Functional and structural effect of intravitreal indocyanine green, triamcinolone acetonide, trypan blue, and brilliant blue g on rat retina

MACULAR ATROPHY AFTER MACULAR HOLE SURGERY ASSISTED BY MEMBRANE BLUE DUAL: A CASE SERIES

PURPOSE

The aim of this study is to describe the clinical and multimodal imaging findings in patients with macular atrophy after macular hole surgery assisted by Membrane Blue Dual.

METHOD

This study is a monocenter, retrospective, observational case series that included patients who presented with macular atrophy following macular hole surgery.

RESULTS

Among the patients included in this study, four were operated for idiopathic macular hole and one for total retinal detachment associated with macular hole. In all patients, the internal limiting membrane was brittle and adherent, and multiple stains were required. One month postoperatively, all patients showed a reduced visual acuity except the patient with total retinal detachment. At fundus examination all patients showed patchy atrophy with a mottled hypopigmented and hyperpigmented appearance in the macular region. Optical coherence tomography scans demonstrated a closed macular hole with retinal thinning, disruption of the external retinal layers, and irregular retinal pigment epithelium thickening. Fundus autofluorescence showed a well-defined area of both hypoautofluorescence and hyperautofluorescence involving the macular area.

CONCLUSION

Macular atrophy after Membrane Blue Dual-assisted internal limiting membrane peeling represents a severe complication that vitreoretinal surgeons should be aware of and that should be taken into account in preoperative evaluation and surgical procedure planning. To reduce the risk of this complication, we recommend to ensure the best conditions of visibility, to reduce as much as possible the intensity and the distance of the endoillumination from the retina, and to use as little dye as possible.

Internal limiting membrane peeling with different dyes in the surgery of idiopathic macular hole: a systematic review of literature and network Meta-analysis

AIM

To evaluate the effect of internal limiting membrane (ILM) peeling with indocyanine green (ICG), brilliant blue G (BBG), triamcinolone acetonide (TA), trypan blue (TB), or without dye for the treatment of idiopathic macular hole (IMH).

METHODS

A search was conducted using PubMed, EMBASE, and CENTRAL (Cochrane Central Register of Controlled Trials) for related studies published before October 2018.

RESULTS

A total of 29 studies and 2514 eyes were included in this network Meta-analysis. For IMH closure, the rank from the best to the worse treatment was: BBG, TB, TA, ICG, and no dye. There was a significant difference in postoperative IMH closure rate between BBG and no dye. The rank of the best to the worse treatment to improve visual acuity was: BBG, TB, no dye, TA, and ICG. The improvement rate of visual acuity after using BBG was significantly higher than ICG. The improvement rate of visual acuity was more favorable with TB than ICG, TA, and no dye.

CONCLUSION

BBG can contribute to better anatomical and functional outcomes compared to other dyes for ILM peeling in patients with IMH. The results show that the best treatment of ILM peeling with dyes is BBG.

A Review of Surgical Outcomes and Advances for Macular Holes

The surgical outcomes of macular holes (MHs) have improved greatly in recent years. The closure rate is as high as 90-100%, but the outcomes of some special types of MHs remain unsatisfactory. Internal limiting membrane (ILM) peeling dramatically improves the anatomic success rate, but recent studies have found that it could also cause mechanical and subclinical traumatic changes to the retina. Dyes are widely used, and apart from indocyanine green (ICG), the toxicities of other dyes require further research. Face-down posturing is necessary for MHs larger than 400 μm, and the duration of this posture is determined by the type of tamponade and the case. The ellipsoid zone has been shown to be highly correlated with visual outcome and recovery. New surgical methods include the inverted ILM flap technique and the ILM abrasion technique. However, they require further research to determine their effectiveness.

Photochemical degradation of trypan blue

Purpose

To investigate the photochemical degradation of trypan blue (TB) and to identify decomposition products.

Methods

Defined solution samples of TB and a mixture with lutein/zeaxanthin were exposed to blue light. Thermal degradation processes were ruled out using controls not subjected to irradiation. All samples were analyzed using optical microscopy, UV/Vis spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and nuclear magnetic resonance (NMR) spectrometry. Degradation kinetics were determined based on changes in absorbance; intermediates were identified by analyzing mass differences of characteristic fragment ion peaks within the fragmentation patterns, and assignments were verified by NMR.

Results

TB demonstrated a photochemical degradation, which can be triggered by lutein/zeaxanthin. Intermediates vary depending on the presence of lutein/zeaxanthin. The self-sensitized photodegradation of TB occurs under generation of dimethyl sulfate and presumed formation of phenol. In contrast, within the presence of lutein/zeaxanthin the decomposition of TB indicates the formation of methoxyamine and sulfonyl arin. Thermal degradation processes were not observed.

Conclusions

TB demonstrated a photodegradation that may be triggered by lutein/zeaxanthin and results in the formation of cytotoxic decomposition products. Our findings contribute to understand degradation mechanisms of TB and may elucidate previous clinical and experimental observations of cellular toxicity after TB application.

