Preclinical investigation of internal limiting membrane staining and peeling using intravitreal brilliant blue G

Bibliometric and visual analysis of retinal fibrosis research from 1993 to 2023

BACKGROUND

Retinal fibrosis, a common pathological feature of various retinal diseases, significantly impairs vision. The mechanisms of retinal fibrosis are complex, with cytokine involvement playing a pivotal role. This article aims to elucidate the current research trends and key areas of focus in the study of retinal fibrosis.

METHODS

Publications from "Web of Science core collection", "PubMed" and "Scopus" were analyzed using R Studio ("Bibliometrix" and "ggplot2" packages) for publication counts, geographic distribution, and collaborations, while "CiteSpace" and "VOSviewer" visualized institutional partnerships and keyword co-occurrence. The methodology follows the PRISMA 2020 guidelines strictly.

RESULTS

In this analysis, a total of 1985 studies were analyzed. Key topics included "vitrectomy", "epiretinal membrane", "optical coherence tomography (OCT)", "macular membrane", and "macular hole". Keyword co-occurrence analysis emphased macular disease, fibrosis diagnosis, pharmacological treatment, and prognosis across various groups with cytokines as prominent research topics. Additionally, the findings suggested future research would focus on elucidating fibrosis mechanisms, advancing diagnostic techniques, and identifying potential drug targets. The journal "Retina" had the highest citation count for retinal fibrosis. The United States showed the greatest collaboration in retinal fibrosis research, particularly with China.

CONCLUSIONS

Current retinal fibrosis research focused on OCT diagnostics, cytokine mechanisms, and associated diseases such as diabetic retinopathy and macular degeneration. Future research will explore the integration of artificial intelligence in treatment strategies and the mechanisms underlying post-anti-VEGF injection fibrosis.

Presumed phototoxicity from macular vital staining with Brilliant Blue G and Trypan Blue: A post-market surveillance study, systematic review, and synthesis of the literature

Vital dyes are used to help visualize the retinal surface during macular surgery; however, they have been associated with phototoxicity. We synthesize and collate post-market surveillance data in two of the most commonly used dyes, Brilliant Blue G and Trypan Blue. We identified 69 cases, 59 of which were from the literature and 10 from manufacturer post-market surveillance. Of 69 vitrectomies, 39 were for macular hole, 24 for epiretinal membrane, 2 for vitreomacular traction, and 4 were not specified. The incidence of dye-mediated phototoxicity is likely rare, but is not possible to quantify, due to potential reporting and publication bias favouring dissemination of unusual safety events, but conversely underreporting is possible. Additionally, phototoxicity was reported prior to the introduction of vital stains, so it can be difficult to establish whether vital staining was contributory. Prolonged surgery and repeat staining were identified as risk factors. Characteristic clinical features were macular pigmentary change with hypo- and hyper-autofluoresence, often sparing the fovea. Final visual acuity tended to be worse than preoperatively, with some cases reduced to counting fingers. A reporting template is provided to encourage complete and standardised toxicity reporting and help build a robust evidence base.

Epiretinal membrane: an overview and update

Epiretinal membrane (ERM) is a frequently diagnosed macular disease associated with aging, characterized by a fibrous membrane forming on the internal limiting membrane (ILM) and leading to visual dysfunctions such as metamorphopsia. Various hypotheses regarding the pathology of metamorphopsia have been proposed; however, the complete pathophysiologic mechanism underlying ERM remains unclear. Optical coherence tomography (OCT) provides detailed images enabling precise diagnosis and characterization of ERM, with several recent studies using the latest OCT imaging techniques. Surgical removal of ERM is the only treatment option; however, criteria for surgical intervention are not established, complicating the decision-making processes. Furthermore, the debate on whether simultaneous peeling of the ILM during ERM surgery enhances outcomes or poses unnecessary risks is ongoing, with no definite conclusion having yet been reached. This review also focuses on epiretinal proliferation, which is different from ERM and is characteristic of lamellar macular hole (LMH). Recently, diagnostic criteria for LMH and related diseases were proposed. Reports on effective surgical procedures for LMH exist, although more research is needed to confirm the long-term outcomes. Thus, this review article aims to provide an overview and updated knowledge of ERM, LMH, and related diseases.

[Selective vital dyes in macular surgery : Do they increase the probability of intraoperative identification of the internal limiting membrane also for an experienced surgeon?]

BACKGROUND

Various vital dyes exist on the market for intraoperative internal limiting membrane (ILM) identification. The aim of this study was to verify the added value of these dyes for ILM identification and in the difficulty of ILM peeling during pars plana vitrectomy (ppV) by a single surgeon highly experienced in this operation.

MATERIAL AND METHODS

In this study 400 ppV surgical reports involving ILM peeling were retrospectively analyzed. Intraoperative assessment of identification or difficulty of intraoperative ILM peeling had to be documented in the surgical report. The total group consisted of 2 cohorts each with 200 surgical reports (first cohort without selective vital dyes, period 2004-2006; second cohort with vital dyes in the majority of ppVs, period 2013-2020).

RESULTS

The difference between both groups in terms of intraoperative identification of ILM was statistically significant (p < 0.001); however, no statistically significant difference (p = 0.951) was found between the two groups in terms of difficulty of ILM peeling. In logistic regression analysis neither patient gender, age, eye side, lens status nor posterior vitreous limiting membrane status were significantly associated with ILM identification.

CONCLUSION

The introduction of intravital dyes represents a decisive advancement in retinal surgery. In the investigated sample this benefit was evident from two precisely defined surgical cohorts of a single highly experienced surgeon. This underlines the additional benefit of using selective vital dyes to identify ILM in macular surgery for less experienced surgeons.

Injectable in situ cross-linking hyaluronan hydrogel for easier removal of posterior vitreous cortex in vitrectomy

PURPOSE

Removing transparent vitreous tissues, such as a residual vitreous cortex (VC) or proliferative membrane, without damaging the retina is often problematic in vitrectomy. We examined the feasibility of an injectable in situ cross-linking hyaluronan hydrogel (XL-HA) for vitrectomy.

STUDY DESIGN

Experiments using ex vivo and in vivo animal models.

METHODS

HA-dibenzocyclooctyne and HA-azidoethylamine solutions were mixed to form XL-HA, which then gradually formed a hydrogel. We tested the function of XL-HA in ex vivo porcine eyes. We then examined the performance of XL-HA in in vivo rabbit models of posterior vitreous detachment, posterior VC removal, and proliferative vitreoretinopathy.

