yet established. Bevacizumab has the potential to inhibit the important physiological functions of VEGF, such as wound healing and development of collaterals deemed significant in myocardial or peripheral ischaemia, thus potentially causing systemic adverse events.4 Regarding intravitreal steroid as an adjunct has also shown a temporary effect on macular oedema, with no long-term benefit on visual acuity, but being associated with side effects. The studies have not shown any additional benefit of intravitreal steroid over laser photocoagulation.5 In conclusion, anti-VEGF or steroid can be used in gross macular oedema as an adjunct for short-term benefit, to reduce the macular thickness, followed by focal or grid laser to give a sustained response. Macular laser photocoagulation is still the gold-standard treatment. Multi-centre controlled trials are needed to compare IVB alone and in combination with laser photocoagulation in DME, to assess the long-term benefit and safety, the number of injections needed for maintenance of the effect, and the associated risk.

Management of macular edema secondary to branch retinal vein occlusion: an evidence-based update

Retinal vein occlusions are common retinal vascular disorders with the potential for significant vision-related morbidity. Retinal vein occlusions are classified as either branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), or hemiretinal vein occlusion (HRVO) based on the specific occlusion site. The most common cause of decreased vision in patients afflicted with BRVO is the accumulation of fluid within the macula (macular edema). The Branch Vein Occlusion Study (BVOS) demonstrated the efficacy of grid laser photocoagulation in the treatment of BRVO-related macular edema. After publication of that report, grid laser became the standard of care for decreased vision due to BRVO-associated macular edema in patients similar to those enrolled in the BVOS. However, several recent major randomized, controlled clinical trials have investigated new therapeutic modalities for the treatment of decreased vision due to macular edema secondary to BRVO. This article aims to provide insight into current evidence-based approaches to management of macular edema secondary to BRVO. A companion article reviews approaches for management of macular edema secondary to CRVO.

Management of macular edema secondary to central retinal vein occlusion: an evidence-based

Retinal vein occlusions are common retinal vascular disorders with the potential for significant vision-related morbidity. Retinal vein occlusions are classified as either branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), or hemiretinal vein occlusion (HRVO) based on the specific occlusion site. Decreased vision in patients afflicted with CRVO may result from retinal ischemia and/or the accumulation of fluid within the center of the retina (macular edema). The Central Vein Occlusion Study (CVOS) Group demonstrated that grid laser photocoagulation is not an effective treatment for decreased vision due to CRVO-related macular edema. Since publication of that report, the standard of care for patients with decreased vision due to CRVO-associated macular edema was observation. However, in the past 5 years, several major randomized controlled clinical trials have investigated new therapeutic modalities for the treatment of macular edema secondary to CRVO. This article aims to provide insight into current evidence-based approaches to the management of macular edema secondary to CRVO. A companion article reviews approaches for the management of macular edema secondary to BRVO.

Steroids and Macular Edema from Retinal Vein Occlusion

The possibility of applying long-lasting steroids, such as triamcinolone and subsequently dexamethasone implant, directly in the eye, without the systemic side effects observed after their oral or intravenous administration, aroused great enthusiasm among ophthalmologists. The SCORE study, a multicenter clinical trial, compared the efficacy and safety of 1-mg and 4-mg doses of preservative-free intravitreal triamcinolone with observation in central retinal vein occlusion (CRVO) participants with macular edema secondary to perfused CRVO. This study marked a turning point in the management of retinal vein occlusion (RVO), since it was the first report on an effective treatment of macular edema due to CRVO. But in branch retinal vein occlusion (BRVO), the SCORE study showed no difference in visual acuity for the standard care group compared with the triamcinolone groups; however, the rates of adverse events (particularly elevated intraocular pressure and cataract) were highest in the 4-mg group. The authors concluded that laser grid photocoagulation should remain the benchmark against which other treatments should be compared. The Geneva Study, a randomized, controlled, clinical trial, conducted to evaluate the safety and efficacy of an intravitreal implant that delivers sustained levels of dexamethasone (Ozurdex™), studied the largest group of RVO patients with macular edema (1267 patients), including 35% CRVO and 65% BRVO. The study demonstrated that this slow-release device could both reduce the risk of vision loss and improve the speed and incidence of visual improvement in eyes with macular edema secondary to CRVO and BRVO, with fewer side effects, such as elevation of intraocular pressure or cataract. Other ongoing studies evaluate the safety and efficacy of anti-vascular endothelial growth factor injection; preliminary results showed that these therapies are effective in decreasing macular edema and improving visual acuity, with fewer ocular adverse effects, but their duration of action seems limited. These recent studies result in a great change in the management of macular edema from RVO. Unfortunately, long-term studies on safety and efficacy are not yet available, and further studies will have to show whether the short-term benefits are only transient or may finally lead to a long-lasting improvement in vision.