Multiple laser treatments for macular edema attributable to branch retinal vein occlusion

Thermo-responsive hydrogel as an anti-VEGF drug delivery system to inhibit retinal angiogenesis in Rex rabbits

BACKGROUND

Wet age-related macular degeneration (Wet AMD) has been treated clinically by intravitreal injection of bevacizumab, which is a kind of the anti-VEGF antibody drug. Nevertheless, because of the short half-life and frequent injections, the use of this treatment is limited.

OBJECTIVE

To confirm whether mPEG-PLGA-BOX can be considered as a VEGF drug delivery system to inhibit retinal angiogenesis.

METHODS

A thermo-responsive hydrogel of methoxy-poly (ethylene glycol)-block-poly (lactic-co-glycolic acid) (mPEG-PLGA-BOX) was synthesized. The thermo-responsive hydrogel mPEG-PLGA-BOX was able to have sol-gel phase transition upon stimulation by the body temperature with improved biocompatibility and biodegradation. The bevacizumab released from mPEG-PLGA-BOX inhibited RF/6A cells according to a JC-1 assay, which indicated that the released bevacizumab was active to be able to suppress the growth of new blood vessels. In an animal study, retinal laser photocoagulation was performed to induce angiogenesis in the eyes of Rex rabbits using an 810-mm laser.

RESULTS

The retina was penetrated when the laser power was more than 500 mW and the exposure time was more than 500 ms. New blood vessels were created at the 28th day after retinal laser photocoagulation. At this time, intravitreal 0.05-mL injections of mPEG-PLGA-BOX (bevacizumab) solution were administered. The bevacizumab released from mPEG-PLGA-BOX (bevacizumab) solution suppressed the angiogenesis. In an in vivo study, the histomorphology of the rabbit retina also indicated that mPEG-PLGA-BOX after intravitreal injection is not toxic to the rabbit retina.

CONCLUSIONS

Bevacizumab released from mPEG-PLGA-BOX (bevacizumab) solution suppressed angiogenesis, and mPEG-PLGA-BOX can be considered as a novel thermo-responsive hydrogel with potential as a gelling carrier for extended bevacizumab drug release to treat intraocular neovascular diseases.

Evaluation of hyperreflective foci as a prognostic factor of visual outcome in retinal vein occlusion

AIM

To evaluate the potential role of hyperreflective foci (HF) as a prognostic indicator of visual outcome in patients with macular edema (ME) due to retinal vein occlusion (RVO).

METHODS

We retrospectively reviewed 50 eyes of 50 patients with ME due to ischemic central retinal vein occlusion (CRVO), non-ischemic CRVO and branch retinal vein occlusion (BRVO) who were treated with anti-vascular endothelial growth factor (anti-VEGF) at Beijing Tongren Eye Center from January 2013 to July 2016. All patients underwent best-corrected visual acuity (BCVA), spectral domain optical coherence tomography (SD-OCT) at baseline and follow-up. Such factors were evaluated and compared among three groups as baseline and final BCVA, central retinal thickness (CRT), external limiting membrane (ELM) status and the numbers of HF in different position. Multiple linear regression analysis was employed to analyze the relationship between baseline HF and final BCVA. Changes of HF before and after treatment were evaluated too.

RESULTS

Among three groups, HF could be located in each retinal layers, as well as in vitreous cavity. The mean HF in outer retinal layer (ORL) at baseline was 5.29±8.48 in ischemic CRVO with intact ELM, 1.93±2.76 in non-ischemic CRVO, and 1.75±2.05 in BRVO. With disrupted ELM, the mean HF in ORL increased. There was statistically difference of HF in ORL between intact and disrupted ELM. The numbers of HF in ORL were associated with poor visual outcome among three groups. However, HF in inner retinal layer (IRL) and vitreous cavity were not associated with poor visual outcome. Meanwhile, the baseline HF in ORL and vitreous cavity reduced significantly in non-ischemic CRVO and BRVO after anti-VEGF treatment.

CONCLUSION

The numbers of HF in ORL are prognostic factors associated with the final BCVA in patients with ME due to RVO after anti-VEGF treatment.

