Iatrogenic punctate chorioretinopathy after internal limiting membrane peeling

EFFICIENCY AND SAFETY OF INTERNAL LIMITING MEMBRANE PEELING WITH DIFFERENT FORCEPS FOR MACULAR DISEASE

PURPOSE

To compare the efficiency and safety of internal limiting membrane (ILM) peeling between the Sharkskin forceps and End-grasping forceps in various macular diseases.

METHODS

It is a prospective cohort block-randomized study conducted in a tertiary medical center. Seventy subjects with macular hole, epiretinal membrane, vitreomacular traction syndrome, or myopic foveoschisis, receiving pars plana vitrectomy and ILM peeling surgery were equally divided into Sharkskin forceps group and End-grasping forceps group. The duration of ILM peeling, the number of attempts to initiate peeling, and peeling-related retinal damage were evaluated by recorded video and optical coherence tomography.

RESULTS

In the Sharkskin group, the authors demonstrated significantly fewer attempts to initiate ILM peeling compared with End-grasping group, with an average of 1.9 and 3.1 attempts ( P = 0.0001) and a lower incidence of retinal microstructural damage (20% vs. 45%, P < 0.0001). Moreover, the mean depth of inner retinal injury at the initiating site exhibited distinct difference postoperatively at 3 months between the Sharkskin group then the End-grasping group (4.3 vs. 30.0 µ m, P = 0.001).

CONCLUSION

Sharkskin forceps provide better efficiency and outcome in ILM peeling in patients with various vitreomacular interface diseases, including reduced risk of retinal injury and fewer attempts to initiate ILM flap.

Real-Time (iOCT) Guided Epiretinal Membrane Surgery Using a Novel Forceps with Laser-Ablated Microstructure Tip Surface

Purpose: We investigated intraoperative OCT (iOCT)—guided epiretinal membrane (ERM) and internal limiting membrane (ILM) removal using a novel forceps with a laser-ablated tip surface; it was designed to help prevent indentation force, shear stress, or tractional trauma when grasping very fine membranes. Patients and Methods: This retrospective study included patients who underwent 23- and 25-gauge pars plana vitrectomy (PPV) for vitreoretinal interface disorders. ERM and ILM peeling was performed under guidance with microscope-integrated iOCT using novel ILM forceps with laser-ablated tip surfaces. These forceps were engineered to enhance friction when grasping tissue. Evaluation of ERM/ILM manipulation included postoperative slow-motion video analysis of the number of grasping attempts, initial ILM mobilization, and observed damage to retinal tissue. Results: ERM/ILM removal was successfully performed in all patients, with an average of four grasp actions to initial membrane mobilization (91%). Additional use of a diamond-dusted membrane scraper was used in two cases (9%). Mean best-recorded visual acuity (BRVA) logMAR improved from 0.5 ± 0.34 to 0.33 ± 0.36 (p = 0.05) and mean central retinal thickness (CRT) improved from 462 ± 146 µm to 359 ± 78 µm (p = 0.002). Postoperative iOCT video analysis demonstrated hyper-reflectivity of the inner retinal layers associated with retinal hemorrhage in five eyes (22%), but no grasping-related retinal breaks. Conclusions: The texturized surface on the tips of the ILM forceps were found to be helpful for mobilizing ILM edges from the retinal surface. iOCT-guided ERM surgery also allowed for improved intraoperative tissue visualization. We believe that these two technologies helped reduce both unnecessary surgical maneuvers and retinal damage.

Risk factors for epiretinal membrane formation and peeling following pars plana vitrectomy for primary rhegmatogenous retinal detachment, an OCT guided analysis

Background

To evaluate the rate and risk factors of epiretinal membrane (ERM) formation and need for ERM peeling after pars plana vitrectomy (PPV) for uncomplicated primary rhegmatogenous retinal detachment (RRD).

Methods

Retrospective, single-center, cohort study of 119 consecutive patients (119 eyes) that underwent RRD repair using PPV. The primary outcomes were ERM formation, classified using an optical coherence tomography grading system, and the rate of ERM peeling. Visual acuity, postoperative complications, and risk factors for ERM formation and peeling were also identified.

