A systematic review and meta-analysis of clinical outcomes of vitrectomy with or without intravitreal bevacizumab pretreatment for severe diabetic retinopathy

Vitrectomy for diabetic retinopathy: A review of indications, techniques, outcomes, and complications

Diabetic retinopathy is one of the most severe forms of retinopathy and a leading cause of blindness all over the world. Of a greater concern is proliferative diabetic retinopathy which leads to vitreous haemorrhage and tractional retinal detachment in such cases. A majority of these cases require a surgical intervention to improve vision and prevent further vision loss. Surgical manouevers in these cases require a complex combination of vitrectomy, membrane dissection, judious usage of endodiathermy, endolaser, vital dyes, bimanual dissection and usage of intraoperative and post-operative tamponades. Each case presents a unique challenge and necessitates an appropriate combination of the steps mentioned above. In the current review we present the current understanding of the need for surgery in diabetic retinopathy, various surgical approaches and a summary of current literature on the same. Multiple surgical video clips demonstrating these steps are also included in this review.

Comparison of 27-gauge beveled-tip and 25-gauge flat-tip microincision vitrectomy surgery in the treatment of proliferative diabetic retinopathy: a randomized controlled trial

PURPOSE

To compare the effectiveness and safety of a 27-gauge (27G) beveled-tip microincision vitrectomy surgery (MIVS) with a 25-gauge (25G) flat-tip MIVS for the treatment of proliferative diabetic retinopathy (PDR).

METHODS

A prospective, single-masked, randomized, controlled clinical trial included 52 eyes (52 patients) with PDR requiring proliferative membrane removal. They were randomly assigned in a 1:1 ratio to undergo the 27G beveled-tip and or 25G flat-tip MIVS (the 27G group and the 25G group, respectively). During surgery, the productivity of cutting the membrane, the number of vitrectomy probe (VP) exchanges to microforceps, total operation time, vitrectomy time and intraoperative complications were measured. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) and postoperative complications were also assessed to month 6.

RESULTS

Forty-seven eyes (47 patients) completed the follow-up, including 25 in the 27G group and 22 in the 25G group. During surgery in the 27G group, cutting the membrane was more efficient (P = 0.001), and the number of VP exchanges to microforceps was lower (P = 0.026). The occurrences of intraoperative hemorrhages and electrocoagulation also decreased significantly (P = 0.004 and P = 0.022). There were no statistical differences in the total operation time or vitrectomy time between the two groups (P = 0.275 and P = 0.372), but the former was slightly lower in the 27G group. Additionally, the 27G group required fewer wound sutures (P = 0.044). All the follow-up results revealed no significant difference between the two groups.

CONCLUSIONS

Compared with the 25G flat-tip MIVS, the 27G beveled-tip MIVS could be more efficient in removing the proliferative membrane while reducing the occurrence of intraoperative hemorrhages and electrocoagulation using appropriate surgical techniques and instrument parameters. Its vitreous removal performance was not inferior to that of the 25G MIVS and might offer potential advantages in total operation time. In terms of patient outcomes, advanced MIVS demonstrates equal effectiveness and safety to 25G flat-tip MIVS.

TRIAL REGISTRATION

The clinical trial has been registered at Clinicaltrials.gov (NCT0544694) on 07/07/2022. And all patients in the article were enrolled after registration.

27‑Gauge vitrectomy vs. 25‑gauge vitrectomy in the management of proliferative diabetic retinopathy with preoperative intravitreal injection of conbercept

Small-gauge vitrectomy has become popular due to its notable advantages, including less trauma, shortened convalescence and improved manoeuvrability. The aim of the present study was to compare the surgical outcomes of 27-gauge (27-G) vitrectomy with those of 25-gauge (25-G) vitrectomy in the management of proliferative diabetic retinopathy (PDR) with preoperative intravitreal injection of conbercept. The data of 48 consecutive patients with PDR (48 eyes) were retrospectively collected. The patients underwent conbercept intravitreal injection and pars plana vitrectomy with a 27-G group (23 eyes) or 25-G group (25 eyes) vitrectomy system. The operating time, suturing rate, endodiathermy rate, postoperative best-corrected visual acuity (BCVA), intraocular pressure (IOP) and complications were recorded. The mean postoperative BCVA at final follow-up was significantly improved compared with that at the baseline in both groups (P<0.001 for both). The differences in the mean BCVA changes between the two groups were not significant (P>0.99), and no differences were observed in the final central foveal thickness (P=0.51) between the two groups. The final IOP remained stable compared with that at the baseline in the 27-G group (P=0.36) and the 25-G group (P=0.05). The suturing rate was significantly decreased in the 27-G group compared with the 25-G group (P=0.04). There were no significant differences between the two groups in terms of the operating time (P=0.18), rate of endodiathermy use (P>0.99), iatrogenic retinal breaks (P=0.42) or postoperative recurrent vitreous haemorrhage (P>0.99). In addition, no case of ocular hypotony was observed in either group. In conclusion, 27-G vitrectomy was as efficient and safe as 25-G vitrectomy in the management of PDR in terms of operating time and complications. With reference to the literature, preoperative conbercept injection appears to assist in decreasing the incidence of intraoperative and postoperative complications.

Anti-vascular endothelial growth factors in combination with vitrectomy for complications of proliferative diabetic retinopathy

BACKGROUND

Vitrectomy is an established treatment for the complications of proliferative diabetic retinopathy (PDR). However, a number of complications can occur during and after vitrectomy for PDR. These include bleeding and the creation of retinal holes during surgery, and bleeding, retinal detachment and scar tissue on the retina after surgery. These complications can limit vision, require further surgery and delay recovery. The use of anti-vascular endothelial growth factor (anti-VEGF) agents injected into the eye before surgery has been proposed to reduce the occurrence of these complications. Anti-VEGF agents can reduce the amount and vascularity of abnormal new vessels associated with PDR, facilitating their dissection during surgery, reducing intra- and postoperative bleeding, and potentially improving outcomes.

OBJECTIVES

To assess the effects of perioperative anti-VEGF use on the outcomes of vitrectomy for the treatment of complications for proliferative diabetic retinopathy (PDR).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 6); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 22 June 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that looked at the use of anti-VEGFs and the incidence of complications in people undergoing vitrectomy for PDR.   DATA COLLECTION AND ANALYSIS: Two review authors independently assessed and extracted the data. We used the standard methodological procedures expected by Cochrane. The critical outcomes of the review were the mean difference in best corrected visual acuity (BCVA) between study arms at six (± three) months after the primary vitrectomy, the incidence of early postoperative vitreous cavity haemorrhage (POVCH, within four weeks postoperatively), the incidence of late POVCH (occurring more than four weeks postoperatively), the incidence of revision surgery for POVCH within six months, the incidence of revision surgery for recurrent traction/macular pucker of any type and/or rhegmatogenous retinal detachment within six months and vision-related quality of life (VRQOL) measures. Important outcomes included the proportion of people with a visual acuity of counting fingers (1.8 logMAR or worse), the number of operative retinal breaks reported and the frequency of silicone oil tamponade required at time of surgery.

MAIN RESULTS

The current review includes 28 RCTs that looked at the pre- or intraoperative use of intravitreal anti-VEGFs to improve the outcomes of pars plana vitrectomy for complications of PDR. The studies were conducted in a variety of countries (11 from China, three from Iran, two from Italy, two from Mexico and the remaining studies from South Korea, the UK, Egypt, Brazil, Japan, Canada, the USA, Indonesia and Pakistan). The inclusion criteria for entry into the studies were the well-recognised complications of proliferative retinopathy: non-clearing vitreous haemorrhage, tractional retinal detachment involving the macula or combined tractional rhegmatogenous detachment. The included studies randomised a total of 1914 eyes.  We identified methodological issues in all of the included studies. Risk of bias was highest for masking of participants and investigators, and a number of studies were unclear when describing randomisation methods and sequence allocation. Participants receiving intravitreal anti-VEGF in addition to pars plana vitrectomy achieved better BCVA at six months compared to people undergoing vitrectomy alone (mean difference (MD) -0.25 logMAR, 95% confidence interval (CI) -0.39 to -0.11; 13 studies, 699 eyes; low-certainty evidence). Pre- or intraoperative anti-VEGF reduced the incidence of early POVCH (12% versus 31%, risk ratio (RR) 0.44, 95% CI 0.34 to 0.58; 14 studies, 1038 eyes; moderate-certainty evidence). Perioperative anti-VEGF use was also associated with a reduction in the incidence of late POVCH (10% versus 23%, RR 0.47, 95% CI 0.30 to 0.74; 11 studies, 579 eyes; high-certainty evidence). The need for revision surgery for POVCH occurred less frequently in the anti-VEGF group compared with control, but the confidence intervals were wide and compatible with no effect (4% versus 13%, RR 0.44, 95% CI 0.15 to 1.28; 4 studies 207 eyes; moderate-certainty evidence). Similar imprecisely measured effects were seen for revision surgery for rhegmatogenous retinal detachment (5% versus 11%, RR 0.50, 95% CI 0.15 to 1.66; 4 studies, 145 eyes; low-certainty evidence).  Anti-VEGFs reduce the incidence of intraoperative retinal breaks (12% versus 31%, RR 0.37, 95% CI 0.24 to 0.59; 12 studies, 915 eyes; high-certainty evidence) and the need for silicone oil (19% versus 41%, RR 0.46, 95% CI 0.27 to 0.80; 10 studies, 591 eyes; very low-certainty evidence). No data were available on quality of life outcomes or the proportion of participants with visual acuity of counting fingers or worse.

