Indocyanine green effect on cultured human retinal pigment epithelial cells: implication for macular hole surgery

ECCENTRIC MACULAR HOLES AFTER VITRECTOMY WITH PEELING OF EPIMACULAR PROLIFERATION

PURPOSE

To describe six patients (six eyes) who developed an eccentric macular hole after surgery for idiopathic epimacular proliferation.

METHODS

In a retrospective review of 631 consecutive patients who underwent vitrectomy with peeling of the epimacular proliferation and in most cases the internal limiting membrane (ILM) from May 2001 to May 2005, 6 patients were found to have developed an eccentric macular hole postoperatively.

RESULTS

Eccentric macular holes developed 9 days to 8 months (mean, 3.1 months) after epimacular proliferation peeling. The ILM was peeled in addition to the epimacular proliferation in five of the six cases. Of the six eccentric macular holes, four were located temporal to the fovea, one was located superior to the fovea, and one was located nasal to the fovea. Final visual acuities after a mean follow-up period of 17.3 months were 20/20 in 2 eyes, 20/25 in 1 eye, 20/40 in 2 eyes, and 5/200 in 1 eye. The eye with the eccentric macular hole nasal to the fovea had the poorest final visual acuity of 5/200.

CONCLUSION

Eccentric macular hole occurring after vitrectomy to remove epimacular proliferation is an uncommon postoperative finding. To our knowledge, this is the largest case series of such patients reported. Various explanations have been suggested for the etiology of these holes, but there remains no consensus.

Idiopathic macular hole surgery with low-concentration infracyanine green-assisted peeling of the internal limiting membrane

PURPOSE

To evaluate the efficacy of pars plana vitrectomy with infracyanine green (IFCG)-assisted internal limiting membrane peeling for the treatment of idiopathic macular hole.

DESIGN

Prospective, noncomparative interventional case series.

METHODS

Thirty-eight consecutive eyes of 35 patients with idiopathic macular hole were included in the study. Patients underwent early treatment diabetic retinopathy (ETDRS) visual acuity examination, dilated ophthalmoscopy, and optical coherence tomography before treatment and during follow-up. Fluorescein angiography was done in selected cases. Patients underwent a three-port pars plana vitrectomy with complete posterior hyaloid and epiretinal membrane removal. The internal limiting membrane (ILM) was stained with 0.5 cc of IFCG (0.5 mg/ml, 308 mOsm) and peeled up to the vascular arcades. Perfluoropropane gas (C(3)F(8)) 10% was used as tamponade.

RESULTS

Mean follow-up duration was 10 +/- 5 months (range, 3 to 24 months). Six eyes had stage 2 macular hole, 15 eyes stage 3, and 16 eyes stage 4. Overall, 37 of 38 macular holes closed after a single surgery. Median visual acuity was 20/100 (range, 20/400 to 20/50) before surgery and 20/50 (range, 20/640 to 20/25) after surgery. Visual acuity after surgery was 20/50 or better in 24 of 38 (63.1%) eyes. Twenty-five (65.8%) eyes improved by 2 or more lines, nine (23.7%) eyes were stable, and four (10.5%) eyes worsened by 2 or more lines.

CONCLUSIONS

This study suggests that IFCG (0.05%) effectively stains the ILM with apparent safety, and that IFCG-assisted peeling of the ILM may be useful in the treatment of idiopathic macular hole.

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.

Brilliant blue G selectively stains the internal limiting membrane/brilliant blue G-assisted membrane peeling

PURPOSE

To report the use of the dye brilliant blue G (BBG) for staining of the internal limiting membrane (ILM) during macular hole (MH) and epiretinal membrane (ERM) surgery.

METHODS

This study was designed as an interventional, noncomparative, prospective, clinical case series. Twenty eyes from 20 consecutive patients with MH or ERM underwent BBG-assisted ILM and ERM removal. In MH cases, a posterior vitreous detachment was created, followed by the injection of 0.25 mg/mL BBG solution into the vitreous cavity and immediate washout of the BBG. This technique improved visualization of the ILM, enabling peeling and surgery to be performed successfully. However, in ERM cases, staining of the ERM could not be confirmed at this concentration. Finally, the ILM including the ERM was removed in all cases. Preoperative and postoperative ophthalmic examinations were performed.

RESULTS

Postoperatively, 17 patients (85%) had visual acuity improved by at least 2 Snellen lines. No adverse effects were observed postoperatively during the observation period (mean follow-up +/- SD, 7.3 +/- 1.0 months).

CONCLUSIONS

BBG selectively stains the ILM. This technique can facilitate the management of MH and ERM surgery without any adverse effects, as was shown in this short-term study.

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

PURPOSE

To investigate the effects of intravitreal brilliant blue G (BBG) on the morphology and functions of the retina and its possible use for staining and peeling of the internal limiting membrane (ILM).

METHODS

Rat eyes (n = 78) underwent gas compression vitrectomy. BBG solution was then injected into the vitreous cavity. The eyes were enucleated at 2 weeks and 2 months. Light as well as electron microscopy, terminal nick-end labeling staining, and electroretinography (ERG) were used to investigate retinal damage and function. To test the clinical potential of BBG, ILM staining was evaluated in primate eyes after pars plana vitrectomy followed by ILM peeling.

RESULTS

In the rat eyes, no pathologic changes were observed with light microscopy. Electron microscopy revealed that high doses of BBG induced vacuolization in the inner retinal cells, but apoptosis was not detected. There was no reduction in the amplitude of the ERG waves. In the primate eyes, the ILM was clearly visualized after the intravitreous injection of BBG and was peeled off easily from the retina.

CONCLUSIONS

These results demonstrate that BBG, which has low potential for toxicity, high staining ability, and ease of handling, is a good candidate dye for ILM peeling.

Internal Limiting Membrane Removal during Macular Hole Surgery

PURPOSE

To evaluate the effect of internal limiting membrane (ILM) peeling and other variables in hole closure and functional success rate after idiopathic macular hole surgery.

DESIGN

Retrospective, multicenter, observational study.

METHODS

The records of 1627 patients operated on for idiopathic macular hole were collected retrospectively from 28 surgeons. All patients underwent a single pars plana vitrectomy and were divided into 2 groups: with and without ILM peeling. Preoperative, intraoperative, and postoperative variables were evaluated.

