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

Vitreous rebleeding rate after vitrectomy or phacovitrectomy in patients with proliferative diabetic retinopathy: A retrospective study

BACKGROUND

The most common complication after vitrectomy is the rebleeding in vitreous cavity. It is important to detect the different factors that can increase the vitreous rebleeding rate in these patients.

OBJECTIVE

To carry out a retrospective review of the rate of vitreous rebleeding after vitrectomy or phacovitrectomy.

METHOD

Retrospective, descriptive and comparative study of patients with a diagnosis of proliferative diabetic retinopathy with phacovitrectomy or vitrectomy procedure. Personal background data, type of surgical intervention and grade of the surgeon who carried out the procedure were obtained.

RESULTS

1227 files of diabetic patients with vitrectomy or phacovitrectomy were reviewed. 65% presented systemic arterial hypertension. The average glomerular filtration rate was 63.50 (±32.36) ml/min/1.73 m2 and glycosylated hemoglobin (HBA1C) of 8% (4.6 to 15%). In the comparison of variables, a significant difference in the rate of vitreous rebleeding was obtained comparing phacovitrectomy with vitrectomy. (p = 0.003), in the relationship between vitrectomy with vitreous rebleeding, an odds ratio of 1.44 was obtained.

CONCLUSION

The results obtained show a lower rate of rebleeding in patients undergoing phacovitrectomy in patients with proliferative diabetic retinopathy.

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.

Blood pressure control for diabetic retinopathy

BACKGROUND

Diabetic retinopathy is a common complication of diabetes and a leading cause of visual impairment and blindness. Research has established the importance of blood glucose control to prevent development and progression of the ocular complications of diabetes. Concurrent blood pressure control has been advocated for this purpose, but individual studies have reported varying conclusions regarding the effects of this intervention.

OBJECTIVES

To summarize the existing evidence regarding the effect of interventions to control blood pressure levels among diabetics on incidence and progression of diabetic retinopathy, preservation of visual acuity, adverse events, quality of life, and costs.

SEARCH METHODS

We searched several electronic databases, including CENTRAL, and trial registries. We last searched the electronic databases on 3 September 2021. We also reviewed the reference lists of review articles and trial reports selected for inclusion.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in which either type 1 or type 2 diabetic participants, with or without hypertension, were assigned randomly to more intense versus less intense blood pressure control; to blood pressure control versus usual care or no intervention on blood pressure (placebo); or to one class of antihypertensive medication versus another or placebo.

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently reviewed the titles and abstracts of records identified by the electronic and manual searches and the full-text reports of any records identified as potentially relevant. The included trials were independently assessed for risk of bias with respect to outcomes reported in this review.