AUTHORS' CONCLUSIONS

The perioperative use of anti-VEGF reduces the risk of late POVCH, probably results in lower early POVCH risk and may improve visual outcomes. It also reduces the incidence of intraoperative retinal breaks. The evidence is very uncertain about its effect on the need for silicone oil tamponade. The reported complications from its use appear to be low. Agreement on variables included and outcome standardisation is required in trials studying vitrectomy for PDR.

Pre-operative intravitreal bevacizumab for tractional retinal detachment secondary to proliferative diabetic retinopathy: the Alvaro Rodriguez lecture 2023

The treatment of proliferative diabetic retinopathy (PDR) has evolved significantly since the initial use of panretinal photocoagulation as a treatment in the 1950s. Vascular endothelial growth factor inhibitors have provided an effective alternative without the risk of peripheral vision loss. Despite this, the risk of complications requiring surgical intervention in PDR remains high. Intravitreal bevacizumab has shown promise as a preoperative adjuvant to vitrectomy for PDR complications, albeit with a purported risk for tractional retinal detachment (TRD) progression in eyes with significant fibrous proliferation. Here we will discuss anti-VEGF agent use in PDR and its role in surgical intervention for PDR complications including TRD.

A Systematic Review and Meta-Analysis of Clinical Outcomes of Small Gauge Vitrectomy with or without Intravitreal Anti-Vascular Endothelial Growth Factor Agents Pretreatment for Proliferative Diabetic Retinopathy

BACKGROUND

Proliferative diabetic retinopathy (PDR) is a common visual threatening ocular disease, patients with nonclearing vitreous hemorrhage (VH), tractional retinal detachment (RD), or extensive fibrovascular proliferation are always in need for surgical treatment. Although several studies reported better surgical outcome in patients underwent surgery after anti-VEGF injection, the effect of anti-VEGF pretreatment for small gauge vitrectomy in PDR patients remains to be elucidated.

OBJECTIVES

The objective of the study was to evaluate the benefits of preoperative anti-VEGF treatment in small gauge vitrectomy for PDR patients.

METHODS

A comprehensive literature search in PubMed, Embase, and the Cochrane Central Register of Controlled Trials was performed to identify relevant studies. Meta-analyses were performed for intraoperative (including intraoperative bleeding, endodiathermy, iatrogenic retinal breaks, surgical time, etc.) and postoperative outcome parameters (including best-corrected visual acuity (BCVA), postoperative VH, postoperative RD, etc.).

RESULTS

Ten randomized controlled trials were identified and used for comparing small gauge vitrectomy alone (344 eyes, control group) and small gauge vitrectomy with preoperative anti-VEGF injection (355 eyes). The intraoperative findings showed that the surgical time, the incidence of clinically significant intraoperative bleeding, iatrogenic retinal breaks, silicone oil tamponade, and the frequency of endodiathermy were significantly less in the anti-VEGF pre-treated group than in the vitrectomy alone group (p < 0.01). The postoperative findings showed that the incidences of early postoperative VH, postoperative RD were significantly less in the anti-VEGF pre-treated group than in the control group (p < 0.05). The pooled result of postoperative rubeosis iridis/neovascular glaucoma was borderline (p = 0.072) between cases and controls, while no statistically significant differences in BCVA at last follow-up and incidences of late postoperative VH were found between these two groups (p > 0.05).

CONCLUSIONS

Anti-VEGF injection prior to small gauge vitrectomy in PDR patients might facilitate easier surgical procedure and reduce intra- and postoperative complications. Further studies are needed to verify our findings and evaluate the optimal interval and dosage for preoperative anti-VEGF injection.

An update on the management of diabetic tractional retinal detachment

Background: Tractional retinal detachment (TRD) occurs when contractile forces in the vitreous and neovascular tissue lead to the detachment of the neurosensory retina. The pre-operative use of antivascular endothelial growth factor (anti-VEGF) and advances in microsurgical instrumentation, such as a small gauge vitrectomy (SGV), have improved surgical outcomes.Aim: The purpose of this review is to highlight recent trends in the management of diabetic TRD, supporting earlier surgical intervention and the expanded surgical indications.Methods: PubMed was searched for the following terms: ‘diabetes’ OR ‘diabetic retinopathy’ AND ‘TRD’ AND ‘pars plana vitrectomy (PPV)’ AND ‘anti-VEGF’ AND ‘endophotocoagulation’. Reference lists were reviewed for additional articles. The review was focused on all articles later than 2010 for recent updates on the ever-changing management of this disease entity. No case reports were included in this review article.Results: Management of TRD continues to remain challenging, despite the recent advancements in techniques and instrumentation. Each case needs to be individualised, with careful pre-operative planning, understanding of patient expectations and counselling, coupled with meticulous surgical skills and diligent postoperative management.Conclusion: Management of TRD continues to remain challenging despite recent advances in techniques and instrumentation. Vitrectomy for TRD can improve vision-related quality of life, and the continued evolution and improvement in surgical techniques and adjunctive pharmacotherapy will most likely continue to improve postoperative outcomes.Contribution: The paper presents an overview of current management of tractional retinal detachment in patients with advanced proliferative diabetic retinopathy. 

Intravitreal recombinant tPA before vitrectomy for diabetic tractional retinal detachment: A randomized controlled trial

PURPOSE

To investigate the effect of intravitreal recombinant tissue plasminogen activator (rt-PA) injection before vitrectomy on surgical facility and outcome in diabetic tractional retinal detachments (TRD).

METHODS

Prospective, randomized, interventional clinical trial. A total of 38 eyes with diabetic TRD were candidates for vitrectomy. Patients were randomized 1:1 to receive intravitreal rt-PA, five to seven days before vitrectomy or no injection. Intraoperative surgical facility and anatomic success at month 3 after surgery were assessed.

RESULTS

Mean patient age was 54.2 ± 9.4 years. There was no statistically significant difference between rt-PA and no injection groups with regard to anatomic success (89% versus 95%, respectively, P = 0.547) and best corrected visual acuity at 3 months (2.0 versus 2.1 logMAR, respectively, P = 0.840). However, surgical facility score was statistically significantly lower in rt-PA injection group compared to no injection group (4.1 ± 1.7, 5.8 ± 2.0, respectively, P = 0.007).

CONCLUSIONS

Vitrectomy for TRD was easier after preoperative rt-PA injection, without affecting the anatomic and visual outcomes.

VITRECTOMY FOR DIABETIC COMPLICATIONS: A Pooled Analysis of Randomized Controlled Trials Using Modern Techniques and Equipment

PURPOSE

To report updated clinical outcomes in subjects undergoing pars plana vitrectomy (PPV) using modern techniques and equipment for the treatment of proliferative diabetic retinopathy-related complications. Pooled analysis of five randomized clinical trials conducted at the same institution and included both study and control subjects from the trials.

METHODS

There were 943 subjects who prospectively underwent small-gauge PPV with antivascular endothelial growth factor pretreatment for proliferative diabetic retinopathy-related complications and completed 6-month follow-up.

RESULTS

The visual acuity of the study population improved from median 2.00 (interquartile range 1.3, 2.3) at baseline to median 1.00 (interquartile range 0.5, 1.3) at 6 months. One hundred and eighty-four patients (19.5%) achieved 20/50 or better acuity, and 652 patients (69.1%) achieved 20/200 or better acuity at 6 months. The vision improved or remained stable in 901 patients (95.5%), and 11 patients (1.2%) developed no light perception at 6 months. Intraoperative complications occurred in 343 cases (36.4%), and 199 cases (21.1%) experienced a postoperative complication. The most common postoperative complication was vitreous hemorrhage in 124 cases (62.3% of all complications). Unplanned secondary PPV was necessary in 86 cases (9.1%).

CONCLUSION

This study reports updated clinical outcomes in patients undergoing PPV for proliferative diabetic retinopathy-related complications which compares favorably with the age before small-gauge PPV and antivascular endothelial growth factor pretreatment.

Intravitreal conbercept as an adjuvant in vitrectomy for proliferative diabetic retinopathy: a meta-analysis of randomised controlled trials

PURPOSE

To evaluate the efficacy of intravitreal conbercept (IVC) in pars plana vitrectomy (PPV) for patients with proliferative diabetic retinopathy (PDR).