RESULTS

The ex vivo study showed that XL-HA rapidly embedded triamcinolone acetonide, mimicking VC attached to the retina, and became hard enough to be pinched with tweezers within 3 minutes, allowing us to remove only the triamcinolone acetonide without impairing the internal limiting membrane. In the in vivo rabbit models, XL-HA injection improved posterior vitreous detachment, and the thin and fragile posterior VC or fibrous proliferative membrane was readily peeled off without any damage to the underlying retina as compared with untreated controls. A short-term intraocular biocompatibility test demonstrated that the intraocular pressure remained normal with XL-HA injected into the eye. In addition, transmission electron microscopy showed no obvious abnormalities in the cornea or in the inner and outer retina.

CONCLUSION

The results indicate that XL-HA is a potential adjunctive device to help make vitrectomy safe, effective, and successful.

Development of in situ crosslinked hyaluronan as an adjunct to vitrectomy surgery

Ophthalmologists have used hyaluronan (HA) products as adjuncts to ocular surgery since the 1970s. However, HA products are not always functional in surgeries of the posterior eye segment due to their lack of biomechanical strength. In this study, we developed an in situ crosslinked HA (XL-HA) and evaluated its potential as an adjunct to vitrectomy surgery in an in vitro model with a triamcinolone acetonide (TA) layer used as a pseudo residual vitreous cortex (RVC). Within a few minutes at concentrations over 0.9%, XL-HA, generated by the click chemistry of HA-dibenzocyclooctyne and HA-azidoethylamine, formed a hydrogel with the appropriate hardness for tweezers peeling. XL-HA (concentration, 0.76-1.73%) without dispersion successfully entered the TA layer and removed more than 45% of the total TA. Dynamic viscoelasticity helps to explain the rheological behavior of hydrogels, and the assessment results for XL-HA indicated that suitable concentrations were between 0.97% and 1.30%. For example, 1.30% XL-HA hydrogel reached sufficient hardness at 3 min for tweezers peeling, and the TA removal ability exceeded 70%. These results demonstrated that XL-HA was a potential adjunct to successful vitrectomy.

Stainability of Acrylic Intraocular Lens With Brilliant Blue G: An In Vitro Study

PURPOSE

To evaluate the stainability of several acrylic intraocular lens (IOLs) with Brilliant Blue G (BBG) in vitro.

DESIGN

Clinically relevant, laboratory, experimental study.

METHODS

LS313MF15 as a hydrophilic acrylic IOL and X-70, W60R, CP2.2R, YP2.2R, XC1, and XY1 as hydrophobic acrylic IOLs were included in this study. Prepared acrylic IOLs were evaluated for staining via immersion for different periods in BBG solution with adjusted concentrations. In cases where IOLs were stained blue, the sustained release of BBG and IOL cross-sectional images were evaluated, as well as changes in the optical properties of the IOLs via spectrophotometry.

RESULTS

All acrylic IOLs were stained with BBG in a BBG concentration- and staining time-dependent manner, with almost no sustained release of BBG observed. Lenses with a higher water content exhibited more pronounced staining, and BBG penetrated into the IOLs. A decrease in light transmittance with a peak wavelength of 610 to 620 nm was observed in blue-stained IOLs. LS313MF15 was markedly blue stained even with a short period of staining.

CONCLUSIONS

Any acrylic IOL can be stained with BBG, but hydrophilic IOLs are particularly susceptible to blue staining. Precautions should be taken in surgeries requiring the use of BBG staining, and efforts should be made to ensure that BBG components are sufficiently washed out intraoperatively.

Outer retinal microstructure and visual function after macular hole surgery with and without Brilliant Blue G

PURPOSE

To evaluate the outer retinal microstructure and visual function after idiopathic macular hole (MH) surgery using internal limiting membrane (ILM) peeling with and without Brilliant Blue G (BBG) staining.

STUDY DESIGN

Retrospective, consecutive case series.

METHODS

A total of 49 eyes of 47 patients were enrolled: 23 eyes of 23 patients with MH who underwent ILM peeling without dyes (control group) and 26 eyes of 26 patients who underwent BBG staining (BBG group). The lengths of defects of the photoreceptor ellipsoid zone (EZ), external limiting membrane (ELM), and interdigitation zone (IZ) were measured.

RESULTS

The rate of MH closure after initial surgery was 95.6% (22/23 eyes) for the control group versus 100% (26/26 eyes) for the BBG group. In the 48 eyes with MH closure, the recovery rate of ELM deficiency and change in IZ deficiency showed no difference between the groups. The changes in EZ deficiency at 1 and 12 months were greater in the BBG group than in the control group. (P = 0.047 and 0.031). Visual acuity was better in the BBG group than in the control group during 12 months postoperatively (P < 0.001-0.038).

CONCLUSION

Eyes undergoing BBG-assisted MH surgery achieved faster recovery of the outer retinal structures and greater visual improvement than those of eyes without BBG.

Advances in Vitreoretinal Surgery

Advances in vitreoretinal surgery provide greater safety, efficacy, and reliability in the management of the several vitreoretinal diseases that benefit from surgical treatment. The advances are divided into the following topics: scleral buckling using chandelier illumination guided by non-contact visualization systems; sclerotomy/valved trocar diameters; posterior vitrectomy systems and ergonomic vitrectomy probes; chromovitrectomy; vitreous substitutes; intraoperative visualization systems including three-dimensional technology, systems for intraoperative optical coherence tomography, new instrumentation in vitreoretinal surgery, anti-VEGF injection before vitrectomy and in eyes with proliferative diabetic retinopathy, and new surgical techniques; endoscopic surgery; the management of subretinal hemorrhages; gene therapy; alternative techniques for refractory macular hole; perspectives for stem cell therapy and the prevention of proliferative vitreoretinopathy; and, finally, the Port Delivery System. The main objective of this review is to update the reader on the latest changes in vitreoretinal surgery and to provide an understanding of how each has impacted the improvement of surgical outcomes.

Internal limiting membrane peeling in macular hole surgery

Since the era when macular hole was considered untreatable, macular hole surgery has come a long way to being one of the most successful surgeries. Internal limiting membrane (ILM) peeling has been an essential step of macular hole surgery since the establishment of the role of ILM in the aetiopathogenesis and progression of macular hole. However, the novel technique was not all virtuous. It had some vices which were not evident immediately. With the advent of spectral domain optical coherence tomography, short- and long-term effects of ILM peeling on macular structures were known; and with microperimetry, its effect on the function of macula could be evaluated. The technique has evolved with time from total peeling to inverted flap to just temporal peeling and temporal flap in an attempt to mitigate its adverse effects and to improve its surgical outcome. ILM abrasion technique and Ocriplasmin may eliminate the need of ILM peeling in selected cases, but they have their own limitations. We here discuss the role of ILM in the pathogenesis of macular hole, the benefits and adverse effects of ILM peeling, and the various modifications of the procedure, to then explore the alternatives.

Long-Term Observations of Thickness Changes of Each Retinal Layer following Macular Hole Surgery

Purpose

To determine the long-term changes of the thickness of each retinal layer following macular hole (MH) surgery combined with internal limiting membrane (ILM) peeling.