Results

Postoperative ERM formation occurred in 69 eyes (58.0%); 56 (47.1%) were stage 1, 9 (7.6%) stage 2, 3 (2.5%) stage 3, and 1 (0.8%) stage 4. Only 6 (5.0%) eyes required secondary PPV for a visually significant ERM, with a mean time to reoperation of 488 ± 351 days. Risk factors for ERM formation included intraoperative cryotherapy, more than 1000 laser shots, 360° laser photocoagulation, and choroidal detachment (p < 0.01). Eyes with more than 3 tears had a trend towards increased ERM surgery (p = 0.10).

Conclusions

Visually significant ERM formation following PPV for primary RRD was uncommon in this cohort (5%). Half of the ERMs were detected after the first post-operative year, indicating that this complication may be underreported in studies with only 1-year follow-up.

Quantifying surgical skill in macular surgery

PURPOSE

To evaluate the relationship between patient outcome and surgical experience by developing an objective quality measure of macular hole surgery based on forceps damage to the inner retina.

METHODS

We retrospectively examined 3 macular hole case series >1 year after pars plana vitrectomy, internal limiting membrane peeling and gas tamponade. The patients were operated by (1) a novice surgeon (<20 cases), (2) an intermediate (150+ cases) and (3) an experienced surgeon (2000+ cases). Primary outcome was inner retinal volume defect as segmented from optical coherence tomography (GCL++: thickness from internal limiting membrane to inner plexiform layer). Secondary outcome was retinal function measured by confocal microperimetry using a custom scanning protocol.

RESULTS

Thirty-two patients were examined: 11, 10 and 11 patients in the novice, intermediate and experienced surgeon group, respectively. Median GCL++ volume defect was 23.68 × 10⁶  μm³ (IQR: 22.77 × 10⁶ -44.81 × 10⁶ μm³ ), 8.42 × 10⁶ μm³ (IQR: 4.86 × 10⁶ -10.03 × 10⁶ μm³ ) and 3.55 × 10⁶ μm³ (IQR: 1.44 × 10³ -7.94 × 10⁶ μm³ ) in the novice, intermediate and experienced surgeon group, respectively (p = 0.0004). The novice surgeon volume defect differed significantly from the intermediate and experienced surgeon (p = 0.016 and p = 0.0002, respectively). A subset of 12 patients underwent microperimetry measurements demonstrating correlation between inner retinal volume defect and reduced retinal sensitivity (p = 0.02).

CONCLUSIONS

Forceps induced inner retinal damage commonly occurs during initiation of internal limiting membrane peeling in macular hole surgery. Damage to the structure and function of the inner retina seems to correlate to surgical experience.

Rapid progression of chorioretinal atrophy in punctate inner choroiditis: a case report

Background

The chorioretinal inflammatory lesions occurring in punctate inner choroiditis evolve into punched-out atrophic scars. Typically, the progression is gradual. We report a case of highly myopic punctate inner choroiditis with rapid progression of chorioretinal atrophy.

Case presentation

A 48-year-old Japanese woman with high myopia presented with decreased visual acuity. Best-corrected visual acuity was 20/28 in the right eye and 20/16 in the left eye; axial length was 29.0 mm and 28.7 mm, respectively. Fundoscopy revealed an epiretinal membrane in the left eye. Three years later, the best-corrected visual acuity in the left eye had decreased to 20/33; at this time, the patient underwent vitrectomy with epiretinal membrane and internal limiting membrane peeling in this eye. Six months later, the best-corrected visual acuity in the left eye decreased suddenly to 20/100. Optical coherence tomography showed a nodule-like lesion in the outer retina with disruption of the retinal pigment epithelium and a focally thickened choroid, compatible with PIC. One month later, the choroidal thickness had decreased. The central chorioretinal atrophy expanded rapidly at a rate of 0.45 mm²/year over the next 3 years, and new areas of patchy focal chorioretinal atrophy developed in the perifovea.

Conclusions

Rapid progression of chorioretinal atrophy was observed in a patient with punctate inner choroiditis. Because punctate inner choroiditis is often associated with degenerative myopia, the retina is fragile and may be susceptible to mechanical damage. This case report alerts clinicians to the need for careful management of patients with punctate inner choroiditis, especially after vitrectomy.

OUTER RETINAL INJURY SECONDARY TO MEMBRANE PEELING WITH INTERNAL LIMITING MEMBRANE FORCEPS

PURPOSE

To present a case of visually significant retinal injury due to internal limiting membrane (ILM) peeling using ILM forceps alone.