RESULTS

The overall rate of macular hole closure was 94.1% in the ILM peeling group and 89.0% in the no ILM peeling group (P<0.001). The probability of achieving hole closure after surgery is 2.59 times higher if the ILM is peeled (95% confidence interval [CI], 1.71-3.92; P<0.001), 3.12 times higher for holes lasting less than 6 months (95% CI, 1.70-5.71; P<0.001), 4.94 (95% CI, 2.39-10.20) for stage 2 holes, and 2.34 (95% CI, 1.55-3.53) for stage 3 holes than that of patients with a stage 4 hole (P<0.001).

CONCLUSIONS

Internal limiting membrane peeling seems to improve hole closure for stage 3 and 4 holes and for long-lasting holes. Higher-stage macular holes and longer duration of symptoms are risk factors for surgical failure. In patients obtaining hole closure, there is no difference in functional results between pseudophakic peeled and not peeled patients, whereas in phakic patients, a better functional result in not peeled patients was seen.

Photochemical properties of a potential photosensitiser indocyanine green in vitro

The present study investigates the photochemical properties of a potential photosensitiser, indocyanine green (ICG), in an in vitro HeLa cell system. Cell proliferation was studied after a combined effect of ICG, at a concentration range of 24-94 microM, and therapeutic laser irradiation at several different energy densities. In addition, ICG cytotoxicity was evaluated in HeLa cells and V79 Chinese hamster by the MTT assay. Phototoxicity was evaluated at 1, 24, and 48 h after irradiation. No phototoxic effect was detected 1h after irradiation. The maximum phototoxic effect of ICG on HeLa cells was detected for an ICG concentration of 94 microM, a laser output of 360 mW, and an energy density of 99 J/cm(2) at 24h after irradiation. Potentiation of the ICG phototoxic effect was achieved by adding 20 microM H(2)O(2), which was a non-toxic concentration for HeLa cells in this experimental design. At 48 h after laser irradiation a statistically significant difference was found between the toxicity of ICG plus peroxide, as compared to ICG alone. The addition of H(2)O(2) at a concentration of 20 microM caused a significant increase in phototoxicity of ICG for HeLa cells. Our results confirm that ICG could be a perspective agent for use in photodynamic therapy and that its phototoxic effect can be potentiated by addition of an oxidative agent.

LONG-TERM OUTCOMES OF INTERNAL LIMITING MEMBRANE PEELING WITH AND WITHOUT INDOCYANINE GREEN IN MACULAR HOLE SURGERY

PURPOSE

To compare the long-term anatomic closure rate and visual outcome in patients who underwent internal limiting membrane (ILM) peeling with and without indocyanine green (ICG) dye staining for idiopathic macular hole repair.

DESIGN

Retrospective, nonrandomized, comparative study of consecutive case series.

METHODS

A total of 190 eyes of 182 patients with idiopathic macular holes underwent macular hole repair between March 1998 and June 2003. Surgery consisted of pars plana vitrectomy, lensectomy if phakic, ILM peeling, intravitreal gas tamponade, and 1 week's face-down positioning. In the initial 94 consecutive eyes, ILM peeling was performed without adjuvants (non-ICG group). The subsequent 96 eyes underwent surgery with ICG-stained ILM peeling (ICG group), in which the ILM was stained with intravitreal application of 0.1 to 0.2 mL of 0.1% ICG solution.

RESULTS

Two groups of patients had comparable clinical backgrounds preoperatively. Mean follow-up time was 30.7 months in non-ICG group and 26.2 months in ICG group. Anatomic closure of the macular hole was achieved in 99% of the cases in both groups, with both groups showing statistically significant visual improvement. There was no statistically significant difference in visual acuity between the two groups at each follow-up visit. There were also no intraoperative or postoperative complications attributed to the use of ICG.

CONCLUSIONS

Long-term follow-up of patients undergoing ILM peeling for idiopathic macular hole repair shows equivalent anatomic and visual outcomes with and without the use of ICG.

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.

Secondary paracentral retinal holes following internal limiting membrane removal

AIM

To report on a new postoperative finding after delamination of the internal limiting membrane (ILM) for the treatment of different macular pathologies.

METHODS

Seven patients are described with paracentral retinal holes, all located temporally to the macula, which developed after pars plana vitrectomy and uncomplicated ILM removal for cystoid macular oedema (n = 3), macular pucker (n = 3), and macular hole (n = 1) with the use of indocyanine green (n = 4), trypan blue (n = 1), triamcinolone acetonide (n = 1), or without dye (n = 1).

CONCLUSION

The use of dyes has been incriminated in causing iatrogenic damage to the retina. In this series, the new observation of retinal holes in the macular area is thought to be related to the removal of the ILM itself. The authors speculate that ILM delamination may cause a retinal weakening by Müller cell damage; this may be followed by a structural breakdown and, consequently, hole formation.

An isotonic preparation of 1 mg/ml indocyanine green is not toxic to hyperconfluent ARPE19 cells, even after prolonged exposure

PURPOSE

To investigate the in vitro toxicity of indocyanine green and infracyanine green (ICG) to cultured ARPE19 cells, in particular with respect to the concentration and time dependence of this toxicity.

METHODS

ARPE19 cells were grown for at least 1 week past confluence (hyperconfluent cells) before being subjected to challenge with ICG. Cell survival was tested with the MTT assay.

RESULTS

When applied in isotonic solutions, ICG in all concentrations (below 5 mg/ml) and at all exposure times tested (2 mins-2 hours) was found not to affect the survival of ARPE19 cells. ARPE19 cultures older than 30 days were more resistant to a 5 mg/ml hypotonic ICG solution than younger cultures.

CONCLUSION

When toxicity of ICG was tested in hyperconfluent ARPE19 cultures, these cells were found to be more resistant to the dye than has been previously reported for more immature ARPE19 cells.

Light absorbing properties of indocyanine green (ICG) in solution and after adsorption to the retinal surface: an ex-vivo approach

BACKGROUND

To evaluate potential differences in light absorbing properties and stability of indocyanine green (ICG) adsorbed to the retinal surface and of ICG dissolved in water and balanced salt solution.

