Emerging and Re-emerging viral infections and their ocular manifestations: A focus on ocular neovascularization

Emerging and re-emerging viral infections represent a significant and escalating global health concern, frequently associated with a spectrum of systemic complications. Among these, ocular manifestations are increasingly recognized, contributing substantially to visual morbidity. The present review aims to provide an overview of the ocular sequelae of major emerging and re-emerging viral pathogens, highlighting their suggested and established roles in ocular neovascularization (ONV). It discusses the virological and immunological mechanisms, including direct viral cytopathic effects, virally-induced inflammation, dysregulation of angiogenic and anti-angiogenic factors (e.g., Vascular Endothelial Growth Factor), and activation of hypoxia-inducible pathways, which can contribute to neovascular processes in various ocular compartments such as the cornea, iris, retina, and choroid. The major viral agents addressed in this review are Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Human Immunodeficiency Virus (HIV), West Nile virus (WNV), Dengue Virus (DENV), and other viruses with known or suspected ONV association. This study reviewed and summarized the literature regarding case reports and experimental models describing the association of these viral agents with ONV. Furthermore, it addresses diagnostic considerations and therapeutic strategies. Understanding the intricate interplay between these viral infections and ocular neovascular pathways is crucial for developing targeted therapeutic strategies to prevent vision loss in affected populations.