Comparing intravitreal triamcinolone acetonide and bevacizumab injections for the treatment of diabetic macular oedema: a randomized double-blind study

Comparing the efficacy of glucocorticoids and anti-VEGF in treating diabetic macular edema: systematic review and comprehensive analysis

Introduction

The aim of this study was to better understand the efficacy of various drugs, such as glucocorticoids and anti-vascular endothelial growth factors (VEGF), in the treatment of diabetic macular edema (DME), and to evaluate various clinical treatment regimens consisting of different therapeutic measures.

Methods

This study included randomized controlled trials up to February 2023 comparing the efficacy of corticosteroid-related therapy and anti-VEGF therapy. PubMed, the Cochrane Library, and Embase were searched, and the quality of the studies was carefully assessed. Finally, 39 studies were included.

Results

Results at 3-month followup showed that intravitreal injection of bevacizumab (IVB) + triamcinolone acetonide (TA) was the most beneficial in improving best-corrected visual acuity and reducing the thickness of macular edema in the center of the retina in patients with DME. Results at 6-month follow-up showed that intravitreal dexamethasone (DEX) was the most effective in improving patients' bestcorrected visual acuity and reducing the thickness of central macular edema.

Discussion

Overall, IVB+TA was beneficial in improving best-corrected visual acuity and reducing central macular edema thickness over a 3-month follow-up period, while DEX implants had a better therapeutic effect than anti-VEGF agents at 6 months, especially the patients with severe macular edema and visual acuity impaired.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=397100, identifier CRD42023397100.

Intravitreal steroids compared to anti-vascular endothelial growth factor treatment for diabetic macular edema: a meta-analysis

TOPIC

Diabetic macular edema (DME) can be treated with either intravitreal anti-VEGF injections or intravitreal corticosteroid injections.

CLINICAL RELEVANCE

We provide an updated meta-analysis of the comparative efficacy and safety of intravitreal steroids and anti-VEGF agents for DME.

METHODS

A systematic search was performed on Ovid MEDLINE, Embase, and Cochrane Controlled Register of Trials from January 2005 to November 2021. Inclusion criteria included published randomized clinical trial data comparing the efficacy and safety of intravitreal steroids versus anti-VEGF agents for DME. Nonrandomized, noncomparative, and non-English studies were excluded.

RESULTS

Fourteen randomized clinical trials reporting on 827 eyes were included. Between these 2 treatments, our analysis revealed no significant difference in best-corrected visual acuity (BCVA) outcomes at 3 months (P = 0.11), 6 months (P = 0.21), 12 months (P = 0.24), and final follow-up (P = 0.91). Retinal thickness was significantly lower with steroid treatment at 3 months (P = 0.04), 6 months (P < 0.00001), and final follow-up (weighted mean difference = 39.99 μm; 95% confidence interval [CI] = 14.58,65.41; P = 0.002); however, there was no significant difference at 12 months (P = 0.18). Intravitreal anti-VEGF agents were associated with a lower incidence of intraocular pressure-related adverse events (risk ratio = 0.13; 95% CI = 0.05, 0.34; P < 0.00001). There was no significant difference between comparators for other adverse events, including cataract-related adverse events (P = 0.22).

CONCLUSIONS

Overall, intravitreal steroid treatment for DME was associated with no significant differences in BCVA, a significantly lower retinal thickness, and a higher risk of intraocular pressure-related events. The certainty of evidence ranged from low to moderate and the analysis was limited by heterogeneity. Our results reinforce the importance of a continual reevaluation of the role of intravitreal steroids in DME management.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Intravitreal bevacizumab versus intravitreal triamcinolone for diabetic macular edema-Systematic review, meta-analysis and meta-regression

BACKGROUND

The most frequent cause of vision loss from diabetic retinopathy is diabetic macular edema (DME). Earlier clinical trials tried to examine the role of intravitreal triamcinolone (IVT) and intravitreal bevacizumab (IVB) in DME; they either qualified IVT over IVB or IVB over IVT or did not exhibit a significant difference.

OBJECTIVE

This paper aims to compare the efficacy and safety of IVB versus IVT alone or combined IVB+IVT in the treatment of DME.

METHODS

We systematically searched PubMed, CENTRAL, Scopus, Embase, Science Direct, OVID, and Web of Science for randomized controlled trials of IVB versus IVT alone or combined IVB+IVT and IVT versus the combined IVB+IVT in DME patients.