METHODS

A meta-analysis of randomized control trials (RCTs) using online databases was performed. The intraoperative outcome measures were the incidence of intraoperative bleeding and endodiathermy application, and the mean surgical time. The postoperative outcome measures were mean change in best-corrected visual acuity (BCVA) from baseline, postoperative vitreous clear-up time and incidence of recurrent vitreous hemorrhage (VH).

RESULTS

Eight RCTs were selected for meta-analysis. They included 409 eyes (215 eyes in IVC group and 194 eyes in no conbercept group). Preoperative IVC application was associated with less intraoperative bleeding and endodiathermy applications (RR = 0.34, 95% CI, 0.23-0.50, P < 0.00001, and RR = 0.26, 95% CI, 0.12-0.56, P = 0.0005) compared to no conbercept. It also shortened surgical time (WMD = -15.87, 95% CI, -22.04 to -9.69, P < 0.00001). In addition, preoperative or intraoperative IVC achieved better BCVA outcome (WMD = -0.37, 95% CI, -0.62 to -0.13, P = 0.003), shorter vitreous clear-up time postoperatively (WMD = -5.44, 95% CI, -6.31 to -4.57, P < 0.00001) and a lower rate of VH recurrence (RR = 0.45, 95% CI, 0.22-0.91, P = 0.03).

CONCLUSION

IVC is an effective adjuvant in PPV for PDR, with better intraoperative and postoperative outcomes.

Comparison of before versus after intravitreal bevacizumab injection, growth factor levels and fibrotic markers in vitreous samples from patients with proliferative diabetic retinopathy

PURPOSE

In diabetic retinopathy patients, intravitreal bevacizumab (IVB) injections are widely used to facilitate dissection of retinal fibrovascular membranes during surgery, reduce the rate of perioperative hemorrhage, and prevent recurrent neovascularization. Previous studies have shown that IVB may worsen fibrosis and thereby impair vision. The aim of this study was to determine which markers are associated with fibrosis.

METHODS

Twenty-three patients with proliferative diabetic retinopathy (PDR) underwent pars plana vitrectomy (PPV) with IVB pretreatment for intraocular hemorrhage (IOH) and/or tractional retinal detachment (TRD). Vitreous samples were obtained at the time of IVB injection and again at the beginning of PPV, about a week later. Using Western blot analysis, the concentrations of vascular endothelial growth factor (VEGF), placental growth factor (PIGF), insulin like growth factor-1 (IGF-1), angiogenin-1 (Ang-1), and vascular endothelial cadherin (VE-cadherin) were measured in vitreous samples.

RESULTS

After treatment with IVB, VEGF, PIGF, and VE-cadherin concentrations in the vitreous significantly decreased (p < 0.001, p < 0.001, and p = 0.001, respectively), whereas the concentrations of IGF-1 increased (p = 0.001). There were no significant changes in Ang-1 concentrations in the vitreous after IVB injection (p = 0.732). There were no statistically significant differences in VEGF-A, PIGF, VE-cadherin, IGF, and Ang-1 levels before and after IVB injection when the IOH and TRD groups underwent subgroup analysis (p = 0.696, p = 0.516, p = 0.498, p = 0.188, and p = 0.243, respectively).

CONCLUSION

The levels of VEGF and other cytokines changed in the vitreous after IVB. The adverse effects associated with IVB, such as fibrosis, may result from modulation of vitreous cytokine concentrations. In the treatment of PDR, drugs that optimize the effects of PIGF, IGF-1, and VE-cadherin to reduce these side effects may be useful.

Intravitreal bevacizumab prior to vitrectomy for proliferative diabetic retinopathy: a systematic review

Background:

Diabetic retinopathy is a leading cause of visual loss in the working population. Pars plana vitrectomy has become the mainstream treatment option for severe proliferative diabetic retinopathy (PDR) associated with significant vitreous haemorrhage and/or tractional retinal detachment. Despite the advances in surgical equipment, diabetic vitrectomy remains a challenging operation, requiring advanced microsurgical skills, especially in the presence of tractional retinal detachment. Preoperative intravitreal bevacizumab has been widely employed as an adjuvant to ease surgical difficulty and improve postoperative prognosis.Aims: This study aims to assess the effectiveness of preoperative intravitreal bevacizumab in reducing intraoperative complications and improving postoperative outcomes in patients undergoing vitrectomy for the complications of PDR.

Methods:

A literature search was conducted using the PubMed, Cochrane, and ClinicalTrials.gov databases to identify all related studies published before 31/10/2020. Prespecified outcome measures were operation time, intraoperative iatrogenic retinal breaks, best-corrected visual acuity in the last follow-up visit, the presence of any postoperative vitreous haemorrhage and the need to re-operate. Evidence synthesis was performed using Fixed or Random Effects models, depending on the heterogeneity of the included studies. Heterogeneity was assessed using Q-statistic and I². Additional meta-regression models, subgroup analyses and sensitivity analyses were performed as appropriate.

Results:

Thirteen randomized control trials, with a total of 688 eyes were included in this review. Comparison of the intraoperative data showed that bevacizumab reduced operation time (p < 0.001), minimized iatrogenic retinal breaks (p < 0.001), provided better long-term visual acuity outcomes (p = 0.005), and prevented vitreous haemorrhage (p < 0.001) and the need for reoperation (p = 0.001 < 0.05). Findings were strongly corroborated by additional sensitivity and subgroup analyses.

Conclusion:

Preoperative administration of bevacizumab is effective in reducing intraoperative complications and improving the postoperative prognosis of diabetic vitrectomy.

PROSPERO registration number: CRD42021219280

Potential bias of preoperative intravitreal anti-VEGF injection for complications of proliferative diabetic retinopathy

PURPOSE

Intravitreal anti-VEGF injection (IVI) is administered before vitrectomy to assist management of proliferative diabetic retinopathy (PDR)-related complications. In the clinical setting, retinal surgeons determine the use of preoperative IVI based on individual criteria. In this study, we investigated factors related to the potential bias of retinal surgeons in using IVI prior to vitrectomy for PDR-related complications, and evaluated the real-world outcomes of surgeon-determined preoperative IVI.

METHODS

Medical records of 409 eyes of 409 patients who underwent 25-gauge vitrectomy for PDR complications at seven Japanese centers (22 surgeons) were retrospectively reviewed. Ocular factors, demographic and general clinical factors, surgical procedures, and postoperative complications were compared between IVI group (patients who received preoperative IVI; 87 eyes, 21.3%) and non-IVI group (patients who did not receive preoperative IVI; 322 eyes, 78.7%). In addition, baseline HbA1c in IVI group and non-IVI group was compared between eyes with and without postoperative complications.

RESULTS

At baseline, IVI group was younger (P<0.001), had shorter duration of diabetes treatment (P = 0.045), and higher frequencies of neovascular glaucoma [NVG] (P<0.001) and tractional retinal detachment [TRD] (P<0.001) compared to non-IVI group. Although IVI group had higher frequencies of intraoperative retinal break and tamponade procedure, there were no significant differences in postoperative complications and additional treatments between two groups. Baseline HbA1c levels were also not correlated with postoperative complications of VH, NVG, and RD both in IVI group and non-IVI group. Logistic regression analysis identified age (P<0.001, odds ratio [OR] 0.95), presence of NVG (P<0.001, OR 20.2), and presence of TRD (P = 0.0014, OR 2.44) as preoperative factors in favor of IVI.

CONCLUSIONS

In this multicenter real-world clinical study, younger age and presence of NVG and TRD were identified as potential biases in using IVI before vitrectomy for PDR complications. Eyes that received preoperative IVI had more intraoperative retinal breaks requiring tamponade than eyes not receiving IVI, but postoperative outcome was not different between the two groups.

Cellular targets in diabetic retinopathy therapy

Despite the existence of treatment for diabetes, inadequate metabolic control triggers the appearance of chronic complications such as diabetic retinopathy. Diabetic retinopathy is considered a multifactorial disease of complex etiology in which oxidative stress and low chronic inflammation play essential roles. Chronic exposure to hyperglycemia triggers a loss of redox balance that is critical for the appearance of neuronal and vascular damage during the development and progression of the disease. Current therapies for the treatment of diabetic retinopathy are used in advanced stages of the disease and are unable to reverse the retinal damage induced by hyperglycemia. The lack of effective therapies without side effects means there is an urgent need to identify an early action capable of preventing the development of the disease and its pathophysiological consequences in order to avoid loss of vision associated with diabetic retinopathy. Therefore, in this review we propose different therapeutic targets related to the modulation of the redox and inflammatory status that, potentially, can prevent the development and progression of the disease.

