Plasmin enzyme-assisted vitreoretinal surgery in congenital X-linked retinoschisis: surgical techniques based on a new classification system. Retina. 2007;27:1079-1085. [PMID: 18040249 DOI: 10.1097/iae.0b013e31806196d0]

Invivo generated autologous plasmin enzyme assisted vitrectomy, partial circumferential-oral retinotomy, silicone oil injection in patients with chronic retinal detachment without posterior vitreous detachment

PURPOSE

To report the results of invivo generated autologous plasmin enzyme(IVAP) assisted vitrectomy, partial circumferential-oral retinotomy and silicone oil injection for surgical treatment of patients with chronic retinal detachment without posterior vitreous detachment(PVD).

METHODS

Study was performed in retrospective, comparative manner. A total of 16 consecutive eyes with chronic retinal detachment who had intravitreal injection of 50 µgr of t-PA and 0.1 ml of autologous whole blood, 3 days before surgery, underwent lens extraction with phacoemulsification, IVAP assisted vitrectomy, partial circumferential-oral retinotomy, and silicone oil injection(Study Group) were compared to a similar group of 15 eyes who had undergone vitrectomy, with or without lens extraction and silicone oil injection(Control Group) for the treatment of chronic retinal detachment. Primary outcome measures were initial retinal reattachment and number of operations at postoperative 6 months.

RESULTS

Mean age of 16 patients of whom 7 were female, was 39.31 ± 17.76 years in study group and 15 patients of whom 4 were female, was 35.40 ± 11.92 years (p = 0.607). Mean follow-up time was 10.68 ± 7.15 months in study group and 29.13 ± 18.83 months in control group (p = 0.001). Initial retinal reattachment was achieved in 87.50% (14 out of 16 patients) in the study group, whereas it was 46.66% (7 out of 15 patients) in the control group (p = 0.017). The mean number of operations for reattachment in the study group was 1.12 ± 0.34, whereas it was 1.46 ± 0.51 in the control group (p = 0.039) at postoperative 6 months While the preoperative LogMAR visual acuity was 1.25 ± 0.64, it was 0.53 ± 0.37 at postoperative 6 months in study group (p = 0.001). Conversely, in the control group, the preoperative LogMAR visual acuity was 1.22 ± 0.33, it was 1.20 ± 0.89 at postoperative 6 months (p = 0.780). At postoperative 6 months,, epiretinal membrane developed in 2 eyes of the study group, 1 eye in the control group, and phthisis bulbi occurred in 1 eye of control group.

CONCLUSION

IVAP assisted vitrectomy, partial circumferential-oral retinotomy and silicone oil injection is effective and safe for the surgical treatment of chronic retinal detachment without PVD.

A Literary Pediatric Retina Fellowship With Michael T. Trese, MD

Michael T. Trese, MD (1946-2022), a vitreoretinal surgeon, made significant contributions to the field of retina. Although most known for his work in pediatric retina surgery, he was a pioneer in areas such as medical retina, translational research, and telemedicine. This article reviews his major contributions to spread his knowledge more widely to vitreoretinal trainees and specialists. We discuss six areas where Trese made a lasting impact: lens-sparing vitrectomy, familial exudative vitreoretinopathy, congenital X-linked retinoschisis, autologous plasmin enzyme, regenerative medicine, and telemedicine. [Ophthalmic Surg Lasers Imaging Retina 2023;54:701-712.].

Retinal Detachments in Pediatric Patients With X-Linked Retinoschisis: Characteristics and Surgical Outcomes

BACKGROUND AND OBJECTIVE

Retinal detachments (RDs) are a complication of X-linked retinoschisis (XLRS) with a poor prognosis. This study aims to report outcomes of XLRS-RD repair in pediatric patients.

MATERIALS AND METHODS

The study is a retrospective analysis of pediatric patients undergoing vitreoretinal surgery for XLRS-RDs from 2000 to 2022.

RESULTS

Nine patients (11 eyes) met inclusion criteria. All patients were boys, with a mean age of 8 years. Most RDs arose inferiorly (64%). Seven (64%) detachments were macula-involving. Seven (64%) detachments were repaired with combined scleral buckling and vitrectomy, two (18%) detachments were repaired with vitrectomy alone, one (9%) detachment underwent a primary scleral buckling procedure, and one (9%) asymptomatic detachment with a pigment demarcation line was observed. Silicone oil was used in eight of nine (89%) eyes undergoing vitrectomy. Final visual acuity was 20/200 or better in eight (73%) eyes. One eye that underwent surgical intervention remained unattached at follow-up.

CONCLUSION

Surgical repair in patients with XLRSRDs was associated with successful reattachment, although visual prognosis varied. [Ophthalmic Surg Lasers Imaging Retina 2023;54:574-579.].

