Indocyanine green-assisted peeling of the retinal internal limiting membrane during vitrectomy surgery for macular hole repair

RANDOMIZED TRIAL COMPARING MICROSERRATED VERSUS CONVENTIONAL INTERNAL LIMITING MEMBRANE FORCEPS FOR INTERNAL LIMITING MEMBRANE PEELING

PURPOSE

To evaluate anatomic outcomes and surgeon response following the use of microserrated (Sharkskin, Alcon, Forth Worth, TX) internal limiting membrane (ILM) forceps compared with conventional (Grieshaber; Alcon) ILM forceps for peeling of the ILM.

METHODS

Patients were prospectively assigned in a 1:1 randomized fashion to undergo ILM peeling using microserrated forceps or conventional forceps. Rates of retinal hemorrhages, deep retinal grasps, ILM regrasping, time to ILM removal, and surgeon questionnaire comparing the use of microserrated and conventional ILM forceps were analyzed.

RESULTS

A total of 90 eyes of 90 patients were included in this study. The mean number of deep retinal grasps was higher in the conventional forceps group (1.51 ± 1.70 vs. 0.33 ± 0.56, respectively [P < 0.0001]). The mean number of failed ILM grasps was higher with conventional forceps (6.62 ± 3.51 vs. 5.18 ± 2.06 [P = 0.019]). Microserrated forceps provided more comfortability (lower number) in initiating the ILM flap (2.16 ± 0.85 vs. 1.56 ± 0.76, P < 0.001), comfortability in regrasping the ILM flap (2.51 ± 1.01 vs. 1.98 ± 0.89, P = 0.01), and comfortability in completing the ILM flap (2.42 ± 1.03 vs. 1.84 ± 1.02, P = 0.01).

CONCLUSION

Surgeons utilizing the microserrated forceps experienced fewer deep retina grasps and fewer failed ILM grasps compared with conventional ILM forceps. The microserrated forceps was also a more favorable experience subjectively among the surgeons.

[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.

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.

Surgical Management of Recurrent and Persistent Macular Holes: A Practical Approach

Primary surgery for macular hole (MH) closure has a high success rate with current methods of pars plana vitrectomy and internal limiting membrane (ILM) peeling. When primary surgery fails, there are several options available for secondary repair, including extension of the ILM peel, creation of an ILM flap, pedunculated ILM flap, lens capsule flap transplantation, autologous retinal transplantation, use of a human amniotic membrane plug, adjuvant autologous platelet concentrate, induction of macular detachments with subretinal blebs, and creation of retinal incisions. In this review, we discuss the practical approach to each of these surgical techniques for the management of recurrent or persistent MHs.

Evaluation of efficacy and safety of new high-density dyes for chromovitrectomy

The purpose of this study is to evaluate the safety and efficacy of two novel heavy dyes for macular surgery: DoubledyneTM and TwinTM. One eye from each of 144 patients undergoing surgery for macular hole or macular pucker was included in the study. The eyes were randomly divided into two groups according to the dye used during surgery. Best correct visual acuity (BCVA), intraocular pressure (IOP) and retinal morphology assessed by ocular coherence tomography (OCT) were evaluated before and 1, 3, 6 and 12 months after surgery. Only one surgeon performed each operation and provided a score ranging from 1 (poor) to 10 (excellent) for quality of staining and comfort in surgery. Statistical analysis was carried out with SPSS to compare parameters before and after surgery and between the two groups. No statistical differences were recorded in quality of staining (p = 0.11), in surgery comfort (p = 0.17) and total time of surgery (p = 0.44) between the two groups. BCVA statistically improved and central macular thickness (CMT) statistically decreased after surgery in both groups (p < 0.05). No toxic dye-related complications or long-term ones affecting the retina were observed in either group. According to this data, although confirmation in further studies with larger populations and longer follow up is required, DoubledyneTM and TwinTM proved to be safe and effective dyes for macular surgery.

Results of Pars Plana Vitrectomy for Different Types of Macular Holes

Purpose

To compare different types of macular holes regarding the anatomic and functional success following pars plana vitrectomy (PPV) and internal limiting membrane (ILM) removal.

Methods

A retrospective review of all patients with macular holes treated by PPV, ILM removal with gas tamponade from January 2014 to July 2017 in Magrabi Eye Hospital.

Results

One hundred fifty-seven eyes of 153 patients were analyzed. The eyes were classified according to the etiology of macular hole into four groups: 79 eyes with idiopathic macular hole (IMH), 51 eyes with traumatic macular hole (TMH), 16 eyes with macular hole in diabetic patients (DMH) and 11 eyes with myopic macular hole (MMH). We classified the IMH group based on the International Vitreomacular Traction Study Classification according to size into 3 subgroups; subgroup 1: ≤250µ, subgroup 2: >250 to 400µ and subgroup 3: ≥400 µ. All types of macular hole showed statistically significant postoperative improvement in BCVA compared to the baseline except cases with MMH. Anatomic postoperative hole closure was achieved in 86.1%, 60.7%, 43.65%, an 45.46% of eyes with IMH, TMH, DMH and MMH, respectively. In eyes with IMH, closure rate in subgroup 1 was significantly higher than in subgroups 2, and 3.