Method

The medical records of 42 eyes of 42 patients (41 to 86 years of age) who underwent MH surgery with ILM peeling between February 2016 and October 2018 were reviewed. A single surgeon operated on all patients, and all were followed for at least 24 months postoperatively. Spectral-domain optical coherence tomography (OCT) was performed to obtain retinal thickness maps of the parafoveal region corresponding approximately to the ILM peeled area. Each retinal layer was automatically segmented by the embedded software, and thickness maps were constructed for the total retinal layer (TRL), inner RL (IRL), middle RL (MRL), and outer RL (ORL). The averaged value of each retinal layer thickness was analyzed in the temporal/upper, temporal/lower, nasal/upper, and nasal lower quadrants.

Results

The TRL thickness was significantly decreased in the temporal areas postoperatively. The IRL thickness thinned progressively and significantly until 6 months without further thinning in the temporal quadrants. The MRL thickness of all areas was significantly thicker than the baseline values at 0.5 months and then gradually decreased in the temporal regions. However, the thickening in the nasal regions returned to the baseline values after 1.5 months. The ORL decreased transiently relative to the baseline values at 0.5 months in all areas.

Conclusions

The ILM peeling does not affect only the thickness of the inner retina but also the middle and outer retinae in the parafoveal region. The chronological changes of the thickness after surgeries varied among the retinal layers and macular regions.

Contractility of temporal inverted internal limiting membrane flap after vitrectomy for macular hole

We investigated the postoperative visual outcomes and morphological changes of the internal limiting membrane (ILM) flap, in patients who underwent the temporal inverted ILM flap technique for macular hole (MH). Between August 2018 and February 2020, 22 eyes of 22 patients with idiopathic or myopic MH who underwent vitrectomy with ILM flap were included in this study and followed-up for more than 6 months. Postoperative MH status, comparison of best-corrected visual acuity (BCVA) before and 6 months after surgery, changes in the ILM flap area at 1 and 6 months postoperatively, and the factors related to changes in ILM flap size, were analyzed. MH closure was achieved in all of the patients. The BCVA at 6 months postoperatively (0.18 ± 0.15) was significantly better than the preoperative BCVA of 0.63 ± 0.37 (P < 0.001, paired t test). The area of the ILM flap decreased significantly from 3.25 ± 1.27 mm² at 1 month to 3.13 ± 1.23 mm² at 6 months (P = 0.024, Wilcoxon signed-rank test). Two eyes showed an ILM flap contraction of more than 20%, and one eye required reoperation due to an increase in metamorphopsia and decreased visual acuity. Among age, sex, ILM flap area at 1 month, preoperative BCVA, and axial length, ILM flap contraction was correlated with patient age and ILM flap area. Although vitrectomy with the inverted ILM flap technique confers a good visual outcome, the ILM flap may contract in younger patients.

Inner retinal structure and visual function after idiopathic epiretinal membrane surgery with and without brilliant blue G

PURPOSE

Vital dyes are frequently used to visualize the internal limiting membrane (ILM) of the neuroretina. This study evaluated and compared the microstructure of the inner retina and visual function with and without brilliant blue G (BBG) staining for ILM peeling during idiopathic epiretinal membrane (ERM) surgery.

STUDY DESIGN

Retrospective, consecutive, interventional case series.

METHODS

Fifty-five patients (55 eyes) with ERM underwent ILM peeling without dyes (non-dye group) and 55 patients (55 eyes) underwent ILM peeling with BBG staining (BBG group). The logMAR visual acuity (VA) and ganglion cell complex (GCC) thickness were measured using optical coherence tomography at baseline and 12 months after surgery.

RESULTS

LogMAR VA improved significantly in both groups at 12 months and the BBG group tended to be better than the non-dye group but with no significant difference between the groups (unpaired t-test, P = 0.490). The average GCC thickness significantly decreased in both groups; however, there was no difference in the rates of change in GCC thickness between the groups. The ratio of GCC thickness to total retinal thickness (%) was significantly higher in the BBG group in the superior quadrant at 12 months postoperatively (P = 0.010).

CONCLUSION

BBG-assisted ERM surgery resulted in better visual improvement and fewer structural changes in the inner retinal layers. BBG-assisted ILM peeling is safe both functionally and anatomically.

The Influence of Crescent-Shaped Selective Internal Limiting Membrane Staining on Vital Dye Toxicity in Temporal Inverted Flap Technique

Purpose: To investigate the macular function and morphology after temporal inverted internal limiting membrane (ILM) flap technique with and without staining of the ILM flap in contact with the retinal pigment epithelium (RPE).Materials and Methods: This retrospective study included 30 patients with idiopathic macular hole (MH), who underwent 27 G vitrectomy and temporal inverted ILM flap technique with brillant blue G (BBG) assisted ILM staining. In Group 1 (n = 16), a large bubble of perfluorocarbon liquid (PFCL) measuring approximately 6-disc diameters was used to cover the hole and central part of the ILM flap whereas in Group 2 (n = 14), only a small drop of PFCL to merely cover the MH was used. Complete ophthalmic examination including microperimetry (MP), optical coherence tomography (OCT) was performed preoperatively, 6 months after surgery.Results: MH closure was achieved in all the eyes in both groups. The sizes of ellipsoid zone (EZ) and external limiting membrane (ELM) defect significantly decreased after surgery relative to the baseline width in both groups (p < .05 for all). The mean improvement in visual acuity (p = .896) and retinal sensitivity was similiar between groups (p = .409). Accordingly, the postoperative mean lengths of the EZ (p = .254) and ELM disruption (p = .406) on OCT scans were similiar between groups. However, 3 of the eyes in Group 2 developed cystoid macular edema between postoperative month-1 and month-6.Conclusion: The crescent-shaped selective staining of the ILM flap could prevent prolonged retinal toxicity of vital dyes in inverted ILM flap technique. Further studies involving larger number of patients with longer follow up are needed to determine the impact of this technique in the management of vital dye toxicity.

Assessment of Macular Function Following Internal Limiting Membrane Peeling With ILM Blue®

Purpose To evaluate clinical outcome after surgery of idiopathic epiretinal membranes (ERM) with internal limiting membrane (ILM) peeling using a commercial combination of Brilliant blue G (BBG, 0.25 mg/ml) with 4% polyethylene glycol (PEG). Methods It was a prospective, single-center study. Macular surgery was performed due to ERM (n = 18) by two experienced surgeons. Exclusion criteria were secondary ERM, previous retinal surgery and pharmacological treatment. Best-corrected visual acuity (BCVA), optical coherence tomography (OCT), and multifocal ERG (RETIscan) were assessed at baseline and three months after surgery. Results The BCVA improved from baseline 0.4 ± 0.13 logMAR to 0.3 ± 0.2 logMAR after three months (p > 0.05). The mean central foveal thickness was reduced from 407 ± 85 μm to 366 ± 56 μm after three months (p > 0.05). At baseline, the mean P1 amplitude (nV/deg²) was 53.5 ± 32.1 in ring 1 and 35.9 ± 20.1 in ring 2. Three months after surgery the mean P1 amplitude was comparable with 57.2 ± 16.3 in ring 1 and 38.0 ± 11.7 in ring 2 compared with the initial situation (p = 0.22 and p = 0.3, respectively). Conclusion BBG with 4% PEG can be used for ILM peeling in patients with idiopathic epiretinal membranes without any sign of short-term toxicity.