From the Hypotheses to Clinical Evidence in Retinal Therapy

The off-label, therapeutic use of intravitreal bevacizumab (IVB) in vascular retinal diseases such as diabetic macular edema and proliferative diabetic retinopathy (PDR) has increased significantly due to its ability to reduce retinal neovascularization and slow progression of disease. Here, we will review the literature and investigative developments on the use of IVB as a preoperative adjuvant to vitrectomy in severe PDR, specifically focusing on its ability to reduce intra- and postoperative complications and its risk for progression or development of traction retinal detachment. In particular, this review will highlight the natural progression of evidence from case series and observations to prospective, randomized clinical trials.

Evaluation of vitrectomy combined preoperative intravitreal ranibizumab and postoperative intravitreal triamcinolone acetonide for proliferative diabetic retinopathy

BACKGROUND

To explore the treatment efficacy of the combination of preoperative intravitreal ranibizumab (IVR) and postoperative intravitreal triamcinolone acetonide (IVTA) in patients undergoing pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR).

METHODS

A retrospective comparative study was performed on 128 eyes of 128 patients who had PDR and underwent PPV. Patients who received a single PPV were assigned to Group A. Those who received PPV with preoperative IVR were assigned to Group B. Patients in Group C underwent PPV combined preoperative IVR and postoperative IVTA. Intraoperative findings, changes in mean best-corrected visual acuity (BCVA) and postoperative adverse events, were retrospectively evaluated at 6-month follow-up.

RESULTS

The incidences of iatrogenic breaks, severe intraoperative bleeding, using long-term internal tamponade agents, recurrent vitreous hemorrhage (VH), and duration of surgery were statistically significantly less in Group B and Group C than in Group A. The postoperative BCVA was statistically significantly better in Groups B and Group C than in Group A, respectively, at 1 month after surgery. The mean 3-month postoperative visual acuity was better in Group C. The incidence of high intraocular pressure (IOP) was significantly higher in Group C at the first postoperative week. There were no statistically significant differences in the incidence of exudative retinal detachment and choroidal detachment among the three groups.

CONCLUSION

In patients undergoing PPV for PDR, preoperative IVR significantly reduced the occurrence of intraoperative and postoperative complications, and the combination of preoperative IVR and postoperative IVTA can better improve the postoperative visual outcome.

Comparison of efficacy of combination therapy of an Intravitreal injection of bevacizumab and photocoagulation versus Pan Retinal Photocoagulation alone in High risk Proliferative Diabetic Retinopathy

Objective:

To compare efficacy of intravitreal bevacizumab augmented with Panretinal photocoagulation versus Panretinal photocoagulation alone in high risk proliferative diabetic retinopathy.

Methods:

This is Randomized clinical control trial study conducted at ISRA University Hospital, Hyderabad from July 2018 to December 2018. A total of 76 eyes were randomized into two groups, 38 eyes undergone PRP plus intravitreal bevacizumab, while 38 eyes had PRP alone. Status of neovessels was assessed before and after treatment with the help of fundus fluorescein angiography. Neovessels at disc (NVD’s) and neovessels elsewhere (NVE’s) were assessed with the disc surface diameter.

Results:

Seventy-six eyes were enrolled in this randomized clinical trial into two groups consecutively, that all completed the six months follow-up. In the PRP group mean BCVA (logMAR) worsened significantly from mean 0.30±0.07 to mean 0.40±0.04 at a 30^th day and mean 0.40±0.04 at day 90. While BCVA become improved from 0.30±0.05 to 0.1±0.03 at week four and 0.1±0.02 at week 12 in PRP-Plus group. There was significant change in regression of NVES in PRP only group at week 4 is 2.25±0.75 (p=0.00004) and at 12 weeks 2.00±0.50 (p=0.00002), while in PRP + intravitreal bevacizumab group at 4^th week was 1±0.5 (p =0.0001) and at 12^th week was 0.75±0.25 (p=0.0001).

Conclusion:

Intravitreal Bevacizumab augmented with PRP is more effective in early regression of neovessels in high risk PDR patients.

Ranibizumab Pretreatment in Vitrectomy with Internal Limiting Membrane Peeling on Diabetic Macular Edema in Severe Proliferative Diabetic Retinopathy

AIM

To evaluate the efficacy of intravitreal ranibizumab (IVR) pretreatment for pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling in severe proliferative diabetic retinopathy (PDR) combined with macular edema (ME).

METHODS

Sixty-three patients with ME and PDR were divided into IVR and control groups. Three days before PPV stripping, ranibizumab was injected into the patients in the IVR group. The patients were followed for 6 months. The best-corrected visual acuity (BCVA), visual acuity improvement, centre macular thickness (CMT), and intraoperative and postoperative complications were compared between the two groups.

RESULTS

The BCVA of the IVR group was significantly improved at 1, 3 and 6 months compared with the preoperative BCVA (P < 0.01). The BCVA of the control group was significantly improved at 3 and 6 months compared with the preoperative BCVA (P < 0.01), but was not significantly improved at 1 month. At 1 and 3 months, the BCVA of the IVR group was significantly better than that of the control group after surgery, with no difference between the two groups at 6 months. The CMT of the IVR group was thinner than that of the control group at 1 and 3 months (P < 0.01), with no significant difference at 6 months after surgery. The surgical time, the risk of intraoperative bleeding, the incidence of iatrogenic retinal breaks, the frequency of endodiathermy and the rate of silicone oil tamponade were significantly different between the two groups (all P < 0.05). There was no significant difference between the two groups in terms of postoperative complications.

CONCLUSIONS

Ranibizumab pretreatment may improve the outcome of PPV with ILM peeling for severe PDR with ME by decreasing ME and intraoperative complications.

[Vitreous body hemorrhage-How long can one wait?]

In the case of acute vitreous body hemorrhage, the ophthalmologist is faced with the question of whether spontaneous absorption can be awaited or whether a vitrectomy is necessary. In addition to the intensity of the bleeding, the underlying cause also plays an important role. A thorough medical history is therefore important. The most common causes in adults include posterior vitreous detachment, diabetic retinopathy, and retinal vascular occlusion. In children, retinal vasculitis, systemic diseases, and trauma (e.g. shaken baby syndrome) must be excluded. If there is no evidence of a retinal tear or detachment using ultrasound, it is usually possible to wait a few weeks under sonographic control to assess the spontaneous tendency to resorb. Overall, the trend is towards earlier surgical interventions due to improved vitrectomy techniques and the desire for early rehabilitation of vision.

Incidence and Risk Factors for Tractional Macular Detachment after Anti-Vascular Endothelial Growth Factor Agent Pretreatment before Vitrectomy for Complicated Proliferative Diabetic Retinopathy

The study’s purpose was to determine the incidence, risk factors, and outcomes of tractional macular detachment after anti-vascular endothelial growth factor (VEGF) pretreatment before vitrectomy for complicated proliferative diabetic retinopathy. Patients who underwent primary vitrectomy for complicated proliferative diabetic retinopathy, from January 2012 to 31 December 2018, were enrolled. Ophthalmic and pre-operative data were extracted from electronic record systems. All eyes with a valuable Optical Coherence Tomography (OCT)performed within 5 days before injection of anti-VEGF and on the day of vitrectomy were included. Multivariable logistic regression showed that significant risk factors for developing tractional macular detachment included days between anti-VEGF and vitrectomy (OR, 0.71 [95% CI 0.65–0.76]; p < 0.001), vitreous hemorrhage (OR, 0.23 [95% CI 0.11–0.49]; p < 0.001), and age (OR, 1.05 [95% CI 1.02–1.08]; p < 0.001). Decision-tree analysis showed that the stronger predictors of tractional macular detachment were the time between anti-VEGF injection and vitrectomy (p < 0.001). Secondary predictors were the presence of vitreous hemorrhage (p = 0.012) in eyes that underwent vitrectomy between 6 and 10 days after anti-VEGF injection and younger age (p = 0.031) in eyes that underwent vitrectomy 10 days after anti-VEGF injection. Tractional macular detachment occurs in 10% of eyes after anti-VEGF injection, the main risk factors being days between anti-VEGF injection and vitrectomy, vitreous hemorrhage, and age.

Preoperative Bevacizumab for Tractional Retinal Detachment in Proliferative Diabetic Retinopathy: A Prospective Randomized Clinical Trial

PURPOSE

To assess the effectiveness and safety of an intravitreal injection of 1.25 mg bevacizumab (IVB) as a preoperative adjunct to small-gauge pars plana vitrectomy (PPV) compared with PPV alone in eyes with tractional retinal detachment secondary to proliferative diabetic retinopathy.

METHODS

This prospective, double-masked, randomized, multicenter, active-controlled clinical trial enrolled 224 eyes of 224 patients between November 2013 and July 2015. All eyes underwent a baseline examination including best-corrected visual acuity, color photos, optical coherence tomography, and fluorescein angiography. Data were collected on intraoperative bleeding, total surgical time, early (<1 month) postoperative vitreous hemorrhage, and mean change in best-corrected visual acuity at 12 months. P < .05 was considered statistically significant.