Conclusion

PPV, ILM peel and C2F6 technique yielded variable anatomic and functional outcomes in different types of macular holes. Anatomic results were most favorable in IMH and least favorable in MMH. The smaller the diameter of the hole the better the results. The underlying pathogenetic mechanisms that lead to different types of macular holes are pivotal in determining the final outcome.

Role of Vital Dyes in Chromovitrectomy

ABSTRACT

Chromovitrectomy, the intraocular application of dyes to assist visualization of preretinal tissues during vitreoretinal surgery, was introduced to avoid ocular complications related to internal limiting membrane peeling, inadequate removal of the vitreous, and incomplete removal of epiretinal membranes. Since 2000, chromovitrectomy has become a popular approach among vitreoretinal specialists. The first vital dye used in chromovitrectomy, indocyanine green, facilitated identification of the fine and transparent internal limiting membrane. Following indocyanine green, trypan blue was introduced to identify epiretinal membranes, and triamcinolone acetonide stained the vitreous well. Recently, additional natural dyes such as lutein and anthocyanin from the açaí fruit have been proposed for intraocular application during vitrectomy. The main goal of this review was to study the role of vital stains in chromovitrectomy and report the latest findings in the literature.

Viscostretch: A Novel Surgical Technique for Refractory Macular Holes

Purpose:

We present a novel technique of subretinal viscodissection for addressing refractory macular holes (MHs).

Methods:

A case report and surgical technique description are provided.

Results:

In this technique, standard pars plana vitrectomy with internal limiting membrane peeling (unless previously peeled) is performed. A cohesive ophthalmic viscosurgical device (OVD) is injected through the MH, focally detaching the parafoveal retinal tissue around the hole. The OVD is removed at the conclusion of the air-fluid exchange. We provide an example of a recurrent 833-µm MH that was successfully closed despite failing initial surgery. There was no retention of subretinal OVD, and anatomic closure was achieved in this patient with a refractory MH.

Conclusions:

In refractory holes with adhesions at the MH base, this technique mobilizes the adjacent retinal tissue and uses the air’s surface tension to facilitate closure. Surgeons can consider using this technique as part of their MH arsenal.

Postoperative eccentric macular holes after surgery for vitreomacular interface diseases

PURPOSE

To assess the incidence, clinical characteristics, and outcome of postoperative eccentric macular hole (ECMH) after epiretinal membrane (ERM), macular hole (MH), and idiopathic vitreomacular traction (VMT) surgery and discuss the underlying possible mechanisms.

METHODS

A retrospective study was carried out for 711 eyes of 711 consecutive patients who underwent 25-gauge pars plana vitrectomy (PPV) with ERM (396 eyes), MH (268 eyes), and VMT (47 eyes) surgery between 2010 and 2016. Mean follow-up time was 19 months.

RESULTS

Eight patients developed ECMH (1.12%). Four of the patients were ERM, three patients were idiopathic full thickness MH, and one patient was ERM and lamellar pseudohole. There was no ECMH in patients with VMT. The average time of hole formation after vitrectomy was 7.25 weeks with a range from 2 to 15 weeks. Three patients developed 2 ECMH, and others had 1 ECMH. The location of the ECMH was mostly in the temporal of fovea. All patients were asymptomatic. No retinal detachment or choroidal neovascularization occurred in any patient and no additional intervention was attempted in the postoperative period in any case.

CONCLUSION

Postoperative ECMH may be seen after vitreomacular interface surgery. They are mostly asymptomatic, usually do not require additional intervention and often located in the parafoveal area. ILM peeling-induced muller cell damage, residual ILM contraction, and iatrogenic trauma may play a role as the underlying cause in our case series.

Vital Dyes in Vitreomacular Surgery

Vital dyes contain complex molecules with chromophores that stain living tissues and have greatly enhanced identification and removal of transparent vitreoretinal tissues during surgery. Several "chromovitrectomy" dyes are frequently used by vitreoretinal specialists, including indocyanine green, trypan blue, brilliant blue G, and triamcinolone acetonide; other dyes are also under investigation. Trypan Blue was approved by the U.S. Food and Drug Administration (FDA) for epiretinal membrane removal, and preservative-free triamcinolone acetonide was approved by the FDA for intraocular use. However, currently available chromovitrectomy dyes have their limitations, and of particular concern for some of them is the possibility for acute and chronic toxicity to the neurosensory retina and retinal pigmented epithelium. The potentially irreversible acute toxicity and other limitations, such as lack of long-term safety profiles, highlight the need for further advancements. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:788-798.].

Risk factors for retinal breaks during macular hole surgery

Purpose

To identify risk factors for retinal breaks during macular hole (MH) surgery.

Patients and methods

This retrospective, observational, comparative study included the medical records of 364 consecutive patients (382 eyes) who underwent vitrectomy for MH at Toho University Sakura Medical Center between January 2012 and May 2017. The patients comprised 135 men and 229 women with mean age 67.6±8.0 years. Six eyes with a pre-existing retinal tear treated by laser photocoagulation before MH surgery were excluded. Data on sex, age, presence or absence of lattice degeneration, axial length (measured using an IOL Master^®), preoperative refraction, whether or not combined lens extraction/vitrectomy had been performed, whether or not the lens was pseudophakic before vitrectomy, and whether or not a posterior vitreous detachment had been created intraoperatively were collected. The lattice degeneration status was classified as none (0), treated using laser photocoagulation (1), or untreated (2).

