Imaging vitreous cortex hyalocyte response to paracentral acute middle maculopathy (PAMM) using En Face OCT.

INTRODUCTION: Vitreous cortex hyalocytes (VCH) are resident macrophage cells that provide immunosurveillance, respond to tissue injury and inflammation, and help maintain the transparency of the media. In this case report we demonstrate the use of en face optical coherence tomography (OCT) to image VCH in vivo in a patient presenting with PAMM secondary to antiphospholipid syndrome. CASE DESCRIPTION: A 38-year-old female with no known medical history presented with complaints of visual disturbances in the right eye. OCT revealed hyperreflective bands in the IPL and INL nasal to the fovea. A diagnosis of PAMM was made. Work-up revealed elevated titers of antiphospholipid antibodies. En face OCT revealed a decline in the inflammatory activation over a seven-month period as evidenced by changes in VCH distribution and morphology. CONCLUSIONS: Our findings suggest that monitoring changes in the distribution and morphology of VCH could have a potential clinical utility for assessing disease severity, predicting recovery, and early recognition of treatment response in various inflammatory ocular pathologies such as PAMM.

Hyalocytes in proliferative vitreo-retinal diseases.

Introduction: Hyalocytes are sentinel macrophages residing within the posterior vitreous cortex anterior to the retinal inner limiting membrane (ILM). Following anomalous PVD and vitreoschisis, hyalocytes contribute to paucicellular (vitreo-macular traction syndrome, macular holes) and hypercellular (macular pucker, proliferative vitreo-retinopathy, proliferative diabetic vitreo-retinopathy) diseases. Areas covered: Studies of human tissues employing dark-field, phase, and electron microscopy; immunohistochemistry; and in vivo imaging of human hyalocytes. Expert opinion: Hyalocytes are important in early pathophysiology, stimulating cell migration and proliferation, as well as subsequent membrane contraction and vitreo-retinal traction. Targeting hyalocytes early could mitigate advanced disease. Ultimately, eliminating the role of vitreous and hyalocytes may prevent proliferative vitreo-retinal diseases entirely.

3-D OCT angiographic evidence of Anti-VEGF therapeutic effects on retinal capillary hemangioma.

PURPOSE: To report the impact of intravitreal anti-vascular endothelial growth factor (VEGF) therapy on a retinal capillary hemangioma (RCH) using clinical OCT angiography (OCT-A) in addition to standard imaging modalities. OBSERVATIONS: A 25-year-old male patient with Von Hippel-Lindau (VHL) disease presented with a history of bilateral RCH. No view was present in the right eye. Examination of the left eye revealed six peripheral RCH, the smallest of which was temporal to the macula with active exudation. This RCH was thought to be the source of cystoid macular edema (CME) involving the fovea, and therefore, the source of vision decline. 11 injections of 1.25mg of Bevacizumab EA across 14-month was given. Comparison of the pre- and post-treatment OCT-A at the temporal RCH showed a reduction of CME and regression of RCH. CONCLUSION: Anti-VEGF therapy appeared to stabilize the visual acuity and produce partial regression of RCH. It offers a safe option when visual acuity is threatened. OCT and OCT-A have the ability to document the impact of antiangiogenic therapy on RCH. 3D renderings of OCT-A offer enhanced sensitivity to recognition of structural and functional changes of RCH which may prove useful for monitoring treatment response.

Hyalocyte origin, structure, and imaging.

Introduction: Hyalocytes have been recognized as resident tissue macrophages of the vitreous body since the mid-19th century. Despite this, knowledge about their origin, turnover, and dynamics is limited. Areas covered: Historically, initial studies on the origin of hyalocytes used light and electron microscopy. Modern investigations across species including rodents and humans will be described. Novel imaging is now available to study human hyalocytes in vivo. The shared ontogeny with retinal microglia and their eventual interdependence as well as differences will be discussed. Expert opinion: Owing to a common origin as myeloid cells, hyalocytes and retinal microglia have similarities, but hyalocytes appear to be distinct as resident macrophages of the vitreous body.