METHODS

The retina of four human donor eyes was prepared by removing the vitreous from the retinal surface. The inner surface of the specimen was covered with two to three drops of a 0.05% or 0.15% ICG solution respectively. After 1 min, the dye was removed by careful irrigation using BSS plus. The retinal specimens were then investigated by diffuse reflection spectroscopy (UV/VIS/NIR Spectrometer Lambda 900/Perkin Elmer equipped with a PELA-1020 integrating sphere accessory) and their absorption evaluated by the Kubelka-Munk function. To control the sensitivity of the setting, diffuse reflectance spectra of ICG adsorbed to a cellulose membrane and Al(2)O(3) were measured. For comparison, absorption spectra of ICG dissolved in water and BSS plus solution were measured in relation to ICG concentration and time using an UV/VIS/NIR Spectrometer Lambda 900/Perkin Elmer.

RESULTS

On the retinal surface, absorption spectra exhibited a steep increase of absorption beginning at 620 nm, with a maximum at 736 nm (0.05%) and a shoulder at 745 (0.15%) and a second maximum at approximately 800 nm for both concentrations. Repeated measurement of the retinal surface 13 days after the ICG exposure revealed no changes in the position of the maxima as compared to the initial measurements. Light absorbing properties of ICG on cellulose or Al(2)O(3) are similar to those seen on the retinal surface with respect to the pattern and location of absorption maxima. In contrast, ICG dissolved in water or BSS plus disclosed variations in absorption characteristics depending on dye concentration, solute and time of measurement.

CONCLUSIONS

Absorption characteristics and stability of ICG bound to the retinal surface could be of relevance when investigating potential pathomechanisms of ICG related toxicity, which might be related not only to intraoperative but also to postoperative light exposure of patients after intravitreal use of ICG.

A Surgical Technique to Protect the Macular Hole in Indocyanine Green-Assisted Vitrectomy

A 38-year-old man with human immunodeficiency virus was referred for evaluation of retinal lesions in both eyes. Optical coherence tomography was performed after dilating the pupils. Biomicroscopy of the retina showed an atypical, solitary, yellowish-white lesion in the macula of both eyes with no inflammation of the vitreous. Optical coherence tomography of the lesions showed an area of extremely low reflectivity with well-defined but irregular borders in the outer retina. The surrounding retina showed normal reflectivity and was of normal thickness. Optical coherence tomography showed selective necrosis of the outer layers due to progressive outer retinal necrosis. Optical coherence tomography may serve as a useful tool for the early diagnosis of progressive outer retinal necrosis.

An experimental method for testing novel retinal vital stains

There is uncertainty surrounding the safety of the vital stains currently used to assist macular surgery, and there may be other agents that are more suitable. This study aimed to validate a method of screening retinal vital stains for their potential surgical utility. Bovine retina was exposed to test agents at a range of concentrations. Masked observers determined the minimum dye concentration that reliably stained the retina, defined as the minimum visible concentration (MVC). Computer image analysis (CIE94 colour difference equation) was used to estimate the magnitude of the colour difference between stained and unstained retina. Agents that had favourable staining characteristics underwent safety testing using a retinal pigment epithelium and glial cell culture model. Cells were exposed to each agent and viability was assessed with a mitochondrial enzyme (MTT) assay, and fluorescent live-dead probe (ethidium homodimer-1/calcein-AM). Frozen sections were used to determine which retinal layers were stained. Techniques were tested on the following agents: alcian blue; diethyloxadicarbocyanine; Evan's blue; fast green; fluorescein; Janus green; methylene blue; naphthol green; neutral red; procian (reactive) yellow; rose bengal; and trypan blue. For most dyes, the results of image analysis showed that colour differences increased linearly with dye concentration, although some displayed a more exponential relationship. Five agents showed favourable staining characteristics: Evan's blue, rose bengal, naphthol green, neutral red, and trypan blue (MVC 0.02, 0.01, 0.1, 0.002, 0.01%, respectively). Safety testing of these five agents did not show toxicity, except in glial cells exposed to rose bengal. Relative to the negative control (saline), these showed a 48% reduction in viability using the MTT assay (p<0.001; t=4.71; CI 30-75%), and qualitative damage on fluorescence microscopy. Frozen sections showed that some agents produced diffuse staining of all retinal layers, others produced selective inner retinal staining. There are thousands of biological stains available and many of these may be more effective or safer than those currently used for retinal surgery. This study provides a means of screening potentially useful vital stains.

Intravitreal Staining of the Internal Limiting Membrane Using Indocyanine Green in the Treatment of Macular Holes

Surgical management of macular holes consists of pars plana vitrectomy, removal of the posterior hyaloid facia, and peeling of the epiretinal membranes (ERM). Additionally, removal of the internal limiting membrane (ILM) may enable an increase in the anatomic and functional success rates. However, recognition of fine ILM is difficult thus increasing the time that the macula is exposed to intraoperative light. Staining the ILM with indocyanine green (ICG) dye during vitrectomy facilitates recognition of the ILM and assures that all adjacent ERM are removed. Therefore, ICG-assisted ILM peeling has gained worldwide popularity among vitreoretinal surgeons. However, there are some concerns about the intravitreal ICG application. Reports in the literature described a variety of application techniques using different concentrations. The postoperative outcomes were controversial reporting heterogeneous anatomical and functional outcomes after ICG application, as well as descriptions of adverse effects related to the dye. We discuss the indications, techniques, surgical results, and complications after intravitreal ICG injection for the treatment of macular holes.

Selective staining of the internal limiting membrane using the sequential intraoperative instillation of whole blood followed by indocyanine green dye

PURPOSE

To reduce the retention of indocyanine green (ICG) on the retina by selectively staining the internal limiting membrane (ILM) with whole blood during ICG-assisted ILM peeling.

DESIGN

Interventional, non-comparative, prospective case series.

METHODS

Autologous whole blood was applied to cover the macular area and selectively removed to expose the area needed to be stained. ICG solution (1 mg/ml) diluted in glucose 5% was used to selectively stain the macular area. The stained ILM was removed completely.

