Bilateral acute retinal necrosis (BARN) represents a broad ophthalmological field of severe retinal pathologies associated with poor visual prognosis and blindness. The purpose of this review is to examine the clinical spectrum in detail over the past few years, exploring laboratory and instrumental diagnosis, and providing useful and up-to-date guidance in this field. A systematic review of this field has been performed through the PRISMA guidelines, searching in the PUBMED database. Serological laboratory tests on blood or polymerase chain reaction (PCR) on aqueous humor or vitreous samples are crucial to identifying the underlying cause and choosing the timeliest strategic treatments. Often, the main cause remains herpesviruses, with Varicella zoster (VZV) predominating over the others. There are also other causes that one needs to be carefully aware of. Anatomical and functional recovery is unfavorable if they are not individuated in a quick time. Early diagnosis and timely treatment offer a better chance of visual improvement and the avoidance of complications. Complications worsen the visual prognosis over months and may require a surgical approach.

Objective: To report a case of ocular toxoplasmosis reactivation in a patient with neurosarcoidosis undergoing immunosuppressive therapy. Methods: Case report and literature review. Results: A 34-year-old male with neurosarcoidosis, treated with Infliximab and Mycophenolate Mofetil, presented with sudden visual decline in his left eye. Multimodal imaging revealed active chorioretinitis. Serological tests showed elevated Toxoplasma IgG levels with normal IgM levels. Treatment with oral corticosteroids and antibiotics led to significant improvements in vitreous turbidity and lesion inactivity at follow-up, despite unchanged visual acuity. Conclusions: This case highlights the risk of toxoplasmosis reactivation in immunosuppressed sarcoidosis patients. It emphasizes the importance of considering ocular toxoplasmosis even with normal IgM levels, and demonstrates the value of multimodal imaging in diagnosis and follow-up.