Behind the closed eye - A case report of orbital apex syndrome

Orbital Apex Syndrome (OAS) is a rare neuro-ophthalmic disorder characterized by vision loss and ophthalmoplegia due to involvement of structures within the orbital apex. It may result from infectious, inflammatory, neoplastic, or vascular etiologies. We report a case of a 42-year-old immunocompromised male, known to have HIV and diabetes mellitus, who presented with acute onset of right eye pain, ptosis, ophthalmoplegia and progressive vision loss, ultimately leading to no perception of light. Fundus examination revealed central retinal artery occlusion of right eye. Imaging and nasal endoscopy revealed findings suggestive of invasive fungal sinusitis. KOH stain and biopsy confirmed mucormycosis. The patient underwent urgent functional endoscopic sinus surgery (FESS) with orbital decompression and was treated with systemic antifungal therapy including liposomal and conventional Amphotericin B. Although visual recovery could not be achieved, timely intervention helped preserve the orbital anatomy and prevented further complications such as orbital exenteration. This case highlights the importance of early recognition, histopathological confirmation, and multidisciplinary management in improving outcomes in OAS, particularly in immunocompromised individuals.