RESULTS

We studied 22 patients with macular holes, eight with macular pucker and four with diabetic macular edemas. The ILM was selectively stained successfully by ICG with whole blood. One month after surgery, we found no autofluorescence in the posterior pole by infrared-sensitive camera.

CONCLUSIONS

Autologous whole blood can help to achieve the goal of selectively staining ILM, further reducing the retention of ICG. It may further reduce ICG toxic effects.

Prevention of Indocyanine Green Toxicity on Retinal Pigment Epithelium with Whole Blood in Stain-Assisted Macular Hole Surgery

PURPOSE

To examine whether whole blood prevents indocyanine green (ICG) toxicity on in vitro retinal pigment epithelium (RPE) and prevents RPE staining in ICG-assisted macular hole (MH) surgery.

DESIGN

In vitro study and prospective case series.

PARTICIPANTS

In vitro study and 20 patients who underwent ICG-assisted MH surgery (20 eyes).

METHODS

In the in vitro study, cultured human RPE cells were covered with balanced saline solution (BSS), heparinized whole blood, plasma, or packed red blood cells, then exposed to various concentrations of ICG. One cohort was incubated in the dark; the other cohort was exposed to light. Indocyanine green toxicity was evaluated by mitochondrial dehydrogenase assay. In the clinical study, a prospective noncomparative review of 20 consecutive patients (20 eyes) with stage 3 to stage 4 MH who underwent surgery with ICG to stain the internal limiting membrane (ILM) was performed. Indocyanine green solution (0.5 mg/ml) was used to stain the ILM after autologous whole blood covered the macular hole area. Postoperative staining of ICG on RPE was detected by an infrared-sensitive camera.

MAIN OUTCOME MEASURES

Cultured human RPE cell viability, macular hole closure rate, median visual acuity preoperatively and postoperatively, postoperative ICG staining, and retinal changes.

RESULTS

Cultured human RPE cells covered by whole blood or plasma showed no decrease of mitochondrial dehydrogenase even in 5.0 mg/ml concentration of ICG for 20 minutes with or without light exposure. Conversely, those exposed to ICG and covered with BSS demonstrated a significant decrease of mitochondrial dehydrogenase after incubation in 5, 2.5, and 1.0 mg/ml for 20 minutes in the dark and in 5 to 0.05 mg/ml with light. Clinically, no postoperative staining on RPE was detected. No atrophic RPE changes or other retinal changes were observed in the previous MH area that was covered by autologous whole blood in all 20 eyes on average follow-up of 10.6 months. The hole closed in 19 eyes (95%) on first surgery. Visual acuity improved in 17 eyes (85%) on most recent follow-up.

CONCLUSIONS

Whole blood prevents ICG toxicity in RPE cell culture and prevents staining of RPE in surgery of MH when the ILM is stained with ICG.

Toxic effects of indocyanine green, infracyanine green, and trypan blue on the human retinal pigmented epithelium

BACKGROUND

Indocyanine green, infracyanine green, and trypan blue are frequently used as aids to visualize structures removed during vitreoretinal surgery. But they may have toxic effects on the retina. We therefore compared the acute and chronic toxicities of these stains on cultured human retinal pigmented epithelial (RPE) cells using clinically relevant concentrations and an identical experimental setup for each agent.

METHODS

Monolayers of RPE cells were incubated with various concentrations of indocyanine green, infracyanine green (each at 0.005%, 0.05%, and 0.5%) or trypan blue (0.05%, 0.06%, 0.1%, 0.15%, and 0.5%) for 5 min (acute exposure) or 6 days (chronic exposure). Using the propidium iodide assay, acute cytotoxicity was monitored at 15-min intervals for up to 3 h. Chronic cytotoxicity was assessed by monitoring cell calcein esterase activity, cell proliferation, and cell morphology (viability) after 6 days of exposure.

RESULTS

Indocyanine and infracyanine green induced acute and chronic toxicities at a concentration above 0.05%. Trypan blue evoked no acute toxicity, but it was chronically cytotoxic at all tested concentrations.

CONCLUSIONS

Despite thorough rinsing after application, significant amounts of the not sufficiently water soluble indocyanine and infracyanine green are retained after surgery by the eye. Trypan blue, being more water-soluble than ICG, is probably retained to the least degree. This circumstance is fortunate given that trypan blue exhibits a chronic cytotoxicity comparable to ICG at all clinically relevant concentrations. During vitrectomy, surgeons should aim to expose retinal tissue to only low concentrations of these stains and for as short a period as possible.

Does intravitreal triamcinolone acetonide-assisted peeling of the internal limiting membrane effect the outcome of macular hole surgery?

PURPOSE

To evaluate functional and anatomical outcome of triamcinolone acetonide assisted internal limiting membrane (ILM) peeling in patients with macular hole.

METHODS

Fifteen eyes of 15 consecutive patients were identified with stage 3 and 4 idiopathic macular holes, these undergoing triamcinolone acetonide assisted ILM peeling for macular holes. These were matched retrospectively with 15 eyes of 15 patients with stage 3 and 4 idiopathic macular holes of less than six months duration, who underwent macular hole surgery with ILM peel augmented with indocyanine green (ICG). Functional and anatomical outcomes were compared between two groups.

RESULTS

There were no significant differences between the two groups with reference to demographic features of age, sex, staging of the macular holes and the proportion subsequently undergoing cataract surgery. The mean follow-up period was 6.4 months in the triamcinolone acetonide group and 7.2 months in the ICG group. The hole closure rate was 100% in both group at primary operation. The mean Snellen line change was +1.24 in the intravitreal triamcinolone group and +1.1 in the ICG group. There was a significant improvement in Snellen and Logmar visual acuity in both groups. These differences in visual outcome between the groups were not statistically significant.

CONCLUSIONS

Our data showed similar outcomes for patients with macular hole where ICG has been used when compared to patients where triamcinolone acetonide has been used for ILM peeling. Further study with longer follow-up and large series is warranted to assess the safety of the triamcinolone acetonide assisted ILM peeling in macular hole surgery.

The effect of indocyanine green on cultured retinal glial cells

BACKGROUND

Recently, indocyanine green (ICG) has been utilized to visualize inner limiting membrane in vitreous surgery. However, the safety of ICG injected into the vitreous has not been well established. The possible toxicity of ICG on Muller cells was investigated using cultured rat retinal glial cells (RGCs).

