Steroid injection in addition to macular laser grid photocoagulation in diabetic macular oedema: a systematic review

Laser Treatment Modalities for Diabetic Retinopathy

Diabetes is a chronic progressive metabolic disorder that is caused by the body's inability to regulate blood glucose levels. If uncontrolled, it can lead to various complications. Among its various complications, long-term diabetes leads to diabetic retinopathy (DR). It is a disease involving blood vessels and the destruction of retinal nerves. It is usually classified into two types: proliferative diabetic retinopathy (PDR) and nonproliferative diabetic retinopathy (NPDR). It progresses and causes loss of vision. The leading cause of loss of vision is diabetic macular edema (DME). The argon laser is used as a modality in the management of PDR. There are various types of laser photocoagulation, such as peripheral retinal laser photocoagulation, focal macular laser photocoagulation, and grid photocoagulation. DR results in various adverse consequences such as vitreous hemorrhage, fibrosis, traction, detachment of the retina, and glaucoma. To assess DR, a detailed fundus examination with a slit lamp biomicroscope needs to be done. Seven-standard field stereoscopic-color fundus photography needs to be done for documentation and follow-up. Patients with diabetes mellitus (DM) type 1 have a greater risk of suffering from DR. Another major complication of the condition is DME, which is characterized by an increase in the permeability of vessels and the thickening of the central part of the retina along with the accumulation of hard exudates on the macula. This article discusses various laser therapy modalities for the treatment of DR, their types, mechanisms, and aims. Clinical features of DR include abnormal dilatation of capillaries, and outpouchings in the form of microaneurysm from the capillary wall are one of the earliest and most dangerous changes; later, non-perfusion of the retina occurs, which is associated with cotton wool spots and blot hemorrhages. In patients suffering from PDR and maculopathy, peripheral retinal laser photocoagulation is used as a mode of intervention.

Macular laser photocoagulation with or without intravitreal triamcinolone pretreatment for diabetic macular edema: a result from five randomized controlled trials

AIM

To assess possible benefits of intravitreal triamcinolone acetonide (IVTA) injection as pretreatment for macular laser photocoagulation (MLP) in patients with diabetic macular edema (DME).

METHODS

Published randomized controlled trials (RCTs) concerning MLP with or without IVTA pretreatment for DME were retrieved from databases CNKI, Medline, EMbase, Web of Science, and the Cochrane Library. A Meta-analysis on eligible studies was conducted using RevMan 5.0 software. Two investigators independently assessed the quality of the trials and extracted data. Main outcome measures included the change in best corrected visual acuity (BCVA), difference in central macular thickness (CMT) and adverse events reporting in particular elevated intraocular pressure within the follow-up period. The results were pooled using weight mean difference (WMD) or odds risk (OR) with their corresponding 95% confidence intervals (CI). A fixed- or random-effect model was employed depending on the heterogeneity of the inclusion trials.

RESULTS

Finally, five independent RCTs were identified and used for comparing MLP with IVTA pretreatment (131 eyes) with MLP alone (133 eyes, control group). The overall study quality was relatively higher according to the modified Jadad scale. The Meta-analysis showed that MLP with IVTA pretreatment significantly reduced CMT at one, three and six months (P=0.002, 0.0003 and 0.04, respectively), compared with MLP alone. The IVTA pretreatment group showed statistically significant improvements in BCVA at the one-month follow up as compared with the control group (P=0.03). At three- and six-month follow up, there was a beneficial trend towards improving visual acuity in the IVTA pretreatment group without statistical significance between groups (P=0.06 and 0.20, respectively). The incidence of elevation of intraocular pressure was significantly higher in the IVTA pretreatment group than in the control group (P<0.0001). No evidence of publication bias was present according to Begg's test and Egger's test. There was a low level of heterogeneity in the included studies.

CONCLUSION

This Meta-analysis indicates that MLP with IVTA pretreatment has a better therapeutic effect in terms of CMT reduction and earlier (1mo) visual improvement for patients with DME as compared with MLP alone. Further confirmation with rigorously well-designed multi-center trials is needed.

[Intravitreal triamcinolone combined with grid laser photocoagulation for patients with cystoid macular edema and advanced diabetic retinopathy: pilot study]

BACKGROUND

To determine if primary intravitreal injection of triamcinolone acetonide (TA) plus grid laser photocoagulation (GLP) is effective in treating cystoid diabetic macular edema (DME).

METHODS

Prospective comparative non-randomized clinical trial. Fourteen eyes (14 patients) diagnosed with cystoid DME were treated with GLP according to the Early Treatment Diabetic Retinopathy Study (ETDRS) guidelines, plus an intravitreal injection of 4 mg of TA. A matched control group (16 eyes [16 patients]) treated with GLP was selected retrospectively from our medical records. Best-corrected visual acuity (BCVA), and quantitative change in optical coherence tomography (OCT) macular thickness were assessed.