RESULTS

A total of 1243 eyes of 17 trials were included in our meta-analysis and regression. Repeated injections of IVB were superior at improving VA comparing with those of IVT at 12, 24, 48-weeks, and IVB+IVT at 12, 24, 48-weeks. Single injections were comparable across the three arms regarding BCVA improvement. CMT reductions were also comparable across the three arms. Meanwhile, the overall safety regarding intraocular pressure and intraocular hypertension significantly favored the IVB group. Improvement in VA was best modified with CMT reduction from 480 um to 320um. This association was significant at 12-weeks in the three arms and persisted till 24-weeks and 48-weeks exclusively in the IVB group.

CONCLUSIONS AND RELEVANCE

Our analysis reveals that repeated successive injections associate with better BCVA compared to single injection. Current evidence affirms that IVB is superior to IVT and IVB+IVT at improving BCVA, comparable at reducing CMT, and presents a better safety profile in the treatment of DME.

Intravitreal steroids for macular edema in diabetes

BACKGROUND

Diabetic macular edema (DME) is secondary to leakage from diseased retinal capillaries with thickening of central retina, and is an important cause of poor central visual acuity in people with diabetic retinopathy. Intravitreal steroids have been used to reduce retinal thickness and improve vision in people with DME.

OBJECTIVES

To assess the effectiveness and safety of intravitreal steroid therapy compared with other treatments for DME.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase on 15 May, 2019. We also searched reference lists, Science Citation Index, conference proceedings, and relevant trial registers. We conducted a top up search on 21 October, 2020.

SELECTION CRITERIA

We included randomized controlled trials that evaluated any type of intravitreal steroids as monotherapy against any other intervention (e.g. observation, laser photocoagulation, anti-vascular endothelial growth factor (antiVEGF) for DME.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and risk of bias and extracted data. Where appropriate, we performed meta-analyses.