Results

The only item identified in logistic regression analysis with the backward elimination method to be a significant risk factor for retinal breaks during MH surgery was the presence of lattice degeneration (P<0.001).

Conclusion

Ophthalmologists should be aware of the increased risk of retinal breaks during MH surgery in eyes with lattice degeneration. Intraoperative retinal breaks may be less likely to occur in eyes with lattice degeneration treated by photocoagulation preoperatively.

Leveraging Engineering of Indocyanine Green-Encapsulated Polymeric Nanocomposites for Biomedical Applications

In recent times, photo-induced therapeutics have attracted enormous interest from researchers due to such attractive properties as preferential localization, excellent tissue penetration, high therapeutic efficacy, and minimal invasiveness, among others. Numerous photosensitizers have been considered in combination with light to realize significant progress in therapeutics. Along this line, indocyanine green (ICG), a Food and Drug Administration (FDA)-approved near-infrared (NIR, >750 nm) fluorescent dye, has been utilized in various biomedical applications such as drug delivery, imaging, and diagnosis, due to its attractive physicochemical properties, high sensitivity, and better imaging view field. However, ICG still suffers from certain limitations for its utilization as a molecular imaging probe in vivo, such as concentration-dependent aggregation, poor in vitro aqueous stability and photodegradation due to various physicochemical attributes. To overcome these limitations, much research has been dedicated to engineering numerous multifunctional polymeric composites for potential biomedical applications. In this review, we aim to discuss ICG-encapsulated polymeric nanoconstructs, which are of particular interest in various biomedical applications. First, we emphasize some attractive properties of ICG (including physicochemical characteristics, optical properties, metabolic features, and other aspects) and some of its current limitations. Next, we aim to provide a comprehensive overview highlighting recent reports on various polymeric nanoparticles that carry ICG for light-induced therapeutics with a set of examples. Finally, we summarize with perspectives highlighting the significant outcome, and current challenges of these nanocomposites.

Inverted internal limiting membrane flap technique for large macular holes: a systematic review and single-arm meta-analysis

PURPOSE

The aim of this systematic review was to determine the anatomical outcome-macular hole (MH) closure rate-and functional outcome-visual acuity (VA) improvement rate-of the inverted internal limiting membrane (ILM) flap technique for large MH.

METHODS

We searched for articles on large MH (> 400 μm) treated with inverted ILM flap technique in databases as of December 1, 2017. And single-arm meta-analysis was performed for the primary outcome of MH closure rate and the secondary outcome of VA improvement rate. In addition, we searched and pooled studies treating large MH with indocyanine green (ICG)-assisted ILM peeling as the reference. R software (version 2.15.2) was used for analysis.

RESULTS

This review includes eight studies that used inverted ILM flap technique to treat large MH (> 400 μm). Based on the single-arm meta-analysis performed in R 2.15.2, the pooled MH closure rate and VA improvement rate following inverted ILM flap technique were 95% (95% CI, 88 to 98%) and 75% (95% CI, 62 to 85%), respectively, in fixed-effect models. There was no substantial methodological heterogeneity. In addition, we selected four studies on large MH treated with ICG-assisted ILM peeling as the reference. The fixed-model pooled MH closure rate and VA improvement rate were 87% (95% CI, 79 to 92%) and 57% (95% CI, 46 to 68%), respectively.

CONCLUSIONS

Inverted ILM flap technique should be an effective and safe method for treating large MH, with high closure rates and good VA improvement. However, further studies in large randomized controlled trials on minimizing surgical complications and understanding the mechanism of this technique are necessary.

Vitrectomy Results for Diffuse Diabetic Macular Edema with and without Inner Limiting Membrane Removal

Purpose

To determine whether vitrectomy for diffuse diabetic macular edema with and without internal limiting membrane (ILM) peeling is equally effective in reducing edema.

METHODS

The authors retrospectively analyzed the surgical outcomes in 73 eyes of 52 patients with diffuse diabetic macular edema. Eighteen eyes (Group A) underwent three-port pars plana vitrectomy with posterior hyaloid membrane (PHM) removal, while 55 eyes (Group B) had pars plana vitrectomy with additional ILM peeling after PHM removal. RESULTS. Intraoperatively the posterior hyaloid was found to be attached to the macula in all eyes. In Group A, macular edema resolved completely in 8 eyes (44.4%) with improvement of visual acuity (VA). In Group B, VA improved in 38 eyes (69.1%) with complete resolution of edema. The results of this study indicated that vitrectomy effectively reduced macular edema but eyes with ILM peeling (Group B) presented better results than those without ILM peeling. Another important factor related to the outcome seems to be the level of glycosylated hemoglobin (HbA1c).

CONCLUSIONS

In eyes with diffuse diabetic macular edema vitrectomy seems to be effective, but additional ILM peeling presented better results.

Macular Edema and Visual Loss after Macular Pucker Surgery with ICG-Assisted Internal Limiting Membrane Peeling

Purpose

To describe the occurrence of massive macular edema and visual loss after indocyanine green-assisted (ICG) macular pucker surgery.