METHODS

Case report.

RESULTS

A 60-year-old woman who underwent ILM peeling for an epiretinal membrane presented with linear central scotomata. Peeling had been initiated and performed with ILM forceps alone, without the use of other surgical instruments. Fundus examination and spectral domain optical coherence tomography imaging confirmed the presence of several discrete areas of inner and outer retinal injury in the macula, which corresponded to her scotomata.

CONCLUSION

This is a case of visually significant retinal injury due to ILM peeling that was performed with ILM forceps alone. Improper peeling technique can transmit injurious forces to the retina. Surgeons must be mindful of the biomechanical forces involved in ILM peeling to minimize traction on the retina.

[Proliferative vitreoretinopathy (PVR) minimal: same, same but different. Characteristics and surgical treatment of PVR-associated macular pucker]

BACKGROUND

Epiretinal membrane formation resulting in a macular pucker is among the typical complications associated with proliferative vitreoretinopathy (PVR) in retinal detachment and has a major impact on the functional outcome after surgical treatment.

METHODS

A literature search was carried out in PubMed.

RESULTS

Approaches to the surgical treatment of PVR-associated macular pucker include complete membrane removal within the vascular arcades aimed at relieving retinal traction at the posterior pole and peeling of the internal limiting membrane (ILM). As a further option it has been suggested that primary ILM peeling in rhegmatogenous retinal detachment repair may reduce or even prevent postoperative epiretinal membrane formation. In addition, correct timing of surgery is a factor that may contribute to successful treatment.

DISCUSSION

Due to the particularly strong adhesion and the frequent occurrence of concurrent retinal detachment, the surgical approach to PVR-associated macular pucker is particularly challenging. As with idiopathic epiretinal membranes, surgical removal has the potential to improve functional outcomes; however, visual improvement depends largely on whether the macula was involved in the original retinal detachment.

Long-term improvement of retinal sensitivity after macular hole surgery over at least 9-year-old follow-up: a case series

PURPOSE

To evaluate the correlations between anatomical and functional changes in idiopathic macular hole (IMH) surgery in long-term follow-up.

METHODS

This is a prospective, interventional single centre case series. The final sample is formed by 14 eyes of 14 patients who had undergone IMH surgery in our institution between 2005 and 2009 and were still followed up in 2019. Reported data were pre- and post-operative best-corrected visual acuity (BCVA), retinal sensitivity and fixation stability values on MP-1 and structural macular features on spectral domain optical coherence tomography. Optical coherence tomography angiography (OCTA) was utilized to assess microvascular characteristics at the final visit. Only patients with a successful MH closure were enrolled, excluding eyes affected by other relevant pathologies.

RESULTS

Mean BCVA improvement was significant after surgery (t test, p value < 0.001) and presented a slight, not statistically significant raise, between the post-operative and long-term follow-up. Differently, mean retinal sensibility (dB) showed a highly statistically significant difference between pre-operative and post-operative (t test, p value = .002) and post-operative and last follow-up (p value < 0.001). In the long-term follow-up, subjects having integrity of the inner segment/outer segment (IS/OS) layer showed no statistically significant difference in BCVA compared with subjects with IS/OS discontinuity (t test, p value = 0.72). OCTA parameters of the operated eye showed no statistical significance compared with the fellow eye.

CONCLUSIONS

In successfully closed MHs, retinal sensibility measured by microperimetry significatively increases after a long follow-up period even when BCVA remains stable or raises slightly. Vessel density organization tends to be quantitatively similar to fellow eye several years after surgery.

Unintentional retinal artery amputation during macular peeling

Objective: To report a case of unintentional retina artery amputation during macular peeling.

Methods: Observational case report

Results: A 73-year-old female underwent surgery to treat epiretinal membrane (ERM) associated with severe staphyloma in her left eye. While the ERM/posterior hyaloid membrane visually enhanced with triamcinolone (TA) was peeled, a movement of the forceps unintentionally involved the inferior temporal branch artery near the inner edge of the staphyloma. The artery was avulsed and amputated. Oozing from the retinal cleft that had once enfolded the artery and microscopic bleeding from the amputation stump were observed. The vitreous hemorrhage obscured a view of the fundus more than 4 weeks after the surgery. After 8 weeks, postoperative visual acuity was improved; however, the superior nasal visual field was lost, and the patient was aware of the broken vessel as a floater in her vision.