MAIN RESULTS

We included 29 RCTs conducted in North America, Europe, Australia, Asia, Africa, and the Middle East that had enrolled a total of 4620 type 1 and 22,565 type 2 diabetic participants (sample sizes from 16 to 4477 participants). In all 7 RCTs for normotensive type 1 diabetic participants, 8 of 12 RCTs with normotensive type 2 diabetic participants, and 5 of 10 RCTs with hypertensive type 2 diabetic participants, one group was assigned to one or more antihypertensive agents and the control group to placebo. In the remaining 4 RCTs for normotensive participants with type 2 diabetes and 5 RCTs for hypertensive type 2 diabetic participants, methods of intense blood pressure control were compared to usual care. Eight trials were sponsored entirely and 10 trials partially by pharmaceutical companies; nine studies received support from other sources; and two studies did not report funding source. Study designs, populations, interventions, lengths of follow-up (range less than one year to nine years), and blood pressure targets varied among the included trials. For primary review outcomes after five years of treatment and follow-up, one of the seven trials for type 1 diabetics reported incidence of retinopathy and one trial reported progression of retinopathy; one trial reported a combined outcome of incidence and progression (as defined by study authors). Among normotensive type 2 diabetics, four of 12 trials reported incidence of diabetic retinopathy and two trials reported progression of retinopathy; two trials reported combined incidence and progression. Among hypertensive type 2 diabetics, six of the 10 trials reported incidence of diabetic retinopathy and two trials reported progression of retinopathy; five of the 10 trials reported combined incidence and progression. The evidence supports an overall benefit of more intensive blood pressure intervention for five-year incidence of diabetic retinopathy (11 studies; 4940 participants; risk ratio (RR) 0.82, 95% confidence interval (CI) 0.73 to 0.92; I2 = 15%; moderate certainty evidence) and the combined outcome of incidence and progression (8 studies; 6212 participants; RR 0.78, 95% CI 0.68 to 0.89; I2 = 42%; low certainty evidence). The available evidence did not support a benefit regarding five-year progression of diabetic retinopathy (5 studies; 5144 participants; RR 0.94, 95% CI 0.78 to 1.12; I2 = 57%; moderate certainty evidence), incidence of proliferative diabetic retinopathy, clinically significant macular edema, or vitreous hemorrhage (9 studies; 8237 participants; RR 0.92, 95% CI 0.82 to 1.04; I2 = 31%; low certainty evidence), or loss of 3 or more lines on a visual acuity chart with a logMAR scale (2 studies; 2326 participants; RR 1.15, 95% CI 0.63 to 2.08; I2 = 90%; very low certainty evidence). Hypertensive type 2 diabetic participants realized more benefit from intense blood pressure control for three of the four outcomes concerning incidence and progression of diabetic retinopathy. The adverse event reported most often (13 of 29 trials) was death, yielding an estimated RR 0.87 (95% CI 0.76 to 1.00; 13 studies; 13,979 participants; I2 = 0%; moderate certainty evidence). Hypotension was reported in two trials, with an RR of 2.04 (95% CI 1.63 to 2.55; 2 studies; 3323 participants; I2 = 37%; low certainty evidence), indicating an excess of hypotensive events among participants assigned to more intervention on blood pressure.

AUTHORS' CONCLUSIONS

Hypertension is a well-known risk factor for several chronic conditions for which lowering blood pressure has proven to be beneficial. The available evidence supports a modest beneficial effect of intervention to reduce blood pressure with respect to preventing diabetic retinopathy for up to five years, particularly for hypertensive type 2 diabetics. However, there was a paucity of evidence to support such intervention to slow progression of diabetic retinopathy or to affect other outcomes considered in this review among normotensive diabetics. This weakens any conclusion regarding an overall benefit of intervening on blood pressure in diabetic patients without hypertension for the sole purpose of preventing diabetic retinopathy or avoiding the need for treatment for advanced stages of diabetic retinopathy.

Management of Complications and Vision Loss from Proliferative Diabetic Retinopathy

PURPOSE OF REVIEW

Diabetes can be associated with profound visual loss due to several mechanisms. As the duration of diabetes and blood glucose levels increase, these changes become more severe. The proliferation of new blood vessels, vitreous hemorrhage, and tractional retinal detachments may ultimately result and can be devastating to visual function. New advances, including anti-vascular endothelial growth factor (VEGF) medications and innovative microsurgical instruments, have provided additional methods for the management of diabetic retinopathy in the clinic and in the operating room, leading to improved outcomes.

RECENT FINDINGS

Advances in earlier treatment of proliferative diabetic retinopathy, especially with anti-VEGF injections, allow for a reduction in severity, improved vision, and more controlled and successful surgery. Modern surgical techniques and instrumentation have also allowed for improved patient outcomes. Future research into sustained delivery and release of anti-VEGF, reducing the need for frequent in-office injections, may prove to be additionally beneficial. Over the last decade, anti-VEGF has become an increasingly common treatment modality for the management of proliferative diabetic retinopathy, vitreous hemorrhages, and tractional retinal detachments. Further research is needed to determine the ideal method of delivery and timing of the treatment.