RESULTS

A total of 214 patients (214 eyes) were randomized in a 1:1 ratio to PPV plus IVB ([study group] 102 eyes) or PPV plus sham ([control] 112 eyes). Iatrogenic retinal breaks were noted intraoperatively in 35 eyes (34.3%) in the study group, and 66 eyes (58.9%) in the control group (P = .001). Grade 2 intraoperative bleeding was noted in 32 (31.3%) eyes in the study group and 58 (51.7 %) eyes in the control group (P = .001). Endodiathermy was necessary in 28 (27.4 %) eyes in the study group, compared with 75 (66.9%) eyes in the control group (P = .0001). Mean surgical time was 71.3 ± 32.1 minutes in the study group and 83.6 ± 38.7 minutes in the control group (P = .061).

CONCLUSION

Preoperative IVB seems to reduce intraoperative bleeding, improving surgical field visualization, and reducing intraoperative and postoperative complications. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Frequency and Risk Factors for Neovascular Glaucoma After Vitrectomy in Eyes with Diabetic Retinopathy: An Observational Study

INTRODUCTION

Vitrectomy is one of the main treatments for proliferative diabetic retinopathy (PDR). Postoperative neovascular glaucoma, in which it is difficult to obtain satisfactory results using conventional filtering surgery, is one of the most serious complications of vitrectomy. It often requires destructive surgery, such as ciliary body photocoagulation or freezing, and the outcome with regard to visual acuity (VA) is extremely poor. The purpose of this study was to evaluate the prevalence of neovascular glaucoma (NVG) after modern vitrectomy techniques and investigate how variables assessed before and after vitrectomy are associated with patients who develop NVG after PDR surgery.

METHODS

This was an observational study including the medical records of patients who underwent vitrectomy for PDR at Tianjin Eye Hospital from June 2014 to July 2016, were followed for at least 24 months postoperatively, and NVG developed within 2 years after surgery was recorded. Each patient underwent complete preoperative ophthalmic examinations in both preoperative and follow-up appointments. Factors associated with survival were determined using the Kaplan-Meier (KM) survival analysis to calculate the incidence of NVG after vitrectomy for PDR. Multivariable analysis was performed with the Cox regression proportional hazards model to verify the results of the analysis and eliminate interference factors between variables. All statistical analyses were performed using R statistical software ( http://www.r-project.org ) for Windows.

RESULTS

In all, 238 patients (238 eyes) fulfilled the study criteria. NVG occurred in 11 of 238 eyes (4.6%). The percentages of NVG development after vitrectomy at 6, 12, and 24 months were 0.42%, 3.3%, and 4.6%, respectively. After step analysis, multivariable regression identified preoperative high intraocular pressure (IOP) combined with retinal vein occlusion (RVO), severe PDR, no postoperative intravitreal injection of ranibizumab (IVR), and higher HbA1c levels as significant predictors of NVG.

CONCLUSION

Preoperative high IOP combined with RVO, severe PDR, no postoperative intravitreal injection of ranibizumab (IVR), and higher HbA1c levels are significant predictors of NVG after vitrectomy.

Surgical management of diabetic tractional retinal detachments

Tractional retinal detachment is an end-stage form of diabetic retinopathy that occurs when contractile forces in the vitreous and neovascular tissue lead to the detachment of the neurosensory retina. We review the literature related to the management of this disease. Preoperative planning includes appropriate patient selection, diagnostic and prognostic imaging, and medical optimization with reduction of systemic risk factors. Use of antivascular endothelial growth factor for preoperative treatment has had significant benefits for tractional retinal detachment repair in improving surgical efficiency and outcomes. Advances in microsurgical instrumentation are discussed, with attention to small-gauge vitrectomy with improved flow dynamics, viewing strategies, and lighting allowing bimanual surgery. Special emphasis is placed on bimanual surgical technique, choice of tamponade, and the avoidance of iatrogenic damage. Complications and special considerations are further explored. Based on our compilation of relevant literature, we propose a surgical algorithm for the management of these complex patients.

A Systematic Review and Meta-Analysis of Clinical Outcomes of Intravitreal Anti-VEGF Agent Treatment Immediately after Cataract Surgery for Patients with Diabetic Retinopathy

Aims

To examine possible benefits of intravitreal anti-vascular endothelial growth factor (VEGF) agent treatment immediately after cataract surgery for patients with diabetic retinopathy (DR).

Methods

A comprehensive literature search was performed using the Cochrane collaboration methodology to identify randomized controlled trials (RCTs) and comparative studies of cataract surgery with or without anti-VEGF agent treatment for any diabetic retinopathy. Meta-analyses were performed for clinical outcome parameters including changes in macular thickness (MT), best-corrected visual acuity (BCVA), incidence of diabetic retinopathy and maculopathy progression, laser treatment rate, and other complications.

Results

Nine RCTs and 3 nonrandomized comparative studies were identified and used for comparing cataract surgery with intravitreal bevacizumab (IVB) or intravitreal ranibizumab (IVR) treatment (338 eyes, intervention group) to cataract surgery alone (329 eyes, control group). Analysis of all data showed that the mean BCVA at 1 week postoperatively had no statistically significant difference in the two groups, but at 1, 3, and 6 months postoperatively, the mean BCVA was statistically significantly better in the anti-VEGF treatment group than that in cataract surgery alone group. Analysis of all data showed that the mean MT was statistically significantly less in the anti-VEGF treatment group at 1 week and 1, 3, and 6 months postoperatively (P=0.05, P=0.006, P=0.0001, and P=0.0001, respectively); but postoperative clinical outcomes were differentiated from the type of anti-VEGF agents, IVB or IVR, and the existing macular edema preoperatively. Intravitreal anti-VEGF agent treatment statistically significantly reduced the incidence of diabetic retinopathy progression and maculopathy progression compared to the control group (P=0.0003, P < 0.00001, respectively).

Conclusion

IVB or IVR treatment immediately after cataract surgery may represent a safe and effective strategy to prevent postoperative macular thickening or reduce macular edema and result in greater mean improvements in visual acuity for diabetic patients.

Pharmacological Adjuncts to Vitrectomy Surgery

Pharmacological adjuncts to vitrectomy surgery are useful tools to better deal with surgery. Their introduction has enriched the therapeutic choice before, during and after operations. Although several classifications could be made to frame adjuncts to vitrectomy, we preferred to divide the pharmacological adjuncts to vitrectomy surgery for therapeutic use in the pre-operatory procedure (neo-adjuvant), for intraoperative use and for post-operatory practice (adjuvant). This type of classification allowed us to explore all the adjuncts based on the timing of their use. The actual interest in vitrectomy surgery is giving rise to considerable interest in new molecules with and without the pharmacological effect that will soon be available for the aid of vitreoretinal surgery.

Lymphatic Vascular Structures: A New Aspect in Proliferative Diabetic Retinopathy

Diabetic retinopathy (DR) is the most common diabetic microvascular complication and major cause of blindness in working-age adults. According to the level of microvascular degeneration and ischemic damage, DR is classified into non-proliferative DR (NPDR), and end-stage, proliferative DR (PDR). Despite advances in the disease etiology and pathogenesis, molecular understanding of end-stage PDR, characterized by ischemia- and inflammation-associated neovascularization and fibrosis, remains incomplete due to the limited availability of ideal clinical samples and experimental research models. Since a great portion of patients do not benefit from current treatments, improved therapies are essential. DR is known to be a complex and multifactorial disease featuring the interplay of microvascular, neurodegenerative, metabolic, genetic/epigenetic, immunological, and inflammation-related factors. Particularly, deeper knowledge on the mechanisms and pathophysiology of most advanced PDR is critical. Lymphatic-like vessel formation coupled with abnormal endothelial differentiation and progenitor cell involvement in the neovascularization associated with PDR are novel recent findings which hold potential for improved DR treatment. Understanding the underlying mechanisms of PDR pathogenesis is therefore crucial. To this goal, multidisciplinary approaches and new ex vivo models have been developed for a more comprehensive molecular, cellular and tissue-level understanding of the disease. This is the first step to gain the needed information on how PDR can be better evaluated, stratified, and treated.

Preoperative Timing of Intravitreal Bevacizumab Injection for Proliferative Diabetic Retinopathy Patients

OBJECTIVE

To evaluate the changes in aqueous concentrations of inflammatory cytokines and fibrosis-related factors, and to detect the expression of vascular endothelial growth factor (VEGF) and proliferating cells in fibrovascular membranes (FVMs) of patients with proliferative diabetic retinopathy (PDR) after injection of intravitreal bevacizumab (IVB).

METHODS

Forty-two eyes of 42 patients with PDR, including 28 eyes that received IVB (1.25 mg) 2, 5, and 14 days before pars plana vitrectomy (PPV), and 14 eyes without IVB, were enrolled, in addition to 10 eyes of 10 patients with nondiabetic ocular diseases. Aqueous concentrations of inflammatory cytokines and fibrosis-related factors were analyzed by a multiplex bead assay. Fluorescence immunostaining was performed to examine the expression of VEGF and proliferating cells in the excised epiretinal membranes.

