Ultrastructure of the membrana limitans interna after dye-assisted membrane peeling

FUNCTIONAL AND STRUCTURAL OUTCOMES AFTER FOVEA-SPARING INTERNAL LIMITING MEMBRANE PEELING FOR MYOPIC MACULAR RETINOSCHISIS BY MICROPERIMETRY

PURPOSE

To determine the morphological and physiological outcomes and safety of vitrectomy with fovea-sparing internal limiting membrane peeling for myopic macular retinoschisis (MRS).

METHODS

Highly myopic eyes (refractive error greater than -8.0 diopters or an axial length longer than 26.5 mm) with MRS that underwent vitrectomy with fovea-sparing internal limiting membrane peeling were analyzed retrospectively. The best-corrected visual acuity, retinal morphology, and the central and paracentral retinal sensitivities at 2°/6° by microperimetry were evaluated before and after the surgery. Postoperative microscotomas were also determined.

RESULTS

Thirty-three eyes with MRS; 16 eyes with and 17 eyes without a foveal retinal detachment, were studied. All 33 eyes had an improvement of MRS and foveal retinal detachment partially or completely after surgery, and none developed a full thickness macular hole. The postoperative best-corrected visual acuity, the central retinal sensitivity, and the retinal sensitivity at 2° were significantly better than the preoperative values. Sixteen eyes developed postoperative microscotomas at paracentral 2° and/or 6°.

CONCLUSION

The results showed that vitrectomy with fovea-sparing internal limiting membrane peeling is an effective and safe method to treat an MRS regardless of the presence of a foveal retinal detachment. However, careful follow-up should be performed to detect postoperative microscotomas.

Predicting Progression of Untreated Macular Pucker Using Retinal Surface En Face Optical Coherence Tomography

PURPOSE

To review visual outcomes in untreated premacular membrane (PMM) with macular pucker (MP) and evaluate novel predictors of progression.

METHODS

In this retrospective observation study, we included 342 eyes with untreated PMM with MP between 2012 and 2015. PMMs were characterized by spectral-domain optical coherence tomography (SD-OCT) imaging based on foveal morphologies, number of retinal contraction centers, central subfield thickness (CST), inner segment ellipsoid band integrity, and photoreceptor deformation index. Additionally, the thickened retina portion was identified by en face OCT and processed digitally to calculate its area. Parameters were retrospectively analyzed using multiple regression analyses to identify associations with change in visual acuity (VA) between initial to final follow-up visit.

RESULTS

In 468 eyes with untreated PMM, VA and CST did not change significantly during a mean observation period of 448 days (p = 0.52 and 0.35, respectively). Specifically, VA improved or stayed the same in 80% and worsened by 2 lines or more in 20% of eyes. The only consistent predictor of PMM progression was area of retinal thickening: for every 1 mm2 of retinal thickening at baseline, the odds of having worsened vision at follow-up increased by 6% (OR 1.0606, 95% CI 1.0031-1.1214, p = 0.0387).

CONCLUSIONS

The majority of eyes with PMM and good visual function at baseline remain stable or spontaneously improve in VA and macular thickness. Area of retinal thickening as evaluated by en face OCT may be a novel predictor of vision loss in untreated PMM with MP.

Infracyanine Green vs. Brilliant Blue G in Inverted Flap Surgery for Large Macular Holes: A Long-Term Swept-Source OCT Analysis

