Visual outcomes following ICG assisted ILM peel for Macular Hole

Customized Color Settings of Digitally Assisted Vitreoretinal Surgery to Enable Use of Lower Dye Concentrations During Macular Surgery

Purpose

This study evaluated the color contrast ratio (CCR) of the internal limiting membrane (ILM) using different color settings of digitally assisted vitreoretinal surgery (DAVS) with different indocyanine green (ICG) concentrations.s

Methods

This is a prospective comparative observational study. Consecutive patients that underwent 25G vitrectomy and ILM peeling using a standard operating microscope (SOM) (25 eyes), DAVS Ver. 1.1 (12 eyes), or DAVS Ver. 1.3 (13 eyes) were enrolled. The SOM and DAVS Ver. 1.1 groups used 0.075% ICG, and the DAVS Ver. 1.3 group used 0.025% ICG. In DAVS Ver. 1.1, macular CCR was compared between four different presets in the red, green, and blue channels: Default (Red (R) 100%, Green (G) 100%, and Blue (B) 100%); Preset 1 (R 20%, G 100%, B 100%); Preset 2 (R 80%, G 80%, B 100%), and Preset 3 (R 85%, G 100%, B 90%). In DAVS Ver. 1.3, macular CCR was evaluated using two different customized settings that modified the hue and saturation: Customized Setting 1 (R 86, G 100, B 100%, Hue +2°, Saturation 90%, Gamma 1.2) and Customized Setting 2 (R 90, G 100, B 100%, Hue +20°, Saturation 100%, Gamma 0.9). All patients underwent ophthalmologic examinations including BCVA at baseline and at 12 months.

Results

In DAVS Ver. 1.1, macular CCR was highest in Preset 3 (P < 0.01). The CCR of Customized Setting 2 of DAVS Ver. 1.3 using 0.025% ICG did not differ from that of Preset 3 in DAVS Ver. 1.1 using 0.075% ICG. Furthermore, there was no significant difference in BCVA between the Customized Setting 2 of DAVS Ver. 1.3 with 0.025% ICG and the Preset 3 of DAVS Ver. 1.1 with 0.075% ICG groups at baseline and at 12 months (P > 0.05, respectively).

Conclusion

Customized DAVS settings enabled surgeons to use a 3-fold lower ICG concentration in ILM peeling.

Comparative effects of commonly used intraocular dyes on the viability of human retina Müller cells

This study investigated the in vitro effect of various vital dyes in common clinical use on human Müller cell viability, and it compared the toxicity of these dyes using a cell culture model. Müller cells were exposed to a series of concentrations (1 %, 0.5 %, 0.25 %, and 0.125 % or 12.9 mM, 6.45 mM, 3.22 mM and 1.61 mM) of Indocyanine green (ICG) for 2, 24, 48, and 72 h. Similarly, groups of Müller cells were stained with "Heavy" brilliant blue G (HBBG), Trypan blue (TB) (0.15 %, or 1.56 mM), Membrane-blue-dual (MBD), and ICG (0.25 %, or 3.22 mM) or BBG (0.025 %, or 0.3 mM) with glucose (GS) (50 %, 66 % and 75 % or 2.78 M, 3.67 M and 4.17 M) for 30, 60, and 120 s. Cell viability was measured with the Cell Counting Kit-8 (CCK-8) and Lactate Dehydrogenase (LDH) release assays. We found that high stain concentration and long exposure time resulted in increased toxicity to Müller cells. Nevertheless, ICG seemed to be safe at the clinically relevant concentration of 0.25 % (3.22 mM) in the short time of exposure. TB was safer than both HBBG and MBD, especially HBBG. Hypertonic GS as a dilution was not safe for Müller cells, and the negative effect was more obvious in 0.025 % (0.3 mM) BBG than that in 0.25 % (3.22 mM) ICG. This is the first report to observe the cytotoxicity of commonly used stains in clinical on human Müller cells in vitro, and to provide some basis for further studies, including in vivo investigation.

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.].

Anatomical and Functional Outcomes of Pars Plana Vitrectomy for Lamellar Macular Defects

PURPOSE

The aim of this study is to investigate the anatomical and functional outcomes of surgical management of lamellar macular defects.

DESIGN

This study is a retrospective observational case series.