RESULTS

PDR eyes without IVB had the highest vitreous VEGF levels, and the level was statistically significant compared with that of PDR eyes that received IVB 2 days before surgery, PDR eyes that received IVB 5 days before surgery, and nondiabetic eyes (p = 0.011, p = 0.012, and p < 0.001, respectively). The expression of fibroblastic cells and connective tissue growth factor increased in epiretinal FVMs of the IVB group 21 days after treatment.

CONCLUSIONS

IVB injection may lead to a decrease in the intraocular concentrations of VEGF after 2-5 days and induce the formation of proliferation after 21 days, which suggests that PPV in PDR patients should take place within 1 week of the administration of preoperative IVB.

Bevacizumab before Diabetic Vitrectomy: A Clinical Trial Assessing 3 Dosing Amounts

PURPOSE

To evaluate the optimal dosing of preoperative intravitreal bevacizumab (IVB) in patients undergoing pars plana vitrectomy (PPV) for manifestations of proliferative diabetic retinopathy (PDR).

DESIGN

Randomized clinical trial.

PARTICIPANTS

Two hundred six patients with severe manifestations of PDR underwent PPV at a single university-based hospital.

METHODS

Patients were randomized into 1 of 3 treatment groups: group A received 0.625 mg IVB (0.025 ml) 1 to 10 days before PPV, group B received 1.25 mg IVB (0.05 ml) 1 to 10 days before PPV, and group C received 2.5 mg IVB (0.1 ml) 1 to 10 days before PPV.

MAIN OUTCOME MEASURES

The primary outcome was best-corrected visual acuity (BCVA) at 6 months. Secondary outcome measures were rates of perioperative tractional retinal detachment (TRD) development, intraoperative and postoperative complications, and incidence of unplanned PPV at 6 months.

RESULTS

One hundred sixty-seven patients underwent PPV and completed 6 months of follow-up. There were no significant differences between treatment groups regarding baseline characteristics, final BCVA, intraoperative complications, postoperative complications, or unplanned PPV rates. There were no patients in group A (0.0%), 3 patients in group B (7.0%), and 5 patients in group C (8.5%) who demonstrated perioperative TRD after IVB administration, but before PPV (P = 0.0283). This difference was significant between groups A and B (P = 0.0494) and between groups A and C (P = 0.0080).

CONCLUSIONS

This randomized clinical trial demonstrated that patients receiving the 0.625-mg dose of IVB before PPV for the treatment of PDR-related manifestations showed similar visual acuity, but a lower incidence of perioperative TRD development compared with patients receiving the 1.25-mg and 2.5-mg doses. Clinicians should consider adopting the lowest effective dose, 0.625 mg, into clinical practice. The current study is limited by the lack of a control group receiving no IVB before PPV.

Intravitreal Injection of Anti-vascular Endothelial Growth Factor Agents for Ocular Vascular Diseases: Clinical Practice Guideline

PURPOSE

To provide the clinical recommendations for the administration of intravitreal anti-vascular endothelial growth factor (VEGF) drugs especially bavacizumab for ocular vascular diseases including diabetic macular edema, neovascular age-related macular degeneration, myopic choroidal neovascularization, retinal vein occlusion and central serous chorioretinopathy.

METHODS

Twenty clinical questions were developed by the guideline technical committee. Relevant websites and databases were searched to find out the pertinent clinical practice guidelines to answer the questions. The technical committee provided possible answers (scenarios) according to the available evidences for each question. All scenarios along with their levels of evidence and the supported articles were sent to the experts for external review. If the experts did not agree on any of the scenarios for one particular clinical question, the technical committee reviewed all scenarios and their pertinent evidences and made the necessary decision. After that, the experts were asked to score them again. All confirmed scenarios were gathered as the final recommendations.

RESULTS

All the experts agreed on at least one of the scenarios. The technical committee extracted the agreed scenario for each clinical question as the final recommendation. Finally, 56 recommendations were developed for the procedure of intravitreal anti-VEGF injection and their applications in the management of ocular vascular diseases.

CONCLUSION

The implementation of this guideline can standardize the management of the common ocular vascular diseases by intravitreal injection of anti-VEGF agents. It can lead to better policy-making and evidence-based clinical decision by ophthalmologists and optimal evidence based eye care for patients.

Antivascular endothelial growth factor agents pretreatment before vitrectomy for complicated proliferative diabetic retinopathy: a meta-analysis of randomised controlled trials

Background/aims

To evaluate the efficacy of antivascular endothelial growth factor (anti-VEGF) agents pretreatment before vitrectomy for patients with complicated proliferative diabetic retinopathy (PDR).

Methods

The PubMed, Embase and the Cochrane Central Register of Controlled Trials were searched up to June 2017 to identify related studies. The Peferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were followed. The StataSE V.12.0 software was used to analyse the relevant data. The weighted mean difference, relative risk and their 95% CIs were used to assess the strength of the association.

Results

14 randomised controlled trials involving 613 patients were assessed, the anti-VEGF pretreatment group included 289 patients and the control group included 324 patients. Our analysis indicated that anti-VEGF pretreatment before vitrectomy for complicated PDR could facilitate much easier surgery regarding less intraoperative bleeding, less endodiathermy, shorter duration of surgery, less iatrogenic retinal breaks, less frequency of using silicone oil and relaxing retinotomy (P<0.05). Additionally, anti-VEGF pretreatment could also achieve better postoperative best-corrected visual acuity, less early recurrent vitreous haemorrhage (VH) and quicker absorption of recurrent VH (P<0.05). However, the incidence of late recurrent VH, recurrent retinal detachment or related secondary surgery could not be reduced (P>0.05).

Conclusion

The pretreatment of anti-VEGF agents before vitrectomy for patients with complicated PDR might facilitate much easier surgery and better visual rehabilitation, reduce the rate of early recurrent VH and accelerate its absorption. Moreover, future better-designed studies with larger sample sizes are required to further evaluate the efficacy of different anti-VEGF agents and reach a firmer conclusion.

Preoperative Bevacizumab Administration in Proliferative Diabetic Retinopathy Patients Undergoing Vitrectomy: A Randomized and Controlled Trial Comparing Interval Variation

PURPOSE

To assess the optimal interval of preoperative intravitreal bevacizumab (IVB) administration in diabetic subjects undergoing pars plana vitrectomy (PPV) for severe manifestations of active proliferative diabetic retinopathy (PDR).

DESIGN

Randomized clinical trial.

METHODS

One hundred and fifty-six patients with PDR-related complications requiring PPV were prospectively randomized into 1 of 2 treatment groups: Group A received IVB (2.5 mg/0.1 mL) 1-3 days before PPV, while Group B received IVB (2.5 mg/0.1 mL) 5-10 days before PPV. The primary outcome was best-corrected visual acuity (BCVA) at 6 months follow-up. Secondary outcome measures were intraoperative surgery time, intraoperative complications, postoperative complications, and incidence of unplanned PPV at 6 months follow-up.

RESULTS

One hundred and twenty-five subjects underwent PPV and completed the 6-month follow-up interval. Group B patients had better final BCVA (P = .033) and were less likely to have a postoperative complication (P = .018) when compared to Group A patients. The mean difference in final BCVA between groups was 0.22 logMAR (95% confidence interval: 0.02-0.43, P = .017). Group A was 3.90 (95% confidence interval: 1.08-17.31, P = .046) times more likely to have a loss of 1 or more logMAR lines of final BCVA when compared to Group B. There were no significant differences among the treatment groups with regard to baseline features, intraoperative surgery time, intraoperative complications, and incidence of unplanned PPV during the study interval.

CONCLUSIONS

This randomized clinical trial demonstrated better postoperative outcomes at 6 months when subjects received preoperative IVB 5-10 days before PPV compared to 1-3 days for the treatment of PDR-related complications.

Diabetic macular oedema: clinical risk factors and emerging genetic influences

Diabetic macular oedema is the major cause of visual impairment in type 1 and type 2 diabetes. As type 2 diabetes becomes more prevalent worldwide, the prevalence of diabetic macular oedema is also expected to rise. Current management of diabetic macular oedema is challenging, expensive and not optimal in a subset of patients. Therefore, it is important to increase our understanding of the risk factors involved and develop preventative strategies. While clinical risk factors for diabetic macular oedema have been identified, few studies have addressed potential genetic risk factors. Epidemiology and family studies suggest genetic influences are of importance. In this review, we summarise known clinical risk factors, as well as discuss the small number of genetic studies that have been performed for diabetic macular oedema.