METHODS

Rat RGCs were cultured in Dulbecco modified Eagle medium supplemented with 20% fetal calf serum. The cytotoxicity of ICG was assayed with viable cell number and resazurin metabolic assay. The expression of the apoptosis-related gene bcl-2 was examined with real-time polymerase chain reaction analysis.

RESULTS

The effects of ICG on the viability of rat RGCs were tested at two different concentrations (0.05% and 0.5%). ICG significantly decreased the viable cell number of RGCs at 0.5%, while there was no significant effect at 0.05%. Similarly, the metabolic activity to resazurin was significantly decreased by exposure to 0.5% ICG. However, ICG showed little effects on resazurin metabolism at 0.05%. The expression levels of bcl-2 mRNA were higher in cells treated with 0.5% ICG than in those treated with 0.05% ICG and untreated control cells.

CONCLUSION

The data suggest that ICG initiates the death of RGCs at high concentrations, in part, through apoptosis-related signal pathways.

Effect of indocyanine green on the growth and viability of cultured human retinal pigment epithelial cells

The aim of this study was to evaluate the effects of indocyanine green (ICG), which is a fluorescent dye recently used for staining during manipulation of the internal limiting membrane (ILM) in surgery, on cultured human retinal pigment epithelial (HRPE) cells. Different concentrations, up to 0.25% (weight/volume), of ICG were added to the culture medium, which contained the cultured human RPE cells. Then the cell-growth curve and cell viability were assayed with a direct cell count and MTS cell proliferation kit, respectively. Two (2) models of experimentations, a dose-response group and a short-term application group, were designed. We obtained data for IC(50) values for 24-, 48-, and 72-hour ICG treatments, which were 0.062%, 0.041%, and 0.035%, respectively. This implies that the longer the culture duration, the lower the concentration of ICG, which can inhibit the HRPE cells. In the group of 3-day sequential incubations with ICG treatment, a 0.01% concentration significantly inhibited HRPE growth. In addition, HRPE cells were damaged immediately after ICG treatment, and the damage was ICG dose-related. In the sequential 3-day incubation, compared to the control group, the surviving HRPE cells of each treated group had the same growth rate. In conclusion, ICG has a relatively toxic effect on cultured HRPE cells, even in much lower concentrations than clinical nondilution status (0.25%). Since an ICG toxic effect on HRPE cells was found in our study (in vitro), we highly recommend staining the ILM with as low a concentration of ICG as possible, and washing out the residual intravitreal ICG as thoroughly as possible after finishing the peeling of the ILM.

Ocular Toxicity of Intravitreal Indocyanine Green

We report 6 cases of indocyanine green (ICG)-related ocular toxicity after intravitreal ICG usage. Five cases had preoperative diagnosis of macular hole, 1 case had preoperative rhegmatogenous retinal detachment complicated with proliferative vitreoretinopathy. All cases received vitrectomy, ICG-assisted internal limiting membrane (ILM) peeling and air-fluid exchange. All eyes had residual ICG left at the end of surgery. Patients were followed up with indirect ophthalmoscopy, visual acuity, color fundus photography, fluorescein angiography, and ocular coherence tomography. Circular foveal retinal pigment epithelium atrophy larger than the area of macular hole and surrounding cuff was noted in 4 of 5 cases with preoperative macular hole. The other eye with preoperative diagnosis of macular hole had shallow anterior chamber and low intraocular pressure lasting for 1 week postoperatively. Diffuse retinal pigment epithelial atrophy was noted in the eye with preoperative proliferative vitreoretinopathy. Four eyes demonstrated optic atrophy postoperatively. Ocular toxicity caused by ICG may present as pigment epithelial atrophy, which is characteristically larger than the previous area of macular hole and surrounding cuff. Disc atrophy, retinal toxicity, and ocular hypotony were also observed in some cases. To prevent toxicity, residual ICG and ICG-stained ILM must be removed as completely as possible.

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.

IS REMOVAL OF INTERNAL LIMITING MEMBRANE ALWAYS NECESSARY DURING STAGE 3 IDIOPATHIC MACULAR HOLE SURGERY?

PURPOSE

To determine the indications for internal limiting membrane (ILM) removal in stage 3 idiopathic macular holes (MHs).

METHODS

Focal posterior vitreous detachments (PVDs) at MH rims were examined preoperatively by optical coherence tomography and binocular slit-lamp fundus examination in 19 patients retrospectively. All eyes underwent pars plana vitrectomy and creation of a PVD, and some eyes underwent a second surgery to remove the ILM. Indications of ILM removal for MH closure were discussed.

RESULTS

Preoperatively, 9 eyes did not (non-PVD group) and 10 eyes did (PVD group) have complete focal PVDs. In all nine eyes in the non-PVD group, MHs were closed after the creation of a PVD without ILM peeling (P <0.05, chi test). In the PVD group, 5 eyes (50%) had MHs closed by making PVD complete without ILM removal, and 5 eyes (50%) required ILM removal in a second surgery. In the end, closure of MHs was achieved in all eyes.

CONCLUSION

Anatomic closure of stage 3 idiopathic MHs without a PVD at the rim of the hole may be achieved only by creating a PVD without ILM removal.

Vitreous surgery with and without internal limiting membrane peeling for macular hole repair

PURPOSE

To compare surgical results for idiopathic macular holes with and without internal limiting membrane (ILM) peeling in a series of consecutive patients during an 8-year period.

METHODS

A retrospective, nonrandomized, comparative trial. Four hundred seventeen eyes with macular holes without ILM peeling were compared with 175 eyes with ILM peeling. All eyes underwent pars plana vitrectomy with intravitreous gas, followed by head-down positioning. No adjunctive therapies were used. Comparison of closure and reopening rates and visual acuity with and without ILM peeling was analyzed.

