Orbital Complications of Chronic Rhinosinusitis: A Contemporary Narrative Review of the Ophthalmologic Impact and Therapeutic Role of Functional Endoscopic Sinus Surgery

Chronic rhinosinusitis (CRS) is a prevalent inflammatory condition of the paranasal sinuses. While the burden of CRS on quality of life and respiratory health is well recognized, its potential impact on orbital structures is an area of growing clinical attention. The orbit is separated from the ethmoid and frontal sinuses by only thin bony laminae. Chronic sinus disease can therefore easily extend beyond the sinuses to involve the orbit, leading to ophthalmologic complications that range from eyelid edema changes to severe, sight-threatening emergencies. Traditionally, orbital complications are more commonly associated with acute sinusitis (particularly in children), but contemporary evidence highlights that chronic rhinosinusitis and its sequelae—including mucoceles, chronic infections (bacterial or fungal), and protracted inflammation—can likewise produce significant orbital consequences. This narrative review synthesizes the current literature on the orbital complications of chronic rhinosinusitis, highlighting clinical, relevant anatomical/pathophysiological pathways, preoperative versus postoperative findings, and the therapeutic impact of FESS. Through this review, clinicians in both otolaryngology and ophthalmology can gain an updated understanding of this interdisciplinary topic, guiding prompt recognition and effective management of CRS patients with orbital involvement.