Highly reflective line in optical coherence tomography images of eyes with macular edema associated with branch retinal vein occlusion

PURPOSE

To determine whether the highly reflective vertical lines seen in spectral-domain optical coherence tomographic (SD OCT) images, which we have termed track lines, after resolution of macular edema associated with branch retinal vein occlusion are related to the integrity of the photoreceptors.

DESIGN

Retrospective, observational, cross-sectional study.

METHODS

We reviewed the medical records of 59 eyes with resolved macular edema associated with branch retinal vein occlusion. The eyes were classified by the presence or absence of the track lines in the SD OCT images after the resolution of macular edema. The correlation between the presence of the track lines and the integrity of the photoreceptors was determined.

RESULTS

Twenty-one of 59 (36%) eyes had track lines in the SD OCT images after a resolution of the macular edema during the follow-up period. At the final visit, 17 (81%) of 21 eyes with the track lines had an interrupted ellipsoid zone at the fovea, whereas 3 eyes (14%) had an intact ellipsoid zone and 1 eye (5%) had an absent ellipsoid zone (P < .0001). The percentage of eyes with a disrupted external limiting membrane at the initial visit was significantly higher in eyes with track lines (90%) than that in eyes without track lines (63%; P = .0324).

CONCLUSIONS

The presence of highly reflective vertical lines in the SD OCT image is associated with a disrupted external limiting membrane before the resolution of macular edema and is associated with an interruption of the ellipsoid zone after resolution of macular edema. Thus, the vertical lines are useful markers of damage to the photoreceptors.

Ranibizumab for Branch Retinal Vein Occlusion Associated Macular Edema Study (RABAMES): six-month results of a prospective randomized clinical trial

PURPOSE

To compare standard-of-care grid laser photocoagulation versus intravitreal ranibizumab (IVR) versus a combination of both in the treatment of chronic (>3 months) macular oedema secondary to branch retinal vein occlusion.

METHODS

Prospective, randomized, multicentre clinical trial. Thirty patients with a best-corrected visual acuity (BCVA) between 20/320 and 20/40 were randomized 1:1:1 to receive grid laser or three monthly injections of 0.5 mg IVR or both followed by 3 months of observation.

RESULTS

Mean change from baseline BCVA at month 6 was +2 letters [laser; 0.04 logMAR, 95% confidence interval (-0.17; 0.25)], +17 letters [IVR; 0.34 (0.19; 0.5)] and +6 letters [combination; 0.12 (0.01; 0.24)] (IVR versus laser p = 0.02 and IVR versus combination p = 0.02). At month 3, mean improvement in central retinal thickness (CRT) was 90.6 μm (laser) (-18.65; 199.8), 379.5 μm (IVR) (204.2; -554.8), and 248 μm (167.2; -328.8) (combination) (IVR versus laser p = 0.005, laser versus combination p = 0.02). During the observation period, CRT improved in laser [37.6 μm (-66.82; 142.0)], but deteriorated in IVR [-142.4 μm (-247.6; -37.16)] and combination [-171.7 μm (-250.4; -92.96)] (laser versus IVR p = 0.01, laser versus combination p = 0.002) indicating recurrent oedema. Less laser retreatments (at 8 weeks) were required in combination group (2/10) than grid group (7/10).

CONCLUSION

Six-month results suggest that ranibizumab may be superior to grid laser in improving visual acuity. Grid combined with IVR neither enhanced functional and morphological improvement of IVR nor did it prevent or prolong recurrence of oedema. In IVR groups, CRT increased slowly after stopping injections, whereas improvement in visual acuity was sustained, indicating that morphological changes occur prior to functional impairment.

Diameters and wall-to-lumen ratio of retinal arterioles in patients with retinal vein occlusion before and after treatment with dexamethasone intravitreal implants

BACKGROUND

To evaluate the diameters and wall-to-lumen ratio (WLR) of retinal arterioles in patients with retinal vein occlusion (RVO) before and after a 0.7 mg dexamethasone (DEX) intravitreal implant and compare it with a matched control group of normal eyes.

METHODS

This was a single-site, multi-investigator, prospective, open-label, observational study in 15 patients with vision loss due to branch or central RVO treated with a single injection of DEX implant. An age-matched control group of 16 normal eyes was recruited. External and internal arteriolar diameters, WLR, and wall thickness were assessed in vivo using scanning-laser Doppler flowmetry. Visual acuity (VA) and central macular thickness (CMT) were evaluated.