Vitreous concentrations of vascular endothelial growth factor as a potential biomarker for postoperative complications following pars plana vitrectomy

INTRODUCTION

The aim of the study was to investigate the effects of vascular endothelial growth factor (VEGF) concentration in vitreous on postoperative complications after pars plana vitrectomy (PPV).

MATERIAL AND METHODS

Ninety subjects were surgically treated with PPV and followed up for 12 months at the Clinical Centre University Sarajevo, Clinic for Eye Disease. Exclusion criteria were presence of other eye diseases, systemic acute/chronic inflammatory conditions, or malignant neoplasms; previously performed PPV surgery; previously received intravitreal or systemic anti-VEGF therapy. A vitreous sample was obtained while performing the PPV procedure, using the Quantikine ELISA test to determine VEGF level, as a risk factor. Outcome measures were intraoperative and postoperative complications reported using categorical data: blunt and sharp dissection of membranes, intraoperative hemorrhage stopped by increasing infusion pressure, pressing with blunt instrument, or using diathermy. The following postoperative complications were assessed on the first day and at the 12-month follow-up visit: vitreous hemorrhage, fibrovascular proliferation (FVP), rubeosis iridis, and neovascular glaucoma (NVG).

RESULTS

Levels of vitreous VEGF at the time of PPV were significantly higher in eyes with: vitreous hemorrhage on the first day after PPV (p = 0.003); FVP on the first day and 12 months after PPV (p = 0.002 and p < 0.001, respectively); iris rubeosis on the first day and 12 months after PPV surgery (p < 0.001, and p = 0.001, respectively); NVG on the first day and 12 months after PPV surgery (p = 0.043 and p = 0.011, respectively), compared to the eyes without complications.

CONCLUSIONS

Preoperative levels of VEGF in vitreous can be a useful biomarker and predictor of the postoperative outcome in terms of intraoperative and postoperative complications.

The treatment methods for post-stroke visual impairment: A systematic review

AIM

To provide a systematic overview of interventions for stroke related visual impairments.

METHOD

A systematic review of the literature was conducted including randomized controlled trials, controlled trials, cohort studies, observational studies, systematic reviews, and retrospective medical note reviews. All languages were included and translation obtained. This review covers adult participants (aged 18 years or over) diagnosed with a visual impairment as a direct cause of a stroke. Studies which included mixed populations were included if over 50% of the participants had a diagnosis of stroke and were discussed separately. We searched scholarly online resources and hand searched articles and registers of published, unpublished, and ongoing trials. Search terms included a variety of MESH terms and alternatives in relation to stroke and visual conditions. Article selection was performed by two authors independently. Data were extracted by one author and verified by a second. The quality of the evidence and risk of bias was assessed using appropriate tools dependant on the type of article.

RESULTS

Forty-nine articles (4142 subjects) were included in the review, including an overview of four Cochrane systematic reviews. Interventions appraised included those for visual field loss, ocular motility deficits, reduced central vision, and visual perceptual deficits.

CONCLUSION

Further high quality randomized controlled trials are required to determine the effectiveness of interventions for treating post-stroke visual impairments. For interventions which are used in practice but do not yet have an evidence base in the literature, it is imperative that these treatments be addressed and evaluated in future studies.

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.

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.

Blood pressure control for diabetic retinopathy

BACKGROUND

Diabetic retinopathy is a common complication of diabetes and a leading cause of visual impairment and blindness. Research has established the importance of blood glucose control to prevent development and progression of the ocular complications of diabetes. Simultaneous blood pressure control has been advocated for the same purpose, but findings reported from individual studies have supported varying conclusions regarding the ocular benefit of interventions on blood pressure.

OBJECTIVES

The primary aim of this review was to summarize the existing evidence regarding the effect of interventions to control or reduce blood pressure levels among diabetics on incidence and progression of diabetic retinopathy, preservation of visual acuity, adverse events, quality of life, and costs. A secondary aim was to compare classes of anti-hypertensive medications with respect to the same outcomes.