In vivo biocompatibility of a new cyanine dye for ILM peeling

PURPOSE

To investigate the biocompatibility of the new cyanine dye: 3,3'-Di-(4-sulfobutyl)-1,1,1',1'-tetramethyl-di-1H-benz[e]indocarbocyanine (DSS) as a vital dye for intraocular application in an in vivo rat model and to evaluate the effects of this dye on retinal structure and function.

METHODS

DSS at a concentration of 0.5% was applied via intravitreal injections to adult Brown Norway rats with BSS serving as a control. Retinal toxicity was assessed 7 days later by means of retinal ganglion cell (RGC) counts, light microscopy, optical coherence tomography (OCT), and electroretinography (ERG).

RESULTS

No significant decrease in RGC numbers was observed. No structural changes of the central retina were observed either in vivo (OCT) or under light microscopy. ERGs detected a temporary reduction of retinal function 7 days after injection; this was no longer evident 14 days after injection.

CONCLUSIONS

DSS showed good biocompatibility in a well-established experimental in vivo setting and may be usable for intraocular surgery as an alternative to other cyanine dyes. In contrast to indocyanine green, it additionally offers fluorescence in the visual spectrum. Further studies with other animal models are needed before translation into clinical application.

Lutein and zeaxanthin toxicity with and without brilliant blue in rabbits

PURPOSE

To evaluate the safety profile of solutions containing lutein and zeaxanthin alone or associated with brilliant blue (BB).

METHODS

Twenty-eight New Zealand rabbits were used to evaluate 4 concentrations of the various dye solutions: 0.5% lutein/zeaxanthin; 0.5% lutein/zeaxanthin associated with 0.0125% BB; 0.3% lutein/zeaxanthin associated with 0.025% BB; and 0.25% lutein/zeaxanthin associated with 0.05% BB. The pHs of the dye solutions ranged from 6.5 to 7.2 and the osmolarities from 280 to 320 mOsm/mL. Each rabbit had 0.1 mL of one of the dyeing solutions injected into the vitreous cavity of the right eye, while balanced salt solution (BSS) was injected into the left eye as the control. Scotopic electroretinography responses were recorded in all eyes at different time points. The animals were sacrificed at 1 and 7 days after injection; the eyes were analyzed by light and transmission electron microscopy.

RESULTS

No significant (P>0.05) differences were seen in the a- and b-wave amplitudes among groups at any given point in time. Light and electron microscopy findings showed no significant abnormalities either, and were similar to the histological findings after intravitreal BSS injection.

CONCLUSIONS

Lutein and zeaxanthin alone or in association with BB showed a good safety profile in this experimental model.

Comparison between subjective and objective internal limiting membrane peeling area during epiretinal membrane surgery

PURPOSE

To determine the reliability of surgeons in estimating internal limiting membrane peeling area during epiretinal membrane surgery and to evaluate their ability to remove a predetermined internal limiting membrane surface.

METHODS

One senior surgeon and two junior surgeons were asked to reach a target internal limiting membrane peeling surface (ILMPS) with an eccentricity of 1 optic disk diameter (centered on the fovea) in patients undergoing epiretinal membrane surgery. The ILMPS was measured on video recordings during epiretinal membrane surgery with no dye and then after brilliant blue G staining.

RESULTS

Thirty patients were included. Median (interquartile range) ILMPS was 9.3 mm(2) (5.7-16.3 mm(2)) and 7.4 mm(2) (3.7-16.4 mm) before and after brilliant blue G, respectively (P = 0.17). The ILMPS was significantly larger in eyes operated by the senior surgeon than in those operated by the junior surgeons (P = 0.01). The senior surgeon reached the target ILMPS more often than the junior surgeons: 87% versus 47%, respectively (P = 0.02).

CONCLUSION

Subjective estimation of the ILMPS with no dye was fair, but this area was larger for the surgeon with greater surgical expertise.

Primary vitrectomy for the treatment of retinal detachment in highly myopic eyes with axial length over 30 mm

OBJECTIVE

To assess the functional and anatomical outcome of primary vitrectomy without scleral buckling for rhegmatogenous retinal detachment (RRD) in highly myopic eyes with axial length over 30 mm.

METHODS

In this retrospective, interventional case series, we evaluated the outcome of primary vitrectomy without scleral buckling in 67 highly myopic patients (67 eyes) with RRD. Anatomical success rate was defined as complete reattachment of the retina without definitive silicone oil tamponade.

RESULTS

Retinal reattachment was achieved with a single surgery in 49 of 67 eyes (73.1%) and after 2 or 3 surgeries in 54 eyes (80.6%). The characteristics of retinal tears did not influence the final outcome. Multivariate analysis revealed that a longer axial length was the only factor associated with a higher failure rate, p = 0.0061. Mean preoperative visual acuity significantly increased after surgery, p = 0.0003.