RESULTS

Mean internal diameter showed a significant reduction in post-treatment RVO patients compared with pre-treatment RVO patients (56.0±18.0 μm vs. 67.9±16.9 μm, respectively; P=0.02). Mean WLR in pre-treatment RVO patients was 0.47±0.19, showing an increase to 0.63±0.23 3 months after treatment (P=0.037). No significant difference was found in arteriolar external diameter between normotensive, pre-treatment, and post-treatment subjects.

CONCLUSION

Treatment with a DEX implant in RVO patients led to significant improvements in both VA and CMT. These changes were accompanied by reductions in arteriolar lumen diameter, which could contribute to decreased capillary leakage and macular swelling.

Presence of foveal bulge in optical coherence tomographic images in eyes with macular edema associated with branch retinal vein occlusion

PURPOSE

To determine whether a significant correlation exists between the presence of a bulge in the photoreceptor inner segment/outer segment (IS/OS) line and the best-corrected visual acuity (BCVA) in eyes with resolved macular edema associated with branch retinal vein occlusion (BRVO).

DESIGN

Retrospective, observational case series.

METHODS

We retrospectively reviewed the medical records of patients who had a complete resolution of macular edema and had an intact IS/OS line in the central fovea in the spectral-domain optical coherence tomographic (SDOCT) images. Thirty-one eyes with macular edema associated with BRVO (BRVO group) and 31 unaffected fellow eyes (control group) of 31 patients were evaluated. In normal eyes, the intact IS/OS line determined by SDOCT has a bulge at the central fovea, called the foveal bulge. The eyes in the BRVO group were classified by the presence or absence of foveal bulge, and the characteristics of the 2 groups were compared.

RESULTS

A foveal bulge was present in 7 of 31 eyes in the BRVO group. The incidence of a foveal bulge was significantly lower in the BRVO group (22.6%) than in the control group (100%; P < .0001). All 7 eyes with foveal bulge had a decimal BCVA of ≥1.0 at the final visit. The incidence of a foveal bulge was significantly higher in eyes with BCVA of ≥1.0 (77.8%) than in the eyes with BCVA of <1.0 (0%; P < .0001).

CONCLUSIONS

The foveal bulge is a good marker of the functional properties of the fovea in eyes with resolved macular edema associated with BRVO.

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.

Association between integrity of foveal photoreceptor layer and visual outcome in retinal vein occlusion

PURPOSE

To investigate the correlation between integrity of foveal photoreceptor layer and initial as well as final visual acuity (VA) after successful resolution of macular oedema (ME) associated with retinal vein occlusion (RVO).

METHODS

We retrospectively studied 31 eyes of 31 patients with resolved ME secondary to RVO. The integrity of foveal photoreceptor layer was studied using the junction between photoreceptor inner and outer segment (IS/OS) on spectral domain optical coherence tomography (SD OCT). The study eyes were categorized into three groups at final visit; V group with completely visible IS/OS, P group with partially detected IS/OS and I group with invisible IS/OS. Disrupted length of IS/OS and external limiting membrane (ELM) were measured.

RESULTS

Final VA (logMAR) was closely associated with the IS/OS integrity at final visit; final VA in V group (0.03 ± 0.05) was better than that in P group (0.21 ± 0.23) (p = 0.027) and final VA in P group was better than that in I group (0.70 ± 0.36) (p = 0.004). Better initial VA (logMAR) and shorter length of disrupted IS/OS at initial visit were closely associated with better final VA (logMAR). In addition, final VA (logMAR) was closely associated with the length of disrupted IS/OS and ELM at final visit.

CONCLUSIONS

  After resolution of ME associated with RVO, the final VA is associated with the integrity of foveal photoreceptor layer. Better VA and the smaller length of disrupted IS/OS on SD OCT at initial visit are indicators of better visual outcome in patients with RVO.

Intravitreal bevacizumab vs. sham treatment in acute branch retinal vein occlusion with macular edema: results at 3 months (Report 1)

BACKGROUND

The goal of this work is to compare the visual and anatomical (central macular thickness; CMT) outcomes of intravitreal bevacizumab (IVB) injections relative to sham treatment in eyes with acute (less than 3 months in duration) branch retinal vein occlusion (BRVO).