RESULTS

Mean follow up was 14.9 months (12 to 19 months). In 3 (21.4%) eyes BCVA increased > 2 ETDRS lines, in 5 (35.7%) eyes BCVA remained the same, and BCVA decreased >2 ETDRS lines in 6 (42.8%) eyes. Central macular thickness, as measured by OCT, decreased a mean of 106.2 μm (30.2%). The difference with the control group was not statistically significant (P = .2). Four (28.5%) eyes developed an increased in intraocular pressure in our study group.

CONCLUSIONS

Although all of our patients showed an improvement of cystoid DME by means of OCT and fluorescein angiography, 42.8% (6 eyes) lost 2 or more lines in BCVA with primary intravitreal injection of TA plus GLP. Primary intravitreal injection of TA plus GLP may not be effective for cystoid DME at 12-months.

Fluocinolone acetonide intravitreal implant for the treatment of diabetic macular edema

Diabetic macular edema (DME) remains one of the leading causes of moderate to severe vision loss. Although laser photocoagulation was the standard of care for several years, few patients achieved significant improvements in visual acuity. As a result, several pharmacotherapies and surgeries have been investigated. The fluocinolone acetonide devices are one of the latest therapies considered for the treatment of DME. Despite bringing significant improvements in visual acuity, fluocinolone devices are associated with cataract formation, increased intraocular pressure (IOP), and surgery to lower IOP. Due to the risk of complications, fluocinolone acetonide devices should be considered only in cases refractive to first-line therapies. In this review, we evaluate current and emerging therapies for DME, with special emphasis on fluocinolone acetonide intravitreal devices.

Combined vitrectomy and intravitreal injection versus combined laser and injection for treatment of intractable diffuse diabetic macular edema

BACKGROUND

The purpose of this study was to compare the safety and efficacy of combined vitrectomy, intravitreal triamcinolone acetonide (IVTA), and bevacizumab injection with that of IVTA and bevacizumab injection and subsequent macular grid laser photocoagulation for the treatment of intractable diffuse diabetic macular edema.

METHODS

This randomized controlled clinical trial was performed at Benha University Hospital, Benha, Egypt, and included 34 eyes from 34 diabetic patients diagnosed with intractable diffuse diabetic macular edema without vitreomacular traction. The patients were divided into two groups. In group 1, pars plana vitrectomy with removal of the posterior hyaloid was performed, and at the end of the procedure, IVTA 0.1 mL (40 mg/mL) and bevacizumab 1.25 mg were injected. In group 2, macular grid laser photocoagulation was performed 2 weeks after the same intravitreal injection combination as used in group 1. The main outcome measures were best-corrected visual acuity (BCVA) and central foveal thickness, which were measured using optical coherence tomography at 3, 6, and 12 months.

RESULTS

Changes in BCVA and central foveal thickness at 3, 6, and 12 months from baseline were highly statistically significant (P < 0.01). Mean BCVA was better in group 1 at 3 months, nearly equal at 6 months, and less at 12 months. Mean central foveal thickness was more improved in group 1 than in group 2 at 3 months, and was better in group 2 at subsequent measurement points. The major adverse events were development of cataract (more common in group 1) and elevation of intraocular pressure (more common in group 2).

CONCLUSION

The combined therapy described here could represent a solution for the treatment of intractable diabetic macular edema, and could have a favorable long-term outcome. Combined treatment of IVTA and bevacizumab plus grid laser resulted in a more favorable reduction in central foveal thickness and improvement in BCVA at 12 months than vitrectomy combined with the same injections. This small study favors the safer, cheaper, and more available line of treatment.

Corticosteroid use for diabetic macular edema: old fad or new trend?

Diabetic retinopathy is the leading cause of blindness in working age individuals in developed countries. Most cases of diabetes related vision loss result from breakdown of the blood-retinal barrier with resultant diabetic macular edema (DME). For over 30 years, laser photocoagulation has been the standard therapy for DME, but most eyes do not experience significant improvements in visual acuity. Intravitreal injections of drugs that inhibit the action of vascular endothelial growth factor (VEGF) lead to gains in vision, but can be expensive and need to be repeated frequently. In addition to VEGF-mediated breakdown of the blood-retinal barrier, recent evidence suggests that inflammation plays an important role in the development of DME. Recognizing this, physicians have injected steroids into the vitreous and developers have created sustained release implants. Intravitreal injections of triamcinolone acetonide lead to rapid resolution of macular edema and significant short-term improvements in visual acuity, but unfortunately, visual acuities diminish when treatment is continued through 2 years. However, intravitreal triamcinolone remains an attractive treatment option for eyes that are pseudophakic, scheduled to undergo cataract surgery, resistant to laser photocoagulation, or require urgent panretinal photocoagulation for proliferative retinopathy. In controlled trials, intraocular implants that slowly release dexamethasone and fluocinolone show promise in reducing macular edema and improving visual acuity. The high incidences of drug related cataracts and glaucoma, however, require that corticosteroids be used cautiously and that patients be selected carefully. The increasing number of patients with DME, the burgeoning cost of medical care and the continuing development of intravitreal steroids suggest that the use of these agents will likely increase in coming years.