Safety and efficacy of brilliant blue g250 (BBG) for lens capsular staining: a phase III physician-initiated multicenter clinical trial

PURPOSE

To evaluate the safety and efficacy of BBG (Brilliant Blue G250) for lens capsular staining during cataract surgery with continuous curvilinear capsulorhexis.

STUDY DESIGN

Prospective clinical study.

METHODS

This clinical trial enrolled 30 eyes of 30 patients who underwent cataract surgery with BBG (0.25 mg/mL Brilliant Blue G250) for capsular staining. Visualization of the lens capsule and the ease of capsulorhexis with BBG staining were evaluated in five grades (grade 0 to 4) by the Independent Data Monitoring Committee and the surgeons. The safety of BBG was also evaluated in terms of ocular and systemic tolerance for 7 days after surgery.

RESULTS

The use of BBG improved visualization of the lens capsule and complete capsulorhexis was performed in all patients. The major endpoint (Independent Data Monitoring Committee evaluation) showed that use of BBG improved visualization of the lens capsule and the ease of capsulorhexis (grades 2 to 4); the committee's grading results were similar to those of the surgeons. Frequent complications observed in more than two eyes were conjunctival injection, corneal edema and intraocular pressure elevation. No severe complications were observed in ocular and systemic evaluations.

CONCLUSION

BBG staining contributed to improved visualization of the lens capsule and aided in the completion of capsulorhexis during cataract surgery. The use of BBG for capsular staining also exhibited favorable safety results.

Quantitative evaluation of digital-image enhancement during heads-up surgery

Image-processing is an advantage of heads-up surgery and expected to facilitate ophthalmic surgeries. To evaluate image-processing quantitatively, we analyzed the surgical images of twenty eyes that underwent vitrectomy with internal limiting membrane (ILM) peeling assisted by Brilliant Blue G (BBG). Still images of the peeling procedure were obtained from the surgical video, and the color difference was calculated between two adjacent spots inside and outside the ILM-peeling contour, i.e., without and with BBG staining, respectively. The color differences were compared between the two settings with and without image-processing, delivered by an algorithm to enhance the color and contrast. Color differences were calculated using two methods: the Euclidean distance based on RGB values (RGB distance) and the Delta-E00 formula provided by the International Commission on Illumination. In five cases, minimum light intensities required to recognize the contour of ILM-peeling were compared during surgeries between the two settings with and without enhancement. Image-processing increased the mean color difference significantly (P < 0.001) from 15.47 and 4.49 to 34.03 and 8.00, respectively, for the RGB distance and Delta-E00. The minimum light intensity was reduced from 15 to 5 on average by image-enhancement. These results showed image-processing enhances color differences and reduces light intensities during vitrectomy.

Effect of brilliant Blue-G on cellular stress response in retinal pigment epithelial cells: In vitro

To assess the cellular stress evoked by exposure of Brilliant Blue-G (BBG), adult retinal pigment epithelial (ARPE-19) cells were treated with various dilutions of BBG in balanced salt solution plus (BSS-PLUS) with and without endoillumination (Alcon Constellation Vision System). The treatments lasted for acute periods of 2 and 5 min. MTT and presto blue assays were performed to assess the changes in cell viability; reactive oxygen species (ROS) production was quantified by DCFDA (dichlorofluorescin diacetate) assay, and the expression of inflammatory stress and endoplasmic reticulum (ER) genes were quantified by qPCR. We observed no reduction in cell viability at 2 min of dye treatment with and without endoillumination while at 5 min exposure, a reduction in cell viability at all concentrations of the dye was observed compared to control. Though there was an increase in ROS with endoillumination, it was insignificant. There was no change in the mRNA expression of TNF-α while that of GRP78, and inflammatory genes viz. IL-8, IL-1β showed a significant increase at 0.5 mg/ml dye with endoillumination. BBG reduced cell viability with increasing concentration and time. The undiluted concentration of the dye results in inflammatory stress compared to the diluted formulations. Interestingly, increased GRP78 at undiluted concentration indicates a protective response in cells exposed to light. However, further studies are needed to evaluate the effect of cellular stress on the visual outcome. We infer that the commercially available formulation of BBG is safe for the RPE, at the recommended dose for a short duration however its toxicity to other cell types need to be addressed.

Comparative analysis of brilliant blue G and an intracameral illuminator in assisting visualization of the anterior capsule in eyes with vitreous hemorrhage

PURPOSE

To compare the safety and efficacy of 0.025 mg/mL brilliant blue G (BBG) and an intracameral illuminator for visualizing the anterior capsule.

SETTING

University-based tertiary referral center, South Korea.

DESIGN

Retrospective cases series.

METHODS

The medical records of patients with vitreous hemorrhage for which they had pars plana vitrectomy and cataract surgery were retrospectively reviewed. The patients were classified into 2 groups. The BBG group comprised patients having capsule staining with BBG. The illuminator group comprised patients who had capsulorhexis assisted with an intracameral illuminator. The status of the endothelial cells was analyzed.

RESULTS

There were 27 eyes in the BBG group and 35 eyes in the illuminator group. In the BBG group, endothelial cell density (ECD) was reduced 3 months after surgery (10.6% loss) (P = .003). The illuminator group had no significant loss (1.5% loss) (P = .264). The ECD loss was greater in the BBG group than the illuminator group 3 months after surgery (P = .01). There was no statistically significant difference in the coefficient of variation of cell area or percentage of hexagonal cells between the 2 groups.

CONCLUSIONS

The ECD loss was higher in eyes with 0.025 mg/mL BBG staining than in eyes using an intracameral illuminator. Further studies are necessary to establish the safety profile of BBG on the endothelium.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Perfluorocarbon liquid-assisted membrane staining and peeling technique for macular diseases

PURPOSE

A surgical technique is described that facilitates membrane peeling in patients with macular diseases by using small amounts of perfluorocarbon liquid (PFCL) and brilliant blue G (BBG) dye.

STUDY DESIGN

Retrospective cohort study.

METHODS

After placing about 1.0-1.5 cc PFCL on the macular area, BBG was applied with a 27-gauge blunt needle at the interface of PFCL and retina. The membrane peeling was performed under PFCL.