Ranibizumab pretreatment in diabetic vitrectomy: a pilot randomised controlled trial (the RaDiVit study)

PurposeOur aim was to evaluate the impact of intravitreal ranibizumab pretreatment on the outcome of vitrectomy surgery for advanced proliferative diabetic retinopathy. The objective was to determine the feasibility of a subsequent definitive trial and estimate the effect size and variability of the outcome measure.Patients and methodsWe performed a pilot randomised double-masked single-centre clinical trial in 30 participants with tractional retinal detachment associated with proliferative diabetic retinopathy. Seven days prior to vitrectomy surgery, participants were randomly allocated to receive either intravitreal ranibizumab (Lucentis, Novartis Pharmaceuticals UK Ltd, Frimley, UK) or subconjunctival saline (control). The primary outcome was best-corrected visual acuity 12 weeks following surgery.ResultsAt 12 weeks, the mean (SD) visual acuity was 46.7 (25) ETDRS letters in the control group and 52.6 (21) letters in the ranibizumab group. Mean visual acuity improved by 14 (31) letters in the control group and by 24 (27) letters in the ranibizumab group. We found no difference in the progression of tractional retinal detachment prior to surgery, the duration of surgery, or its technical difficulty. Vitreous cavity haemorrhage persisted at 12 weeks in two of the control group but none of the ranibizumab group.ConclusionRanibizumab pretreatment may improve the outcome of vitrectomy surgery for advanced proliferative diabetic retinopathy by reducing the extent of post-operative vitreous cavity haemorrhage. However, the effect size appears to be modest; we calculate that a definitive study to establish a minimally important difference of 5.9 letters at a significance level of P<0.05 would require 348 subjects in each arm.

Diabetic Retinopathy Clinical Practice Guidelines: Customized for Iranian Population

PURPOSE

To customize clinical practice guidelines (CPGs) for management of diabetic retinopathy (DR) in the Iranian population.

METHODS

Three DR CPGs (The Royal College of Ophthalmologists 2013, American Academy of Ophthalmology [Preferred Practice Pattern 2012], and Australian Diabetes Society 2008) were selected from the literature using the AGREE tool. Clinical questions were designed and summarized into four tables by the customization team. The components of the clinical questions along with pertinent recommendations extracted from the above-mentioned CPGs; details of the supporting articles and their levels of evidence; clinical recommendations considering clinical benefits, cost and side effects; and revised recommendations based on customization capability (applicability, acceptability, external validity) were recorded in 4 tables, respectively. Customized recommendations were sent to the faculty members of all universities across the country to score the recommendations from 1 to 9.

RESULTS

Agreed recommendations were accepted as the final recommendations while the non-agreed ones were approved after revision. Eventually, 29 customized recommendations under three major categories consisting of screening, diagnosis and treatment of DR were developed along with their sources and levels of evidence.

CONCLUSION

This customized CPGs for management of DR can be used to standardize the referral pathway, diagnosis and treatment of patients with diabetic retinopathy.

The outcomes and prognostic factors of vitrectomy in chronic diabetic traction macular detachment

Purpose

To investigate the outcomes of pars plana vitrectomy (PPV) for chronic diabetic traction macular detachment (CTMD).

Methods

Ninety-six eyes that underwent PPV for CTMD of at least 6 months duration were retrospectively analyzed. Retinal reattachment rate, final vision, and prognostic factors for poor visual outcome were the main outcome measures.

Results

All eyes had long-standing TMD (median 12, range: 6–70 months). The median postoperative follow-up was 15 (range: 3–65) months. Eighty-seven eyes (90.6%) had their retina and macula reattached after one PPV. At final examination, 84 eyes (87.5%) had stable vision or at least one line improvement, and three had no light perception. Seventeen (17.7%) and 41 (43%) eyes had preoperative visual acuity of ≥20/200 and ≥5/200 as compared to 40 (41.6%; P=0.0005) and 64 (66.7%; P=0.0014) eyes at final follow-up, respectively. Age >50 years (Odds ratio [OR] =5.84, 95% confidence interval [CI] =1.53–22.19, P=0.01), preoperative vision <20/400 (OR =7.012, 95% CI =1.82–26.93, P=0.005), and ischemic macula (OR =14.13, 95% CI =3.61–55.33, P<0.001) were significantly associated with final vision <20/400.

Conclusion

PPV for CTMD may be beneficial particularly in patients who are relatively younger and have good baseline vision and no macular ischemia.

Surgical treatment for diabetic vitreoretinal diseases: a review

Over the past four decades, advancements in surgical instrumentations and techniques have significantly improved the postoperative anatomical and visual outcomes of patients with various diabetic vitreoretinal diseases. In particular, surgical interventions for previously serious and untreatable blinding proliferative diabetic retinopathy can now be performed, with much better results. The advents of micro incisional vitrectomy system with better visualization system like binocular indirect ophthalmomicroscope and state-of-the-art instrumentation revolutionized the era of diabetic vitrectomy. High-speed vitrectors, finer instruments, chromo-assisted vitrectomy and use of anti-vascular endothelial growth factors not only change the paradigm but also help achieve much better outcome after diabetic vitrectomies. In this review, we will discuss and summarize the indications, surgical considerations, surgical techniques, potential complications and outcomes of vitreoretinal surgery for diabetic eye diseases.

RANDOMIZED CONTROLLED STUDY OF INTRAVITREAL BEVACIZUMAB 0.16 MG INJECTED ONE DAY BEFORE SURGERY FOR PROLIFERATIVE DIABETIC RETINOPATHY

PURPOSE

To investigate the usefulness of 0.16 mg/0.05 mL intravitreal bevacizumab (IVB) injection 1 day before vitrectomy for proliferative diabetic retinopathy.

METHODS

Sixty-two patients with proliferative diabetic retinopathy (66 eyes) with an indication for primary vitrectomy were randomized to IVB group (34 eyes) or sham control group (32 eyes). Intravitreal bevacizumab group received intravitreal injection of 0.16 mg/0.05 mL bevacizumab, and sham control group received sham injection 1 day before vitrectomy. Vitreous fluid was sampled before vitrectomy was started.

RESULTS

Frequency of reoperation due to recurrent vitreous hemorrhage within 4 weeks after surgery was significantly lower (P = 0.033) in IVB group (3.1%, 1/32) than in sham control group (20.6%, 7/34). The number of intraoperative endodiathermy spots (0.63 ± 1.0 vs. 1.3 ± 1.4, P = 0.025) and frequency of postoperative recurrent vitreous hemorrhage (3.1%, 1/32 vs. 23.5%, 8/34, P = 0.017) were significantly lower in IVB group than in sham control group. Vitreous vascular endothelial growth factor concentrations were 1315.3 ± 1153.4 pg/mL in sham control group and 25.0 ± 13.6 pg/mL in IVB group (P < 0.0001).

CONCLUSION

Intravitreal injection of 0.16 mg/0.05 mL bevacizumab 1 day before vitrectomy blocked vascular endothelial growth factor production in vitreous and significantly reduced the incidence of reoperation due to early postoperative recurrent vitreous hemorrhage.

Changes in vitreous VEGF, bFGF and fibrosis in proliferative diabetic retinopathy after intravitreal bevacizumab

AIM

To evaluate the relationship between intravitreal bevacizumab (IVB) treatment and the levels of vitreous vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and vitreous-retina surface fibrosis in patients with proliferative diabetic retinopathy (PDR).

METHODS

This study was a prospective, open-label, controlled, randomized clinical trial. Sixty-eight eyes of PDR patients (n=53) and macular hole patients (n=15) were enrolled in this study. Thirty-four eyes of the PDR patients received IVB before vitrectomy. Twenty-three of the 34 PDR patients received IVB treatment 5d before vitrectomy (subgroup a), and 11 of the 34 PDR patients received IVB treatment greater than 2wk prior to vitrectomy (subgroup b). Nineteen of the PDR patients did not receive IVB treatment at any time prior to vitrectomy. The levels of bFGF and VEGF in vitreous samples were measured using enzyme-linked immunosorbent assay (ELISA) and the degree of vitreoretinal fibrosis was characterized using clinical data and data obtained intra-operatively.

RESULTS

In PDR patients, VEGF and bFGF levels were significantly increased compared to non-PDR (control) subject's eyes (P<0.01). In PDR patients, vitreous VEGF levels were significantly decreased following IVB treatment compared to PDR patients that did not receive IVB treatment (P<0.01). The degree of vitreoretinal fibrosis was significantly increased in subgroup b compared to subgroup a(P<0.05) and to patients that did not receive IVB (P<0.05). Vitreous bFGF levels were significantly greater in subgroup b than subgroup a (P<0.01) or in patients who did not receive IVB treatment (P<0.05). A Spearman's rank correlation test indicated that higher levels of vitreous bFGF, but not VEGF, correlated with the degree of vitreoretinal fibrosis.

CONCLUSION

We found that bFGF levels increase in PDR patient's vitreous after IVB treatment longer than two weeks prior to vitrectomy and correlated with the degree of fibrosis after IVB treatment. These findings suggest vitreous fibrosis is increased in PDR patients after IVB treatment may be due to increased levels of bFGF.