Methods/Results

A 74 years old female presented with a macular pucker and a hypertrophy of the retinal pigment epithelium (RPE) in her left eye. The preoperative visual acuity (VA) was 20/100. Surgery consisted of cataract extraction, lens implantation and standard pars plana vitrectomy with peeling of epiretinal tissue followed by the removal of the internal limiting membrane (ILM) remnants stained using a 0.05% ICG solution. One day after surgery, VA was counting fingers. There was an extensive macular edema and retinal thickening with hyperfluorescence during fluorescein angiography and pronounced autofluorescence using ICG filters. During follow up, the macular edema resolved completely, but VA decreased to 20/800 at six months postoperatively. There was a central scotoma and unstable fixation seen during microperimetry.

Discussion

This case report indicates that ICG might come into contact with bare retina if injected following removal of epiretinal membranes. Whether the observed RPE hypertrophy might have contributed to the pathogenesis of the adverse effect described remains hypothetical.

Vitrectomy with or without internal limiting membrane peeling for idiopathic epiretinal membrane: A meta-analysis

BACKGROUND

Studies on vitrectomy with and without internal limiting membrane (ILM) peeling for idiopathic epiretinal membrane (ERM) have yielded uncertain results regarding clinical outcomes and recurrence rates.

OBJECTIVE

To compare the clinical outcomes of vitrectomy with and without ILM peeling for idiopathic ERM.

METHODS

Databases, including PubMed, Embase, Cochrane, Web of Science, Google Scholar, CNKI databases, FDA.gov, and ClinicalTrials.gov, published until July 2016, were searched to identify studies comparing the clinical outcomes following vitrectomy with ERM and ILM peeling and with only ERM peeling, for treating idiopathic ERM. Studies with sufficient data were selected. Pooled results were expressed as mean differences (MDs) and risk ratios (RRs) with corresponding 95% confidence intervals (CI) for vitrectomy with and without ILM peeling with regard to postoperative best corrected visual acuity (BCVA), central retinal thickness (CRT), and ERM recurrence rate.

RESULTS

Eleven retrospective studies and one randomized controlled trial involving 756 eyes were identified. This demonstrated that the postoperative BCVA within 12 months was significantly better in the non-ILM peeling group (MD = 0.04, 95% CI: 0.00 to 0.08; P = 0.0460), but that the patients in the ILM peeling group had significantly better postoperative BCVA after 18 months (MD = -0.13, 95% CI: -0.23 to -0.04; P = 0.0049) than did those in the non-ILM peeling group. The non-ILM peeling group exhibited a higher reduction in postoperative CRT (MD = 51.55, 95% CI:-84.23 to -18.88; P = 0.0020) and a higher recurrence rate of ERM (RR = 0.34, 95% CI:0.16 to 0.72; P = 0.0048) than did the ILM peeling group. However, the improvement rates of BCVA (RR = 1.03, 95% CI:0.72 to 1.47; P = 0.8802) and postoperative CRTs (MD = 18.15, 95% CI:-2.29 to 38.60; P = 0.0818) were similar between the two groups.

CONCLUSIONS

Vitrectomy with ILM peeling results in better visual improvement in long-term follow-ups and lower ERM recurrence rates, and vitrectomy with only ERM peeling is more efficacious in reduction of CRT than is vitrectomy with ILM peeling.

INVERTED INTERNAL LIMITING MEMBRANE FLAP TECHNIQUE FOR MACULAR HOLES IN HIGH MYOPIA WITH AXIAL LENGTH ≥30 mm

PURPOSE

To evaluate the closure rate of macular holes in highly myopic eyes treated with the inverted internal limiting membrane flap technique.

METHODS

Retrospective study in 33 consecutive patients (33 eyes) with a myopic macular hole (axial length ≥30 mm) and no associated macular retinoschisis, undergoing 23-gauge pars plana vitrectomy combined with the inverted internal limiting membrane flap technique.

RESULTS

Mean initial logarithm of the minimum angle of resolution best-corrected visual acuity was 0.59 (range, 0.22-1.8) (Snellen fraction, 20/80). At the 1-month postoperative control visit, the macular hole was closed in all patients. Reopening of the hole occurred in 2 patients. Visual acuity improved in 13 patients (39.4%): final mean ETDRS (Early Treatment Diabetic Retinopathy Study) improvement was +80 letters, and logarithm of the minimum angle of resolution was 0.4 (20/50). Staphyloma with macular involvement was present in all patients. Dissociated optic nerve fiber layer was observed in 25 patients (75.7%) and was absent in 2 (6.1%); in the remaining 6 patients, the layer could not be assessed. Gliosis was found in 14 patients (42.4%).

CONCLUSION

Vitrectomy plus the inverted internal limiting membrane flap technique was effective for treating macular holes in eyes with axial length ≥30 mm and no associated retinoschisis.

SPONTANEOUS CLOSURE OF A MACULAR HOLE AFTER FOUR FAILED VITRECTOMIES IN THE SETTING OF NF-1

PURPOSE

To present the case of a patient who developed spontaneous closure of an idiopathic macular hole after four failed attempts at surgical closure.