A novel recombinant human microplasminogen induced complete posterior vitreous detachment without morphological change of retina in juvenile rabbits

Vitreomacular traction syndrome results from persistent vitreoretinal adhesions in the setting of partial posterior vitreous detachment (PVD). Vitrectomy and reattachment of retina is an effective therapeutic approach. The adhesion between vitreous cortex and internal limiting membrane (ILM) of the retina is stronger in youth, which brings difficulties to induce PVD in vitrectomy. Several clinical investigations demonstrated that intravitreous injection of plasmin before vitrectomy could reduce the risk of detachment. In our study, a novel recombinant human microplasminogen (rhμPlg) was expressed by Pichia pastoris. Molecular docking showed that the binding of rhμPlg with tissue plasminogen activator (t-PA) was similar to plasminogen, suggesting rh μPlg could be activated by t-PA to generate microplasmin (μPlm). Moreover, rhμPlg had higher catalytic activity than plasminogen in amidolytic assays. Complete PVD was found at vitreous posterior pole of 125 μg rhμPlg-treated eyes without morphological change of retina in juvenile rabbits via intraocular injection. Our results demonstrate that rhμPlg has a potential value in the treatment of vitreoretinopathy.

Typical and atypical clinical presentations of X-Linked retinoschisis: A case series and literature review

X-linked retinoschisis (XLRS) is an X-linked inherited retinal dystrophy characterized by mild-to-severe visual impairment, splitting of the retinal layers, and a reduction in the dark-adapted b-wave amplitude on the electroretinogram. Typical clinical features include macular and peripheral schisis. Relatively common features reported include rhegmatogenous or tractional retinal detachment, vitreous hemorrhage, retinal pigment epithelial changes, vitreous veils, and various retinal vascular abnormalities with or without exudation. Macular hole and macular folds are atypical presentations of XLRS, along with several other rare findings. Here, we report 4 cases of XLRS with atypical clinical presentations and review the literature on XLRS, with a focus on the variable clinical features of this condition.

EFFICACY OF INNER WALL RETINECTOMY FOR BULLOUS SCHISIS CAVITY HANGING OVER OR THREATENING THE MACULA IN PATIENTS WITH CONGENITAL X-LINKED RETINOSCHISIS

PURPOSE

To present the clinical characteristics, surgical outcomes, and surgical complications of patients with congenital X-linked retinoschisis who underwent vitrectomy for bullous schisis cavity hanging over or threatening the macula.

METHODS

Nine patients with congenital X-linked retinoschisis (12 eyes) who underwent vitrectomy at three tertiary hospitals and completed ≥3 years of postoperative follow-up were retrospectively investigated. Data were collected from patients' charts, including age at vitrectomy, surgical procedures, and postoperative complications.

RESULTS

The age at vitrectomy ranged 4 months to 103 months (median: 14 months). Inner wall retinectomy was performed during the initial vitrectomy in eight eyes. Among the eight eyes that initially underwent inner wall retinectomy, one (12.5%) required subsequent retinal surgery for postoperative complication. Furthermore, four eyes did not undergo initial inner wall retinectomy but required subsequent retinal surgeries for postoperative complications. Three of five eyes (60.0%) treated with silicone oil tamponade and two of seven eyes (28.6%) that were not treated with silicone oil tamponade during the initial vitrectomy required subsequent retinal surgeries for postoperative complications. All eyes maintained a clear central visual axis at the last examination.

CONCLUSION

Inner wall retinectomy seems beneficial in achieving a clear visual axis in eyes with bullous schisis cavity hanging over or threatening the macula in patients with congenital X-linked retinoschisis.

Untangling the Extracellular Matrix of Idiopathic Epiretinal Membrane: A Path Winding among Structure, Interactomics and Translational Medicine

Idiopathic epiretinal membranes (iERMs) are fibrocellular sheets of tissue that develop at the vitreoretinal interface. The iERMs consist of cells and an extracellular matrix (ECM) formed by a complex array of structural proteins and a large number of proteins that regulate cell–matrix interaction, matrix deposition and remodelling. Many components of the ECM tend to produce a layered pattern that can influence the tractional properties of the membranes. We applied a bioinformatics approach on a list of proteins previously identified with an MS-based proteomic analysis on samples of iERM to report the interactome of some key proteins. The performed pathway analysis highlights interactions occurring among ECM molecules, their cell receptors and intra- or extracellular proteins that may play a role in matrix biology in this special context. In particular, integrin β1, cathepsin B, epidermal growth factor receptor, protein-glutamine gamma-glutamyltransferase 2 and prolow-density lipoprotein receptor-related protein 1 are key hubs in the outlined protein–protein cross-talks. A section on the biomarkers that can be found in the vitreous humor of patients affected by iERM and that can modulate matrix deposition is also presented. Finally, translational medicine in iERM treatment has been summed up taking stock of the techniques that have been proposed for pharmacologic vitreolysis.

In vivo generated autologous plasmin assisted vitrectomy in young patients

BACKGROUND

Autologous plasmin enzyme facilitates the induction of posterior vitreous detachment(PVD) during vitrectomy in young patients. We proposed the concept of in-vivo generated plasmin which is based on the injection of tissue plasminogen activator(t-PA) and autologous whole blood(AWB) into the vitreous cavity. The purpose of this pilot study is to report the efficacy of preoperative simultaneous intravitreal injection of(t-PA) and autologous whole blood in facilitating the intraoperative induction of PVD in young patients with various vitreoretinal pathologies.

METHODS

Seventeen eyes of 16 young patients with various vitreoretinal pathologies requiring vitrectomy, who received simultaneous intravitreal injection of 0.1 ml of AWB and 25 µg of t-PA, 3 days prior to surgery were retrospectively reviewed. Outcome measures were the number of attempts required to achieve successful intraoperative separation of the posterior hyaloid; the postoperative visual acuity; and intraoperative and postoperative complications.