SEARCH METHODS

We searched a number of electronic databases including CENTRAL as well as ongoing trial registries. We last searched the electronic databases on 25 April 2014. We also reviewed reference lists of review articles and trial reports selected for inclusion. In addition, we contacted investigators of trials with potentially pertinent data.

SELECTION CRITERIA

We included in this review randomized controlled trials (RCTs) in which either type 1 or type 2 diabetic participants, with or without hypertension, were assigned randomly to intense versus less intense blood pressure control, to blood pressure control versus usual care or no intervention on blood pressure, or to different classes of anti-hypertensive agents versus placebo.

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently reviewed titles and abstracts from electronic and manual searches and the full text of any document that appeared to be relevant. We assessed included trials independently for risk of bias with respect to outcomes reported in this review. We extracted data regarding trial characteristics, incidence and progression of retinopathy, visual acuity, quality of life, and cost-effectiveness at annual intervals after study entry whenever provided in published reports and other documents available from included trials.

MAIN RESULTS

We included 15 RCTs, conducted primarily in North America and Europe, that had enrolled 4157 type 1 and 9512 type 2 diabetic participants, ranging from 16 to 2130 participants in individual trials. In 10 of the 15 RCTs, one group of participants was assigned to one or more anti-hypertensive agents and the control group received placebo. In three trials, intense blood pressure control was compared to less intense blood pressure control. In the remaining two trials, blood pressure control was compared with usual care. Five of the 15 trials enrolled type 1 diabetics, and 10 trials enrolled type 2 diabetics. Six trials were sponsored entirely by pharmaceutical companies, seven trials received partial support from pharmaceutical companies, and two studies received support from government-sponsored grants and institutional support.Study designs, populations, interventions, and lengths of follow-up (range one to nine years) varied among the included trials. Overall, the quality of the evidence for individual outcomes was low to moderate. For the primary outcomes, incidence and progression of retinopathy, the quality of evidence was downgraded due to inconsistency and imprecision of estimates from individual studies and differing characteristics of participants.For primary outcomes among type 1 diabetics, one of the five trials reported incidence of retinopathy and one trial reported progression of retinopathy after 4 to 5 years of treatment and follow-up; four of the five trials reported a combined outcome of incidence and progression over the same time interval. Among type 2 diabetics, 5 of the 10 trials reported incidence of diabetic retinopathy and 3 trials reported progression of retinopathy; one of the 10 trials reported a combined outcome of incidence and progression during a 4- to 5-year follow-up period. One trial in which type 2 diabetics participated had reported no primary (or secondary) outcome targeted for this review.The evidence from these trials supported a benefit of more intensive blood pressure control intervention with respect to 4- to 5-year incidence of diabetic retinopathy (estimated risk ratio (RR) 0.80; 95% confidence interval (CI) 0.71 to 0.92) and the combined outcome of incidence and progression (estimated RR 0.78; 95% CI 0.63 to 0.97). The available evidence provided less support for a benefit with respect to 4- to 5-year progression of diabetic retinopathy (point estimate was closer to 1 than point estimates for incidence and combined incidence and progression, and the CI overlapped 1; estimated RR 0.88; 95% CI 0.73 to 1.05). The available evidence regarding progression to proliferative diabetic retinopathy or clinically significant macular edema or moderate to severe loss of best-corrected visual acuity did not support a benefit of intervention on blood pressure: estimated RRs and 95% CIs 0.95 (0.83 to 1.09) and 1.06 (0.85 to 1.33), respectively, after 4 to 5 years of follow-up. Findings within subgroups of trial participants (type 1 and type 2 diabetics; participants with normal blood pressure levels at baseline and those with elevated levels) were similar to overall findings.The adverse event reported most often (7 of 15 trials) was death, yielding an estimated RR 0.86 (95% CI 0.64 to 1.14). Hypotension was reported from three trials; the estimated RR was 2.08 (95% CI 1.68 to 2.57). Other adverse ocular events were reported from single trials.

