Pneumosinus Dilatans Causing Field of Vision Deviation: A Case Report

Pneumosinus dilatans (PSD) is a rare condition which may cause visual impairment. Here we present the case of a 15-year-old boy with PSD. The vision was 10/10 and the intraocular pressure was in normal range for both eyes. Other eye examinations were normal except for a slight discoloration of the optic nerve. Optical coherence tomography showed a decrease in the thickness of the nerve fiber layer and the patient’s primary field of vision had a mean deviation of -3.44 and -6.39 in the right and left eyes, respectively. Magnetic resonance imaging revealed the diagnosis of pneumosinus dilatans of sphenoid sinuses. Due to deterioration of the field of vision in subsequent exams to a mean deviation of -6.36 and - 9.54 in the right and left eyes respectively, functional endoscopic sinus surgery (FESS) was performed for the patient. FESS resulted in the mean field of vision deviation improving to -5.01 and -7.33 in the right and left eyes, respectively two months after surgery. In conclusion altered field of vision without vision loss can be caused by PSD of the sphenoid sinuses and should be considered as a differential diagnosis after ruling out more common causes of field of vision loss. Surgical treatment is suggested in cases of PSD with worsening visual impairment before severe visual disorder and optic atrophy.