RESULTS

The mean age of the patients was 23.87 ± 10.09 years, ranging from 10 to 39 years. Eight of 16 patients were men. The mean follow-up time was 19.35 ± 5.04 months, ranging from 12 to 26 months. Surgical indications for vitrectomy were chronic retinal detachment (n = 7), traumatic retinal detachment without proliferative vitreoretinopathy(n = 3), traumatic macular hole(n = 1), secondary vasoproliferative tumor(n = 4) and optic pit maculopathy(n = 2). Patients with retinal detachment complicated with PVR and those who were older than 40 years of age were excluded from the study. Separation of the Weiss ring from the optic nerve head was achieved intraoperatively in all cases, with a mean number of 2.86 ± 1.4 attempts. While the mean preoperative LogMAR visual acuity was 1.38 ± 0.59, ranging from 2.40 to 0.50, it was a mean of 0.51 ± 0.29, ranging from 1.00 to 0.10 at final postoperative exam(p < 0.001; paired samples t-test). No preoperative or intraoperative complications were noted.

CONCLUSION

Preoperative simultaneous intravitreal injection of 25 µg t-PA with 0.1 ml of AWB facilitates the intraoperative induction of posterior vitreous detachment in young patients.

Identification of Interphotoreceptor retinoid-binding protein in the Schisis cavity fluid of a patient with congenital X-linked Retinoschisis

Background

This case report describes the surgical outcome in a patient with congenital X-linked retinoschisis (CXLRS) and the results of proteomic analysis of surgically extracted samples from both vitreous and intraschisis cavities by mass spectrometry.

Case presentation

A 3-month-old boy presented with extensive retinoschisis involving macula and retinal periphery in both eyes. Genetic analysis confirmed retinoschisin 1 mutation (c.554C > T), and an electroretinogram showed significant reduction of b-wave and decreased cone and rod responses, which led to a diagnosis of CXLRS. By performing pars plana vitrectomy, including inner wall retinectomy, clear visual axes with stable retinal conditions and functional vision in both eyes were obtained during the 4 years of follow-up. Proteomic analysis of surgically retrieved fluid from the intraschisis cavity revealed a higher expression of interphotoreceptor retinoid-binding protein (IRBP) than that from the vitreous humor. However, both samples showed equal levels of albumin, transferrin, and pigment epithelium-derived factor.

Conclusions

Cellular adhesive imperfection in CXLRS may cause IRBP diffusion from the interphotoreceptor matrix, resulting in the strong expression of IRBP in the intraschisis cavity. An impaired retinoid cycle caused by an absence of IRBP in the retina may potentially underlie the pathology of CXLRS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-02234-5.

Of men and mice: Human X-linked retinoschisis and fidelity in mouse modeling

X-linked Retinoschisis (XLRS) is an early-onset transretinal dystrophy, often with a prominent macular component, that affects males and generally spares heterozygous females because of X-linked recessive inheritance. It results from loss-of-function RS1 gene mutations on the X-chromosome. XLRS causes bilateral reduced acuities from young age, and on clinical exam and by ocular coherence tomography (OCT) the neurosensory retina shows foveo-macular cystic schisis cavities in the outer plexiform (OPL) and inner nuclear layers (INL). XLRS manifests between infancy and school-age with variable phenotypic presentation and without reliable genotype-phenotype correlations. INL disorganization disrupts synaptic signal transmission from photoreceptors to ON-bipolar cells, and this reduces the electroretinogram (ERG) bipolar b-wave disproportionately to photoreceptor a-wave changes. RS1 gene expression is localized mainly to photoreceptors and INL bipolar neurons, and RS1 protein is thought to play a critical cell adhesion role during normal retinal development and later for maintenance of retinal structure. Several independent XLRS mouse models with mutant RS1 were created that recapitulate features of human XLRS disease, with OPL-INL schisis cavities, early onset and variable phenotype across mutant models, and reduced ERG b-wave to a-wave amplitude ratio. The faithful phenotype of the XLRS mouse has assisted in delineating the disease pathophysiology. Delivery to XLRS mouse retina of an AAV8-RS1 construct under control of the RS1 promoter restores the retinal structure and synaptic function (with increase of b-wave amplitude). It also ameliorates the schisis-induced inflammatory microglia phenotype toward a state of immune quiescence. The results imply that XLRS gene therapy could yield therapeutic benefit to preserve morphological and functional retina particularly when intervention is conducted at earlier ages before retinal degeneration becomes irreversible. A phase I/IIa single-center, open-label, three-dose-escalation clinical trial reported a suitable safety and tolerability profile of intravitreally administered AAV8-RS1 gene replacement therapy for XLRS participants. Dose-related ocular inflammation occurred after dosing, but this resolved with topical and oral corticosteroids. Systemic antibodies against AAV8 increased in dose-dependent fashion, but no antibodies were observed against the RS1 protein. Retinal cavities closed transiently in one participant. Technological innovations in methods of gene delivery and strategies to further reduce immune responses are expected to enhance the therapeutic efficacy of the vector and ultimate success of a gene therapy approach.

Outcome of vitreoretinal surgery for rhegmatogenous retinal detachment in X-linked juvenile retinoschisis

Purpose

Rhegmatogenous retinal detachment (RRD) is a vision-threatening complication of X-linked juvenile retinoschisis (XLRS). The aim of this study is to report the anatomical and functional outcomes of vitreoretinal surgery for the treatment of RRD in X-linked juvenile retinoschisis (XLRS).