Conclusions: Macular peeling is technically challenging, so meticulous attention must be paid to avoid any damage on vessels. The retina tissue was stretched in a staphyloma and vessels were bulged into the vitreous space especially at the inner edge of the staphyloma. High levels of TA dye here buried the texture of the retina. Excessive TA should be removed prior to macular peeling.

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.

COMPARATIVE ANALYSIS OF RETINAL REATTACHMENT SURGERY WITH OR WITHOUT INTERNAL LIMITING MEMBRANE PEELING TO PREVENT POSTOPERATIVE MACULAR PUCKER

PURPOSE

To determine whether internal limiting membrane (ILM) peeling during pars plana vitrectomy for rhegmatogenous retinal detachment reduces the incidence of epiretinal membrane (ERM) formation.

METHODS

In this retrospective study, preoperative, intraoperative, and postoperative data from all eyes undergoing pars plana vitrectomy for rhegmatogenous retinal detachment between January 2007 and December 2013 was analyzed. All cases with at least 1-year of follow-up were included. Data collection included vision, intraoperative complications, occurrence of ERM, and spectral domain optical coherence tomography characteristics. The OCTs were retrieved for all eyes and were graded by a single masked grader.

RESULTS

Out of 159 eyes recruited, ILM peeling was done in 78 eyes (49%). Overall occurrence of ERM was 20%. Seven eyes (9%) in ILM peeling group and 25 eyes in the non-ILM peeling group (31%) showed ERM (P = 0.001). Postoperative vision was significantly better in eyes that had ILM peeling (0.48 ± 0.4 logarithm of the minimum angle of resolution [20/63] vs. 0.77 ± 0.6 logarithm of the minimum angle of resolution [20/125], P = 0.003). In multivariable models adjusting for type of tamponade, ILM peeling reduced the likelihood of ERM formation by 75% (P = 0.01).

CONCLUSION

Internal limiting membrane peeling during pars plana vitrectomy for rhegmatogenous retinal detachment significantly reduces ERM formation in the postoperative period and is associated with better visual and anatomical outcomes.

TO PEEL OR NOT TO PEEL THE INTERNAL LIMITING MEMBRANE IN IDIOPATHIC EPIRETINAL MEMBRANES

BACKGROUND

Epiretinal membranes (ERMs) have been described for more than 150 years. Currently, they are a common indication for vitreoretinal surgery. Recently, there has been an increasing trend to peel the internal limiting membrane (ILM). Although ILM peeling has generally been accepted as a fundamental step in macular hole repair, its current role in ERM remains controversial.

METHODS

Literature review.

RESULTS

Proponents of ILM peeling argue that peeling of the ILM reduces the recurrence rate and facilitates a greater resolution of retinal folds. Opponents of ILM peeling show that the visual outcomes between eyes that undergo ILM peeling and those that do not have their ILM peeled are the same. Stripping of the ILM removes the Müller cell footplates, so it is reasonable to expect some Müller cell dysfunction. Adverse events such as eccentric paracentral macular holes, macular microscotomata, and retinal dimpling have been associated with ILM peeling.

CONCLUSION

Internal limiting membrane peeling does not improve the functional outcomes after ERM surgery. Internal limiting membrane peeling reduces ERM recurrences, but many recurrences are not clinically significant. It remains unclear what the long-term effects of ILM peeling are. We should err on the side of caution and avoid routine ILM peeling in primary idiopathic ERM cases and should reserve it for recurrent and high risk of recurrence cases.

[Idiopathic macular hole: history and status quo review]

The article reviews the literature on one of the topical problems of vitreoretinal surgery - idiopathic macular holes. The history, concept, classification and diagnostics, as well as surgical and alternative treatment methods of macular holes are explored.

Effect of internal limiting membrane peeling on the development of epiretinal membrane after pars plana vitrectomy for primary rhegmatogenous retinal detachment

PURPOSE

To investigate the difference in the occurrence of postoperative epiretinal membranes (ERMs) in vitrectomy for rhegmatogenous retinal detachment with and without peeling of the internal limiting membrane (ILM).

