EPIRETINAL MEMBRANE IN EYES WITH VITREOMACULAR TRACTION

Intravitreal Dexamethasone Implant in Vitreoretinal Surgery: An Overview of the Literature

BACKGROUND

The sustained-release intravitreal 0.7 mg dexamethasone implant (DEX implant) (Ozurdex®, Allergan®, an AbbVie Company, North Chicago, Illinois, USA) is widely used to treat various inflammatory retinal disorders. Notably, its application is expanding in the field of vitreoretinal surgery.

METHODS

We conducted a comprehensive literature search across the Web of Science, PubMed, EMBASE, and ScienceDirect databases for articles related to Ozurdex and its applications in vitreoretinal disorders. Additionally, relevant studies were identified from the reference lists of retrieved articles. Our search was limited to studies written in English or those in other languages that provided an English abstract with sufficient information.

RESULTS

Multiple studies have demonstrated the efficacy and safety of the DEX implant across a broad spectrum of vitreoretinal and post-surgical conditions. Notably, the implant's unique pharmacokinetics remain largely unaffected by the vitrectomized status of the eye, ensuring consistent effectiveness in vitreoretinal surgery. Our research highlights the primary off-label applications of the DEX implant, which include epiretinal membrane (ERM), rhegmatogenous retinal detachment (RRD), post-surgical cystoid macular edema (PSCME), and refractory diabetic macular edema (DME).

CONCLUSION

This review highlights the increasing role of the DEX implant in vitreoretinal surgery, emphasizing its effectiveness and safety in various surgical and post-surgical settings, while also addressing associated complications.

Vitreomacular traction - a review

Vitreomacular traction (VMT) is characterised by abnormal adhesion of the posterior cortical vitreous with the macula causing distortion of the foveal contour and associated with symptoms of reduction in visual acuity and/or metamorphopsia. This review article explores the pathophysiology, clinical features, diagnostic and treatment options for VMT. Advances in imaging modalities such as optical coherence tomography (OCT) have revolutionized the understanding of the vitreoretinal interface abnormalities and helps in monitoring the disease progression. The natural history of VMT is variable and either there can be a spontaneous resolution or can present with cystoid oedema or can progress to epiretinal membrane (ERM) or macular hole. In the current manuscript, we perform a major review of the existing literature on VMT and adding the details about the current investigative modalities and surgical techniques.

Impact of phacoemulsification on posterior vitreous detachment formation in eyes with vitreomacular traction

Purpose

To investigate the impact of phacoemulsification on posterior vitreous detachment formation in eyes with vitreomacular traction (VMT) with or without macular holes.

Methods

A retrospective search of the medical records was conducted to identify patients with VMT who underwent cataract surgery at Mass Eye and Ear from 2016 to 2021. Patient demographics, ocular comorbidities, and clinical characteristics were extracted from the record, and optical coherence tomography images were assessed to confirm VMT and the presence of a lamellar or full-thickness macular hole (FMTH). Patients who underwent vitrectomy prior to cataract surgery were excluded.

Results

A total of 22 patients (15 women [68%]) met inclusion criteria (average age, 71 years). Fifteen eyes had an associated epiretinal membrane (63%), 7 had a lamellar hole (29%), and 8 had an FTMH (33%). Epiretinal membrane was present in 3 of 7 eyes with lamellar holes (43%) and 4 of 8 with a FTMH (50%). No eyes developed a complete posterior vitreous detachment following phacoemulsification. In 2 cases, there was progression of the macular hole stage following phacoemulsification. Ten eyes underwent subsequent pars plana vitrectomy (PPV). There was no statistically significant difference in visual acuity between eyes pre- and post-phacoemulsification; however, there was a statistically significant improvement in visual acuity pre- and post-PPV.

Conclusions

Unlike other studies, in this case series of 24 eyes with VMT or VMT with holes, no cases of full posterior vitreous detachment occurred following unremarkable phacoemulsification or YAG capsulotomy.

iERM: An Interpretable Deep Learning System to Classify Epiretinal Membrane for Different Optical Coherence Tomography Devices: A Multi-Center Analysis

Background: Epiretinal membranes (ERM) have been found to be common among individuals >50 years old. However, the severity grading assessment for ERM based on optical coherence tomography (OCT) images has remained a challenge due to lacking reliable and interpretable analysis methods. Thus, this study aimed to develop a two-stage deep learning (DL) system named iERM to provide accurate automatic grading of ERM for clinical practice. Methods: The iERM was trained based on human segmentation of key features to improve classification performance and simultaneously provide interpretability to the classification results. We developed and tested iERM using a total of 4547 OCT B-Scans of four different commercial OCT devices that were collected from nine international medical centers. Results: As per the results, the integrated network effectively improved the grading performance by 1−5.9% compared with the traditional classification DL model and achieved high accuracy scores of 82.9%, 87.0%, and 79.4% in the internal test dataset and two external test datasets, respectively. This is comparable to retinal specialists whose average accuracy scores are 87.8% and 79.4% in two external test datasets. Conclusion: This study proved to be a benchmark method to improve the performance and enhance the interpretability of the traditional DL model with the implementation of segmentation based on prior human knowledge. It may have the potential to provide precise guidance for ERM diagnosis and treatment.