METHODS

This is a retrospective case review of the medical record of a single patient. No statistical analysis was performed. The patient is a 71-year-old white woman with neurofibromatosis Type 1 who presented to the retina clinic of one of the authors.

RESULTS

The patient underwent four vitrectomies with long acting gas by two surgeons over the course of 2 years. After each surgery, the hole either did not close or it closed and then reopened within 1 year. Five months after the last surgery (1 year after the hole last reopened), the patient presented with improved vision and spontaneous closure of the macular hole. The hole has remained closed since then.

CONCLUSION

This case demonstrates that spontaneous closure of a macular hole, associated with excellent visual recovery, can occur after multiple surgical failures. We propose that enhanced scar formation due to neurofibromatosis Type 1 was responsible for both the numerous failures following initially successful surgery (centrifugal traction) and for the spontaneous closure (centripetal traction).

Functional and Morphologic Outcomes after Reoperation for Persistent Idiopathic Macular Hole

Purpose

To determine the relationship between preoperative and postoperative characteristics and visual outcomes after successful surgery for unclosed macular hole (MH).

Methods

The medical charts of 166 eyes of 161 patients who underwent vitrectomy for a MH were reviewed. The MH was not closed in 9 eyes of 9 patients after the initial surgery. The second vitrectomy with additional internal limiting membrane (ILM) peeling and gas tamponade was performed. The preoperative and postoperative best-corrected visual acuity (BCVA), optical coherence tomographic images, MH size, duration of MH before the first operation, and area of ILM peeling were studied.

Results

The MH was closed in all eyes after the second surgery. The BCVA significantly improved from 0.77 to 0.25 logMAR units (20/118 to 20/36, p = 0.002). The postoperative subfoveal ellipsoid zone (EZ) was distinct and continuous in 3 eyes with good visual recovery. The final BCVA was not significantly correlated with the baseline characteristics and area of ILM peeling but was correlated with the postoperative status of the EZ.

Conclusions

All MHs were closed and the mean postoperative visual acuity was significantly improved. The reason for poor visual recovery was the reduced microstructural recovery after the second surgery.

Osmolarity and spectrophotometric property of brilliant blue green define the degree of toxicity on retinal pigment epithelial cells exposed to surgical endoilluminator

Objective

To evaluate the effect of varying concentrations of brilliant blue green (BBG) and their different biochemical characteristics on retinal pigment epithelial (RPE) cells under xenon light source illumination at varying distances to identify safe parameters for intraoperative use.

Methods

Human retinal RPE cells (ARPE-19) were exposed to two concentrations (0.25 and 0.50 mg/mL) of BBG and illuminated with a xenon surgical illuminator at varying distances (10 and 25 mm), intensity levels, and time intervals (1, 5, and 15 minutes). Additionally, the effect of osmolarity was examined by diluting BBG in different concentrations of glucose. Cytotoxicity of BBG and osmolarity effects on cell viability were evaluated using a WST-1 assay. Light absorption and emission characteristic of BBG in different solvents were measured using a plate reader at different wavelengths. Lastly, the activity of caspase-3 was also studied.

Results

Cell viability of ARPE-19 cells was 77.4%±12.7%, 78.7%±17.0%, and 65.0%±19.7% at 1, 5, and 15 minutes to exposure of high illumination xenon light at 10 mm (P<0.05) compared to controls. At both distances of illumination (10 and 25 mm), similar cell viabilities were seen between 1 and 5 minutes of exposure. However, there was a decline in viability when the illumination was carried out to 15 minutes in all groups (P<0.05). There was no significant reduction in cell viability in presence or absence of xenon light in different osmolar solutions concentrations of glucose (P>0.05). Maximal light absorption of BBG was noted between 540 and 680 nm. Activated caspase-3 level was not significant in both the concentrations of BBG (P>0.05).

Conclusion

Our findings suggest that BBG at 0.25 mg/mL during vitreoretinal surgery is safe and not toxic to RPE cells up to 5 minutes under focal high illumination (10 mm) and up to 15 minutes under medium diffuse illumination (25 mm). BBG was safe to be mixed with isotonic glucose solution at the concentration range of 2.5%–10%, regardless of the illumination status.

Combined Epiretinal and Internal Limiting Membrane Peeling Facilitated by High Dilution Indocyanine Green Negative Staining

We describe the utilization of indocyanine green (ICG) dye to facilitate combined/en bloc removal of epiretinal membranes (ERM) along with internal limiting membranes (ILM). The method utilizes a highly diluted preparation of ICG in dextrose water solvent (D5W). Elimination of fluid air exchange step facilitating staining in the fluid phase and low intensity lighting help minimize potential ICG toxicity. The technique demonstrates how ICG facilitates negative staining of ERMs and how ILM peeling concomitantly can allow complete and efficient ERM removal minimizing surgical time and the necessity for dual or sequential staining.

Complications of Macular Peeling

Macular peeling refers to the surgical technique for the removal of preretinal tissue or the internal limiting membrane (ILM) in the macula for several retinal disorders, ranging from epiretinal membranes (primary or secondary to diabetic retinopathy, retinal detachment…) to full-thickness macular holes, macular edema, foveal retinoschisis, and others. The technique has evolved in the last two decades, and the different instrumentations and adjuncts have progressively advanced turning into a safer, easier, and more useful tool for the vitreoretinal surgeon. Here, we describe the main milestones of macular peeling, drawing attention to its associated complications.