MAIN RESULTS

We included 10 trials (4348 participants, 4505 eyes). These trials compared intravitreal steroid therapies versus other treatments, including intravitreal antiVEGF therapy, laser photocoagulation, and sham injection. Most trials had an overall unclear or high risk of bias. One trial (701 eyes ) compared intravitreal dexamethasone implant 0.7mg with sham. We found moderate-certainty evidence that dexamethasone leads to slightly more improvement of visual acuity than sham at 12 months (mean difference [MD] -0.08 logMAR, 95% confidence interval [CI] -0.12 to -0.05 logMAR). Regarding improvement of three or more lines of visual acuity, there was moderate-certainty evidence in favor of dexamethasone at 12 months, but the CI covered the null value (risk ratio (RR) 1.39, 95% CI 0.91 to 2.12). Regarding adverse events, dexamethasone increased by about four times the risk of cataract progression and the risk of using intraocular pressure (IOP)-lowering medications compared to sham (RR 3.89, 95% CI 2.75 to 5.50 and RR 4.54, 95% CI 3.19 to 6.46, respectively; moderate-certainty evidence); about 4 in 10 participants treated with dexamethasone needed IOP-lowering medications. Two trials (451 eyes) compared intravitreal dexamethasone implant 0.7mg with intravitreal antiVEGF (bevacizumab and ranibizumab). There was moderate-certainty evidence that visual acuity improved slightly less with dexamethasone compared with antiVEGF at 12 months (MD 0.07 logMAR, 95% CI 0.04 to 0.09 logMAR; 2 trials; 451 participants/eyes; I² = 0%). The RR of gain of three or more lines of visual acuity was inconsistent between trials, with one trial finding no evidence of a difference between dexamethasone and bevacizumab at 12 months (RR 0.99, 95% CI 0.70 to 1.40; 1 trial; 88 eyes), and the other, larger trial finding the chances of vision gain were half with dexamethasone compared with ranibizumab (RR 0.50, 95% CI 0.32 to 0.79; 1 trial; 432 participants). The certainty of evidence was low. Cataract progression and the need for IOP-lowering medications increased more than 4 times with dexamethasone implant compared to antiVEGF (moderate-certainty evidence). One trial (560 eyes) compared intravitreal fluocinolone implant 0.19mg with sham. There was moderate-certainty evidence that visual acuity improved slightly more with fluocinolone at 12 months (MD -0.04 logMAR, 95% CI -0.06 to -0.01 logMAR). There was moderate-certainty evidence that an improvement in visual acuity of three or more lines was more common with fluocinolone than with sham at 12 months (RR 1.79, 95% CI 1.16 to 2.78). Fluocinolone also increased the risk of cataract progression (RR 1.63, 95% CI 1.35 to 1.97; participants = 335; moderate-certainty evidence), which occurred in about 8 in 10 participants, and the use of IOP-lowering medications (RR 2.72, 95% CI 1.87 to 3.98; participants = 558; moderate-certainty evidence), which were needed in 2 to 3 out of 10 participants. One small trial with 43 participants (69 eyes) compared intravitreal triamcinolone acetonide injection 4 mg with sham. There may be a benefit in visual acuity at 24 months (MD -0.11 logMAR, 95% CI -0.20 to -0.03 logMAR), but the certainty of evidence is low. Differences in adverse effects were poorly reported in this trial. Two trials (615 eyes) compared intravitreal triamcinolone acetonide injection 4mg with laser photocoagulation and reached discordant results. The smaller trial (31 eyes followed up to 9 months) found more visual acuity improvement with triamcinolone (MD -0.18 logMAR, 95% CI -0.29 to -0.07 logMAR), but a larger, multicenter trial (584 eyes, 12-month follow-up) found no evidence of a difference regarding change in visual acuity (MD 0.02 logMAR, 95% CI -0.03 to 0.07 logMAR) or gain of three or more lines of visual acuity (RR 0.85, 95% CI 0.55 to 1.30) (overall low-certainty evidence). Cataract progression was about three times more likely (RR 2.68, 95% CI 2.21 to 3.24; moderate-certainty evidence) and the use of IOP-lowering medications was about four times more likely (RR 3.92, 95% CI 2.59 to 5.96; participants = 627; studies = 2; I² = 0%; moderate-certainty evidence) with triamcinolone. About 1 in 3 participants needed IOP-lowering medication. One small trial (30 eyes) compared intravitreal triamcinolone acetonide injection 4mg with intravitreal antiVEGF (bevacizumab or ranibizumab). Visual acuity may be worse with triamcinolone at 12 months (MD 0.18 logMAR, 95% CI 0.10 to 0.26 logMAR); the certainty of evidence is low. Adverse effects were poorly reported in this trial. Four trials reported data on pseudophakic participants, for whom cataract is not a concern. These trials found no decrease in visual acuity in the second treatment year due to cataract progression.

AUTHORS' CONCLUSIONS

Intravitreal steroids may improve vision in people with DME compared to sham or control. Effects were small, about one line of vision or less in most comparisons. More evidence is available for dexamethasone or fluocinolone implants when compared to sham, and the evidence is limited and inconsistent for the comparison of dexamethasone with antiVEGF treatment. Any benefits should be weighed against IOP elevation, the use of IOP-lowering medication and, in phakic patients, the progression of cataract. The need for glaucoma surgery is also increased, but remains rare.

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.

Therapeutic Effect of Traditional Chinese Medicine on a Rat Model of Branch Retinal Vein Occlusion

Branch retinal vein occlusion (BRVO) is a common retinal vascular disorder leading to visual impairment. Currently, the general strategies for BRVO are symptomatic therapies. Cardiovascular aspects are essential risk factors for BRVO. The traditional Chinese medicine hexuemingmu (HXMM), consisting of tanshinol and baicalin, dilates the vasculature and accelerates microcirculation. Therefore, the aim of this study was to determine the efficacy and possible mechanism of HXMM in a BRVO rat model established by laser photocoagulation. Successful BRVO rat models were treated with different doses of HXMM. Fundus photography and fluorescein fundus angiography (FFA) of the animals were applied. The retinal layers were measured by optical coherence tomography (OCT). Full-field electroretinography (ffERG) was applied to evaluate the retinal function. The ear vein flow velocity was measured via a microcirculation detector. The expression of the vascular endothelial growth factor (VEGF-α) was measured via western blotting and immunofluorescent staining. Our study found that retinal edema predominantly occurred in the inner nuclear layer (INL) and outer nuclear layer (ONL). The retinal edema of the treated groups was significantly relieved in the early stage of BRVO as visualized via OCT detection and HE staining. The amplitudes of the b wave and oscillatory potentials (OPs) waves of ffERG in the treated groups were increased compared with those of the control group at several detection points (3, 5, 7, 10, 14, and 21 d postocclusion). The expression of VEGF-α was reduced in the treated groups at an early stage of BRVO. Furthermore, the ear vein flow velocity of the HXMM treatment groups was faster than that of the control group. Thus, our study indicates that the traditional Chinese medicine HXMM could ameliorate retinal edema and rescue the retinal structure and function in BRVO models through promoting occluded vein recanalization, improving microcirculation, and regulating the expression of VEGF-α.