METHODS

Overall, the records of 89 eyes of 78 consecutive patients with a clinical diagnosis of either lamellar macular hole, macular pseudohole, or foveal pseudocyst were reviewed. Twenty-one (23.6%) of the 89 eyes underwent pars plana vitrectomy by a single ophthalmologist. Preoperative and postoperative visual acuities (VAs) were compared, and the anatomical outcome of vitrectomy was examined by studying the restoration of the foveal contour on optical coherence tomography (OCT) scans. Comparisons of visual acuity and OCT measurements between vitrectomized and nonvitrectomized eyes were made. Comparisons were also made between the 3 different types of lamellar macular defects.

RESULTS

Anatomical closure of the lamellar macular holes was achieved with a single surgical procedure in all vitrectomized eyes as confirmed by OCT. Visual acuity improved in 15 eyes (71%), from 0.39 ± 0.30 logMAR preoperatively to 0.26 ± 0.19 logMAR postoperatively (t20 = 2.425; P = 0.025). Macular pseudohole was associated with better presenting VA (F2,86 = 8.524; P < 0.001) and postoperative VA (F2,18 = 8.920; P = 0.002) than the other types of lamellar defects. Better postoperative VA was significantly correlated with better preoperative VA (r = 0.579; P = 0.006) and greater preoperative central foveal thickness (r = -0.535; P = 0.012).

CONCLUSIONS

Pars plana vitrectomy provided a high success rate of anatomical and functional improvement for eyes with all types of lamellar macular defects.

Use of autologous whole blood during internal limiting membrane peeling and macular hole surgery is protective for indocyanine green toxicity

OBJECTIVE

To compare indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling with and without autologous whole blood (WB) protection during macular hole repair surgery.

MATERIAL AND METHODS

We retrospectively reviewed 50 eyes with an idiopathic macular hole. Group 1 contained 22 eyes that underwent ILM peeling with WB protection and group 2 contained 28 eyes that underwent ILM peeling without WB. Anatomic and visual results were compared.

RESULTS

After surgery, macular hole closure was achieved in 96% of the group 1 eyes and in 93% of the group 2 eyes. The preoperative mean best-corrected visual acuity (BCVA) was logarithm of the minimum angle of resolution (logMAR) 0.95 in group 1 and logMAR 0.89 in group 2 (p = .544). The postoperative mean BCVA was logMAR 0.57 in group 1 and logMAR 0.92 in group 2 (p = .017).

CONCLUSION

Macular hole surgery protected with WB facilitates improved visual recovery in ICG-assisted ILM peeling.

[Vital dyes in vitreoretinal surgery. Current application concepts]

This article reviews the most relevant vital dyes and adjuncts currently available for use in vitreoretinal surgical procedures. The current concepts of intraocular application as well as the staining properties are described, and the issue of biocompatibility is discussed.

Comparison of in vitro toxicity of single vs double exposures of indocyanine green in human retinal pigment epithelial cell cultures

PURPOSE

To compare the in vitro effect of a single brief indocyanine green (ICG) exposure with a double exposure on retinal pigment epithelial (RPE) cells.

DESIGN

In vitro laboratory experimental study.

METHODS

Human ARPE-19 cells were exposed to a single dilute ICG exposure (0.5 mg/ml) or to two sequential exposures of identical volume and concentration. Viability was measured with a mitochondrial dehydrogenase assay and compared with nonexposed control cells.

RESULTS

Cell viability was not statistically different between the single-exposed, double-exposed, or control cell populations.

CONCLUSIONS

When used intraoperatively to stain the internal limiting membrane, dilute ICG dye sometimes does not adequately enhance visualization of the internal limiting membrane. Occasionally, it is necessary to repeat the dye exposure to achieve the desired visibility. In this study, RPE cells subjected to two consecutive short exposures of ICG showed no marked difference in cell survival when compared with cells exposed to a single application of ICG and to control cells.

Färbetechniken in der Makulachirurgie

Over recent years, evolving surgical experience and the development of techniques in surgery for macular hole, macular pucker and other vitreoretinal diseases have improved anatomic and functional success rates. Today, there is common agreement by many surgeons that removal of the internal limiting membrane (ILM) is an effective and safe treatment option for conditions that involve the vitreoretinal interface.However, the ILM is a delicate and barely visible structure and its removal represents a challenge to the vitreoretinal surgeon. The introduction of vital dyes for ILM staining has led to better visibility of the ILM and epiretinal membranes, potentially making ILM peeling more controllable, easier and safer. It has opened the door, especially for the less experienced surgeon, to follow the principle of ILM removal in macular surgery. While the use of trypan blue and triamcinolone during such surgery seems to be safe, questions of the potential toxicity of indocyanine green (ICG) are currently being discussed. However, the underlying pathomechanisms are not yet completely understood. Whether the observations made on ICG-related toxicity will be sufficient to call ICG a "toxic adjunct" is currently under investigation. Further studies are required to better understand the safety margins of ICG and to investigate other vital dyes offering equal staining characteristics and a better safety profile.