Current Trends about Inner Limiting Membrane Peeling in Surgery for Epiretinal Membranes

The inner limiting membrane (ILM) is the basement membrane of the Müller cells and can act as a scaffold for cellular proliferation in the pathophysiology of disorders affecting the vitreomacular interface. The atraumatic removal of the macular ILM has been proposed for treating various forms of tractional maculopathy in particular for macular pucker. In the last decade, the removal of ILM has become a routine practice in the surgery of the epiretinal membranes (ERMs), with good anatomical results. However many recent studies showed that ILM peeling is a procedure that can cause immediate traumatic effects and progressive modification on the underlying inner retinal layers. Moreover, it is unclear whether ILM peeling is helpful to improve vision after surgery for ERM. In this review, we describe the current understanding about ILM peeling and highlight the beneficial and adverse effects associated with this surgical procedure.

Vitrectomy for idiopathic macular hole

BACKGROUND

A macular hole is an anatomic opening in the retina that develops at the fovea. Macular holes can be seen in highly myopic eyes or following ocular trauma, but the great majority are idiopathic. Pars plana vitrectomy was introduced to treat full-thickness macular holes, which if left untreated have a poor prognosis since spontaneous closure and visual recovery are rare.Vitrectomy is a surgical technique involving the removal of the vitreous body that fills the eye. The surgeon inserts thin cannulas into the eyes through scleral incisions to relieve traction exerted by the vitreous or epiretinal membranes to the central retina and to induce glial tissue to bridge and close the hole.

OBJECTIVES

The primary objective of this review was to examine the effects of vitrectomy for idiopathic macular hole on visual acuity. A secondary objective was to investigate anatomic effects on hole closure and other dimensions of visual function, as well as to report on adverse effects recorded in included studies.

SEARCH METHODS

We searched the Cochrane Eyes and Vision Group Trials Register (4 March 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 2), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to March 2015), EMBASE (January 1980 to March 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to March 2015), the Web of Science Conference Proceedings Citation Index-Science (CPCI-S) (January 1980 to March 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 4 March 2015.

SELECTION CRITERIA

We included randomised controlled trials comparing vitrectomy (with or without internal limiting membrane peeling) to no treatment (that is observation) for macular holes.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently extracted the data. We estimated best corrected visual acuity and macular hole closure at 6 to 12 months of follow-up.

MAIN RESULTS

Three studies provided data on the comparison between vitrectomy and observation in eyes with macular hole and visual acuity less than 20/50. Two studies, conducted in the USA and published in 1996 and 1997, used a similar protocol and included participants with stage II macular hole (42 eyes randomised, 36 analysed, number of participants not reported) or participants with stage III/IV hole (129 eyes of 120 participants, 115 eyes in analyses). The third study, conducted in the UK and published in 2004, included 185 eyes of 174 participants with full-thickness macular hole (41 eyes with stage II holes and 74 eyes with stage III/IV holes in analyses). Studies were of good quality for randomisation and allocation concealment, whereas visual acuity measurement was unmasked.At 6 to 12 months, visual acuity was improved by about 1.5 Snellen lines (-0.16 logMAR, 95% confidence intervals -0.23 to -0.09 logMAR, 270 eyes, moderate-quality evidence). The chances of macular hole closure at 6 to 12 months were greatly increased using vitrectomy, yielding an odds ratio of 31.4 (95% confidence intervals 14.9 to 66.3, 265 eyes, high-quality evidence; raw sum data: 76% vitrectomy, 11% observation). Vitrectomy was beneficial both in smaller (stage II) and in larger (stage III/IV) macular holes.The largest study reported that cataract surgery was needed in about half of cases at two years after operation and that retinal detachment occurred in about 5% of operated eyes.

AUTHORS' CONCLUSIONS

Vitrectomy is effective in improving visual acuity, resulting in a moderate visual gain, and in achieving hole closure in people with macular hole. However, these results may not apply to modern surgery due to technological improvements in vitrectomy techniques.

A review of current management of vitreomacular traction and macular hole

The paper presents a review of the sequence of events of posterior vitreous detachment (PVD), vitreomacular adhesion (VMA), vitreomacular traction (VMT), and macular hole (MH) from their pathophysiological aspects, clinical features, diagnostic implications, and current management strategies. A treatment algorithm to be used in clinical practice in patients with VMA, VMT, and MH based on the presence of symptoms, visual acuity, associated epiretinal membrane, and width of the vitreous attachment is presented. Observation, pharmacologic vitreolysis with ocriplasmin, and surgical treatment are positioned as treatment options in the different steps of the therapeutic algorithm, with clear indications of the paths to be followed according to the initial presenting manifestations and the patient's clinical course.

Novel 'heavy' dyes for retinal membrane staining during macular surgery: multicenter clinical assessment

PURPOSE

  To evaluate the feasibility of two novel 'heavy' dye solutions for staining the internal limiting membrane (ILM) and epiretinal membranes (ERMs), without the need for a prior fluid-air exchange, during macular surgery.