RESULTS

Initial success rate significantly improved from 81% to 92% with ILM peeling. ILM peeling significantly improved the initial success rates in all categories of preoperative features. Reopening rates significantly decreased from 7% to 0.6% with ILM peeling. Among successful cases, line improvement was 6.0 in ILM-reserved eyes and 5.8 in ILM-peeled eyes. Among all cases, line improvement was 5.4 in ILM-reserved eyes and 5.7 in ILM-peeled eyes. Initial success rate of holes measuring more than 400 microm was significantly less than that of holes measuring less than 400 microm with or without ILM peeling. Initial success rate of holes older than 6 months old was significantly less than that for holes less than 6 months old without ILM peeling.

CONCLUSIONS

Internal limiting membrane peeling shows high closure and low reopening rates in macular hole surgery. ILM peeling is beneficial in older holes but is limited in larger holes. ILM peeling does not significantly improve visual acuity.

Long-term follow-up of indocyanine green–assisted peeling of the retinal internal limiting membrane during vitrectomy surgery for idiopathic macular hole repair

OBJECTIVE

To determine the long-term efficacy of indocyanine green (ICG)-assisted retinal internal limiting membrane (ILM) peeling during macular hole repair.

DESIGN

Retrospective, interventional, noncomparative case series.

PARTICIPANTS

One hundred twenty-one eyes of 114 patients with stage 2, 3, or 4 idiopathic macular holes that underwent ICG-assisted macular hole repair during the period of August 1999 to January 2003.

INTERVENTION

All eyes underwent a pars plana vitrectomy, including peeling of the posterior cortical hyaloid when necessary. Indocyanine green dye (0.5%) was instilled over the macula, and after removal of the ICG, the retinal ILM was peeled. Medium- to long-acting gas tamponade was used in all cases, and all patients were asked to position themselves facedown for 1 to 2 weeks.

MAIN OUTCOME MEASURES

Long-term postoperative anatomic results, visual acuity (VA), and complications.

RESULTS

Patients were observed postoperatively for an average of 26 months (range, 12-53). Anatomic closure of the macular hole was achieved in 118 eyes (98%) with a single surgery. Reoperation was successful at closing 2 of the 3 macular holes that did not close initially. One macular hole reopened 16 months after the original surgery, and the patient has not yet undergone further surgery. Visual acuity improved by > or =2 lines in 116 eyes (96%). Mean visual improvement after surgery was 6 lines (range, 0-14), and 96 eyes (79%) achieved a final VA of 20/50 or better. There were no intraoperative or postoperative complications attributed to the use of ICG.

CONCLUSIONS

Long-term follow-up of patients who underwent ICG-assisted ILM peeling for idiopathic macular hole repair demonstrates excellent anatomic and visual results.

Retinal Function and Histologic Changes Following Intravitreal Injection of Indocyanine Green in a Rabbit Model

The aim of this animal study was to investigate the effects of intravitreal injection of indocyanine green (ICG) applied in macular hole surgery on retinal functional, morphology, and histologic changes. Eighteen (18) New Zealand albino rabbits were divided equally into three groups (6 rabbits in each). In Group A, both eyes of each rabbit were vitrectomized by perflouropropane gas compression. One (1) month later, 0.1 cc of different doses of ICG was injected into the vitreous in the left eyes. In the right eyes, 0.1 cc of balanced salt solution was injected intravitreally, allowing them to serve as control eyes. In Group B, the same doses of ICG were injected intravitreally. ICG was washed out by fluid-fluid exchange 3 minutes after injection. In Group C, the same doses of ICG were injected intravitreally in nonvitectomized eyes. Scotopic and photopic electroretinogram (ERG) recordings and indirect ophthalmoscopy examinations were performed to detect any functional and morphologic changes. Rabbit eyes were enucleated 4 months after ICG injections to observe histologic changes. Significant decreased of scotopic and photopic ERG amplitude and marked histologic changes were noted in eyes injected with 0.5 mg/cc and 0.1 mg/cc of ICG in nonvitrectomized eyes (Group C). In vitrectomized eyes (Group A), decreased scotopic and photopic ERGs and mild histologic changes were noted in eyes injected with 0.5 mg/cc, but no histologic changes were noted in eyes injected with 0.1 mg/cc. There was a transient, mild decrease in scotopic and photopic ERGs and no morphologic changes were noted in the eyes with fluid-fluid exchange (Group B). The toxicity of intravitreous ICG is dose- and time-dependent. ICG at 0.5 mg/cc, with short exposure time, is recommended in macular hole surgery.

EFFICACY OF INTERNAL LIMITING MEMBRANE REMOVAL FOR RETINAL DETACHMENTS RESULTING FROM A MYOPIC MACULAR HOLE

PURPOSE

To evaluate the efficacy of internal limiting membrane (ILM) or epiretinal membrane removal during pars plana vitrectomy for a retinal detachment resulting from a macular hole in myopic eyes.

METHODS

A retrospective study was conducted in a single institution. Twenty-six highly myopic eyes with a retinal detachment resulting from a macular hole were studied. During pars plana vitrectomy, ILM peeling (ILM-peeled group) was performed on 13 eyes, and the ILM was not removed (ILM-preserved group) in 12 eyes. Main outcome measures were anatomic reattachment, optical coherence tomography-determined macular hole closure, and visual acuity. Follow-up periods were longer than 12 months in all cases.

RESULTS

The anatomic reattachment rate after the initial surgery was significantly higher in the ILM-peeled group (92.3%) than in the ILM-preserved group (50%). The macular holes of 8 (72.7%) of the 11 ILM-peeled and reattached eyes and 2 (50%) of the 4 ILM-preserved and reattached eyes were successfully closed by the initial surgery. No significant difference was found in the postoperative visual acuity and the improvement of visual acuity between the ILM-peeled group and the ILM-preserved group. There was also no significant difference of the postoperative visual acuity and improvement of the visual acuity between the two groups in cases with an initial anatomic success.

CONCLUSION

These results indicate that removal of the ILM contributes to a successful reattachment and is an effective treatment for macular hole and retinal detachment in highly myopic eyes. The authors suggest that the higher success rate after ILM peeling resulted from the release of the traction of the prefoveal vitreous and the epiretinal membrane over the detached retina.

TRYPAN BLUE IN MACULAR PUCKER SURGERY: AN EVALUATION OF HISTOLOGY AND FUNCTIONAL OUTCOME

PURPOSE

To evaluate possible adverse effects of trypan blue on the ultrastructure of the human retina, to report on functional outcome of macular pucker surgery with and without the use of trypan blue, and to evaluate the ultrastructure of tissue harvested during surgery.