Methods

This is a retrospective, interventional, consecutive case series in which case records of 34 eyes of 28 XLRS patients, who underwent surgery for RRD, were reviewed. Statistical analysis used is as follows: visual outcomes were categorized into three groups: improved, remained stable or deteriorated. Wilcoxon signed-rank test was used to determine the difference in visual acuity at baseline and at final visit. Univariate binary logistic regression analysis was used to determine the risk factors for retinal detachment. Any P value < 0.05 was considered as statistical significant.

Results

Mean age of the boys at presentation was 9.2 ± 3.5 years. Indication for surgery was RRD in all eyes. Concurrent vitreous haemorrhage was present in four eyes (11.8%). The primary surgical intervention was scleral buckle in 12 eyes and pars plana vitrectomy in 22 eyes. Persistence of subretinal fluid/redetachment was seen in 15 eyes of which 11 eyes underwent additional surgeries. At final follow up, 27 eyes (79.4%) were noted to have an attached retina. Of the total eyes, in 20, 6 and 8 eyes the visual acuity improved, stabilized and deteriorated, respectively.

Conclusion

Favourable outcomes are seen in a majority of eyes after vitreoretinal surgery for RRD in XLRS; however, multiple surgical interventions may be necessary.

Congenital X-Linked Retinoschisis: An Updated Clinical Review

We present an updated clinical review of the pathophysiology, progression, and current treatments in pediatric patients with congenital X-linked retinoschisis (CXLRS). CXLRS is an X-linked inherited retinal degeneration characterized by splitting of the superficial layers of the retina. Most recent classification divides CXLRS into 4 distinct clinical phenotypes: type 1, foveal; type 2, foveolamellar; type 3, complex; and type 4, foveoperipheral. The majority of retinoschisis cavities remain stable throughout life and may spontaneously collapse. However, a select number of patients progress to macula-involving peripheral retinoschisis, rhegmatogenous, and combined tractional-rhegmatogenous detachments that require further intervention. Although several advances have been made over the past several decades, medical therapy remains limited to case series‒based carbonic anhydrase therapy and prophylactic laser retinopexy. Recent advances in genetic-based clinical trials with the retinoschisis gene are promising. Vitreoretinal surgical approaches remain complex, case-based, and require careful planning depending on the configuration and location of the retinoschisis cavity.

Special considerations for pediatric vitreoretinal surgery

In this review, the authors present special considerations a vitreoretinal surgeon should take into account before embarking on surgery in a pediatric eye. First, the anatomy of a pediatric eye is different from an adult and changes as the child grows. This is important especially in relation to the placement of transconjunctival ports. The structural characteristics of the sclera are also different, with lower scleral rigidity found in pediatric eyes. When considering vitrectomy, a posterior pars plicata lens-sparing technique should be considered. However, this may not be possible in complicated total detachments where anterior translimbal vitrectomy may be the method of choice. Scleral buckles are preferred for certain cases, and division of the encirclage is advocated in children below the age of 2 years, once the retina has stabilized. Enzymatic vitreolysis has been described as a preoperative adjunct to enhance complete detachment of the posterior hyaloid and reduce iatrogenic retinal breaks. However, its use in pediatric eyes has been limited, and larger studies are warranted. Finally, postoperative visual rehabilitation and treatment of amblyopia are key to maximizing functional outcomes in the pediatric patient. Co-management with a pediatric ophthalmologist and enlisting the co-operation of the parents are essential.

Plasmin Enzyme-Assisted Vitrectomy in Pediatric Patients with Vitreoretinal Diseases

PURPOSE

To evaluate the efficacy and safety of using plasmin-assisted vitrectomy in pediatric patients with vitreoretinal diseases.

METHODS

We prospectively recruited children aged 16 years or younger who presented with vitreoretinopathies and underwent plasmin-assisted vitrectomy between 2012 and 2013. The main outcome measure was the induction of posterior vitreous detachment (PVD) using a suction power of 200 mm Hg or less during surgery.

RESULTS

Eleven eyes of 11 patients (mean age: 3.7 years; average follow-up duration: 14.1 months) were included. Of these 11 patients, there were 3 (27%) cases of stage 5 retinopathy of prematurity, 2 (18%) cases of persistent fetal vasculature, 2 (18%) cases of rhegmatogenous retinal detachment, 2 (18%) cases of idiopathic epiretinal membrane, 1 (9%) case of traumatic macular pucker, and 1 (9%) case of traumatic vitreous hemorrhage (9%). PVD was achieved in all cases (100%) during surgery using low suction after plasmin treatment (mean: 150 ± 39 mm Hg; range: 100-200). Overall, anatomical success was achieved in 8 eyes (73%). Visual acuity improved in all 5 (100%) patients for whom vision could be measured at 6 months after the operation. Cataracts were found in 4 eyes (36%), and a rise in transient intraocular pressure was observed in 1 eye (9%).

CONCLUSIONS

Plasmin-assisted vitrectomy offers an effective and less traumatic intervention for a variety of pediatric vitreoretinal diseases.