Effectiveness and Safety of Intravitreal Dexamethasone Implant (Ozurdex) in Patients with Diabetic Macular Edema: A Real-World Experience

INTRODUCTION

There are few real-life studies on the intravitreal 0.7-mg dexamethasone implant for the treatment of diabetic macular edema (DME) conducted in Latin America. We aimed to assess the effectiveness and safety of this implant in clinical practice.

METHODS

Twenty-seven centers from Brazil and one from Argentina provided information on patients with DME treated with Ozurdex. The efficacy outcome variables were best-corrected visual acuity (BCVA) in Snellen and central retinal thickness (CRT). Safety was assessed by the elevation in intraocular pressure (IOP), occurrence of cataracts, and adverse events.

RESULTS

A total of 329 eyes (both treated cases and naïve eyes) from 282 patients underwent treatment. The time since diagnosis of DME ranged from 1 to 156 months. The median BCVA was 0.7 logMAR/50 letters at baseline and 0.3 logMAR/70 letters after treatment (both p < 0.001). Median CRT values decreased from 425 µm at baseline to 270 µm after treatment (p < 0.001). Increases in IOP of at least 10 mm Hg were observed in 7.4% of eyes, and 4% of eyes had cataract evolution. No cases of endophthalmitis were reported.

CONCLUSION

These real-life results suggest that the intravitreal dexamethasone implant is effective and safe for eyes with DME.

Comparison of intravitreal bevacizumab and triamcinolone acetonide theraphies for diffuse diabetic macular edema

AIM

To compare therapeutic effects of intravitreal triamcinolone acetonide (IVTA) versus intravitreal bevacizumab (IVB) injections for bilateral diffuse diabetic macular edema (DDME).

METHODS

Forty eyes of 20 patients with bilateral DDME participated in this study. For each patient, 4 mg/0.1 mL IVTA was injected to one eye and 2.5 mg/0.1 mL IVB was injected to the other eye. The effects of injection for diabetic macular edema (DME) were evaluated using best-corrected visual acuity (BCVA), central macular thickness (CMT) by optical coherence tomography (OCT) and intraocular pressure (IOP) by applanation tonometer. Patients underwent eye examinations, including BCVA, CMT, and IOP at pre-injection, 1, 4, 8, 12 and 24wk after injection. During the follow-up, second injections were performed to eyes which have CMT greater than 400 µm at 12wk for salvage therapy.

RESULTS

BCVA (logarithm of the minimum angle of resolution) at pre-injection, 1, 4, 8, 12 and 24wk after injection was 0.71±0.19, 0.62±0.23, 0.63±0.12, 0.63±0.13, 0.63±0.14 and 0.61±0.24 in the IVTA group and 0.68±0.25, 0.61±0.22, 0.60±0.24, 0.62±0.25, 0.65±0.26 and 0.59±0.25 in the IVB group, respectively. CMT (µm) at pre-injection, 1, 4, 8, 12 and 24wk after injection was 544±125, 383±96, 335±87, 323±87, 333±92, 335±61 in the IVTA group and 514±100, 431±86, 428±107, 442±106, 478±112, 430±88 in the IVB group respectively. Reduction ratios of mean CMT were 29% at 1wk, 38% at 4wk, 40% at 8wk, 38% at 12wk, and 38% at 24wk in the IVTA group. Second IVTA injections were performed to the 6 eyes (30%) at 12wk. Reduction ratios of mean CMT were 16% at 1wk, 17% at 4wk, 14% at 8wk, 7% at 12wk, and 16% at 24wk in the IVB group. Second IVB injections were performed to the 15 eyes (75%) at 12wk.

CONCLUSION

This study showed earlier and more frequent macular edema recurrences in the eyes treated with bevacizumab compared with the ones treated with triamcinolone acetonide. Triamcinolone acetonide was found to provide more efficient and long-standing effect in terms of reducing CMT compared with the bevacizumab.