RESULTS

The amount of BBG dye with PFCL-assisted staining technique has the potential to be smaller than in conventional staining method. Since the displacement angle of the membrane during peeling procedures is considerably increased by PFCL, combined with its high specific gravity and interfacial tension, the risk of tearing the membrane during manipulation is reduced to a great extent. The postoperative visual function in patients with PFCL-assisted peeling was comparable to that of patients without PFCL-assisted peeling.

CONCLUSION

The PFCL-assisted technique enables sufficient membrane staining with minimal amounts of BBG dye, with tearing of the epiretinal membrane or internal limiting membrane being less likely than with the conventional method.

INTERNAL LIMITING MEMBRANE PEELING-DEPENDENT RETINAL STRUCTURAL CHANGES AFTER VITRECTOMY IN RHEGMATOGENOUS RETINAL DETACHMENT

PURPOSE

To examine retinal changes after vitrectomy with internal limiting membrane (ILM) peeling, we used 3-dimensional optical coherence tomography (3D-OCT) in rhegmatogenous retinal detachment cases.

METHODS

The 68 eyes from 67 patients with rhegmatogenous retinal detachment were studied, including 35 detached macula cases (51%) and 33 attached macula cases. Internal limiting membrane peeling was performed with fine forceps after brilliant blue G staining. The 3D-OCT images were obtained with volume-rendering technologies from cross-sectional OCT images.

RESULTS

The 3D-OCT detected 45 eyes (66%) with ILM peeling-dependent retinal changes, including dissociated optic nerve fiber layer appearance, dimple sign, temporal macular thinning, ILM peeling area thinning, or forceps-related retinal thinning. The ILM peeled area was detectable in only 9 eyes with 3D-OCT, whereas it was undetectable in other 59 eyes. The dissociated optic nerve fiber layer appearance was detected in 8 of the total cases (12%), and dimple signs were observed in 14 cases (21%). Forceps-related thinning was also noted in eight cases (24%) of attached macula cases and in four cases (11%) of detached macula cases. No postoperative macular pucker was noted in the observational period.

CONCLUSION

The 3D-OCT clearly revealed spatial and time-dependent retinal changes after ILM peeling. The changes occurred in 2 months and remained thereafter.

Foetal bovine serum can reduce toxicity of indocyanine green, brilliant blue G and trypan blue in ARPE-19 cellular model that suggests new surgical staining protocols for internal limiting membrane peeling procedure

BACKGROUND

To investigate and compare the cytotoxicity of indocyanine green (ICG), brilliant blue G (BBG) and trypan blue (TB) using ARPE-19 cells that have been pre-treated/post-treated with balanced salt solution (BSS) or foetal bovine serum (FBS).

METHODS

The cultured human retina pigment epithelium ARPE-19 cells were pre-treated/post-treated with BSS or FBS (represent the autologous serum in clinic) in parallel with cells being soaked with various concentrations of ICG, BBG and TB. The cells were then assessed for viability, growth rate, reactive oxygen species (ROS) level, mitochondrial membrane potential (Δψ) and mitochondrial mass as cytotoxic indices. For the FBS pre-treated cells, only ROS was examined.

RESULTS

Using the MTT assay, cytotoxicity seemed to appear when the dye concentration was above 2.5 mg/mL for ICG but no cytotoxicity for BBG and TB at the concentrations used. Cell growth was arrested at a concentration 1 mg/mL when ICG or BBG were present but no arrest at any of the tested concentrations was found for TB with the cell-growth curve was slowest for ICG. Cellular ROS levels increased at all concentrations of all dyes, but the increasing slopes were decreased after FBS post-treatment washout.

CONCLUSIONS

As a rinse buffer FBS performs much better than BSS in terms of cell rescue, which agrees with a clinical report when autologous whole blood was applied to macular hole surgery. However, FBS pre-treatment seems to be much better than FBS use as washout buffer in post-treatment.

The Effect of an Inverted Internal Limiting Membrane Flap on Retinal Function after Macular Hole Surgery

PURPOSE

To study the effect of an inverted internal limiting membrane (ILM) flap on the retina.

DESIGN

Prospective case series.

PARTICIPANTS

Twenty-nine patients with large (>400 μm) unilateral macular holes underwent surgery using a modified inverted ILM flap technique.

METHODS

The macular ILM was peeled, and a large (2-3 disc diameter) ILM flap was made on the superior side of the hole, and then the flap was inverted on the inferior side.

MAIN OUTCOME MEASURES

In all patients, multifocal electroretinograms (mfERGs) were recorded from operated eyes and normal fellow eyes. The peak time and amplitude of N1, P1, and N2 in the focal ERG from the upper retina without the ILM flap and those from the lower retina with the ILM flap were evaluated. In 14 patients, microperimetry was also performed in both eyes, and the averaged sensitivity was measured from the upper and lower areas.

RESULTS

The peak times of P1 and N2 from the upper and lower retina were significantly longer in operated eyes than in the fellow eyes (P1 upper and lower: P < 0.04, N2 upper: P < 0.01, and N2 lower: P < 0.04), although we could not identify a significant difference in peak time and amplitude of N1, P1, and N2 between the upper retina and lower retina in both eyes (fellow eye-N1 amplitude: P > 0.2, N1 peak time: P > 0.5, P1 amplitude: P > 0.9, P1 peak time: P > 0.4, N2 amplitude: P > 0.9, N2 peak time: P > 0.9; operated eye-N1 amplitude: P > 0.8, N1 peak time: P > 0.4, P1 amplitude: P > 0.6, P1 peak time: P > 0.4, N2 amplitude: P > 0.9, N2 peak time: P > 0.9). We could not observe a significant difference in sensitivity between the upper and lower retinas in both eyes (fellow eye: P = 0.28, operated eye: P = 0.66).

CONCLUSIONS

The results of this study revealed no significant difference between the upper retina without the ILM flap and the lower retina with the ILM flap, suggesting that an inverted ILM flap has little effect on retinal function.

20 g PPV with indocyanine green-assisted ILM peeling versus 23 g PPV with brilliant blue G-assisted ILM peeling for epiretinal membrane

To compare the anatomical and visual outcomes of 20 gauge (g) pars plana vitrectomy (PPV) with indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling and 23 g PPV with brilliant blue G (BBG)-assisted ILM peeling for idiopathic epiretinal membrane (ERM). 38 eyes of 38 patients with idiopathic ERM were included. They were divided in two groups: group 1 (18 eyes) underwent 20 g PPV with ICG-assisted ILM peeling and group 2 (20 eyes) 23 g PPV with BBG-assisted ILM peeling. Postoperative best-corrected visual acuity (BCVA) and central macular thickness (CMT) were compared. Average BCVA in group 1 improved significantly from 0.60 logarithm of the minimal angle of resolution (log MAR) at baseline to 0.3 log MAR postoperatively. Average BCVA in group 2 improved significantly from 0.60 log MAR at baseline to 0.3 log MAR postoperatively. Mean CMT reduced significantly from 473 to 375 μm in group 1 and from 486 to 396 μm in group 2. There were no significant differences in the BCVA and CMT between the groups. Both surgical methods appeared to be safe and provided similar anatomical and visual outcomes.