Modified technique for safer indocyanine-green-assisted peeling of the internal limiting membrane during vitrectomy for macular hole repair

BACKGROUND

During macular hole surgery, indocyanine green (ICG) has access to the subretinal space and can lead to toxic and phototoxic damage of the retinal pigment epithelium (RPE). To reduce its toxicity and to avoid contact between ICG and the RPE, we have developed a modified technique by using autologous whole blood.

METHODS

Thirty-one eyes underwent vitrectomy for idiopathic macular hole repair. Autologous whole blood (0.1 ml) was injected into the buffered saline solution (BSS)-filled vitreous cavity over the posterior pole and aspirated with a flute cannula. A small clot remained covering the macular hole. The internal limiting membrane (ILM) was stained by using 0.05% ICG solution. The ICG was dissolved in 5% glucose to obtain an iso-osmotic solution. This ICG was injected into the BSS-filled vitreous cavity over the posterior pole and removed after 10 s. The ILM was peeled and a long-acting gas tamponade applied. Pre- and postoperative best-corrected visual acuity and optical coherence tomography (OCT) findings are reported.

RESULTS

Macular hole closure was achieved in 30 of 31 eyes (97%). The mean preoperative logMAR acuity was 0.99 (range: 0.4 to 2.0). Mean postoperative logMAR acuity was 0.496 (range: 0.0 to 1.0). The average improvement in vision was 0.66 logMAR units (range: 1.5 to 0.0). No postoperative RPE alterations were observed biomicroscopically or on OCT.

CONCLUSION

This surgical technique leads to favorable anatomic and functional results. ICG toxicity is reduced by modifying osmolarity, concentration and contact time and by injecting ICG under BSS. Autologous whole blood acts as a mechanical barrier and prevents ICG from entering in the subretinal space.

Epiretinal membrane surgery with or without internal limiting membrane peeling

BACKGROUND

The purpose of the present paper was to evaluate the visual outcome and recurrence rate of epiretinal membrane (ERM) formation following vitreoretinal surgery with and without internal limiting membrane (ILM) peel.

METHODS

The medical records of 42 consecutive patients who underwent surgery for macular ERM by a single surgeon were reviewed. All patients underwent pars plana vitrectomy and ERM removal with a subset undergoing ILM peel. Recurrence of macular ERM within 18 months and the final visual outcome after surgery were compared between patients with and without ILM removal.

RESULTS

Twenty-five patients (59.5%) underwent ERM surgery with ILM peeling and 17 patients (40.5%) underwent ERM surgery without ILM peeling. The mean preoperative logMAR visual acuity was 0.77 and 0.96 for the ILM peeling and non-ILM peeling groups, respectively. Visual acuity improved significantly in both the ILM and non-ILM peeling groups after ERM surgery (P < 0.001 and P = 0.003, respectively). Eighteen months after surgery, 3/17 eyes without ILM peeling (17.6%) developed recurrent macular ERM, compared with none of the 25 eyes with ILM peeling (log-rank test, P = 0.030).

CONCLUSIONS

Internal limiting membrane removal during macular ERM surgery may minimize the recurrence of ERM, without adverse visual outcome. Further controlled prospective studies are needed to determine the role of ILM peeling in ERM surgery.

Makulaforamen

The theory of macular hole pathogenesis, which had so far been based on biomicroscopy, has been considerably altered by optical coherence tomography. The precise presentation of vitreofoveal pathology shows that forces acting in different directions are associated with different stages of the disease, making surgical treatment adapted to the different stages possible. Some surgical procedures are still controversial, and there is still no gold standard in macular hole surgery. Especially no agreement exists on the benefit of internal limiting membrane peeling, possibly assisted by staining with indocyanine green. Also details of endotamponade and postoperative positioning are controversial. Therefore, the method of surgical treatment depends a lot on the individual surgeon. This review summarizes the broad spectrum of the literature and the present knowledge in this field.