METHODS

The medical records of the 135 patients, who underwent vitrectomy for primary rhegmatogenous retinal detachment from November 2007 to August 2011, were analyzed retrospectively. Of the subjects, 70 patients underwent ILM peeling during the surgery and 65 did not. The best-corrected visual acuity, fundus photograph, and optical coherence tomography were collected 3, 6, and 12 months postoperatively. The relationship between ILM peeling and the preoperative findings of rhegmatogenous retinal detachment and development of a postoperative ERM was analyzed.

RESULTS

No ERM occurred in the ILM peeling group, whereas an ERM occurred in 14 of 65 patients who underwent vitrectomy without ILM peeling (21.5%). This difference was significant (P < 0.001). The occurrence of a postoperative ERM was not significantly correlated with other preoperative factors. In the macular-on group, the overall mean best-corrected visual acuity was better in the ILM peeling group and was significantly higher 12 months postoperatively (P = 0.03).

CONCLUSION

Internal limiting membrane peeling seems to prevent the occurrence of a postoperative ERM in patients with primary rhegmatogenous retinal detachment.

Effect of internal limiting membrane abrasion on retinal tissues in macular holes

PURPOSE

The purpose of this study was to identify the structural and histological effects of a Tano diamond-dusted membrane scraper (DDMS) on the retinal surface after internal limiting membrane (ILM) abrasion in macular hole surgery.

METHODS

Institutional experimental study was performed in 11 eyes. All eyes underwent ILM abrasion in the operating room with a DDMS for macular hole repair as an alternative to traditional ILM peeling. Three human donor eyes underwent an identical procedure in the laboratory. Retinal tissues were removed by ILM abrasion with a DDMS during vitrectomy for macular hole repair and retinal tissues remaining in human donor eyes. Main outcome measures were microscopic and immunohistological characteristics of instrument tip tissues and retinal structure after ILM abrasion.

RESULTS

The tips of the Tano DDMS showed evidence of cellular membranes and ILM removal. The retinas showed distinct areas of lamellar ILM removal without penetration of the retinal nerve fiber layer (RNFL).

CONCLUSIONS

Application of the Tano DDMS instrument is sufficient to remove membranes from the surface of the ILM and layers of the ILM without disruption of the underlying RNFL. Internal limiting membrane abrasion can be a useful and effective alternative to complete ILM removal for macular surgery.

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.

Force sensing micro-forceps for robot assisted retinal surgery

Membrane peeling is a standard vitreoretinal procedure, where the surgeon delaminates a very thin membrane from retina surface using surgical picks and forceps. This requires extremely delicate manipulation of the retinal tissue. Applying excessive forces during the surgery can cause serious complications leading to vision loss. For successful membrane peeling, most of the applied forces need to be very small, well below the human tactile sensation threshold. In this paper, we present a robotic system that combines a force sensing forceps tool and a cooperatively-controlled surgical robot. This combination allows us to measure the forces directly at the tool tip and use this information for limiting the applied forces on the retina. This may prevent many iatrogenic injuries and allow safer maneuvers during vitreoretinal procedures. We show that our system can successfully eliminate hand-tremor and excessive forces in membrane peeling experiments on the inner shell membrane of a chicken embryo.

Assessment of retinal function before and after idiopathic macular hole surgery

PURPOSE

To evaluate preoperative and postoperative retinal function in patients who underwent macular surgery for idiopathic macular hole.

DESIGN

Prospective, comparative, interventional case series.

METHODS

Thirty eyes of 30 patients with idiopathic macular hole were included in the study. Patients underwent pars plana vitrectomy and peeling of the internal limiting membrane (ILM). ILM visualization was improved in 15 patients by using triamcinolone acetonide and in the remaining 15 patients by using infracyanine green dye. Spectral-domain optical coherence tomography examination was performed to document macular hole closure. Retinal function was assessed preoperatively and postoperatively over a period of 12 months by best-corrected visual acuity (BCVA) measurement (ETDRS chart), MP-1 microperimetry, and focal electroretinogram recording (fERG). Focal electroretinograms were recorded in response to a sinusoidally modulated (41 Hz), uniform field presented to the macular (18 degrees) and foveal (2.25 degrees) region.

