Safety evaluation of subretinal injection of trypan blue in rats

Comparative Study of Conventional Inverted ILM Flap Covering and ILM Flap Filling Technique in Idiopathic Macular Hole Treatment: A Meta-Analysis and Systematic Review

Objective

This meta-analysis was performed to evaluate the anatomical efficacy and functional improvement of the conventional inverted internal limiting membrane (ILM), flap covering technique, and ILM flap filling technique for patients with idiopathic macular hole (MH).

Methods

Literature from Pubmed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science were comprehensively retrieved. The primary outcomes included the MH closure rate and postoperative best-corrected visual acuity (BCVA). The secondary outcomes were the proportion of external limiting membrane (ELM) and ellipsoid zone (EZ) defect recovery. Pooled odds ratios (ORs), weighted mean differences (WMDs), and 95% confidence intervals (CIs) were calculated using STATA 17.0 software.

Results

7 studies that contained 139 eyes in the inverted ILM flap covering group and 121 eyes in the ILM flap filling group were selected. Pooled data suggested that the surgical treatment resulted in an overall MH closure rate of up to 97.12% (135/139 eyes) in the inverted ILM flap covering group and 99.17% (120/121 eyes) in the filling group, with no significant difference between the 2 groups (OR = 1.98, 95% CI: 0.55 to 7.09, and P=0.29). Similarly, the 2 techniques demonstrated equal effectiveness on the anatomical closure in MH with the average diameter smaller than 650 μm (OR = 2.17, 95% CI: 0.48 to 9.77, and P=0.31) and larger than 650 μm (OR = 1.58, 95% CI: 0.14 to 17.37, and P=0.71). However, compared with the filling technique, the inverted ILM flap covering technique was superior in postoperative BCVA (WMD = 0.11, 95% CI: 0.04 to 0.18, and P=0.0017) and presented a significantly higher proportion of reconstitution of ELM (OR = 0.02, 95% CI: 0.00 to 0.08, and P < 0.0001) and EZ (OR = 0.11, 95% CI: 0.04 to 0.32, and P=0.0001).

Conclusion

The inverted ILM flap covering technique was associated with the superior reconstitution of outer layers of the retina, including ELM and EZ, and more improvement in postoperative BCVA than the ILM flap filling technique.

Subretinal Injection Techniques for Retinal Disease: A Review

Inherited retinal dystrophies (IRDs) affect an estimated 1 in every 2000 people, this corresponding to nearly 2 million cases worldwide. Currently, 270 genes have been associated with IRDs, most of them altering the function of photoreceptors and retinal pigment epithelium. Gene therapy has been proposed as a potential tool for improving visual function in these patients. Clinical trials in animal models and humans have been successful in various types of IRDs. Recently, voretigene neparvovec (Luxturna^®) has been approved by the US Food and Drug Administration for the treatment of biallelic mutations in the RPE65 gene. The current state of the art in gene therapy involves the delivery of various types of viral vectors into the subretinal space to effectively transduce diseased photoreceptors and retinal pigment epithelium. For this, subretinal injection is becoming increasingly popular among researchers and clinicians. To date, several approaches for subretinal injection have been described in the scientific literature, all of them effective in accessing the subretinal space. The growth and development of gene therapy give rise to the need for a standardized procedure for subretinal injection that ensures the efficacy and safety of this new approach to drug delivery. The goal of this review is to offer an insight into the current subretinal injection techniques and understand the key factors in the success of this procedure.

Efficacy of different doses of dye-assisted internal limiting membrane peeling in idiopathic macular hole: a systematic review and network meta-analysis

PURPOSE

Pars plana vitrectomy is the gold standard for the treatment of idiopathic macular hole. Several chromovitrectomy dyes have been used to improve the visualization of the internal limiting membrane (ILM), including indocyanine green, trypan blue (TB), brilliant blue G (BBG), and triamcinolone acetonide (TA). We conducted a network meta-analysis (NMA) to establish the optimum concentration of chromovitrectomy dye-assisted ILM peeling for IMH.

METHODS

We searched PubMed, Embase, and Cochrane Library for relevant studies before January 2020. We performed a random-effects NMA using STATA version 15.1 to assess mean difference and odds ratios with 95% confidence intervals.

RESULTS

We identified twelve retrospective trails and five randomized controlled trials (RCTs), comprising 1 492 patients of IMH on stage II-IV for ILM peeling. The results of IMH closure rate show that the effect of ILM peeling without dye was better than 0.25% ICG, the effects of ILM peeling with 0.5% ICG or TA were better than without dye, and the effects of ILM peeling with 0.05% BBG, 0.15% TB, 0.5% ICG or 0.05% ICG were better than 0.25% ICG. Ranking probability analysis shows that the rates of IMH closure after ILM peeling with 0.15% TB or 0.05% BBG were better than nine other concentrations of chromovitrectomy dyes.

CONCLUSION

The 0.15% TB and 0.05% BBG were recommended as the better efficient treatment-assisted ILM peeling for IMH closure. For retina specialists who prefer to use ICG to assist ILM peeling, 0.05% ICG may be a good choice. However, high-quality large-scale RCTs are recommended to confirm the NMA results.

Chromophore-Assisted Retinal Break Detection to Manage Challenging Situations in Retinal Detachment Redo Surgery

Introduction

The purpose of this case series is to demonstrate that subretinal blue dye injection, with and without 180-degree endolaser retinopexy, can be considered a useful tool in finding occult rhegmatogenous retinal breaks in eyes with recurrent retinal detachment. Case Presentation. Three patients with recurrent retinal detachment were treated between January and March 2018. In all cases, the intraoperative internal search did not demonstrate any obvious break or hole. MembraneBlue-Dual (Trypan Blue 0.15% + Brilliant Blue G 0.025% + 4% PEG) was then injected into the subretinal space using a 41-gauge cannula. The eye was rotated such that the dye was pushed through a tiny break which was causing the retinal detachment. 180-degree laser retinopexy was performed on a single eye. After silicon oil removal and absorption of the gas tamponade, retinas remained attached at three-months follow-up.

Conclusions

Chromophore-assisted occult retinal break detection can be considered a useful but not risk-free surgical technique in managing some unexpected and challenging intraoperative situations.