From the analysis of pharmacologic vitreolysis to the comprehension of ocriplasmin safety

INTRODUCTION

Pharmacologic vitreolysis is a strategy used to treat anomalous posterior vitreous detachment, by weakening vitreoretinal adhesion with an intravitreal drug. Pharmacologic vitreolysis facilitates surgery, and abnormalities of the vitreoretinal interface including vitreomacular traction (VMT) and early stage macular hole (MH) could be resolved. Ocriplasmin is a recombinant protease, active against fibronectin and laminin, which are important components of the vitreoretinal interface. Ocriplasmin has been approved for symptomatic treatment of VMT and MH with visible traction, and it functions by dissolving the proteins that link the vitreous to the macula, thereby creating a complete posterior vitreous detachment (PVD).

AREAS COVERED

This paper reviews the current knowledge and status of investigations regarding the use of ocriplasmin for pharmacologic vitreolysis and its safety.

EXPERT OPINION

Ocriplasmin is a non-specific enzyme; therefore, it dissolves vitreal proteins as well as possibly proteins associated with visual function in the retina, choroid, and lens. Ocular adverse events (OAEs) of ocriplasmin include transient visual loss, intraocular inflammation, vitreous floaters, lens opacification, zonular instability of the lens, and intraocular hemorrhage. The prevalence of the OAEs is very low; however, on rare occasions, they can result in widespread retinal dysfunction. Research into the acute and long-term safety of ocriplasmin is required.

Induction of Posterior Vitreous Detachment in Pediatric Vitrectomy by Preoperative Intravitreal Injection of Tissue Plasminogen Activator

PURPOSE

To report the efficacy of intravitreal injection of tissue plasminogen activator (tPA) with or without autoserum in induction of posterior vitreous detachment (PVD) in pediatric vitrectomy.

METHODS

Retrospective, interventional case series of pediatric patients receiving intravitreal injection of tPA preoperatively to facilitate PVD in vitrectomy from January 2011 to December 2014 at the Changhua Christian Hospital, Taiwan. All patients received intravitreal injections of 25 µg of tPA 3 days before vitrectomy. For cases without preexisting vitreous hemorrhage, 0.1 mL of intravitreal autologous serum was co-administered. Main outcome measures included successful rate of posterior vitreous detachment in vitrectomy, visual outcome, and related ocular complications.

RESULTS

Four boys and 2 girls were included. Ages ranged from 39 weeks' postmenstrual age to 8 years. The indications for vitrectomy were traumatic macular hole (cases 1 and 2); premacular hemorrhage secondary to retinopathy of prematurity (case 3); abusive head trauma with premacular hemorrhage, subinternal limiting membrane hemorrhage, and macular hole (case 4); trauma with dense vitreous hemorrhage (case 5); and vitreous hemorrhage with unknown cause (case 6). Successful PVD was induced intraoperatively in all cases and the macular hole was closed successfully in 3 of 3 cases (cases 1, 2, and 4). No surgical complications were noted. Visual outcome improved in all 3 eyes with checkable preoperative visual acuity (cases 1, 2, and 6).

CONCLUSIONS

Intravitreal injection of tPA 3 days before vitrectomy may be a helpful adjunct to induce pediatric PVD.

Pharmacologic vitreolysis: New strategy for treatment of anomalous vitreo-macular adhesion

Persistent anomalous vitreo-macular adhesion (VMA) is a well-known factor, associated with a variety of sight threatening diseases - including macular hole, vitreo-macular traction syndrome, cystoid and diabetic macular edema, exudative age- related macular degeneration, myopic traction maculopathy and others. With the advent of optical coherence tomography our understanding of these pathologies and the ability of their early diagnosis has gone much far in the past two decades. The release of macular traction has been of exclusive surgical capability. Notwithstanding good results, vitrectomy is hampered by the inability of complete vitreo-retinal separation (i.e., smooth, bare internal limiting membrane), compulsory postoperative positioning in macular hole cases, surgical complications, and high costs. With aim to offer less invasive and safe treatment modality for anomalous VMA, investigators have made enormous progress in the past decade. Leading among the studied nonsurgical measures is the intravitreal application of pharmacologic agents for the induction of vitreo-retinal separation and vitreous liquefaction, a method termed pharmacologic vitreolysis. Several vitreolytic agents have been studied to date, the most potent among them proved to be plasmin. Recently, ocriplasmin (formerly known as microplasmin) - a more stable than plasmin recombinant product, proved to be safe and efficient in releasing VMA in large studies, and consequently received FDA approval. It’s role in clinical practice is now in the process of being determined. This paper aims to review and summarize the current knowledge and status of investigation on this new approach for the treatment of VMA.

Ocriplasmin for foveal schisis in X-linked retinoschisis

PURPOSE

To report a case of foveal schisis in X-linked retinoschisis treated with ocriplasmin.

METHODS

Case report.

RESULTS

A 27-year-old man with X-linked retinoschisis was treated with a single intravitreal injection of ocriplasmin. After injection, a posterior vitreous detachment was induced and the macular schisis cavity resolved at 1 week. Central macular thickness on optical coherence tomography decreased from 731 μm to 185 μm, visual acuity remained unchanged, and there were no adverse events. However, the macular schisis cavity recurred at 1 month.

CONCLUSION

This is the first reported case of using ocriplasmin to treat foveal schisis in X-linked retinoschisis. Although vitreomacular traction was relieved, the schisis cavity recurred shortly after initial closure.