DESIGN

Experimental study and prospective matched-pair analysis of two consecutive, interventional case series.

METHODS

Possible adverse effects on the ultrastructure of the human retina by trypan blue were evaluated in three donor eyes in an experimental study using trypan blue in concentrations of 0.02%, 0.15%, and 0.25%. The retinas were histologically evaluated. In the clinical study, the functional outcome (visual acuity, Goldmann perimetry) of 10 eyes of 10 consecutive patients with intraoperative use of trypan blue (0.15%) was analyzed (group 1) and compared with the functional outcome in a matched group of patients (preoperative visual acuity, pre- and postoperative lens status) who had undergone vitrectomy without trypan blue assistance (group 2). Only patients with an idiopathic macular pucker were included. Epiretinal tissue of all eyes was harvested and prepared for ultrastructural analysis using light and electron microscopy.

RESULTS

In the postmortem study, no significant alterations of the inner retina suggesting adverse effects of trypan blue concentrations of 0.02% were observed. In contrast, a disorganization of the innermost retina and an absence of the internal limiting membrane (ILM) was seen after the application of undiluted 0.15% and 0.25% trypan blue. In the clinical study, the median best-corrected visual acuity was 20/50 in both groups (range, 20/200-20/40) before surgery. Mean age was 70 years in group 1 (with trypan blue) and 69 years in group 2 (without trypan blue). Mean follow-up time was 4 months in group 1 and 5.6 months in group 2. Postoperatively, median visual acuity had increased to 20/32 (range, 20/100-20/25; Wilcoxon test P = 0.01) in group 1 and to 20/40 (range, 20/100-20/25; P = 0.09) in group 2. The difference between the two groups was not statistically significant (P = 0.4). Four of 10 patients without and 7 of 10 patients with trypan blue staining experienced an improvement of visual acuity (gain of 2 lines or more). No postoperative visual field defects were noted in either group. Histologic analysis of tissue harvested intraoperatively revealed the regular picture of undisturbed fibrocellular membranes. In some specimens, a layer of interspersed collagen was noted between epiretinal cells and the ILM, suggesting two different morphologic types of macular pucker. In a few sections, areas of cellular elements were detected adjacent to the retinal surface of the ILM.

CONCLUSION

Trypan blue in a concentration of 0.02% is not associated with morphologic alterations of the inner retinal layers in our postmortem study. After application of 0.15% and 0.25% trypan blue solutions, a disorganization of the inner retinal layers was observed; the ILM was absent. We did not find any adverse effects of an intraocular trypan blue concentration of 0.02% on functional status. Our study further indicates that the functional results of surgery with and without the use of trypan blue are comparable. As the question of toxicity of a dye can not be answered by morphological observations alone, further experimental studies will be needed.

Visual outcomes following ICG assisted ILM peel for Macular Hole

PURPOSE

To evaluate the anatomical and visual outcome of indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling for macular hole surgery. A literature search identified potential factors that may affect the functional success of the procedure.

METHODS

Retrospective case note review of 14 consecutive patients undergoing phaco-vitrectomy, gas and ICG-assisted ILM peeling for macular hole from July 2001 to July 2002. A 0.5% ICG solution (osmolarity 270 mOsm) was left in contact with the retina for 1-3 min. The outcome measures were hole closure, change in visual acuity, and macular pigmentary changes.

RESULTS

Anatomical hole closure was achieved in 13 of 14 eyes (92.8%). The mean logMAR Snellen acuities were 0.80 (range 0.60-1.30) preoperatively and 0.77 (0.48-1.30) postoperatively. Seven eyes (50%) developed retinal pigmentary changes in the macular area.

CONCLUSIONS

ICG-assisted ILM peeling for macular hole surgery achieves high rates of anatomical hole closure, but functional results are less encouraging. Previous studies suggest toxicity of the ICG to the retina, at the level of the RPE or inner retina. The results may be optimized by using a lower concentration, iso-osmolar, viscous solution, and by minimizing contact time of the solution and intensity, and duration of illumination.

Comparison of the in vitro toxicity of indocyanine green to that of trypan blue in human retinal pigment epithelium cell cultures

PURPOSE

To compare the in vitro toxicity of indocyanine green (ICG) to that of trypan blue (TB) in human retinal pigment epithelium cell cultures. The use of ICG and TB in macular hole surgery is discussed.

DESIGN

In vitro cell biology experimental study.

METHODS

The ICG dye and TB were applied to ARPE-19, a commercially available human retinal pigment epithelium cell line. Cultures were established and maintained according to supplier protocols. The ICG dye, TB or Hank's balanced salt solution (controls) were then applied to the cells at varying concentrations and over various exposure periods. Fiberoptic light was also applied to cells to assess for the possibility of a potentiating phototoxic effect. Cell viability fractions were determined using a well-studied mitochondrial dehydrogenase assay.

RESULTS

The TB was not toxic to the retinal pigment epithelium cell cultures at any concentration or over any period of exposure, whereas ICG dye demonstrated dose-dependent and exposure-dependent toxicity. The ICG dye was found to be toxic to the cells at all tested concentrations between 5.0 mg/ml (stock concentration, 26.1% cell survival) and 0.5 mg/ml (92.8% cell survival) over a 3-minute exposure. No toxicity to TB was seen at the stock concentration of 1.5 mg/mL. Addition of light to the cultures did not significantly alter cell viability with either dye. Long periods of exposure, 2 hours, 24 hours, and 72 hours, to minute concentrations of either dye did not produce significant cell death.

CONCLUSIONS

Indocyanine green demonstrates more toxicity than TB to human retinal pigment epithelium cell cultures. This is independent of any phototoxic potentiating effect of fiberoptic light or solvent toxicity. A clinically useful concentration of 0.5-mg/ml ICG causes low cytotoxicity at 3 minutes' exposure (cell survival 92.8%) and shows no detectable toxicity at 1-minute exposure (cell survival 102%).