AUTHORS' CONCLUSIONS

Hypertension is a well-known risk factor for several chronic conditions in which lowering blood pressure has proven to be beneficial. The available evidence supports a beneficial effect of intervention to reduce blood pressure with respect to preventing diabetic retinopathy for up to 4 to 5 years. However, the lack of evidence to support such intervention to slow progression of diabetic retinopathy or to prevent other outcomes considered in this review, along with the relatively modest support for the beneficial effect on incidence, weakens the conclusion regarding an overall benefit of intervening on blood pressure solely to prevent diabetic retinopathy.

Anti-vascular endothelial growth factor for proliferative diabetic retinopathy

BACKGROUND

Proliferative diabetic retinopathy (PDR) is a complication of diabetic retinopathy that can cause blindness. Although panretinal photocoagulation (PRP) is the treatment of choice for PDR, it has secondary effects that can affect vision. An alternative treatment such as anti-vascular endothelial growth factor (anti-VEGF), which produces an inhibition of vascular proliferation, could improve the vision of people with PDR.

OBJECTIVES

To assess the effectiveness and safety of anti-VEGFs for PDR.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 3), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to April 2014), EMBASE (January 1980 to April 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and 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 28 April 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing anti-VEGFs to another active treatment, sham treatment or no treatment for people with PDR. We also included studies that assessed the combination of anti-VEGFs with other treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data and assessed risk of bias for all included trials. We calculated the risk ratio (RR) or the mean difference (MD), and 95% confidence intervals (CI).

MAIN RESULTS

We included 18 RCTs with 1005 participants (1131 eyes) of whom 57% were men. The median number of participants per RCT was 40 (range 15 to 261). The studies took place in Asia (three studies), Europe (two studies), the Middle East (seven studies), North America (three studies) and South America (three studies). Eight RCTs recruited people eligible for PRP, nine RCTs enrolled people with diabetes requiring vitrectomy and one RCT recruited people undergoing cataract surgery. The median follow-up was six months (range one to 12 months). Seven studies were at high risk of bias and the remainder were unclear risk of bias in one or more domains.Very low quality evidence from one study of 61 people showed that people treated with bevacizumab and PRP were less likely to lose 3 or more lines of visual acuity at 12 months compared with people treated with PRP alone (RR 0.19, 95% CI 0.05 to 0.81). People treated with anti-VEGF had an increased chance of gaining 3 or more lines of visual acuity but the effect was imprecise and compatible with no effect or being less likely to gain vision (RR 6.78, 95% CI 0.37 to 125.95). No other study reported these two outcomes. On average, people treated with anti-VEGF (bevacizumab, pegaptanib or ranibizumab) had better visual acuity at 12 months compared with people not receiving anti-VEGF (MD -0.07 logMAR, 95% CI -0.12 to -0.02; 5 RCTs, 373 participants, low quality evidence). There was some evidence to suggest a regression of PDR with smaller leakage on fluorescein angiography but it was difficult to estimate a pooled result from the two trials reporting this outcome. People receiving anti-VEGF were less likely to have vitreous or pre-retinal haemorrhage at 12 months (RR 0.32, 95% CI 0.16 to 0.65; 3 RCTs, 342 participants, low quality evidence). No study reported on fluorescein leakage or quality of life.All of the nine trials of anti-VEGF before or during vitrectomy investigated bevacizumab; most studies investigated bevacizumab before vitrectomy, one study investigated bevacizumab during surgery.People treated with bevacizumab and vitrectomy were less likely to lose 3 or more lines of visual acuity at 12 months compared with people given vitrectomy alone but the effect was imprecise and compatible with no effect or being more likely to lose vision (RR 0.49, 95% CI 0.08 to 3.14; 3 RCTs, 94 participants, low quality evidence). People treated with bevacizumab were more likely to gain 3 or more lines of visual acuity (RR 1.62, 95% CI 1.20 to 2.17; 3 RCTs, 94 participants, low quality evidence). On average, people treated with bevacizumab had better visual acuity at 12 months compared with people not receiving bevacizumab but there was uncertainty in the estimate (the CIs included 0; i.e. were compatible with no effect, and there was considerable inconsistency between studies; MD -0.24 logMAR, 95% CI -0.50 to 0.01; 6 RCTs, 335 participants, I(2) = 67%; low quality evidence). People receiving bevacizumab were less likely to have vitreous or pre-retinal haemorrhage at 12 months (RR 0.30, 95% CI 0.18 to 0.52; 7 RCTs, 393 participants, low quality evidence). No study reported on quality of life.Reasons for downgrading the quality of the evidence included risk of bias in included studies, imprecision of the estimates, inconsistency of effect estimates and indirectness (few studies reported at 12 months).Adverse effects were rarely reported and there was no evidence for any increased risk with anti-VEGF but given the relatively few studies that reported these, and the low event rate, the power of the analysis to detect any differences was low.