Ophthalmic use of blood-derived products

There is a wide spectrum of blood-derived products that have been used in many different medical and surgical specialties with success. Blood-derived products for clinical use can be extracted from autologous or allogeneic specimens of blood, but recombinant products are also commonly used. A number of blood derivatives have been used for a wide range of ocular conditions, from the ocular surface to the retina. With stringent preparation guidelines, the potential risk of transmission of blood-borne diseases is minimized. We review blood-derived products and how they are improving the management of ocular disease.

Lens subluxation after plasmin and SF6 injections in rabbit eyes

Purpose

To investigate the rate of lens subluxation following plasmin and/or SF₆ injections in eyes, and whether a subsequent elevated level of vascular endothelial growth factor (VEGF) and vitreous tap would aggravate subluxation.

Methods

Four groups of rabbits were used. Group 1 received an intravitreal injection (IVI) of plasmin and SF₆ in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF₆ in the right eye; and group 4 received an IVI of balanced salt solution in the right eye. After treatment, IVIs of VEGF were given and vitreous tap was performed three times, followed by clinical observation of lens subluxation and scanning electronic microscope evaluation of the zonular fibers.

Results

After IVIs of plasmin and SF₆, and VEGF and vitreous tap had been performed one to three times, lens subluxation was noted in 0%, 43%, 71%, 71%, and 86% of the eyes in group 1. After IVIs of plasmin, VEGF, and vitreous tap had been performed one to three times, lens subluxation was noted in 11%, 22%, 44%, 44%, and 67% of the eyes in group 2. The eyes in group 3 and 4 did not show signs of lens subluxation after VEGF IVIs and vitreous tap. Histology confirmed zonular fiber damage in the eyes treated with plasmin.

Conclusions

The incidence of lens subluxation increased following plasmin injections in the eyes, and this was aggravated by the subsequent high VEGF level in the eyes and vitreous tapping. Zonular fibers were disrupted following plasmin treatment. These effects should be kept in mind when using plasmin enzymes in patients with vitreoretinal abnormalities.

Major challenges in vitreoretinal surgery

Since the first vitrectomy surgery was used for treatment of vitreoretinal diseases, surgical techniques and instrumentation have been rapidly improved in the past decades. However, there are complicated vitreoretinal diseases that cannot be successfully treated, even with state-of-the-art surgeries. The outcomes of some complicated cases are still poor due to different reasons and debates still remain in some areas regarding what are the best treatments. There is still a lack of full understanding on many complicated vitreoretinal diseases, such as the molecular basis of proliferative vitreoretinopathy (PVR), the role of scleral buckling (SB) in the management of rhegmatogenous retinal detachment (RRD), the optimal surgical consideration for pediatric RD, and the possibility of surgical management for various retinal degenerations and congenital retinal anomalies. This review discusses the current understandings of some complicated vitreoretinal diseases.

Profile of ocriplasmin and its potential in the treatment of vitreomacular adhesion

The recent approval by the US Food and Drug Administration of ocriplasmin for the treatment of symptomatic vitreomacular adhesion (VMA), often associated with vitreomacular traction (VMT) and macular hole (MH), has brought new attention to the field of pharmacologic vitreolysis. The need for an enzyme to split the vitreomacular interface, which is formed by a strong adhesive interaction between the posterior vitreous cortex and the internal limiting membrane, historically stems from pediatric eye surgery. This review summarizes the different anatomic classifications of posterior vitreous detachment or anomalous posterior vitreous detachment and puts these in the context of clinical pathologies commonly observed in clinical practice of the vitreoretinal specialist, such as MH, VMT, age-related macular degeneration, and diabetic macular edema. We revisit the outcome of the Phase II studies that indicated ocriplasmin was a safe and effective treatment for selected cases of symptomatic VMA and MH. Release of VMA at day 28 was achieved by 26.5% of patients in the ocriplasmin group versus 10.1% in the placebo group (P<0.001). Interestingly, for MHs, the numbers were more remarkable. Predictive factors for successful ocriplasmin treatment were identified for VMT (VMA diameter smaller than 1,500 μm) and MH (smaller than 250 μm). In comparison with the highly predictable outcome after vitrectomy, the general success rate of ocriplasmin not under clinical trial conditions has not fully met expectations and needs to be proven in real-world clinical settings. The ocriplasmin data will be compared in the future with observational data on spontaneous VMA release, will help retina specialists make more accurate predictions, and will improve outcome rates.

Ocriplasmin for symptomatic vitreomacular adhesion: an evidence-based review of its potential

Vitreomacular traction is a multicategory entity that may cause substantial visual loss due to the formation of a macular hole or traction-induced tissue distortion. The advent of optical coherent tomography (OCT) has demonstrated the anatomic features of persistent vitreomacular attachment (VMA) more definitively, including in many asymptomatic or minimally symptomatic patients. The indications for intervention are unclear, since it is not possible to predict which eyes might be likely to develop progressive visual loss. This has been especially important since for many years, the only treatment option involved surgical intervention (vitrectomy) to release the persistent VMA. Recently, a pharmacolytic agent, ocriplasmin, has become available after many years of development and investigation, and may offer a feasible alternative to surgery, or even a risk/benefit ratio sufficiently favorable to offer intervention at an earlier stage of VMA. Several studies, including a large, prospective clinical trial, have established the foundation of its rationale and efficacy, providing the basis of its approval. The role for ocriplasmin in clinical practice is in the process of being determined. This paper summarizes current knowledge and status of investigations regarding ocriplasmin-induced pharmacologic vitreolysis, and offers some evidence-based considerations for its use.

