Successful Reduction of Intraocular Pressure in a Patient with Glaucoma Secondary to Sturge-Weber Syndrome Using a Suprachoroidal Shunt.

AIM: We present a case of successful reduction of intraocular pressure (IOP) in a patient with Sturge-Weber syndrome (SWS) and moderate open angle glaucoma using a suprachoroidal shunt. BACKGROUND: Patients with SWS glaucoma often have elevated episcleral venous pressure resulting in elevated IOP. This makes the conventional pathway for aqueous humor outflow a poor target for IOP reduction, yielding it difficult to treat. Medication and procedures that facilitate uveoscleral outflow have been more successful. CASE DESCRIPTION: We present a case where a suprachoroidal shunt device (CyPass®) was used to reduce IOP in a patient with SWS. The IOP reduction has persisted for 12 months without complication or the requirement for topical prostaglandin analog use. CONCLUSION: The uveoscleral pathway is a preferred target for IOP reduction in patients with elevated episcleral venous pressure. The CyPass device offers a promising ab interno minimally invasive glaucoma surgery (MIGS) approach to reduce IOP in cases where a pathologic pressure gradient exists in the trabecular meshwork. CLINICAL SIGNIFICANCE: Glaucoma in patients with SWS has been historically difficult to treat. Previous surgical procedures that have been successful are more invasive and have required the creation of alternative drainage routes of aqueous humor. The CyPass device offers a promising less invasive option to reduce IOP in these patients. HOW TO CITE THIS ARTICLE: Junttila TL, Alberto N, Winkels M, et al. Successful Reduction of Intraocular Pressure in a Patient with Glaucoma Secondary to Sturge-Weber Syndrome Using a Suprachoroidal Shunt. J Curr Glaucoma Pract 2020;14(1):43-46.

Prompt vitrectomy for management of endophthalmitis in setting of unexposed glaucoma drainage implant.

PURPOSE: To highlight a rare case of fulminant endophthalmitis in the late post-operative stage after glaucoma drainage device implantation without evidence of device exposure, and to share the unique management that resulted in successful restoration of vision and intraocular pressure control. OBSERVATIONS: Endophthalmitis after glaucoma drainage implantation (GDI) is a rare complication most often associated with exposure of the device. Management options are limited, but removal of GDI is a common approach in the setting of an exposed implant. Visual acuity outcomes are often significantly reduced despite adequate treatment. There is little in the existing literature about management of late-onset endophthalmitis in the setting of a GDI without implant exposure. Here we present such a case that was successfully managed by prompt pars plana vitrectomy and removal of tube from the anterior chamber with subsequent re-insertion and patch graft. Our case results in a restoration of baseline visual acuity and IOP control at 7 months follow up. CONCLUSIONS AND IMPORTANCE: Endophthalmitis occurring after GDI implantation is a challenging complication to manage. Many physicians resort to removal of device for treatment, and a majority would treat initially with intravitreal antibiotic injection of antibiotics rather than prompt pars plana vitrectomy. This article provides a different approach that avoids removal of the device.

Myocyte Dedifferentiation Drives Extraocular Muscle Regeneration in Adult Zebrafish.

PURPOSE: The purpose of this study was to characterize the injury response of extraocular muscles (EOMs) in adult zebrafish. METHODS: Adult zebrafish underwent lateral rectus (LR) muscle myectomy surgery to remove 50% of the muscle, followed by molecular and cellular characterization of the tissue response to the injury. RESULTS: Following myectomy, the LR muscle regenerated an anatomically correct and functional muscle within 7 to 10 days post injury (DPI). Following injury, the residual muscle stump was replaced by a mesenchymal cell population that lost cell polarity and expressed mesenchymal markers. Next, a robust proliferative burst repopulated the area of the regenerating muscle. Regenerating cells expressed myod, identifying them as myoblasts. However, both immunofluorescence and electron microscopy failed to identify classic Pax7-positive satellite cells in control or injured EOMs. Instead, some proliferating nuclei were noted to express mef2c at the very earliest point in the proliferative burst, suggesting myonuclear reprogramming and dedifferentiation. Bromodeoxyuridine (BrdU) labeling of regenerating cells followed by a second myectomy without repeat labeling resulted in a twice-regenerated muscle broadly populated by BrdU-labeled nuclei with minimal apparent dilution of the BrdU signal. A double-pulse experiment using BrdU and 5-ethynyl-2'-deoxyuridine (EdU) identified double-labeled nuclei, confirming the shared progenitor lineage. Rapid regeneration occurred despite a cell cycle length of 19.1 hours, whereas 72% of the regenerating muscle nuclei entered the cell cycle by 48 hours post injury (HPI). Dextran lineage tracing revealed that residual myocytes were responsible for muscle regeneration. CONCLUSIONS: EOM regeneration in adult zebrafish occurs by dedifferentiation of residual myocytes involving a muscle-to-mesenchyme transition. A mechanistic understanding of myocyte reprogramming may facilitate novel approaches to the development of molecular tools for targeted therapeutic regeneration in skeletal muscle disorders and beyond.

Microanatomy of adult zebrafish extraocular muscles.

Binocular vision requires intricate control of eye movement to align overlapping visual fields for fusion in the visual cortex, and each eye is controlled by 6 extraocular muscles (EOMs). Disorders of EOMs are an important cause of symptomatic vision loss. Importantly, EOMs represent specialized skeletal muscles with distinct gene expression profile and susceptibility to neuromuscular disorders. We aim to investigate and describe the anatomy of adult zebrafish extraocular muscles (EOMs) to enable comparison with human EOM anatomy and facilitate the use of zebrafish as a model for EOM research. Using differential interference contrast (DIC), epifluorescence microscopy, and precise sectioning techniques, we evaluate the anatomy of zebrafish EOM origin, muscle course, and insertion on the eye. Immunofluorescence is used to identify components of tendons, basement membrane and neuromuscular junctions (NMJs), and to analyze myofiber characteristics. We find that adult zebrafish EOM insertions on the globe parallel the organization of human EOMs, including the close proximity of specific EOM insertions to one another. However, analysis of EOM origins reveals important differences between human and zebrafish, such as the common rostral origin of both oblique muscles and the caudal origin of the lateral rectus muscles. Thrombospondin 4 marks the EOM tendons in regions that are highly innervated, and laminin marks the basement membrane, enabling evaluation of myofiber size and distribution. The NMJs appear to include both en plaque and en grappe synapses, while NMJ density is much higher in EOMs than in somatic muscles. In conclusion, zebrafish and human EOM anatomy are generally homologous, supporting the use of zebrafish for studying EOM biology. However, anatomic differences exist, revealing divergent evolutionary pressures.