METHODS

In a double-masked randomized clinical trial (RCT), patients with acute BRVO were randomly assigned to one of two treatment groups: IVB (two injections of 1.25 mg IVB 6 weeks apart) or sham treatment. Primary outcome measures included changes in best-corrected visual acuity (BCVA) and CMT in optical coherence tomography (OCT) during follow-up (FU) examinations. Any complications secondary to injections were considered secondary outcomes. FU results after 6 and 12 weeks are reported.

RESULTS

Eighty-one eyes (43 OD) of 81 patients (47 females) were enrolled in the study. Forty-two patients were enrolled in the IVB group, and 39 patients were enrolled in the sham group. Visual acuity and CMT improved in the IVB group after week 6 (two Snellen lines and 262 μm, respectively) and week 12 (three Snellen lines and 287 μm, respectively). After week 6, visual improvements in the IVB group were significantly increased relative to that of the sham group. However, visual improvements at week 12 were not significantly different between the two groups (1.5 Snellen lines visual improvement in the sham group at week 12).

CONCLUSIONS

In acute BRVO, two IVB injections resulted in significant improvement of vision and CMT at 6 weeks relative to the sham group. However, the visual improvements in the IVB group were not significantly different from those in the sham group at 12 weeks. IVB injections accelerate an initial improvement of visual acuity but do not have any significant effects on vision after 12 weeks.

Pegaptanib sodium for macular edema secondary to branch retinal vein occlusion

PURPOSE

To assess the efficacy and safety of intravitreous pegaptanib sodium (Macugen; EyeTech Pharmaceuticals/Pfizer Inc, New York, New York, USA) for macular edema secondary to branch retinal vein occlusion (BRVO).

DESIGN

Prospective, randomized, dose-finding study.

METHODS

Twenty subjects from three clinical practices in the United States with BRVO of more than 1 month's and fewer than 6 months' duration; best-corrected visual acuity (BCVA) 70 to 25 Early Treatment Diabetic Retinopathy Study letters inclusive (approximately 20/40 to 20/320 Snellen); and central foveal thickness of 250 microm or more were included. Subjects were randomized 3:1 to intravitreous injections of pegaptanib 0.3 or 1 mg at baseline and at weeks 6 and 12 with subsequent injections at 6-week intervals at investigator discretion until week 48. Principal efficacy outcomes were change from baseline to week 54 in BCVA, center point thickness, central subfield thickness, and macular volume as measured by optical coherence tomography.

RESULTS

Fifteen subjects received pegaptanib 0.3 mg and 5 received pegaptanib 1 mg. Eighteen subjects completed the 54-week follow-up. Results were similar in both the 0.3- and 1-mg groups. Overall improvements from baseline to week 54 occurred in mean BCVA (+14 +/- 13 letters), center point thickness (-205 +/- 195 mum), central subfield thickness (-201 +/- 153 mum), and macular volume (-2.2 +/- 1.6 mm(3)). The response was rapid after the first injection, with a mean BCVA improvement of 11 +/- 7 letters at 1 week from the baseline of 56 +/- 12 letters (approximately 20/80 Snellen). One retinal detachment and no cases of endophthalmitis or traumatic cataract were seen.

CONCLUSIONS

Intravitreous pegaptanib offers a promising alternative as a treatment for macular edema secondary to BRVO.

Comparison between intravitreal bevacizumab and triamcinolone for macular edema secondary to branch retinal vein occlusion

Purpose

To compare the effects of intravitreal bevacizumab to those of triamcinolone acetonide injection for the treatment of macular edema secondary to branch retinal vein occlusion.

Methods

This retrospective study included 50 eyes of 50 patients who received a single injection of intravitreal bevacizumab (1.25 mg/0.05 mL, 22 eyes) or triamcinolone acetonide (4 mg/0.1 mL, 28 eyes) as the only treatment for macular edema secondary to branch retinal vein occlusion; all patients had a post-injection follow-up duration of >24 weeks. Best corrected visual acuity (BCVA), intraocular pressure (IOP), and central macular thickness (CMT) by optical coherence tomography were measured for up to 24 weeks after injection.