Background and Objectives: To compare the long-term toxicity of infracyanine green (IFCG) to brilliant blue G (BBG) in inverted internal limiting membrane flap surgery (I-ILMFS) for large, full-thickness macular holes (FTMHs). Materials and Methods: Prospective randomized study including 39 eyes with ≥ 400 µm idiopathic FTMH who underwent I-ILMFS with either IFCG or BBG. Postoperative 6- and 12-month corrected distance visual acuity (CDVA), closure rate, and swept-source optical coherence tomography parameters, including ellipsoid zone (EZ) and external limiting membrane (ELM) mean defect length, central foveal thicknesses (CFT), parafoveal macular thickness (MT), ganglion cells and inner plexiform layer (GCL++) thickness, and peripapillary nerve fiber layer (pRNFL) thickness, were compared. Results: Nineteen eyes were included in the IFCG group and 20 eyes in the BBG group. In all cases a FTMH closure was found. CDVA improved at 6 and 12 months in both groups (p < 0.0005); the increase at 12 months was greater in the BBG group (p = 0.036). EZ and ELM defects did not differ between groups at either follow-up time. CFT at 12 months was greater in the BBG group (p = 0.041). A 12-months compared to 6-months MT decrease was present in both groups (p < 0.01). The GCL++ superior inner sector was thicker in the BBG group at 12 months (p = 0.036), as were the superior outer sector (p = 0.039 and p = 0.027 at 6 and 12 months, respectively) and inferior outer sector (p = 0.011 and p = 0.009 at 6 and 12 months, respectively). Conclusion: In our study BBG in I-ILMFS exhibits better long-term CDVA and retinal thickness than does IFCG, suggesting a lesser toxicity from BBG. These findings support the use of BBG over IFCG in I-ILMFS.

Pharmacological Adjuncts to Vitrectomy Surgery

Pharmacological adjuncts to vitrectomy surgery are useful tools to better deal with surgery. Their introduction has enriched the therapeutic choice before, during and after operations. Although several classifications could be made to frame adjuncts to vitrectomy, we preferred to divide the pharmacological adjuncts to vitrectomy surgery for therapeutic use in the pre-operatory procedure (neo-adjuvant), for intraoperative use and for post-operatory practice (adjuvant). This type of classification allowed us to explore all the adjuncts based on the timing of their use. The actual interest in vitrectomy surgery is giving rise to considerable interest in new molecules with and without the pharmacological effect that will soon be available for the aid of vitreoretinal surgery.

Incidence and prevalence of vitreomacular traction with and without macular hole in Germany

PURPOSE

Symptomatic vitreomacular adhesion (sVMA) comprises vitreomacular traction (VMT) and stage 1 and 2 full-thickness macular holes (MHs) associated with vitreomacular adhesion (VMA). We aimed to estimate the incidence and prevalence of sVMA in Germany.

MATERIALS AND METHODS

A systematic literature review was conducted to identify the incidence and prevalence of sVMA based on international epidemiologic studies, weighted for study size and then averaged across eligible studies. A second systematic review aimed to estimate the proportion of vitrectomy undertaken for sVMA in Germany. This was combined with the reported number of vitrectomies in Germany in 2016 to estimate the number of patients undergoing vitrectomy for sVMA.

RESULTS

The prevalence of sVMA is 1,365 per 100,000 population, with an incidence of 6.96 per 100,000 per year. For Germany, this translates to 1,119,300 cases, with 5,700 new cases reported annually. Analyzing the national hospital statistics, ~2,300 patients undergo vitrectomy due to sVMA in Germany each year, of which about 1,700 patients have VMT.

CONCLUSION

Incidence figures, driven by patients presenting to clinic, are much lower than expected based on population-based studies, suggesting that many patients with sVMA exist outside of the clinic system.

Evaluation of TGF-Beta 2 and VEGFα Gene Expression Levels in Epiretinal Membranes and Internal Limiting Membranes in the Course of Retinal Detachments, Proliferative Diabetic Retinopathy, Macular Holes, and Idiopathic Epiretinal Membranes

Purpose

To evaluate the expression profiles of the VEGFα and TGFβ in the ERMs and ILMs in retinal disorders.

Methods

In this nonrandomized prospective study, 75 patients (34 females and 41 males) referred to pars plana vitrectomy (PPV) due to different retinal diseases were enrolled to the study. The samples of ERMs and ILMs collected during PPV were immediately put in TRIzol® Reagent (Life Technologies, USA) and stored at −70°C until RNA extraction. Gene expression analysis was done with TaqMan® Gene Expression Assays (Applied Biosystems, USA) following the manufacturer's instructions.