RESULTS

Macular hole closure was achieved in all patients in both groups. At 12 months, visual acuity improved in both groups (P < .001), and there were no statistically significant differences between groups. Mean macular sensitivity within the central 2 and 8 degrees increased in both groups, and there were no statistically significant differences between groups at any follow-up. In the triamcinolone acetonide group, 12 months after surgery the amplitude of the fERG's first harmonic (1F) increased both in the macular region (P < .001) and in the foveal region (P < .05). In the infracyanine green group, at 12 months the amplitude of the first harmonic (1F) decreased in both areas. The decrease was significant in the macular region (P < .05) and not significant in the foveal region (P = .095).

CONCLUSION

Vitrectomy and ILM peeling assisted with either triamcinolone acetonide or infracyanine green staining improves visual acuity and mean macular sensitivity at 12 months in patients affected by idiopathic macular hole. However, triamcinolone acetonide staining is associated with an increase of fERG's first harmonic amplitude in the foveal and macular region, whereas in the case of infracyanine green staining it seems to decrease after surgery. The reduction of the amplitude of fERG's first harmonic suggests that infracyanine green may have a late toxic effect on photoreceptor cells.

Outcomes of 23-gauge pars plana vitrectomy and internal limiting membrane peeling with brilliant blue in macular hole

Purpose:

The evaluation of anatomic and visual outcomes in macular hole cases treated with internal limiting membrane (ILM) peeling, brilliant blue (BB), and 23-gauge pars plana vitrectomy (PPV).

Materials and methods:

Fifty eyes of 48 patients who presented between July 2007 and December 2009 with the diagnosis of stage 2, 3, or 4 macular holes according to Gass Classification who had undergone PPV and ILM peeling were included in this study. Pre- and postoperative macular examinations were assessed with spectral-domain optical coherence tomography. 23 G sutureless PPV and ILM peeling with BB was performed on all patients.

Results:

The mean age of patients was 63.34 ± 9.6 years. Stage 2 macular hole was determined in 17 eyes (34%), stage 3 in 24 eyes (48%), and stage 4 in 9 eyes (18%). The mean follow-up time was 13.6 ± 1.09 months. Anatomic closure was detected in 46/50 eyes (92%), whereas, in four cases, macular hole persisted and a second operation was not required due to subretinal fluid drainage. At follow-up after 2 months, persistant macular hole was detected in one case and it was closed with reoperation. At 12 months, an increase in visual acuity in 41 eyes was observed, while it remained at the same level in six eyes. In three eyes visual acuity decreased. There was a postoperative statistically significant increase in visual acuity in stage 2 and 3 cases (P < 0.05), however, no increase in visual acuity in stage 4 cases was observed.

Conclusion:

PPV and ILM peeling in stage 2, 3, and 4 macular hole cases provide successful anatomic outcomes, however, in delayed cases, due to photoreceptor loss, it has no effect on functional recovery. BB, used for clarity of ILM, may be beneficial due to its low retinal toxicity.

Value of internal limiting membrane peeling in surgery for idiopathic macular hole and the correlation between function and retinal morphology