Prevalence and predictive factors for posterior vitreous attachment in eyes undergoing epiretinal membrane surgery

BACKGROUND

To report the prevalence of posterior vitreous attachment (PVA) in patients with idiopathic epiretinal membrane (iERM) and to determine associated preoperative predictive factors.

METHODS

Retrospective observational case series of 408 eyes who underwent surgery for iERM without vitreomacular traction. The status of the posterior hyaloid was assessed intraoperatively. Predictive factors were analysed using univariate and multivariate logistic regression. We also evaluated the effect of PVA on the anatomical and functional outcomes of surgery.

RESULTS

Eighty-two (20.1%) eyes were found to have an undetached posterior hyaloid during vitrectomy. In multivariate analysis, axial length (AL) and lens status were strongly associated with the posterior vitreous status (p = 0.031 and p = 0.048). The odds of having a PVA decreased by a factor 0.81 per mm of AL (95% CI, 0.66-1.00). Phakic eyes had a 2.88-fold increased risk of exhibiting PVA compared to those with previous cataract extraction (95% CI, 1.10-7.52). The presence of PVA did not have any effect on postoperative anatomical and functional outcomes. In contrast, we found that eyes with shorter axial length, low preoperative visual acuity and disruption of the ellipsoid zone exhibited worse visual recovery (p = 0.006, p < 0.001 and p = 0.037).

CONCLUSION

PVA was observed in 20.1% of eyes undergoing vitrectomy for iERM. Shorter AL and phakic status were strong predictive factors of PVA in those eyes. However, the morphological features and the surgical prognosis of iERMs with PVA did not differ from those with posterior vitreous detachment.

Prevalence and Associations of Vitreomacular Traction: The Beijing Eye Study

Purpose

To explore the prevalence and associations of vitreous macular traction (VMT) in Chinese population.

Methods

A population-based cross-sectional study with 3468 individuals (mean age of 64.6 ± 9.8 years) based on Beijing Eye Study 2011. Participants underwent detailed ophthalmic examinations, including spectral domain optical coherence tomography (SD-OCT). VMT was defined as abnormal posterior vitreous detachment with anatomical deformation of the fovea, which may include pseudocyst, macular schisis, cystoid macular edema, and subretinal fluid.

Main Outcome Measure

Prevalence of VMT.

Results

A VMT was detected in 151 (2.3%) eyes (prevalence rate (mean ± SE): 2.3± 0.2%; 95% CI: 1.9%, 2.7%) of 80 (2.4%) subjects (prevalence rate: 2.4± 0.3%; 95% CI: 1.9%, 2.9%). Mean age of all subjects with VMT was 70.1± 8.7 years (median, 70.0 years; range, 50–90 years), mean refractive error was −0.22 ± 2.38D (median, 0.25 D; range, −15.00 to 5.25D). In multivariate analysis, prevalence of VMT was associated with elder age (P=0.001, OR 1.06), female gender (P = 0.036, OR 1.77), subfoveal retinal thickness (P = 0.005, OR 1.01), and subfoveal choroidal thickness (P = 0.026, OR 0.10).

Conclusion

In adult Chinese in Greater Beijing, the prevalence of VMT was 2.3% for eyes or 2.4% for subjects. While it was associated with elder age, female gender, thicker subfoveal retinal thickness and thinner subfoveal choroidal thickness.

SURGICAL OUTCOMES OF VITREOMACULAR TRACTION TREATED WITH FOVEAL-SPARING PEELING OF THE INTERNAL LIMITING MEMBRANE

PURPOSE

To compare sensitivity of the retina after complete internal limiting membrane (ILM) peeling versus foveal-sparing ILM peeling in vitrectomy for vitreomacular traction syndrome.

METHODS

This was a randomized, prospective, comparative study. Thirty-four eyes were randomized to undergo peeling with foveal sparing of the ILM (FS group) or complete peeling group. Foveal and perifoveal retinal sensitivity, visual acuity, and central macular thickness were the main outcome measures.