Removal of sodium from the solvent reduces retinal pigment epithelium toxicity caused by indocyanine green: implications for macular hole surgery

BACKGROUND

s/aims: Staining of internal limiting membrane with indocyanine green (ICG) has been reported to be associated with postoperative atrophic retinal pigment epithelium (RPE) change. Here the authors examined whether removing sodium from the solvent reduces ICG induced RPE cytotoxicity.

METHODS

Human RPE cells were exposed to ICG (0.25 and 0.025 mg/ml) reconstituted with balanced salt solution (BSS) or Na(+) free BSS. Light microscopy, trypan blue dye exclusion, acridine orange/ethidium bromide staining, and DNA electrophoresis were used to evaluate the cytotoxic effects of ICG. ICG uptake was measured by optical absorption at 790 nm.

RESULTS

Sodium removal reduced the ICG induced changes in cell morphology and improved the RPE cell viability. When RPE cells were incubated for 4 hours in 0.25 mg/ml ICG dissolved in BSS and sodium free BSS, 86.3% (SD 6.7%) and 2.4% (1.1%) of the cells were stained with trypan blue, respectively. After ICG treatment, RPE dies mainly through a necrotic mechanism. ICG uptake by RPE was also reduced with sodium removal.

CONCLUSIONS

ICG induced cytotoxicity in cultured human RPE was reduced with removal of sodium from the solvent. This reconstitution method may provide a safer intravitreal use of ICG in macular hole surgery.

Indocyanine green induces apoptosis in human retinal pigment epithelial cells

PURPOSE

To examine whether indocyanine green (ICG) dye induces apoptosis in human retinal pigment epithelial (RPE) cells.

DESIGN

Laboratory investigation.

METHODS

Pure cultures of human RPE cells were isolated. Retinal pigment epithelial cells were incubated with different concentrations of ICG dye (1 mg/ml, 5 mg/ml, or 20 mg/ml) for 30 minutes. The rate of RPE cell apoptosis was assessed with Annexin V-FITC staining and propidium iodide (PI) by flow cytometry.

RESULTS

Retinal pigment epithelial cells maintained their monolayer morphology after incubation with ICG dye. However, ICG induced a statistically significant amount of apoptosis in RPE cells at all the concentrations (1 mg/ml, 5 mg/ml, and 20 mg/ml) after 30 minutes of incubation (P <.05). The solvent solution alone (without the ICG dye) did not induce any significant apoptosis in RPE cells, when compared with culture medium.

CONCLUSIONS

The incubation of RPE cells with ICG dye increased the number of apoptotic RPE cells in vitro. Our findings indicate that the decision over the intravitreal application of ICG dye needs to be made with caution.

Macular hole surgery with and without indocyanine green assistance

PURPOSE

To compare the results of macular hole surgery with the use of indocyanine green (ICG) to assist internal limiting membrane (ILM) peeling and macular hole surgery without indocyanine green use.

METHODS

A retrospective, comparative, consecutive study of 68 patients with macular holes. In total, 34 patients underwent vitrectomy and ILM peeling, and 34 patients underwent vitrectomy and ILM peeling with the assistance of indocyanine green. The main outcome measures were postoperative visual acuity and macular hole status.

RESULTS

Indocyanine green increased the ability to visualise and peel the ILM. The average preoperative visual acuity in the group where ICG was used was 6/36 and the group where ICG was not used was 6/60. The average follow-up was 25 weeks for the ICG group and 53 weeks for the group with no ICG. Both groups were also compared at 25 weeks follow-up. Hole closure rate for the group with ICG was 97% compared to 91% without ICG. The mean postoperative visual acuity was 6/24 for the group with ICG and 6/12 for the group without ICG, a difference of two lines on the Snellen chart when compared with the preoperative acuity (P-value 0.299, Student's t-test). Both groups had a mean improvement of Snellen acuity of two lines (ICG group: P-value 0.0002, Student's t-test; no ICG group: P-value 0.00004, Student's t-test). In all, 83% of patients in the ICG group maintained or improved their visual acuity compared to 91% in the group without ICG.

DISCUSSION

There is no doubt that indocyanine green stains and assists in visualisation and therefore increases the ease of peeling the ILM in macular hole surgery. Initially, there was concern regarding a poorer outcome for patients with the use of ICG, which has also been previously discussed in the literature. When the two groups were compared at a similar follow-up time of approximately 25 weeks, it was shown that there was no statistically significant difference between the outcomes in the two groups. This study had an improved hole closure rate for the group where ICG was used, although it was not statistically significant.

Anatomic and visual outcomes after indocyanine green-assisted peeling of the retinal internal limiting membrane in idiopathic macular hole surgery

PURPOSE

To report anatomic and visual outcomes after vitrectomy and adjunctive retinal internal limiting membrane (ILM) peeling with and without intravitreal indocyanine green for idiopathic macular hole repair.

DESIGN

Retrospective comparative study of consecutive case series.

METHODS

Three consecutive groups of idiopathic macular hole cases underwent modifications of surgical technique. Group I (48 eyes of 47 patients) underwent a standard vitrectomy, fluid/gas exchange, and 1 week's face-down positioning, group II (21 eyes of 21 patients) an adjunctive ILM peeling without use of indocyanine green, and group III (28 eyes of 28 patients) an adjunctive peeling of ILM stained with intravitreal application of 0.1 to 0.2 ml of 0.5% indocyanine green dye.

RESULTS

Three groups of patients had comparable clinical characteristics as to age, gender, estimated duration of macular hole, preoperative visual acuity, and follow-up time. The rate of macular hole closure after a single surgery, as determined by optical coherence topography was 85.4% in group I, 85.7% in group II, and 100% in group III. Groups I and II showed a statistically significant visual improvement, but group III did not show significant visual acuity improvement as the mean logarithm of the minimal angle of resolution visual acuity was from 0.767 (20/120) preoperatively to 0.691 (20/100) postoperatively (P =.342). Eight cases in group III developed within a few postoperative months of optic disk pallor and irreversible peripheral visual field loss, predominantly affecting the nasal field.

CONCLUSIONS

Intravitreal indocyanine green-assisted ILM peeling improves anatomic success in macular hole surgery, but it may potentially lead to unfavorable visual acuity outcome and peripheral visual field loss.