CONCLUSION

The study demonstrated fair efficacy of vitrectomy and fluid-gas exchange in the treatment of retinal detachment in highly myopic eyes with an axial length over 30 mm.

Microfiltration of brilliant blue G dye

BACKGROUND

Brilliant blue G (BBG) is a safe and effective dye used to highlight the internal limiting membrane during macular surgery. The authors proposed that the utilization of a 0.22-μm filter intraoperatively can reduce the risk of inoculating an eye with contaminated BBG.

METHODS

An in vitro model of contaminated BBG was prepared. Laboratory stock cultures of 7 organisms including, Staphyloccocus epidermidis, Streptococcus pneumoniae, Staphyloccocus aureus, Haemophilus influenza, Klebsiella pneumoniae, Fusarium species, and Candida albicans, were prepared in five 10-fold dilutions and injected into BBG vials. These mixtures were drawn with either a 5-μm filter, 0.22-μm, or without a filter and cultured on appropriate plates and growth conditions.

RESULTS

No culture plates that had inoculate drawn through a 0.22-μm filter showed evidence of growth. There was evidence of growth for all organisms when no filter was used. A 5 μm was insufficient to filter Fusarium species.

CONCLUSION

Using a 0.22-μm filter in the intraoperative processing of BBG would likely reduce the risk of infectious endophthalmitis resulting from contaminated dye.

The structural effect of intravitreal Brilliant blue G and Indocyanine green in rats eyes

PURPOSE

To compare the potential retinal toxicity of two commercially Brilliant blue G dyes (Brilliant Peel and Ocublue Plus) and Indocyanine green (ICG) at usual clinical concentration.

METHODS

Brilliant Peel 0.025% (n=9), Ocublue Plus 0.025% (n=9), and ICG 0.05% (n=9) were injected intravitreally into Sprague-Dawley rat left eyes with balanced salt solution injected in the contralateral eyes as control. Evaluation of the effect of the dyes on retinal architecture was done by histological analysis of neurosensory retinal thickness and retinal ganglion cell (RGC) counts 7 days after intravitreal injection. Paired t-test was done to detect the presence of biologically significant thinning in neurosensory retina and five retinal layers for each dye (paired t-tests). One-way ANOVA and Tukey's Honestly Significant Difference test were used to assess whether different dyes caused significant thinning in mean neurosensory retinal thickness and reduction of mean RGC density.

RESULTS

Eyes treated with ICG had significantly thinner mean total neurosensory retinal thickness compared with the control eyes (P-value=0.01), followed by those treated with Ocublue Plus (P-value=0.03). Brilliant Peel did not cause significant thinning in any of the five retinal layers (all P-values>0.05). No significant difference in mean thinning of the total retinal thickness was detected between dyes (P-value=0.11). The mean thickness of the photoreceptor outer segment and outer plexiform layers were significantly reduced in ICG-injected eyes when compared with the control eyes (P-value=0.02). No significant difference in mean thinning between the three dyes was detected at all five retinal layers using one-way ANOVA (all P-values>0.35). RGC density was significantly reduced for ICG (P-value=0.01) but only marginally for Ocublue Plus (P-value=0.05). No significant reduction in RGC density was observed for Brilliant Peel (P-value=0.2).

CONCLUSION

Intravitreal Brilliant Peel is safe to rats retina. The retinal thinning and reduction in RGC density induced by Ocublue Plus requires further studies to determine the safety profile of this product. Potential retinal toxicity is seen with ICG 0.05%.

Toxicity profiles of subretinal indocyanine green, Brilliant Blue G, and triamcinolone acetonide: a comparative study

BACKGROUND

This study introduces a novel porcine model to examine the histopathological and electrophysiological consequences of retinotoxicity exerted by dyes commonly used for internal limiting membrane (ILM) staining.

METHODS

Indocyanine green (ICG) 0.5 mg/ml, Brilliant Blue G (BBG) 0.25 mg/ml and triamcinolone acetonide (TA) 13 mg/ml was injected subretinally in 12 vitrectomized pig eyes. At 6 weeks, retinas were examined by multifocal electroretinography (mfERG), ophthalmoscopy, fluorescein angiograpy, histopathology, and apoptosis assay.

RESULTS

mfERG responses were significantly lower in ICG-injected eyes than in healthy fellow eyes (p = 0.039). The ratio between injected eyes and healthy fellow eyes was lower in the ICG group than in the BBG (p = 0.009) and TA group (p = 0.025). No difference between BBG and TA existed. All retinas were reattached, and fluorescein angiographies showed a window defect corresponding to the injected areas but no blood-retina barrier break-down. Histopathology confirmed damage to the outer retina after ICG, but not after BBG and TA. No apoptosis was found at 6 weeks.

CONCLUSIONS

Subretinal ICG induces histological and functional damage to the retina, suggesting that ICG should be used with caution in macular hole surgery, where subretinal migration can occur. In contrast, BBG and TA appear safe after subretinal injection.