Results

BCVA was improved at 1, 4, 8,12 weeks post-injection in the bevacizumab group, and at 1, 4, 8 weeks post-injection in the triamcinolone group. No significant difference was found between the two groups except at 12 weeks. CMT decreased significantly within each group, and no significant difference between groups was found. In the bevacizumab group, no elevated IOP was observed, whereas IOP was significantly increased at 4, 8, and 12 weeks after triamcinolone injection; IOP was therefore significantly different between the two groups.

Conclusions

Intravitreal bevacizumab is a comparatively simple treatment method that can effectively improve BCVA and reduce CMT without ocular and systemic complications. Consequently, intravitreal bevacizumab injections may be useful as both an alternative and primary treatment for macular edema secondary to branch retinal vein occlusion.

Bevacizumab compared with macular laser grid photocoagulation for cystoid macular edema in branch retinal vein occlusion

INTRODUCTION

To evaluate the outcome of cystoid macular edema treated with intravitreal injections of bevacizumab and macular grid laser photocoagulation (GLP), in patients with perfused branch retinal vein occlusion.

METHODS

Thirty eyes of 30 consecutive patients with cystoid macular edema secondary to nonischemic branch retinal vein occlusion were assigned to either GLP group or to intravitreal bevacizumab (IB) group. Complete ophthalmologic examinations were performed just before GLP and IB injection at 1, 3, 6, and 12 months after treatment. Changes in logarithm of minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA), central macular thickness (CMT) shown by optical coherence tomography-3 were evaluated.

RESULTS

Baseline BCVA (logMAR) and CMT were, respectively, 0.89 +/- 0.13 and 650 +/- 140 microm for the GLP group, 0.87 +/- 0.16 and 690 +/- 120 microm for the IB group. After the treatment, at 1, 3, 6, and 12 months in the GLP group, BCVA had improved by 0.19, 0.22, 0.21, and 0.20 logMAR, CMT had decreased by 40%, 41.3%, 40.5%, and 42%. In the IB group, BCVA had improved by 0.31, 0.32, 0.30, and 0.31 logMAR and CMT had decreased by 59.5%, 59%, 60%, and 60.3%. The group receiving bevacizumab had better BCVA and lower CMT values at all time points (P < 0.05).

CONCLUSION

Intravitreal bevacizumab injection improves BCVA and reduces CMT more than GLP. Intravitreal bevacizumab injection was well tolerated and could be used as primary treatment in patients with cystoid macular edema secondary to perfused branch retinal vein occlusion.

Foveal photoreceptor layer in eyes with persistent cystoid macular edema associated with branch retinal vein occlusion

PURPOSE

To study the correlation of visual acuity and the foveal photoreceptor layer in eyes with persistent cystoid macular edema associated with branch retinal vein occlusion (BRVO).

DESIGN

Retrospective chart review.

METHODS

We studied retrospectively the medical records of 42 eyes of 42 patients with persistent cystoid macular edema secondary to BRVO, eyes in which the foveal thickness was greater than 250 microm at final examination. On the vertical image obtained by optical coherence tomography at the final examination, we measured thickness of the foveal photoreceptor layer that was beneath the foveal cystoid spaces. We also assessed status of the junction between inner and outer segments of the photoreceptors (IS/OS) in the fovea.

RESULTS

The photoreceptor layer beneath the foveal cystoid spaces was detected as a distinct layer with thickness varying between 33 microm and 124 microm (mean, 71.1 +/- 26.8 microm). Final visual acuity showed no correlation with total foveal thickness (r = 0.336, P = .092). However, it did show a close correlation with thickness of the foveal photoreceptor layer (r = -0.571, P < .0001). Of the 42 eyes, 15 showed a continuous IS/OS line in the fovea. Visual acuity in these eyes with a continuous IS/OS line in the fovea was significantly better than that in eyes with a discontinuous or interrupted IS/OS line (P < .0001).

CONCLUSIONS

Both the thickness and the integrity of the foveal photoreceptor layer are associated with visual function in eyes with persistent cystoid macular edema associated with BRVO.

Association between integrity of foveal photoreceptor layer and visual acuity in branch retinal vein occlusion

AIM

To study the correlation between integrity of the photoreceptor layer after resolution of macular oedema (MO) associated with branch retinal vein occlusion (BRVO) and final visual acuity (VA), and to determine prognostic factors for visual outcome.