Comparative Effectiveness of Intravitreal Bevacizumab With or Without Triamcinolone Acetonide for Treatment of Diabetic Macular Edema

Background: Bevacizumab and triamcinolone acetonide (TA) are both common choices for treatment of diabetic macular edema (DME), but the comparative efficacy of combined or separate applications is still not determined. Objectives: To compare the treatment efficacy of intravitreal bevacizumab (IVB) and the combination of IVB and intravitreal triamcinolone (IVT) for DME patients. Methods: PubMed, EMBASE, and the Cochrane library were systematically reviewed for randomized controlled trials comparing IVB with IVB/IVT. Data on visual acuity (VA) and central macular thickness (CMT) changes at 3 and 6 months were extracted and data on adverse events were collected. A meta-analysis was performed using the software RevMan 5.3. The methodological quality and bias risks were also evaluated. Results: VA improved more significantly in the IVB/IVT group compared with the IVB group at 3 months (mean difference [MD] = 0.07; 95% CI = 0.01 to 0.13), whereas there was no significant difference at 6 months (MD = −0.01; 95%CI = −0.11 to 0.09). The CMT reduction in the IVB/IVT group was significantly greater than that in the IVB group at 3 months (MD = 48.40; 95%CI = 30.23 to 66.57), but no statistically significant difference was found at 6 months (MD = 0.47; 95%CI = −24.11 to 25.04). Ocular hypertension was detected in 9/243 eyes in the IVB/IVT group but none of the IVB eyes. Conclusion: IVB/IVT is more effective for improving VA and decreasing CMT at 3 months in DME. A single injection of TA along with the first IVB could improve outcome within 3 months, but this is not sustained at 6 months. Continuous IVT/IVB treatment should be performed in further trials to clarify its long-term potential efficacy.

Neuropeptides and diabetic retinopathy

Diabetic retinopathy, a common complication of diabetes, develops in 75% of patients with type 1 and 50% of patients with type 2 diabetes, progressing to legal blindness in about 5%. In the recent years, considerable efforts have been put into finding treatments for this condition. It has been discovered that peptidergic mechanisms (neuropeptides and their analogues, activating a diverse array of signal transduction pathways through their multiple receptors) are potentially important for consideration in drug development strategies. A considerable amount of knowledge has been accumulated over the last three decades on human retinal neuropeptides and those elements in the pathomechanisms of diabetic retinopathy which might be related to peptidergic signal transduction. Here, human retinal neuropeptides and their receptors are reviewed, along with the theories relevant to the pathogenesis of diabetic retinopathy both in humans and in experimental models. By collating this information, the curative potential of certain neupeptides and their analogues/antagonists can also be discussed, along with the existing clinical treatments of diabetic retinopathy. The most promising peptidergic pathways for which treatment strategies may be developed at present are stimulation of the somatostatin-related pathway and the pituitary adenylyl cyclase-activating polypeptide-related pathway or inhibition of angiotensinergic mechanisms. These approaches may result in the inhibition of vascular endothelial growth factor production and neuronal apoptosis; therefore, both the optical quality of the image and the processing capability of the neural circuit in the retina may be saved.

Intravitreal triamcinolone versus intravitreal bevacizumab for diabetic macular edema: a meta-analysis

AIM

To compare the efficacy of the sole intravitreal triamcinolone (IVT) versus intravitreal bevacizumab (IVB) alone or IVB combined with IVT in the treatment of diabetic macular edema (DME).

METHODS

Pertinent publications were identified through systematic searches of database and manually searching. Methodological quality of the literatures was valuated according to the Jadad Score. RevMan 5.1.0 was used to do the meta-analysis. Heterogeneity was determined and sensitivity was conducted.

RESULTS

Six studies were ultimately included in the meta-analysis. The results of our analysis showed IVT had a statistically significant improvement in vision over the IVB at 1 month and 3 months (P<0.01). However, the reduction was not significant regarding central macular thickness (CMT) during the earlier (1 month and 3 months) follow-up period (P=0.12, P=0.41, respectively). At later visit (6 months), IVT had a significant decrease in CMT when compared to IVB (P<0.01) while no significant improvement in visual acuity (VA) was observed (P=0.14). The incidence of intraocular hypertension was 13/102 in IVT group during follow-up period while 0/103 in IVB group. The difference was significant (P<0.01). With regards to IVT versus IVB combined with IVT, there were no significant differences in CMT at 1 month (P=0.86) and 3 months (P=0.06). The incidence of intraocular hypertension was 6/67 in IVT group during follow-up period while 4/66 in IVB+IVT group. But the difference was not significant (P=0.53).