AUTHORS' CONCLUSIONS

There was very low or low quality evidence from RCTs for the efficacy and safety of anti-VEGF agents when used to treat PDR over and above current standard treatments. However, the results suggest that anti-VEGFs can reduce the risk of intraocular bleeding in people with PDR. Further carefully designed clinical trials should be able to improve this evidence.

Vitreous and plasma VEGF levels as predictive factors in the progression of proliferative diabetic retinopathy after vitrectomy

Purpose

To investigate the vitreous and plasma levels of vascular endothelial growth factor (VEGF) in patients with proliferative diabetic retinopathy (PDR) and to determine whether they predict a disease prognosis after primary vitrectomy.

Methods

Fifty patients (50 eyes) with PDR who underwent pars plana vitrectomy (PPV) and 56 healthy controls (56 eyes) were enrolled in this retrospective study. Clinical data were collected and analyzed. Vitreous and plasma VEGF concentrations were measured using enzyme-linked immunosorbent assays. VEGF levels and clinical data were compared and analyzed to see if they provide a prognosis of PDR progression after primary vitrectomy at more than 6 months follow-up. Correlation of VEGF concentrations between vitreous fluid and plasma was analyzed.

Results

The average BCVA was significantly improved after surgery (P<0.001). Vitreous and plasma VEGF levels were significantly elevated in PDR patients than those in healthy controls (P_vitreous<0.001; P_plasma<0.001). Both vitreous and plasma VEGF levels were significantly higher in PDR progression group than in stable group (P_vitreous<0.001; P_plasma = 0.004). Multivariate logistic regression analyses showed that the increased vitreous VEGF level was associated with the progression of PDR after primary PPV (OR = 1.539; P = 0.036). Vitreous VEGF level was positively associated with plasma VEGF level in PDR patients (P<0.001).

Conclusion

The increased VEGF level in vitreous fluid may be identified as a significant predictive factor for the outcome of vitrectomy in patients with PDR.

A review of anti-VEGF agents for proliferative diabetic retinopathy

Previous research has implicated vascular endothelial growth factor (VEGF) in the pathogenesis of diabetic retinopathy (DR). Although many studies reviewed the use of anti-VEGF for diabetic macular oedema, little has been written about the use of anti-VEGF for proliferative diabetic retinopathy (PDR). This study is a review of relevant publications dealing with the use of anti-VEGF for the treatment of PDR. The articles were identified through systematic searches of PUBMED and the Cochrane Central Register of Controlled Trials. At the end of each section, we summarized the level of evidence of the scientific literature. Off-label use of anti-VEGF agents was found to be beneficial in PDR, especially in cases with neovascular glaucoma, persistent vitreous haemorrhage, and before vitrectomy. The disadvantages of the use of anti-VEGF are its short-effect duration, causing tractional retinal detachment in cases with pre-existing pre-retinal fibrosis and endophthalmitis in rare cases. There is no conclusive evidence from large randomized trials regarding the efficacy of anti-VEGF treatment in PDR. However, numerous case series, sound biochemical mechanism of action, and increasing experience with using anti-VEGF drugs can be used to support the ongoing use of this treatment modality in selected patients.