Results

The gene expression levels of VEGFα as well as of TGFβ2 were significantly higher in ERMs than in ILMs in all studied groups. The level of TGFβ2 expression exhibits a significantly lower values in iERMs as compared with the RRD group (p = 0.043). There were differences in TGFβ2 expression in ILM in groups studied: DR versus RRD, p = 0.003; DR versus iERM, p = 0,047; and iERM versus RRD, p = 0.004.

Conclusions

Our results revealed that factors associated with angiogenesis and wound healing processes in eyes with RRD, PDR, iERM, and MH were more upregulated in ERMs than in ILMs. This may indicate that ILM is not responsible for reproliferation and its peeling should be avoided in routine PPV.

Photochemical degradation of trypan blue

Purpose

To investigate the photochemical degradation of trypan blue (TB) and to identify decomposition products.

Methods

Defined solution samples of TB and a mixture with lutein/zeaxanthin were exposed to blue light. Thermal degradation processes were ruled out using controls not subjected to irradiation. All samples were analyzed using optical microscopy, UV/Vis spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and nuclear magnetic resonance (NMR) spectrometry. Degradation kinetics were determined based on changes in absorbance; intermediates were identified by analyzing mass differences of characteristic fragment ion peaks within the fragmentation patterns, and assignments were verified by NMR.

Results

TB demonstrated a photochemical degradation, which can be triggered by lutein/zeaxanthin. Intermediates vary depending on the presence of lutein/zeaxanthin. The self-sensitized photodegradation of TB occurs under generation of dimethyl sulfate and presumed formation of phenol. In contrast, within the presence of lutein/zeaxanthin the decomposition of TB indicates the formation of methoxyamine and sulfonyl arin. Thermal degradation processes were not observed.

Conclusions

TB demonstrated a photodegradation that may be triggered by lutein/zeaxanthin and results in the formation of cytotoxic decomposition products. Our findings contribute to understand degradation mechanisms of TB and may elucidate previous clinical and experimental observations of cellular toxicity after TB application.

Diagnostic Electron Microscopy of Retina

The electron microscopy techniques were used in various fields as an analytical technique under in vitro conditions, which provides the sufficient resolution for better visualization and interpretation. This review gives a brief overview of the analytical application of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques and critical findings in different retinal pathologies. This review article aims to improvise understanding of retinal microstructures for clinicians which will help to improve the interpretation of the current advanced imaging techniques.

LONG-TERM RETROSPECTIVE ANALYSIS OF VISUAL ACUITY AND OPTICAL COHERENCE TOPOGRAPHIC CHANGES AFTER SINGLE VERSUS DOUBLE PEELING DURING VITRECTOMY FOR MACULAR EPIRETINAL MEMBRANES

PURPOSE

To determine the long-term effect of internal limiting membrane with associated epiretinal membrane (ERM) peeling versus single peeling alone in terms of best-corrected visual acuity and anatomical outcomes on spectral-domain optical coherence tomography.

METHODS

This retrospective comparative cohort study of patients who had follow-up of >1 year and underwent surgery for ERM by a single surgeon (S.C.) from January 1, 2008 to December 31, 2012 compared cases in which the internal limiting membrane was stained with brilliant blue G to facilitate double peeling (n = 42) and single peeling (n = 43) of the ERM alone for up to 3 years of follow-up. For continuous variables, an independent two-tailed t-test was performed. For binary variables, the Fisher's exact test was performed. Statistical significance was defined as P < 0.05.

RESULTS

Eighty-five of 142 patients fit the inclusion criteria. At the last follow-up, the single-peeling group were more likely to have ERM remaining in the central fovea postoperatively (P = 0.0020, becoming significant by postoperative Year 1, P = 0.022) and less likely to develop inner retinal dimpling (P = 0.000, becoming significant by postoperative Month 3, P = 0.015). At 3 years, central foveal thickness had decreased in the single-peeling group by -136.9 µm and by -84.1 μm in the double-peeling group, which was not significantly different (P = 0.08). Mean best-corrected visual acuity improved in both the groups at all time points. There was no statistically significant difference between the 2 groups at 3 years (P = 0.44; single-peeling group, 0.32 ± 0.42, Snellen 20/42; double-peeling group, 0.23 ± 0.27, Snellen 20/34).