METHODS

  In this prospective nonrandomized multicenter cohort study, the high molecular weight dyes ILM-Blue™ [0.025% brilliant blue G, 4% polyethylene glycol (PEG)] and MembraneBlue-Dual™ (0.15% trypan blue, 0.025% brilliant blue G, 4% PEG) were randomly used in vitrectomy surgeries for macular disease in 127 eyes of 127 patients. Dye enhanced membrane visualization of the ILM and ERMs, 'ease of membrane peeling', visually detectable perioperative retinal damage, postoperative best-corrected visual acuity (BCVA), dye remnants and other unexpected clinical events were documented by 21 surgeons.

RESULTS

  All surgeries were uneventful, and a clear bluish staining, facilitating the identification, delineation and removal of the ILM and ERMs, was reported in all but five cases. None of the surgeries required a fluid-air exchange to assist the dye application. BCVA at 1 month after surgery improved in 83% of the eyes in the MembraneBlue-Dual™ group and in 88% in the ILM-Blue™ group. No dye remnants were detected by ophthalmoscopy, and no retinal adverse effects related to the surgery or use of the dyes were observed.

CONCLUSION

  The 'heavy' dye solutions ILM-Blue™ and MembraneBlue-Dual™ can be injected into a fluid-filled vitreous cavity and may facilitate staining and removal of the ILM and/or ERMs in macular surgery without an additional fluid-air exchange.

Idiopathic macular hole: analysis of visual outcomes and the use of indocyanine green or brilliant blue for internal limiting membrane peel

BACKGROUND

Our aim was to analyze outcomes of idiopathic macular hole surgeries in relation to staging and the use of indocyanine green (ICG) or brilliant blue (BB) for internal limiting membrane (ILM) peel.

METHODS

Baseline, surgical, and outcome data for 351 consecutive primary macular hole surgeries was prospectively collected using electronic medical record software between 2001 and 2011. The outcomes for these cases were analysed in relation to staging and the use of ICG (0.5 mg/ml) or BB for ILM peel.

RESULTS

Mean age was 68.9 years (range 39-87) with 66.4 % females and 54.1 % right eyes. Follow-up duration was median 0.55 years. Vision was significantly improved from logMAR 0.97 (SD 0.45) (Snellen equivalent 20/185) preoperatively to 0.65 (SD 0.51) (20/90) at final follow-up. One hundred and eighteen patients had stage 2 macular holes, 185 stage 3, and 48 stage 4. Mean duration of symptoms varied with stage of hole: stage 2 0.53 years (SD 0.43), stage 3 0.79 years (SD 0.68), and stage 4 1.20 years (SD 1.26), p = 0.0002. Closure rates of the holes were significantly different, with stage 2 closing in 95.8 %, stage 3 in 73.0 %, and stage 4 in 56.3 %, p < 0.0001. At final follow-up, mean visual acuity (VA) was 0.42 (SD 0.33) (20/50) for stage 2, 0.75 (SD 0.53) (20/110) for stage 3, and 0.87 (SD 0.60) (20/145) for stage 4 holes, p < 0.0001. Postoperative VA was 0.71 (SD 0.53) (20/100) for patients in whom ICG was used, and 0.52 (SD 0.43) (20/70) for BB, p = 0.003. The proportion of patients who achieved a closed hole was less for ICG (73.2 %) than BB (89.9 %), p = 0.0005. For those patients with stage 2 hole who achieved hole closure, mean improvement in VA was significantly better for BB (0.47, SD 0.36) than for ICG (0.30, SD 0.31), p = 0.01.

CONCLUSIONS

Macular hole stage is a useful measure to help predict the chance of postoperative hole closure and visual outcome. The relationship between duration of symptoms and increasing stage suggests macula hole patients require prompt referral for consideration of early surgery. Better visual outcomes were achieved with BB for ILM peel than with ICG.

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.

The retinal biocompatibility of dyes in the ex vivo model of the isolated superfused vertebrate retina

BACKGROUND

Peeling of the internal limiting membrane or epiretinal membranes is a successful principle in macular surgery to achieve a functional benefit. Different dyes are used to facilitate the identification of intraocular tissues. The aim of our work was to investigate the retinal tolerance to the different dyes and their solvent carriers to provide valuable data for surgeons in handling for an optimal intraoperative use.

METHODS

Using the ex vivo model of the isolated superfused vertebrate retina technique, the effects of the dyes were tested on human and bovine retinal function. The retinas were perfused with an oxygen preequilibrated standard solution. The electroretinogram (ERG) was recorded using Ag/AgCl electrodes. After recording stable ERG amplitudes, the dyes brilliant blue G, indocyanine green, trypan blue, patent blue, triamcinolone and their solvent carriers were investigated.

RESULTS

Reductions of the ERG amplitudes were found for each tested dye. The effects after application of the dyes were dependent on time and concentration of the applied dyes, which were different for each dye.

CONCLUSION

In part, the ERG has shown strong effects already after a short period of dye application. Surgeons who rely on the intraocular use of the dyes should keep in mind our findings, and the use of some dyes should be limited to selected cases. The well-considered use of the dyes by the surgeons could lead to a better functional outcome and avoid a possible harmful outcome of the surgery after mishandling.