New Therapeutic Approaches in Diabetic Retinopathy

Diabetic retinopathy is a common microvascular complication of diabetes mellitus. It affects a substantial proportion of US adults over age 40. The condition is a leading cause of visual loss. Much attention has been given to expanding the role of current treatments along with investigating various novel therapies and drug delivery methods. In the treatment of diabetic macular edema (DME), intravitreal pharmacotherapies, especially anti-vascular endothelial growth factor (anti-VEGF) agents, have gained popularity. Currently, anti-VEGF agents are often used as first-line agents in center-involved DME, with recent data suggesting that among these agents, aflibercept leads to better visual outcomes in patients with worse baseline visual acuities. While photocoagulation remains the standard treatment for proliferative diabetic retinopathy (PDR), recent FDA approvals of ranibizumab and aflibercept in the management of diabetic retinopathy associated with DME may suggest a potential for pharmacologic treatments of PDR as well. Novel therapies, including small interfering RNAs, chemokines, kallikrein-kinin inhibitors, and various anti-angiogenic agents, are currently being evaluated for the management of diabetic retinopathy and DME. In addition to these strategies, novel drug delivery methods such as sustained-release implants and refillable reservoir implants are either under active evaluation or have recently gained FDA approval. This review provides an update on the novel developments in the treatment of diabetic retinopathy.

Anti-vascular endothelial growth factor for prevention of postoperative vitreous cavity haemorrhage after vitrectomy for proliferative diabetic retinopathy

BACKGROUND

Postoperative vitreous cavity haemorrhage (POVCH) is a significant complication following vitrectomy for proliferative diabetic retinopathy (PDR). It delays visual recovery and can make further treatment difficult if the view of the fundus is significantly obscured. A number of interventions to reduce the incidence of POVCH have been proposed, including the perioperative use of anti-vascular endothelial growth factor (anti-VEGF). Anti-VEGFs reduce vascular proliferation and the vascularity of neovascular tissue, which is often the source of bleeding following vitrectomy.

OBJECTIVES

This updated review aimed to summarise the effects of anti-VEGF use to reduce the occurrence of POVCH after vitrectomy surgery for PDR.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2015), PubMed (January 1966 to May 2015), EMBASE (January 1980 to May 2015), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to May 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 26 May 2015.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) and quasi-RCTs that looked at the use of anti-VEGFs and the incidence of POVCH in people undergoing vitrectomy for PDR.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed and extracted the data. We used standard methodological procedures expected by Cochrane.The primary outcomes of the review were the incidence of early and late POVCH following perioperative anti-VEGF administration. Secondary outcomes included best-corrected visual acuity at six months following surgery, the incidence of vitreous cavity washout or revision vitrectomy at six months, adverse effects of intervention (cataract, iris rubeosis and rubeotic glaucoma, retinal detachment, increased inflammation and systemic side effects), quality of life measures performed at least six months following vitrectomy, and density of POVCH.

MAIN RESULTS

The current review included 12 RCTs that looked at the pre- or intraoperative use of intravitreal bevacizumab to prevent postoperative vitreous haemorrhage during pars plana vitrectomy for complications of PDR. The studies were conducted in a variety of countries (three from Iran, two from Italy, two from Egypt, and the remaining from South Korea, USA, Mexico, Pakistan, and Japan). The inclusion criteria for entry into the studies were standard complications of proliferative retinopathy: non-clearing vitreous haemorrhage, tractional retinal detachment involving the macula, or combined tractional rhegmatogenous detachment. The included studies randomised a total of 654 eyes. The average age of the participants was 54 years.We identified methodological issues in all included studies. Risk of bias was highest for masking of participants and investigators (four studies were an 'open label' design), and a number of studies were unclear when describing randomisation methods and sequence allocation.Participants receiving intravitreal bevacizumab in addition to pars plana vitrectomy were less likely to experience early POVCH (grade 2) compared to people undergoing pars plana vitrectomy alone (risk ratio (RR) 0.28, 95% confidence interval (CI) 0.08 to 0.96, 2 studies, 144 eyes, high-quality evidence). This corresponds to an absolute effect of 130 fewer people (95% CI 167 fewer to 7 fewer) with early POVCH per 1000 people when treated with intravitreal bevacizumab. We saw similar results for all grades of POVCH (RR 0.35, 95% CI 0.23 to 0.53, 9 studies, 512 eyes) and when excluding cases where assessment of outcome was impossible due to presence of silicone oil (RR 0.34, 95% CI 0.19 to 0.60, 6 studies, 302 eyes).The effect of pre- or intraoperative intravitreal bevacizumab on the incidence of late postoperative haemorrhage was uncertain (RR 0.72, 95% CI 0.30 to 1.72, 3 studies, 196 eyes, low-quality evidence). The absolute effect was 55 fewer people (95% CI 138 fewer to 143 more) with late POVCH per 1000 people when treated with intravitreal bevacizumab. This outcome was rarer and was only reported in a few studies. We are currently unable to provide an estimate of the effect of intravitreal bevacizumab on postoperative visual acuity due to significant study heterogeneity.No local or systemic complications of intravitreal bevacizumab were reported by the RCTs. The risk of postoperative retinal detachment was lower in the participants treated with pre- or intraoperative bevacizumab (RR 0.46, 95% CI 0.19 to 1.08, 7 studies, 372 participants, low-quality evidence); the absolute effect was 49 fewer people (95% CI:73 fewer to 8 more) with postoperative retinal detachment per 1000 people when treated with intravitreal bevacizumab.

AUTHORS' CONCLUSIONS

The use of pre- or intraoperative bevacizumab lowers the incidence of early POVCH. The reported complications from its use appear to be low. Futher randomised studies that look at other anti-VEGF medications are ongoing and will strengthen the current review findings, giving both surgeons and patients evidence to guide treatment choices in the management of proliferative retinopathy.

[The role of the vitreous body in diseases of neighboring structures]

BACKGROUND

The vitreoretinal interface is not merely the space between the vitreous body and the retina but it is also a site for highly complex pathologies with the vitreous body exerting an influence on all the neighbouring structures.

METHODS

A literature search was performed in Pubmed and current book articles

RESULTS

This review article highlights the role of the vitreous body in vitreomacular adhesion and traction, in the development of macular holes and epiretinal membranes as well as its role in age-related macular degeneration. In the retinal periphery the vitreous structures play a pivotal role in retinal tears and detachment as well as in diabetic and other proliferative vitreoretinopathies. The role of the vitreous bodyin the emergence of various forms of cataract is often underestimated.

DISCUSSION

Vitreo-etinal surgeons should thoroughly understand the pathophysiological relationship between the vitreous body and the neighboring structures, especially in the era of medical vitreolysis.

Common Sequence Variation in the VEGFC Gene Is Associated with Diabetic Retinopathy and Diabetic Macular Edema

PURPOSE

To investigate associations between single nucleotide polymorphisms (SNPs) in the VEGFC gene and the development of diabetic retinopathy (DR) in white patients with type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM).

DESIGN

Cross-sectional, case control study.

PARTICIPANTS

White patients with T1DM or T2DM (n = 2899) were recruited from ophthalmology and endocrine clinics in Australia and the United Kingdom. Patients with T2DM were required to have diabetes mellitus (DM) for at least 5 years and be receiving oral hypoglycemic treatment or insulin.

METHODS

Participants were categorized according to their worst-ever DR grading, as having "no DR" (no history of nonproliferative DR [NPDR], proliferative DR [PDR], or diabetic macular edema [DME]) or "any DR" (further subclassified as NPDR or PDR, without or with DME). Clinical characteristics, glycemic control (hemoglobin A1c [HbA1c]), and presence of diabetic complications were determined at recruitment. Genotyping was performed for 13 VEGFC tag SNPs.

MAIN OUTCOME MEASURES

Odds ratios (ORs) were determined for associations with DR of VEGFC tag SNPs, individually and within haplotypes. Logistic regression was used to adjust for clinical covariates, including DM type, age, sex, DM duration, hypertension, nephropathy, HbA1c, and smoking.

RESULTS

Participants with DM but "no DR" (n = 980) were compared with 1919 participants with DM and "any DR." Three VEGFC SNPs were associated with DR after logistic regression: rs17697419 (P = 0.001; OR, 0.67; confidence interval [CI], 0.52-0.85), rs17697515 (P = 0.001; OR, 0.62; CI, 0.47-0.81), and rs2333526 (P = 0.005; OR, 0.69; CI, 0.54-0.90). rs17697515 Was also specifically associated with DME in those with T2DM (P = 0.004; OR, 0.53; CI, 0.35-0.82). Haplotype analysis revealed 2 significantly associated haplotypes, both protective against DR development.

CONCLUSIONS

Significant associations were found between VEGFC tag SNPs (individually and within haplotypes) and the presence of any DR or DME in white participants with T1DM and T2DM.