METHODS

We retrospectively studied 46 eyes from 46 patients with resolved MO secondary to BRVO, the foveal thickness of which was less than 250 microm at final observation. We assessed the status of the third high reflectance band (HRB) in the fovea using optical coherence tomography (OCT) at final observation, and studied OCT images taken at the initial visit in the hope of identifying a factor that would be prognostic of visual outcome.

RESULTS

No differences were found in initial VA or in foveal thickness between eyes with or without complete third HRB at final observation. However, final VA in eyes without a complete HRB was significantly poorer (p<0.002). Additionally, initial status of the third HRB in the parafoveal area of unaffected retina was associated with final VA; lack of visualisation of the third HRB at 500 microm (p = 0.0104) or 1000 microm (p = 0.0167) from the fovea on initial OCT images was associated with poor visual recovery after resolution of the MO.

CONCLUSION

Integrity of the photoreceptor layer in the fovea is associated with VA in resolved MO, and status of the third HRB before treatment might be predictive of visual outcome.

Intravitreal bevacizumab (Avastin) in the treatment of macular edema secondary to branch retinal vein occlusion

PURPOSE

To report the authors' experience after intravitreal bevacizumab (Avastin, Genentech) injection in patients with macular edema (ME) secondary to branch retinal vein occlusive disease (BRVO).

METHODS

A consecutive retrospective review of patients with ME secondary to BRVO who were treated with intravitreal bevacizumab (1.25 mg/0.05 mL). Patients underwent complete ophthalmic evaluation, which included nonstandardized Snellen visual acuity testing, optical coherence tomography (OCT), and/or angiographic testing at baseline and follow-up visits.

RESULTS

There were 27 consecutive patients who received intravitreal bevacizumab injections. The mean length of follow-up was 5.3 months (median 6 months, range 3-8 months). The mean visual acuity improved from 20/200(-) at baseline to 20/100(-) at 1 month and 20/100(+) at 3 months and last follow-up (P < 0.001). The mean central 1 mm macular thickness was 478 microm at baseline and decreased to 310, 336, and 332 microm at 1 month, 3 months, and last follow-up (P < 0.001). Patients received an average of two injections (range one to three). No adverse side effects were observed following injections.

CONCLUSION

The observed anatomic (by ophthalmic examination, OCT, and/or fluorescence angiography) and visual acuity improvements and lack of serious adverse side effects after intravitreal bevacizumab injection demonstrates, in principle, the potential of bevacizumab for the treatment of ME in this setting.

Evaluation of arteriovenous crossing sheathotomy for decompression of branch retinal vein occlusion

PURPOSE

To report the effects of arteriovenous adventitial sheathotomy on anatomical and functional improvements in patients with macular oedema due to branch retinal vein occlusion (BRVO).

METHODS

Pars plana vitrectomy and arteriovenous sheathotomy was performed on 11 patients with BRVO who had vision loss due to macular oedema. Ten patients with macular oedema due to BRVO and who have been treated with grid laser photocoagulation were included in the control group. The measurement of visual acuity with ETDRS chart was taken preoperatively and at 1, 3, 6, and 9 months follow-up in the study group and at 1, 3, 6, and 9 months after grid laser in the control group.

RESULTS

The mean preoperative logMAR visual acuity was 0.84+/-0.3 in the surgical group and 1.06+/-0.4 in the control group. The postoperative mean logMAR visual acuity was 0.41+/-0.2, 0.40+/-0.2, 0.40+/-0.3, and 0.36+/-0.3 at 1, 3, 6, and 9 months follow-up, respectively. In the control group the postlaser mean logMAR visual acuity was 0.92+/-0.3, 0.87+/-0.4, 0.85+/-0.3, and 0.82+/-0.3 at 1, 3, 6, and 9 months follow-up, respectively. The improvements of visual acuity in both groups were statistically significant when compared to pretreatment (P=0.003 and P=0.007 at 9 months in the study and control group, respectively).

CONCLUSION

Arteriovenous sheathotomy for decompression of BRVO in patients who have vision loss due to macular oedema was safe and effective for anatomical and functional improvement and resulted in significantly better visual outcomes than a matched control group of laser-treated eyes.