Intravitreal bevacizumab for proliferative diabetic retinopathy with new dense vitreous hemorrhage after full panretinal photocoagulation

PURPOSE

To evaluate the efficacy and safety of intravitreal bevacizumab (IVB) injections for the treatment of proliferative diabetic retinopathy (PDR) with new dense vitreous hemorrhage (VH) after previous full panretinal photocoagulation (PRP).

METHODS

Prospective study of consecutive PDR with prior complete PRP patients, who presented with new dense VH, were treated with IVB injection. Complete ophthalmic examination and/or ocular ultrasonography were performed at baseline and 1, 6, and 12 weeks and 6, 9, and 12 months after the first injection. Reinjection was done in non-clearing and recurrent VH.

RESULTS

Eighteen eyes of 18 patients, mean age 47.7 ± 12.69 years were included. In all, 14 (77.78%) patients had type 2 diabetes mellitus. Systemic hypertension and dyslipidemia were the most common systemic diseases. All cases were phakic eye with previous complete PRP. Patients received 1.6 ± 0.42 intravitreal injections over a 12-month period. VH cleared completely in 7 (38.89%), 9 (50%), and 13 (72.22%) eyes after 6 weeks, 6 months, and 12 months, respectively. Re-bleeding, however, occurred in 10 (56%) eyes during the follow-up period, and 5 (28%) eyes still had residual VH at the last visit. Statistically significant visual gain was observed in 9 (50%) eyes. Unfortunately, 2 (11%) eyes had severe visual loss because of the tractional retinal detachment (TRD). Mild ocular complication was detected in one patient.

CONCLUSION

IVB injection had good efficacy and safety for treatment of new VH in patients with PDR and prior complete PRP. This procedure may be especially relevant for diabetic patients at high-risk for surgical intervention.

Angiofibrotic response to vascular endothelial growth factor inhibition in diabetic retinal detachment: report no. 1

OBJECTIVES To assess the effect of bevacizumab injection on connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF) in the ocular fluids of patients with diabetic traction retinal detachment, and to determine whether intraoperative and postoperative complications are decreased in eyes given adjunctive preoperative bevacizumab injection. METHODS Twenty eyes of 19 patients were randomized to receive intravitreal bevacizumab or sham injection 3 to 7 days before vitrectomy for severe proliferative diabetic retinopathy. We collected aqueous samples before injection and at the time of vitrectomy and extracted undiluted vitreous samples. RESULTS Five eyes had decreased vascularization of membranes from preinjection to the time of vitrectomy (all in the bevacizumab treatment arm). Median visual acuities were 20/400 in control eyes at baseline and postoperative month 3 (POM3) and 8/200 in the bevacizumab-treated group at baseline and 20/100 at POM3 (P= .30 between control and bevacizumab-treated groups at POM3). All retinas were attached at POM3. Vitreous levels of VEGF were significantly lower in the bevacizumab group than in the control group (P= .03). Vitreous levels of CTGF were slightly lower in the bevacizumab group compared with the control group, but this difference was not statistically significant (P= .38). Levels of CTGF in the aqueous were strongly correlated with CTGF levels in the vitreous of controls (Spearman correlation coefficient, 0.95 [P< .001]). CONCLUSIONS Intravitreal bevacizumab injection reduces vitreous levels of VEGF and produces a clinically observable alteration in diabetic fibrovascular membranes. Ocular fluid levels of CTGF are not significantly affected within the week after VEGF inhibition. Retinal reattachment rates and visual acuity are not significantly altered by preoperative intravitreal bevacizumab injection at POM3. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01270542.

Diabetic angiopathy and angiogenic defects

Diabetes is one of the most serious health problems in the world. A major complication of diabetes is blood vessel disease, termed angiopathy, which is characterized by abnormal angiogenesis. In this review, we focus on angiogenesis abnormalities in diabetic complications and discuss its benefits and drawbacks as a therapeutic target for diabetic vascular complications. Additionally, we discuss glucose metabolism defects that are associated with abnormal angiogenesis in atypical diabetic complications such as cancer.