Review and perspectives on pharmacological vitreolysis

The vitreous is involved in multiple diseases when an incomplete posterior vitreous detachment (PVD) occurs. An incomplete PVD can lead to several pathological conditions. Such visually threatening conditions are traditionally of exclusive surgical interest. In contrast, pharmacological vitreolysis is the effort to reduce or eliminate the pathogenetic role of the vitreous solely by means of drug delivery. Here we aim to review and summarize the evidence available to date about this challenging new approach.

Microplasmin (ocriplasmin) in pediatric vitreoretinal surgery: update and review

PURPOSE

To discuss the potential role of microplasmin (ocriplasmin) as a surgical adjunct to vitrectomy in pediatric vitreoretinopathies.

METHODS

Literature review of the laboratory and clinical evidence to date for the use of both autologous plasmin enzyme as an adjunct to vitrectomy and more recently recombinant microplasmin (ocriplasmin) as monotherapy for focal vitreomacular traction in adults.

RESULTS

Autologous plasmin enzyme is currently being used as a surgical adjunct to vitrectomy, with supporting Levels 2 and 3 published evidence in a range of pediatric vitreoretinopathies including Stage 5 retinopathy of prematurity and congenital X-linked retinoschisis. The availability of autologous plasmin enzyme is limited. In recent Phase 3 clinical trials, intravitreal ocriplasmin versus sham injection resulted in resolution of focal vitreomacular traction in 27% versus 10% (P < 0.001, n = 652).

CONCLUSION

Ocriplasmin may potentially be used as a surgical adjunct to vitrectomy in place of autologous plasmin enzyme. A Phase 2, randomized, placebo-controlled surgical trial is under way to assess this.

Ocriplasmin for vitreoretinal diseases

Fibronectin and laminin are clinically relevant plasmin receptors in the eye. Located at the vitreoretinal interface, they are cleaved by ocriplasmin (Microplasmin, ThromboGenics, Iselin, NJ), a novel ophthalmic medication. A series of clinical trials to study ocriplasmin for the treatment of vitreoretinal diseases such as vitreomacular traction, macular hole, and exudative age-related macular degeneration are underway. The results are promising and may impact patient care.

Long-term outcomes of vitrectomy for progressive X-linked retinoschisis

PURPOSE

To evaluate the long-term outcomes of vitrectomy for progressive X-linked retinoschisis.

DESIGN

Prospective, nonrandomized, consecutive, interventional case series.

METHODS

Twenty-eight eyes of 22 patients who were diagnosed with progressive X-linked retinoschisis were divided into 2 groups: a nonsurgical group (n = 11) and a vitrectomy group (n = 17). The main outcome measures included best-corrected visual acuity, the area of the macular schisis cavity measured by optical coherence tomography, the retinal anatomic status, and complications.

RESULTS

The mean follow-up period was 34.7 months (range, 10 to 68 months). The mean best-corrected visual acuity increased from 20/125 at baseline to 20/55 at the final follow-up in the vitrectomy group (P = .001), but decreased from 20/100 at baseline to 20/400 at the final follow-up in the nonsurgical group (P = .000). In the vitrectomy group, the macular schisis cavity resolved in all 17 eyes; the mean area of the macular schisis cavity decreased from 0.85 mm(2) at baseline to 0.23 mm(2) at the final follow-up (P = .000), and the retinas of 16 eyes (94%) were attached after surgery. In the nonsurgical group, retinal schisis progressively extended in 9 eyes (82%); the mean area of the macular schisis cavity increased from 0.82 mm(2) at baseline to 1.21 mm(2) at the final follow-up (P = .000); in 8 eyes (72%), retinal detachment developed, and 2 eyes (18%) experienced vitreous hemorrhage, which terminated the observations.

CONCLUSIONS

Vitrectomy may be an effective and essential treatment for patients with progressive X-linked retinoschisis to prevent a deterioration of vision before severe complications developed in their eyes.

Evaluation and management of pediatric rhegmatogenous retinal detachment

Pediatric rhegmatogenous retinal detachments are rare, accounting for less than ten percent of all rhegmatogenous retinal detachments. While most retinal detachments in the adult population are related to posterior vitreous detachment, pediatric retinal detachment are often related to trauma or an underlying congenital abnormalities or genetic syndrome. The anatomy of pediatric eyes, the often late presentation of the disease, and the high incidence of bilateral pathology in children all pose significant challenges in the management of these patients. We discuss the epidemiology of pediatric rhegmatogenous retinal detachment, review the genetic syndromes associated with a high incidence of retinal detachment, and examine other common causes of retinal detachment in this age group. We then outline an approach to evaluation and management and describe the expected outcomes of repair of retinal detachment in the pediatric population.