Effect of distance and duration of illumination on retinal ganglion cells exposed to varying concentrations of brilliant blue green

Background

The objective of the study was to determine the safety parameters of using brilliant blue green (BBG) for chromovitrectomy by assessing the cytotoxicity of BBG on cultured retinal ganglion cells (RGCs) exposed to illumination.

Methods

RGCs were exposed to two concentrations of BBG (0.25 and 0.5 mg/mL) under metal halide illumination at varying distances (1 and 2.5 cm), intensities (990 and 2,000 Fc), and durations (1, 5 and 15 minutes). Cell viability was assessed using the WST-1 and CellTiter 96^® AQueous One solution cell proliferation assays.

Results

Using the WST-1 assay, with high-intensity illumination, viability of RGCs ranged from 97.5±16.4% of controls with minimum BBG and light exposure (0.25 mg/mL BBG and illuminated for 1 minute at 2.5 cm distance) to 53.1±11.3% of controls with maximum BBG and light exposure (0.50 mg/mL and illuminated for 15 minutes at 1 cm distance; P < 0.01). With medium-intensity illumination, RGCs showed better viability, ranging from 95.1±7.2% of controls with minimum BBG and light exposure to 72.3±12.8% of controls with maximum BBG and light exposure. CellTiter 96^® AQueous One assay showed similar results.

Conclusion

RGCs seem to safely tolerate up to 5 minutes of exposure to 0.5 mg/mL BBG under diffuse medium-intensity illumination (990 Fc).

Long-term outcomes of 3 surgical adjuvants used for internal limiting membrane peeling in idiopathic macular hole surgery

PURPOSE

Indocyanine green (ICG), an adjuvant used for peeling of the internal limiting membrane (ILM) during vitreous surgery for idiopathic macular hole (MH), has been reported to be toxic, possibly affecting postoperative visual acuity. We compared the long-term outcomes (within 2 years) of brilliant blue G (BBG), ICG, and triamcinolone acetonide (TA).

PATIENTS AND METHODS

This study involved 97 eyes of 94 patients who underwent vitreous surgery for MH at the Yamagata University Hospital between June 2002 and November 2010. The surgical adjuvants used were BBG for 15 eyes, ICG for 61 eyes, and TA for 21 eyes. We compared the postoperative visual acuities, initial closure rates, final closure rates, and complications of the 3 groups.

RESULTS

In all 3 groups, the visual acuity significantly improved after surgery. The magnitude of the improvement at 2 years after surgery was significantly better in the BBG group than in the ICG group (Mann-Whitney test, P = 0.020). The postoperative visual acuity did not significantly differ between the BBG and TA groups (P = 0.627) or between the ICG and TA groups (P =0 .137). Thus, the surgery using BBG resulted in a significantly better outcome in visual acuity than did the surgery using ICG. The 3 groups did not differ in initial or final closure rates or in incidence of complications.

CONCLUSION

Analysis of the long-term outcomes of vitreous surgeries provided evidence that BBG is a useful adjuvant for ILM peeling.

Comparisons of retinal nerve fiber layer thickness after indocyanine green, brilliant blue g, or triamcinolone acetonide-assisted macular hole surgery

Purpose. To compare the postoperative changes of the retinal nerve fiber layer (RNFL) thickness in patients with macular holes (MHs) treated with vitrectomy with indocyanine green- (ICG-), brilliant blue G- (BBG-), or triamcinolone acetonide- (TA-)assisted internal limiting membrane (ILM) peeling. Methods. Sixty-one eyes of 61 consecutive patients with MHs were studied. Each eye was randomly selected to undergo either ICG- (n = 18), BBG- (n = 21), or TA-assisted (n = 22) ILM peeling. The circumferential retinal nerve fiber layer (RNFL) thickness was determined by spectral-domain optical coherence tomography (SD-OCT) before and 1, 3, 6, 9, and 12 months postoperatively. The mean overall and the sectoral thicknesses of the RNFL were obtained for each group. Results. A transient increase of the RNFL thickness was seen in the mean overall and sectoral thicknesses except for the nasal/inferior sector at 1 month after surgery for the three groups. Then, the thickness gradually decreased and returned to the baseline level in all sectors except for the nasal/inferior sector. The differences in the RNFL thickness among the groups were not significant for at least 12 months postoperatively. Conclusions. The degree of change of the RNFL thickness was not significantly related to the type of vital stain used during MH surgery.

Comparisons of cone electroretinograms after indocyanine green-, brilliant blue G-, or triamcinolone acetonide-assisted macular hole surgery

PURPOSE

To compare the function of retinal ganglion cells (RGCs) using the photopic negative response (PhNR) in patients who had undergone indocyaine green (ICG)-assisted, brilliant blue G (BBG)-assisted, or triamcinolone acetonide (TA)-assisted internal limiting membrane (ILM) peeling during macular hole (MH) surgery.

METHODS

Forty-eight eyes of 48 patients with a macular hole were randomly divided into those undergoing ICG-assisted, BBG-assisted, or TA-assisted vitrectomy (n = 16 for each group). Full-field cone ERGs were recorded before and 1, 3, 6, 9, and 12 months postoperatively. The amplitudes and implicit times of the a-waves and b-waves and the amplitudes of the oscillatory potentials (OPs) and PhNRs were measured. The mean deviations (MDs) of standard automated perimetry and the best-corrected visual acuity (BCVA) were measured. The circumferential retinal nerve fiber layer (RNFL) thickness was evaluated by SD-OCT.

RESULTS

All macular holes were closed with a significant improvement of the BCVA and MD without differences among the groups. There was no significant difference between the preoperative and postoperative RNFL thickness. The implicit times of the a-waves and b-waves were significantly prolonged, and the ΣOPs amplitude was significantly decreased postoperatively in all groups. These ERG changes were not significantly different among the groups. The postoperative PhNR amplitudes were significantly lower in the ICG group than in the BBG or TA group.

CONCLUSIONS

The results indicate that the PhNR may detect subclinical impairments of RGCs caused by the possible toxic effect of ICG. This finding adds to the data that BBG and TA may be safer than ICG for use during MH surgery.