Interventions for age-related visual problems in patients with stroke

BACKGROUND

The prevalence of eye problems increases with age and, consequently, so does the level of visual impairment. As the incidence of stroke also increases with age, a significant proportion of stroke patients will have age-related visual problems. It is possible that the effect of interventions for age-related visual problems may differ in the population of stroke patients compared to the wider population of older people. The interaction between the problems arising directly from stroke and those arising directly from age-related visual problems will be complex. Interventions for age-related visual problems may also be affected by the presence of other stroke-related co-morbidities. Consequently, the nature and outcome of interventions for age-related visual problems may be different in patients with stroke.

OBJECTIVES

The aim of this review is to determine if interventions for age-related visual problems improve functional ability following stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (March 2011), the Cochrane Eyes and Vision Group Trials Register (December 2009) and nine electronic bibliographic databases including: the Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), MEDLINE (1950 to February 2011), EMBASE (1980 to February 2011), CINAHL (1982 to February 2011), AMED (1985 to February 2011) and PsycINFO (1967 to February 2011). We also searched reference lists and trials registers, handsearched journals and conference proceedings, and contacted experts.

SELECTION CRITERIA

Randomised trials in adults after stroke, where the intervention is specifically targeted at assessing, treating or correcting age-related visual problems, or improving the ability of the patient to cope with visual impairment. Primary outcome was functional ability in activities of daily living and secondary outcomes included functional ability in extended activities of daily living, visual acuity, visual field, visual function, balance, falls, depression and anxiety, discharge destination/residence after stroke, quality of life and social isolation, adverse events and death.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened abstracts and planned to extract data and appraise trials. We planned that assessment of methodological quality would be undertaken for allocation concealment, blinding of outcome assessor, method of dealing with missing data and other potential sources of bias.

MAIN RESULTS

We considered 7357 titles, 460 abstracts and 85 full papers. We identified no studies for inclusion in this review.

AUTHORS' CONCLUSIONS

There are no implications for practice arising from this review. Evidence relating to the management of patients (from the general population) with age-related visual problems is available from other Cochrane reviews and is likely to be the best evidence available for making treatment decisions about individual patients. Subgroup analyses within these reviews to explore the effect of interventions for age-related visual problems in patients with stroke are recommended. We recommend that the objectives and selection criteria for this Cochrane review are amended and clarified prior to any future updates.

A shift in the balance of vascular endothelial growth factor and connective tissue growth factor by bevacizumab causes the angiofibrotic switch in proliferative diabetic retinopathy

Introduction

In proliferative diabetic retinopathy (PDR), vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF) may cause blindness by neovascularisation followed by fibrosis of the retina. It has previously been shown that a shift in the balance between levels of CTGF and VEGF in the eye is associated with this angiofibrotic switch. This study investigated whether anti-VEGF agents induce accelerated fibrosis in patients with PDR, as predicted by this model.

Methods

CTGF and VEGF levels were measured by ELISA in 52 vitreous samples of PDR patients, of which 24 patients had received intravitreal bevacizumab 1 week to 3 months before vitrectomy, and were correlated with the degree of vitreoretinal fibrosis as determined clinically and intra-operatively.

Results

CTGF correlated positively, and VEGF correlated negatively with the degree of fibrosis. The CTGF/VEGF ratio was the strongest predictor of fibrosis. Clinically, increased fibrosis was observed after intravitreal bevacizumab.

Conclusions

These results confirm that the CTGF/VEGF ratio is a strong predictor of vitreoretinal fibrosis in PDR, and show that intravitreal anti-VEGF treatment causes increased fibrosis in PDR patients. These findings provide strong support for the model that the balance of CTGF and VEGF determines the angiofibrotic switch, and identify CTGF as a possible therapeutic target in the clinical management of PDR.