RESULTS

Parafoveal retinal sensitivity exhibited a significant improvement in both the FS and complete peeling groups (+2.43 ± 0.82 dB and +1.79 ± 0.86 dB, respectively; P = 0.037). Significant improvements were observed in both visual acuity and central macular thickness in both groups. No cases of epiretinal membrane recurrence were observed in the FS group.

CONCLUSION

Both the FS and complete peeling surgical techniques are safe and yielded good anatomical and functional results; however, a significant difference in favor of FS was found in relation to the best-corrected visual acuity and perifoveal retinal sensitivity. Preservation of the foveal ILM disc allowed the anatomical restoration of the foveal architecture in most vitreomacular traction syndrome cases without signs of stiffening or ILM fibrosis over a follow-up period of 1 year.

Clinical Update on Metamorphopsia: Epidemiology, Diagnosis and Imaging

Purpose: To discuss the pathophysiology of metamorphopsia, its characterisation using retinal imaging and methods of assessment of patient symptoms and visual function.Methods: A literature search of electronic databases was performedResults: Metamorphopsia has commonly been associated with vitreomacular interface disorders (such as epiretinal membrane) and has also regularly been noted in diseases of the retina and choroid, particularly age-related macular degeneration and central serous chorioretinopathy. Developments in optical coherence tomography retinal imaging have enabled improved imaging of the foveal microstructure and have led to the localisation of the pathophysiology of metamorphopsia within the retinal layers of the macula. Alteration of alignment of inner and outer retinal layers at various retinal loci has been identified using multimodal imaging in patients with metamorphopsia in a range of conditions. Although the Amsler Grid assessment of metamorphopsia is a useful clinical indicator, new emerging methods of metamorphopsia assessment with psychophysical tests such as M-CHARTS and preferential hyperacuity perimetry, have been developed.Conclusions: It appears that there is a complex relationship between visual acuity and metamorphopsia symptoms that vary between retinal conditions. Although metamorphopsia has traditionally been challenging to measure in the clinic, advances in technology promise more robust, easy-to-use tests. It is possible that home assessment of metamorphopsia, particularly in conditions such as age-related macular degeneration, may help to guide the need for further clinic evaluation and consideration of treatment.

OCT-A in the Management of Vitreoretinal Diseases and Surgery

ABSTRACT

Optical coherence tomography angiography is a relatively new noninvasive technique that is changing our approach in the management of several retinal diseases such as neovascular age-related macular degeneration, occlusive retinal diseases, or diabetic retinopathy, but it could also be useful in nonprimary vascular retinal pathologies such as vitreoretinal interface surgical disorders.In idiopathic vitreoretinal interface disorders and surgical retinal diseases, the study of vascular involvement, not commonly assessed by invasive methods, could be useful to reveal specific vascular abnormalities. Such information may be useful for a more detailed phenotyping of each clinical picture before and after surgical treatment, providing potential new prognostic biomarkers.The review discusses the current and potential utility of optical coherence tomography angiography to study vitreoretinal pathologies of surgical interest.

Transplantation Site Affects the Outcomes of Adipose-Derived Stem Cell-Based Therapy for Retinal Degeneration

Adipose-derived stem cells (ASCs) have shown a strong protective effect on retinal degenerative diseases (RDD) after being transplanted into the subretinal space in an animal model. Recently, several clinical trials have been conducted to treat RDD with intravitreal transplantation of stem cells, including ASCs. However, the outcomes of the clinical trials were not satisfactory. To investigate if the transplantation site alters the outcome of stem cell-based therapy for RDD, we isolated rat ASCs (rASCs) and labeled them with green fluorescent protein. Autologous rASCs were grafted into the vitreous chamber or subretinal space in a rat RDD model induced by sodium iodate (SI). The electric response was recorded by ERG. The anatomic structure of the retina was observed in cryosections of rat eyes at posttransplantation weeks 1, 2, and 4. Neural retina apoptosis and epiretinal membrane- (ERM-) like structure formation were investigated by immunostaining. The intravitreal transplantation of rASCs resulted in an extinguished electric response, although the rosette formation and apoptosis of neural retina were reduced. However, the rASCs that grafted in the subretinal space protected the retina from the damage caused by SI, including a partial recovering of the electric response and a reduction in rosette formation. Intravitreally grafted rASCs formed a membrane, resulting in retina folding at the injection site. Müller cells, retinal pigment epithelial cells, and microglial cells migrated from the retina to the rASC-formed membrane and subsequently formed an ERM-like structure. Furthermore, vitreous fluid promoted rASC migration, and rASC-conditioned medium enhanced Müller cell migration as indicated by in vitro studies. These data suggested that the vitreous chamber is not a good transplantation site for ASC-based therapy for RDD and that a deliberate decision should be made before transplantation of stem cells into the vitreous chamber to treat RDD in clinical trials.