Brilliant Blue G assisted epiretinal membrane surgery

We report intensely staining epiretinal membrane (ERM) with Brilliant Blue G (BBG) under air for two minutes. ERM peeling was performed in 21 cases. After removal of posterior hyaloid, 0.2 mL BBG was first applied on the macula, to stain ERM under air conditions for 2 minutes. Internal limiting membrane (ILM) was intensely stained and peeled in all cases following ERM removal. In 4 cases, the ERM was also observed to be intensely stained with BBG and peeled with an ILM forceps. Postoperatively, the ganglion cell layer thickness was lower in three of the cases, however VA improved in all cases and multifocal electroretinogram revealed no toxicity. Light microscopy of ERM revealed masses of cells whereas; the ILM did not. The increased staining characteristics of ERM and ILM may be resulted from longer contact time of BBG under air pressure.

Internal limiting membrane contrast after staining with indocyanine green and brilliant blue G during macular surgery

PURPOSE

To evaluate the difference in color contrast by performing a color contrast ratio (CR) analysis and resulting visibility of the internal limiting membrane (ILM) when stained with indocyanine green and brilliant blue G (BBG) during macular surgery by performing a color CR analysis.

METHODS

The authors analyzed 40 consecutive cases in which vitrectomy with ILM removal was performed to treat a macular hole or an epiretinal membrane. The surgical procedure was performed in 21 patients (21 eyes) after staining with indocyanine green and in 19 patients (19 eyes) after staining with BBG. The color CRs were estimated based on digital analysis of the red, green, and blue data of the digital images captured, and the CRs obtained with the two dyes were compared.

RESULTS

Color contrast analysis was performed in all 40 eyes, in which the ILM was removed after staining with indocyanine green or BBG, and the CRs were estimated in every eye. The CR (mean ± SD) obtained with indocyanine green and BBG was 4.3 ± 0.3 and 2.4 ± 0.1, respectively. Indocyanine green provided a significantly higher CR than BBG (P = 0.015).

CONCLUSION

Digital color contrast analysis can be used to evaluate the visibility of digital images, and it may be useful when choosing the dye to use for staining the ILM better.

Chromovitrectomy: update

The basic concept for the application of vital dyes during vitreoretinal surgery is to assist in highlighting preretinal membranes and tissues which are very thin and semitransparent and thus difficult to detect. The vital dyes may be classified according to different criteria, where the most commonly applied includes chemical classification. In ophthalmic surgery, vital dyes are widely used in cataract and vitreoretinal surgery. The vital dyes, indocyanine green, infracyanine green, and brilliant blue stain the internal limiting membrane, and trypan blue and triamcinolone acetonide help to visualize epiretinal membranes and vitreous, respectively. This review exhibits the current literature regarding the properties of vital dyes, techniques of application, indications, and toxicities during vitreoretinal surgery and, also suggests that the field of chromovitrectomy represents an expanding area of research.

Combined 25-gauge vitrectomy and cataract surgery with toric intraocular lens with idiopathic epiretinal membrane

PURPOSE

To evaluate the stability of axis rotation, astigmatism correction, and improvement in uncorrected distance visual acuity (UDVA) up to 6 months postoperatively using an astigmatism-correcting intraocular lens (IOL) in a 25-gauge transconjunctival sutureless vitrectomy combined with cataract surgery.

SETTING

Department of Ophthalmology, Kagawa University Faculty of Medicine, Kagawa, Japan.

DESIGN

Prospective nonrandomized interventional study.

METHOD

Eyes with a preoperative corneal cylinder of more than 0.75 diopter (D) had a triple procedure for idiopathic epiretinal membrane (ERM) using an Acrysof IQ toric IOL. Outcome measures were the amount of IOL axis rotation up to 3 months postoperatively, UDVA, corrected distance visual acuity, and corneal and refractive astigmatism up to 6 months postoperatively. A comparison was performed between patients with a target postoperative spherical refraction of emmetropia (toric emmetropic group) and patients who previously had a triple procedure for idiopathic ERM using a nontoric IOL (control group).

RESULTS

The mean IOL axis rotation from the end of surgery until 3 months postoperatively was 3.67 degrees ± 3.13 (SD). Six months postoperatively, the mean corneal and refractive cylinders were 1.32 ± 0.61 D and 0.51 ± 0.31 D, respectively, showing a significant difference (P<.0001, paired t test). In addition, the mean UDVA was significantly improved 6 months postoperatively in the control and toric emmetropic group (0.57 logMAR versus 0.35 logMAR) (P=.028), although the toric group was more improved than the control group.

CONCLUSION

In vitrectomy (triple procedure) for idiopathic ERM with a toric IOL, postoperative IOL axis stability was similar to that reported for cataract surgery alone. Furthermore, the UDVA was better than with implantation of a spherical IOL.

Dynamic increase in extracellular ATP accelerates photoreceptor cell apoptosis via ligation of P2RX7 in subretinal hemorrhage

Photoreceptor degeneration is the most critical cause of visual impairment in age-related macular degeneration (AMD). In neovascular form of AMD, severe photoreceptor loss develops with subretinal hemorrhage due to choroidal neovascularization (CNV), growth of abnormal blood vessels from choroidal circulation. However, the detailed mechanisms of this process remain elusive. Here we demonstrate that neovascular AMD with subretinal hemorrhage accompanies a significant increase in extracellular ATP, and that extracellular ATP initiates neurodegenerative processes through specific ligation of Purinergic receptor P2X, ligand-gated ion channel, 7 (P2RX7; P2X7 receptor). Increased extracellular ATP levels were found in the vitreous samples of AMD patients with subretinal hemorrhage compared to control vitreous samples. Extravascular blood induced a massive release of ATP and photoreceptor cell apoptosis in co-culture with primary retinal cells. Photoreceptor cell apoptosis accompanied mitochondrial apoptotic pathways, namely activation of caspase-9 and translocation of apoptosis-inducing factor (AIF) from mitochondria to nuclei, as well as TUNEL-detectable DNA fragmentation. These hallmarks of photoreceptor cell apoptosis were prevented by brilliant blue G (BBG), a selective P2RX7 antagonist, which is an approved adjuvant in ocular surgery. Finally, in a mouse model of subretinal hemorrhage, photoreceptor cells degenerated through BBG-inhibitable apoptosis, suggesting that ligation of P2RX7 by extracellular ATP may accelerate photoreceptor cell apoptosis in AMD with subretinal hemorrhage. Our results indicate a novel mechanism that could involve neuronal cell death not only in AMD but also in hemorrhagic disorders in the CNS and encourage the potential application of BBG as a neuroprotective therapy.

Use of lutein and zeaxanthin alone or combined with Brilliant Blue to identify intraocular structures intraoperatively

PURPOSE

To determine whether a natural dye solution based on lutein and zeaxanthin alone or combined with Brilliant Blue stains and facilitates peeling of intraocular membranes in human eyes.