CONCLUSION

Current evidence shows IVT is superior in improving VA at earlier follow-up (1 month and 3 months) and in reducing CMT at later follow-up (6 months) for DME. At other time, it is in favor of IVT treatment but there are no statistically significances. However, IVT has the side-effect of ocular hypertension. There is no adequate evidence of the benefit adding IVB to IVT in contrast to IVT alone.

Current treatments in diabetic macular oedema: systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review is to appraise the evidence for the use of anti-VEGF drugs and steroids in diabetic macular oedema (DMO) as assessed by change in best corrected visual acuity (BCVA), central macular thickness and adverse events

DATA SOURCE

MEDLINE, EMBASE, Web of Science with Conference Proceedings and the Cochrane Library (inception to July 2012). Certain conference abstracts and drug regulatory web sites were also searched.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Randomised controlled trials were used to assess clinical effectiveness and observational trials were used for safety. Trials which assessed triamcinolone, dexamethasone, fluocinolone, bevacizumab, ranibizumab, pegaptanib or aflibercept in patients with DMO were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Risk of bias was assessed using the Cochrane risk of bias tool. Study results are narratively described and, where appropriate, data were pooled using random effects meta-analysis.

RESULTS

Anti-VEGF drugs are effective compared to both laser and placebo and seem to be more effective than steroids in improving BCVA. They have been shown to be safe in the short term but require frequent injections. Studies assessing steroids (triamcinolone, dexamethasone and fluocinolone) have reported mixed results when compared with laser or placebo. Steroids have been associated with increased incidence of cataracts and intraocular pressure rise but require fewer injections, especially when steroid implants are used.

LIMITATIONS

The quality of included studies varied considerably. Five of 14 meta-analyses had moderate or high statistical heterogeneity.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The anti-VEGFs ranibizumab and bevacizumab have consistently shown good clinical effectiveness without major unwanted side effects. Steroid results have been mixed and are usually associated with cataract formation and  intraocular pressure increase. Despite the current wider spectrum of treatments for DMO, only a small proportion of patients recover good vision (≥20/40), and thus the search for new therapies needs to continue.

Pharmacokinetic study of vitreous and serum concentrations of triamcinolone acetonide after posterior sub-tenon's injection

PURPOSE

To compare a theoretical pharmacokinetic model of triamcinolone acetonide after posterior sub-Tenon's injection with experimental serum and undiluted vitreous triamcinolone acetonide concentrations obtained during pars plana vitrectomy.

DESIGN

Clinical-practice, prospective, interventional case series study.

METHODS

This study compared computer-modeled triamcinolone acetonide diffusion after posterior sub-Tenon's injection with triamcinolone acetonide levels in experimental undiluted vitreous and serum samples from 57 patients undergoing vitrectomy assessed via mass spectrometry and high-pressure liquid chromatography. At least 5 pairs of samples were collected at each of 7 time points (1 day, 3 days, and 1, 2, 3, 4, and 8 weeks) after triamcinolone acetonide injection, with 6 controls without injection. Cortisol levels were measured in 31 sets of samples.

RESULTS

The theoretical model predicted that triamcinolone acetonide levels in systemic blood, vitreous, and choroidal extracellular matrix would plateau after 3 days at 15 ng/mL, 227 ng/mL and 2230 ng/mL, respectively. Experimental vitreous levels of triamcinolone peaked at 111 ng/mL at day 1, then reached a plateau in the range 15 to 25 ng/mL, while serum triamcinolone levels peaked at day 3 near 35 ng/mL and plateaued near 2 to 8 ng/mL. Serum triamcinolone and cortisol levels were inversely correlated (Spearman -0.42, P = .02).

CONCLUSIONS

The theoretical model predicts efficient delivery of triamcinolone acetonide from the posterior sub-Tenon's space to the extracellular choroidal matrix. The experimental findings demonstrate low levels of serum triamcinolone that alter systemic cortisol levels and higher vitreous levels lasting at least 1 month. Both assessments support trans-scleral delivery of posterior sub-Tenon's triamcinolone.