CONCLUSION

Brilliant blue G-assisted internal limiting membrane peeling for ERM results in a more thorough removal of residual ERM around the paracentral fovea. However, there is no difference in long-term best-corrected visual acuity at 3 years and a greater likelihood of inner retinal dimpling.

Characteristics of the retinal surface after internal limiting membrane peeling in highly myopic eyes

PURPOSE

To document the characteristics of the retinal surface using en face optical coherence tomography (OCT) after internal limiting membrane (ILM) peeling during pars plana vitrectomy (PPV) for myopic macular diseases.

DESIGN

Retrospective, interventional case series.

METHODS

We examined 20 eyes of 20 patients with high myopia who underwent PPV with ILM peeling. The patients were followed for at least 6 months postoperatively, and OCT images were examined using spectral-domain OCT. To assess the incidence and patterns of the retinal dimple sign, we reconstructed en face OCT images and quantified the number of dimples during the follow-up period.

RESULTS

We identified 3 retinal dimple signs (ie, foveal-centered pattern, linear pattern, and paravascular pattern). The total numbers of retinal dimples at baseline and 1, 3, and 6 months postoperatively were 0, 31.8 ± 23.7, 47.95 ± 29.5, and 54.6 ± 30.7, respectively. There were significantly more dimples temporal to the macula compared to the other 3 quadrants at 1, 3, and 6 months postoperatively (P = .025, P = .0021, and P = .0060, respectively). However, the retinal sensitivities assessed by microperimetry were not correlated with the number of dimples.

CONCLUSION

Development of the retinal dimple sign after PPV and ILM peeling in highly myopic eyes was seen in all cases on en face OCT images. Although retinal dimples are benign, care should be taken after ILM peeling in highly myopic eyes.

"Dissociated optic nerve fiber layer appearance" after internal limiting membrane removal is inner retinal dimpling

PURPOSE

To examine volume-rendered spectral-domain optical coherence tomography images in patients who had undergone vitrectomy, many of whom had internal limiting membrane removal to investigate a condition termed "dissociated optic nerve fiber layer appearance."

METHODS

Patients who had undergone vitrectomy for either macular hole or epiretinal membrane were evaluated. Spectral-domain optical coherence tomography B-scan images were acquired with the use of eye tracking at an interval of either 30 μm or 60 μm. These were registered and exported to a volume-rendering program, and the resultant volume-rendered images were evaluated. The images were graded for the presence of inner retinal abnormalities, and correlates were made to corresponding alterations seen in fundus photographs and B-scan spectral-domain optical coherence tomography images.

RESULTS

There were 25 eyes of 24 patients with a mean age of 72.4 (± 7.3) years, 15 of whom were women. The primary preoperative diagnosis was macular hole in 10 eyes (40%) and epiretinal membrane in 15 eyes (60%). As part of the surgery, 18 eyes (72%) had planned peeling of the internal limiting membrane. Volume rendering showed that 13 eyes had pitting or dimples of the inner retinal surface that seemed to follow the course of the nerve fiber layer in the region of the macula. The inner retinal dimples occurred only in eyes that had internal limiting membrane peeling. Correlation of the volume-rendered images with B-scan spectral-domain optical coherence tomography showed focal areas of thinning of the ganglion cell layer with decreased reflectivity from the nerve fiber layer in the areas of the dimples.

CONCLUSION

A high proportion of eyes with internal limiting membrane peeling develop inner retinal dimples that course along the path of the nerve fiber layer. The dimples seem to be the result of an interplay between trauma and healing processes constrained by nerve fiber layer and do not appear to be because of dissociation of optic nerve fibers. The true nature of the abnormalities induced should be investigated to evaluate the long-term risks and benefits of routine internal limiting membrane peeling.

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

Background

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

Methods and Findings

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

Conclusions

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