METHODS

In this study of 60 cadaveric eyes, open-sky vitrectomy including posterior hyaloid detachment was performed. Different lutein and zeaxanthin concentrations (0.01-20%) were tested alone or combined with different Brilliant Blue concentrations (0.0125-0.025%) in the corneal endothelium, corneal epithelium, anterior and posterior capsule, vitreous cavity through the macula including the posterior hyaloid, and internal limiting membrane. The various dye solutions were in contact with the intraocular membranes for <1 minute and then were removed by mechanical aspiration or membrane peeling initiated and completed with intraocular forceps. The specimens were examined by light and electron transmission microscopy.

RESULTS

Contact between lutein and zeaxanthin and the retinal, lens, and vitreous surface resulted in orange and greenish staining of the intraocular membranes, which facilitated surgical steps in all eyes. Lutein and zeaxanthin alone was useful for vitreous identification and lutein and zeaxanthin combined with Brilliant Blue had strong affinity for internal limiting membrane and anterior capsule. Light microscopy confirmed internal limiting membrane removal in all eyes tested. No dye solutions remained in the eyes after the membrane removal.

CONCLUSION

A natural dye solution based on lutein and zeaxanthin alone or combined with Brilliant Blue efficiently stained the anterior capsule, vitreous, and internal limiting membrane in human cadaveric eyes and may be a useful tool for vitreoretinal or cataract surgery.

Treatment of idiopathic macular hole with silicone oil tamponade

Purpose

We analyzed the anatomical and visual outcomes after surgical treatment of idiopathic macular holes with pars plana vitrectomy, internal limiting membrane (ILM) peeling using Brilliant Blue dye, and silicone oil tamponade without postoperative posturing.

Methods

This was a retrospective interventional study of 10 eyes in eight patients who underwent surgical treatment of idiopathic macular holes using pars plana vitrectomy, ILM peeling using Brilliant Blue dye, and silicone oil tamponade without postoperative posturing. The preoperative staging of macular holes and postoperative anatomic outcomes were assessed using spectral-domain optical coherence tomography.

Results

All patients were women with a mean age of 66.86 ± 4.8 years. In two patients, bilateral macular holes were present and both eyes were operated on. Stage 2 macular hole was diagnosed in three eyes, three eyes had stage 3, and four eyes had stage 4 macular holes. Anatomical success and closure of the macular hole was achieved in nine eyes (90%) after one operation. In one eye, the macular hole was closed after reoperation. The preoperative mean best-corrected visual acuity (BCVA) was 0.15 decimal units (0.8 logMAR units). Until the end of the follow-up period, BCVA was 0.25 decimal units (0.6 logMAR units). Visual acuity was improved in seven patients (70%). In two patients (20%), visual acuity remained at the same level, and in one eye (10%), visual acuity decreased. Postoperatively, all patients reported a significant reduction of metamorphopsia.

Conclusion

Initial results after 20G pars plana vitrectomy with peeling of the ILM, use of dye (Brilliant Blue), and tamponade with silicone oil without postoperative posturing gave good anatomical and functional outcome in terms of visual acuity and reduction of metamorphopsia. Taking into account the age of the patients, this method, which does not require prolonged postoperative face-down posturing, was well tolerated by the patients. Because the anatomical and visual outcome as well as the rate of postoperative complications are comparable to those when gas is used as a tamponading agent, silicone oil tamponade can also be safely used as a first option in surgery of macular holes. However, a longer period of follow-up of the operated eyes, as well as a larger group of operated eyes, will be required to identify long-term outcomes of this surgical treatment.

Development and preclinical evaluation of a new viewing filter system to control reflection and enhance dye staining during vitrectomy

PURPOSE

We developed a new artificial image enhancement system and evaluated its usefulness in controlling intraoperative reflection and enhancing of Brilliant Blue G (BBG) staining.

METHODS

The system was composed of three kinds of filters (a polarizing filter, a blue-enhancing filter, and a sharp-cut filter Y) and attached to the inferior surface of the operating microscope. Twenty-seven post-mortem extracted porcine eyes were used for a series of examinations. We performed surgery using the 23G-vitrectomy system with a halogen light and xenon lights and compared the reduction of intraoperative reflection under air condition and visibility and BBG contrast with and without this system. The evaluation of images was calculated in CIE 1976 (L*, a*, b*) color space (CIELAB) carried out by ImageJ software. The transmission of each filter and absorbance of BBG was measured by a spectrophotometer. We measured spectral irradiance at each wavelength about each filter from each light source with a spectroradiometer.

RESULTS

Under both light sources, intraoperative reflection was controlled using a polarizing (PL) filter or combination of filters under air condition. Evaluation of the value of L* within the cutter surface was changed by 37.8 % under the halogen light, and 61.6 % (averaged) under the xenon light with inserted filters versus no filter. The BBG intensity difference was obtained with sharp-cut Y filter under both light source and PL with blue enhancing filter under the halogen light using each L*, a*, b* parameter with statistically significant (p < 0.01, 0.05). However, there was a relative decrease in the observation illuminance when the filter inserted according to the attenuation total spectral irradiance.

CONCLUSIONS

This system can reduce intraoperative reflections under the air condition and obtain an excellent BBG staining intensity induced by various light sources.

A comparison of brilliant blue G, trypan blue, and indocyanine green dyes to assist internal limiting membrane peeling during macular hole surgery

PURPOSE

To compare surgical outcomes with three dyes, brilliant blue G (BBG), trypan blue (TB) and indocyanine green (ICG), used to facilitate internal limiting membrane peeling during macular hole surgery.

METHODS

This comparative, interventional cases series consisted of 50 eyes of 50 patients with senile idiopathic macular holes, who underwent vitrectomy with internal limiting membrane peeling using BBG (n = 15), TB (n = 20), or ICG (n = 15). The cases involving use of BBG and TB were enrolled prospectively and concurrently, and the cases using ICG were selected through chart reviews. We compared the intraoperative surgical facilitation with the 3 dyes and the surgical outcomes in terms of macular hole closure and visual improvement at 6 months.

RESULTS

The 3 groups were similar in mean age, sex distribution, preoperative best-corrected visual acuity, and duration of follow-up (P = 0.957, 0.974, 0.939, and 0.5524, respectively). Of the 3 dyes, BBG appeared to provide greatest intraoperative facilitation: most convenient to use and remove, and similar to ICG in terms of internal limiting membrane staining. Six months postoperatively, macular hole closed in 100%, 95%, and 86% eyes (P = 0.48) and visual improvement occurred in 80%, 85%, and 33% eyes (P = 0.005) in BBG, TB, and ICG groups, respectively. The BBG and TB groups also had a better final best-corrected visual acuity than ICG group (P = 0.05) and smaller percentage of visual decline (5% and 6.7% vs. 40% respectively; P = 0.049).

CONCLUSION

Brilliant blue G was comparable with TB in optimizing visual and functional outcomes, while it was similar to ICG in ease of internal limiting membrane peeling.

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.