Idiopathic macular hole is characterized by a full thickness anatomic defect in the foveal retina leading to loss of central vision, metamorphopsia and a central scotoma. Classic macular hole surgery consists of vitrectomy, posterior vitreous cortex separation and intraocular gas tamponade, but during the past decade focus has especially been on internal limiting membrane (ILM) peeling as adjuvant therapy for increasing closure rates. With increasing use of ILM peeling and indocyanine green (ICG) staining, which is used for specific visualization of the ILM, concerns about the safety of the procedure have arisen. At present, it is not known whether ICG-assisted ILM peeling potentially reduces the functional outcome after macular hole surgery. The purpose of the present PhD thesis was to examine whether ICG-assisted ILM peeling offers surgical and functional benefit in macular hole surgery. We conducted a randomized clinical trial including 78 pseudophakic patients with idiopathic macular hole stages 2 and 3. Patients were randomly assigned to macular hole surgery consisting of (i) vitrectomy alone without instrumental retinal surface contact (non-peeling), (ii) vitrectomy plus 0.05% isotonic ICG-assisted ILM peeling or (iii) vitrectomy plus 0.15% trypan blue (TB)-assisted ILM peeling. Morphologic and functional outcomes were assessed 3, 6 and 12 months after surgery. The results show that surgery with ILM peeling, for both stages 2 and 3 macular holes, is associated with a significantly higher closure rate than surgery without ILM peeling (95% versus 45%). The overall functional results confirm that surgery for macular hole generally leads to favourable visual results, with two-thirds of eyes regaining reading vision (>or=20/40). Macular hole surgery can be considered a safe procedure with a low incidence of sight-threatening adverse events; the retinal detachment rate was 2.2%. Visual outcomes in eyes with primary hole closure were not significantly different between the intervention groups; however, for the stage 2 subgroup with primary macular hole closure, there was a trend towards a better mean visual acuity in the non-peeling group (78.2 letters) compared to the ICG-peeling group (70.9 letters), p = 0.06. Performing repeated macular hole surgery was associated with a significant reduction in functional outcome indicating that primary focus should be on closing the macular hole in one procedure. Morphological studies of closed macular holes with contrast-enhanced optical coherence tomography (OCT) found thinning and discontinuity of the central photoreceptor layer matrix that were highly specific for predicting the likelihood of an eye having regained reading vision 12 months after macular hole surgery. Additionally, healing after macular hole surgery appeared to begin with the contraction of the inner aspect of the retina, forming a roof over a subfoveal fluid-filled cavity, and to end with a gradual restoration of the anatomy in the outer layers of the retina at the junction of the photoreceptor inner and outer segments. We found the more intact this structure was on contrast-enhanced OCT 3 months after macular hole surgery, the better the visual acuity after 12 months, whereas late rather than early resolution of subfoveal fluid had no impact on final visual outcome. The use ILM peeling and intraoperative dyes did not have any functionally important effects on postoperative macular structure. Based on the above findings, we conclude that ILM peeling should be performed in all cases of full thickness macular hole surgery. The use of 0.05% intraoperative isotonic ICG with short exposure time appears to be a safe alternative in stage 3 macular hole surgery, whereas a slight reduction in functional potential not can be excluded when performing 0.05% isotonic ICG-assisted ILM peeling in stage 2 macular hole surgery.

Two cases of severe degeneration of the macula following vitrectomy with indocyanine green-assisted internal limiting membrane peeling for idiopathic macular hole

We describe three eyes of two cases of severe degeneration of the macula following vitrectomy with indocyanine green-assisted internal limiting membrane peeling for idiopathic macular hole. We need to remember the possibility of these complications and have to select the procedures that are safest to use for macular hole surgery.

Mechanisms of intravitreal toxicity of indocyanine green dye: implications for chromovitrectomy

PURPOSE

Indocyanine green (ICG) dye was shown to improve the visualization of preretinal tissues during chromovitrectomy. However, controversy arose regarding the safety of intravitreal ICG application, because worse functional outcomes and a higher incidence of retinal pigment epithelium (RPE) changes and visual field defects were reported. The mechanisms of ICG-related toxicity and their relevance for chromovitrectomy are reviewed.

METHODS

A literature search was performed from 1998 through 2005 for relevant information related to the mechanisms of intravitreal ICG toxicity. Animal and clinical data on intravitreal ICG-related toxicity were collected to clarify the mechanisms of the risk of intravitreal ICG injection.

RESULTS

Over 80 controversial in vitro, ex vivo, and in vivo animal investigations as well as clinical reports on intravitreal ICG staining were found in the literature. The main postulated mechanisms of intravitreal ICG-related toxicity were as follows: biochemical direct injury to the ganglion cells/neuroretinal cells, RPE cells, and superficial retinal vessels; apoptosis and gene expression alterations to either RPE cells or neuroretinal cells; osmolarity effect of ICG solution on the vitreoretinal interface; light-induced injury; and mechanical cleavage effect to the internal limiting membrane/inner retina. Whereas the exact mechanism of intravitreal ICG-related damage remains yet to be determined, most animal experiments proposed that ICG dye has a dose-dependent toxic effect on retinal tissue. This hypothesis was supported by clinical data, because better functional outcomes were obtained when low dye concentrations and short incubation times were reported.