X-linked juvenile retinoschisis: clinical diagnosis, genetic analysis, and molecular mechanisms

X-linked juvenile retinoschisis (XLRS, MIM 312700) is a common early onset macular degeneration in males characterized by mild to severe loss in visual acuity, splitting of retinal layers, and a reduction in the b-wave of the electroretinogram (ERG). The RS1 gene (MIM 300839) associated with the disease encodes retinoschisin, a 224 amino acid protein containing a discoidin domain as the major structural unit, an N-terminal cleavable signal sequence, and regions responsible for subunit oligomerization. Retinoschisin is secreted from retinal cells as a disulphide-linked homo-octameric complex which binds to the surface of photoreceptors and bipolar cells to help maintain the integrity of the retina. Over 190 disease-causing mutations in the RS1 gene are known with most mutations occurring as non-synonymous changes in the discoidin domain. Cell expression studies have shown that disease-associated missense mutations in the discoidin domain cause severe protein misfolding and retention in the endoplasmic reticulum, mutations in the signal sequence result in aberrant protein synthesis, and mutations in regions flanking the discoidin domain cause defective disulphide-linked subunit assembly, all of which produce a non-functional protein. Knockout mice deficient in retinoschisin have been generated and shown to display most of the characteristic features found in XLRS patients. Recombinant adeno-associated virus (rAAV) mediated delivery of the normal RS1 gene to the retina of young knockout mice result in long-term retinoschisin expression and rescue of retinal structure and function providing a 'proof of concept' that gene therapy may be an effective treatment for XLRS.

Emerging nonsurgical methods for the treatment of vitreomacular adhesion: a review

With the dissemination of optical coherence tomography over the past two decades, the role of persistent vitreomacular adhesion (VMA) in the development of numerous macular pathologies - including idiopathic macular hole, vitreomacular traction syndrome, cystoid and diabetic macular edema, neovascularization in diabetic retinopathy and retinal vein occlusion, exudative age-related macular degeneration, and myopic traction maculopathy - has been established. While invasive vitreoretinal procedures have long been utilized to address complications related to these disorders, such an approach is hampered by incomplete vitreoretinal separation and vitreous removal, surgical complications, and high costs. In light of such limitations, investigators have increasingly looked to nonsurgical means for the treatment of persistent pathologic VMA. Chief among these alternative measures is the intravitreal application of pharmacologic agents for the induction of vitreous liquefaction and/or vitreoretinal separation, an approach termed pharmacologic vitreolysis. This article aims to review the available evidence regarding the use of pharmacologic agents in the treatment of VMA-related pathology. In addition, a discussion of vitreous molecular organization and principles of physiologic posterior vitreous detachment is provided to allow for a consideration of vitreolytic agent mode of action and molecular targets.

Surgical treatment for complications of congenital retinoschisis

This study examined the clinical features of complications of congenital retinoschisis and the clinical efficacy of vitreoretinal surgery in the treatment of these complications. The clinical efficacy of surgical treatments was retrospectively analyzed in 10 patients with congenital retinoschisis (10 eyes) complicated with rhegmatogenous retinal detachment (n=5), vitreous hemorrhage (n=2) and macula- involving schisis (n=1). All the patients suffered foveal and peripheral schisis. They were treated with scleral buckling (n=1) or vitrectomy (n=9). After the surgical treatment, the retina was reattached in patients with rhegmatogenous retinal detachment; the refractive media became transparent in those with vitreous hemorrhage; the visual acuity in 80% of patients was improved; no remarkable progression of schisis was found; no severe operative complications occurred. It was concluded that vitreoretinal surgery in the treatment of complications of congenital retinoschisis is safe and effective, and helps improve and maintain the visual function.

Idiopathic bilateral retinal dialyses complicated by posterior retinal tear after blunt trauma

PURPOSE

The purpose of this study was to present a case of posterior rupture in a previously detached retina after blunt trauma.

METHOD

This is a case report.

RESULT

A child with idiopathic bilateral retinal dialyzes sustained accidental blunt trauma to the left eye while awaiting surgery. This caused a posterior rupture of the retina in an already preexisting retinal detachment. The right eye underwent uneventful cryopexy and a buckle procedure. The left eye was managed conservatively while awaiting spontaneous posterior vitreous separation. Unfortunately, the retina detached further to involve the macula with progression of proliferative vitreoretinopathy. The child required three subsequent vitrectomies in the left eye to stabilize the retina.

CONCLUSION

This case highlights the etiology of retinal dialyzes and the dilemmas in the management of complicated retinal detachment.

Surgical management of retinopathy of prematurity

PURPOSE OF REVIEW

The surgical management of retinopathy of prematurity continues to employ a paradigm of peripheral laser followed by vitrectomy for patients who develop retinal detachment. This review addresses significant advances that have been made in our understanding of the indications, timing, techniques, and outcomes of these interventions.

RECENT FINDINGS

The indications for laser are highly dependent on the diagnosis of plus disease. Recognition of plus disease is variable and subjective. Efforts are underway to develop more objective measures of plus using image analysis software. Intravitreal injection of bevacizumab is emerging as an adjunct to laser for aggressive posterior retinopathy of prematurity. Although vitrectomy for retinal detachment is effective in eyes without plus, management of eyes with retinal detachment and persistent plus continues to be a major challenge. Older children with regressed retinopathy of prematurity may suffer from vitreous hemorrhage in the absence of retinal tears, detachments, or active neovascularization.

SUMMARY

Our understanding of the best indications, timing, and techniques for the surgical management of retinopathy of prematurity continues to evolve and outcomes have improved in recent years. Areas that generate significant ongoing interest and investigation include the assessment of plus disease and the use of adjuncts for aggressive posterior retinopathy of prematurity.