Dyes for Eyes™: hydrodynamics, biocompatibility and efficacy of 'heavy' (dual) dyes for chromovitrectomy

As epiretinal membranes (ERMs), the internal limiting membrane (ILM) and the vitreous cortex are essentially transparent tissues, or translucent structures, nontraumatic removal may be challenging in various types of macular surgery. Vital dyes stain these thin tissues, thus allowing for better visualization of these structures during vitrectomy and selective 'membrane peeling' from the underlying retina. To avoid swirling of the dye within the fluid-filled vitreous cavity, and to better target the dye onto the macula, a fluid-air exchange is commonly performed. However, this may jeopardize visualization of the macula during peeling due to clouding of the posterior lens capsule, and may lead to postoperative visual field defects. Recently, a new dye solution for staining the ERM and ILM simultaneously has been developed that circumvents the need for fluid-air exchange, i.e. MembraneBlue-Dual™. This paper will focus on the hydrodynamics and biocompatibility of this 'heavy' dual dye and its efficacy for staining of the ILM and/or ERMs during posterior segment surgery in a multicenter clinical setting.

Effects of light exposure, pH, osmolarity, and solvent on the retinal pigment epithelial toxicity of vital dyes

PURPOSE

To investigate the in vitro effect of pH, osmolarity, solvent, and light interaction on currently used and novel dyes to minimize dye-related retinal toxicity.

DESIGN

Laboratory investigation.

METHODS

Retinal pigment epithelium (RPE) human cells (ARPE-19) were exposed for 10 minutes to different pH solutions (4, 5, 6, 7, 7.5, 8, and 9) and glucose solutions (2.5%, 5.0%, 10%, 20%, 40%, and 50%) with osmolarity from 142 to 2530 mOsm, with and without 0.5 mg/mL trypan blue. R28 cells were also incubated with glucose (150, 310, and 1000 mOsm) and mannitol used as an osmotic control agent in both experiments. Dye-light interaction was assessed by incubating ARPE-19 for 10 minutes with trypan blue, brilliant blue, bromophenol blue, fast green, light green, or indigo carmine (0.05 mg/mL diluted in balanced saline solution) in the presence of high-brightness xenon and mercury vapor light sources.

RESULTS

Solutions with nonphysiologic pH, below 7 and above 7.5, proved to be remarkably toxic to RPE cells with or without trypan blue. Also, all glucose solutions were deleterious to RPE (P < .001) even in iso-osmolar range. No harmful effect was found with mannitol solutions. Among the dyes tested, only light green and fast green were toxic to ARPE-19 (P < .001). Light exposure did not increase RPE toxicity either with xenon light or mercury vapor lamp.

CONCLUSIONS

Solutions containing glucose as a dye solvent or nonphysiologic pH should be used with care in surgical situations where the RPE is exposed. Light exposure under present assay conditions did not increase the RPE toxicity.

Indocyanine green-assisted internal limiting membrane peeling in macular hole surgery: a meta-analysis

Background

The opinion of application of indocyanine green (ICG) in the macular hole surgery was contradictory. Here we conducted a meta-analysis to evaluate the effect of in internal limiting membrane (ILM) peeling for macular hole surgery.

Methods and Findings

We searched electronic databases for comparative studies published before July 2012 of ILM peeling with and without ICG. Twenty-two studies including 1585 eyes were included. Visual acuity (VA) improvement, including the postoperative rate of ≥20/40 VA gained (OR, 0.65; 95% CI, 0.43 to 0.97; P = 0.033) and increased LogMAR (WMD, −0.09; 95% CI, −0.16 to −0.02; P = 0.011), was less in the ICG group. The risk of visual field defects was greater in the ICG group than in the non-ICG group. There was no significant difference in the rate of anatomical outcomes between ILM peeling procedures performed with and without ICG. RPE changes and other postoperative complications were not significantly different between the ICG and non-ICG groups. An additional analysis showed that the VA improvement of the ICG group was less than the non-ICG group only within the first year of follow up. A subgroup analysis showed that the rate of VA improvement was lower in the ICG group than in other adjuncts group. A higher rate of secondary closure and less VA improvement were observed in a high proportion (>0.1%) of the ICG group. A sensitivity analysis after the randomized-controlled trials were excluded from the meta-analysis demonstrated no differences compared with the overall results.

Conclusions

This meta-analysis demonstrated that there is no evidence of clinical superiority in outcomes for ICG-assisted ILM peeling procedure over the non-ICG one. The toxicity of ICG should be considered when choosing the various staining methods.

Techniques, rationale, and outcomes of internal limiting membrane peeling

BACKGROUND

The internal limiting membrane represents the structural interface between the retina and the vitreous and has been postulated to serve several essential functions. Recently, internal limiting membrane peeling has been used in the treatment of a variety of retinal disorders. We review the history, techniques, rationale, and outcomes of internal limiting membrane peeling.

METHODS

A review of the literature.

RESULTS

Internal limiting membrane peeling has been used to successfully treat a variety of retinal disorders including macular hole, epiretinal membrane, diabetic macular edema, retinal vein occlusion, and others.

CONCLUSION

Internal limiting membrane peeling may serve as an important component in the armamentarium of retinal surgery.