CONCLUSIONS

Much evidence supports that ICG dye has a dose-dependent toxic effect on the retina. Therefore, the following recommendations to minimize toxic effects on the retina are proposed: dye injection in concentrations as low as possible; avoidance of repeated ICG injections onto bare retina; dye injection far from the macular hole to prevent direct dye contact with the RPE; short incubation time of ICG in the vitreous cavity to diminish the concentration in contact with the retinal tissue; and the light pipe kept far from the retina throughout the whole surgical procedure.

INDOCYANINE GREEN???ASSISTED INTERNAL LIMITING MEMBRANE PEELING FOR MACULAR HOLES

BACKGROUND

Indocyanine green (ICG) staining facilitates definitive internal limiting membrane (ILM) peeling during macular hole surgery (MHS), but might cause toxicity.

PURPOSE

To determine if ICG to assist in ILM peeling has an effect on anatomic or visual results in MHS with ILM peeling.

METHODS

Retrospective, comparative review including primary analysis of 173 cases undergoing MHS. Visual acuity >or=20/50, <or=20/200, three-line visual acuity improvement, and anatomic success rates were analyzed as endpoints.

RESULTS

The single operation hole closure rate was 87% with ICG versus 83% without ICG (P = 0.52). Postoperative median best-corrected visual acuity was 20/70 and 20/80 in the ICG and no ICG groups with median follow-up intervals of 8 and 9 months. The use of ICG was associated with a higher rate of <or=20/200, but ILM peeling and ICG use was not associated with better anatomic success, visual improvement, or >or=20/50 visual acuity.

CONCLUSIONS

ICG usage during macular hole surgery was not associated with worse visual outcomes, suggesting possible toxic effects reported are not clinically significant. If the ILM cannot be peeled effectively, ICG should be considered a safe option.

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.

Retinal tolerance to dyes

BACKGROUND

Dye solutions for intraoperative staining of epiretinal membranes and the internal limiting membrane improve the visualisation of these thin structures and facilitate their removal. In the present study the authors investigated the effects of indocyanine green 0.05%, trypan blue 0.15%, and patent blue 0.48% on bovine retinal function.

METHODS

Bovine retina preparations were perfused with a standard solution and the electroretinogram (ERG) was recorded repeatedly. After recording of stable ERG amplitudes the nutrient solution was substituted by one of the dye solutions. The duration of retinal exposure to a dye solution was varied between 10 seconds and 2 minutes. Thereupon, the preparation was reperfused with standard solution for at least 115 minutes. The percentage of b-wave reduction after exposition was calculated.

RESULTS

Reductions of the b-wave amplitude were found for each dye solution tested. The effects after application of patent blue and indocyanine green were completely reversible within the recovery time for an exposure period of 60 and 30 seconds, respectively. The application of trypan blue lead to a loss of the b-wave when the retina was exposed for 15 seconds or longer. This effect was only partly reversible within the recovery time.

CONCLUSION

The ERG showed toxic effects of trypan blue after a short period of retinal exposure. The intraocular application of trypan blue should be limited to selected cases. However, intraocular application of indocyanine green and patent blue in a sufficient concentration and taking account of a short period of retinal exposure seems possible.

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.

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.

Morphological damage in rabbit retina caused by subretinal injection of indocyanine green

PURPOSE

To investigate the effects of subretinal indocyanine green (ICG) on retinal morphology in rabbit eyes.

METHODS

Retinal bleb detachments were produced by injections of ICG at dosages of 25 mg/ml, 5 mg/ml, and 0.5 mg/ml or with an injection of balanced salt solution (BSS) into the subretinal space of albino rabbit eyes. Morphological change was assessed by light and transmission electron microscopy from the viewpoint of dose and time. Some sections were also probed with the TUNEL technique to detect apoptotic cells.

RESULTS

At 14 days after subretinal injection of BSS and 0.5 mg/ml ICG, the structure of the retina was well preserved. However, injections of 5 mg/ml or 25 mg/ml caused thinning of the retina, especially loss of the outer retinal layer. In eyes injected with 5 mg/ml ICG, the photoreceptors began disappearing within 3 days after the injection and over time showed the development of retinal atrophy. TUNEL-positive cells appeared abundantly in the photoreceptor layers 1 and 3 days after the injection of 5 mg/ml ICG. Transmission electron microscopy confirmed apoptosis in the photoreceptors.

CONCLUSION

These data indicate that subretinal ICG induces apparent morphological damage of the retina in a dose-dependent manner.