Hidden Threats: Can We Afford to Miss Subtle Visual Field Defects?

During a routine checkup at our hospital on May 17, 2024, a 29-year-old man’s seemingly normal vision concealed a startling discovery. Despite a history of intermittent headaches for 1 year, his best-corrected visual acuity was 20/20 in both eyes, and intraocular pressures were normal at 20 mmHg bilaterally. He had normal ocular motility in all directions, with reactive pupils. Fundoscopy showed a cup-to-disc ratio of 0.6:1 in both eyes, a sloping superior neuroretinal rim, and a present foveal reflex in the macula. Visual fields revealed isolated areas of field depression in the superior temporal quadrants of both eyes, while optical coherence tomography in the right eye showed generalized retinal nerve fiber layer (RNFL) thinning and the left eye showed inferior RNFL thinning. With a history of intermittent headaches, these subtle visual field abnormalities warranted further scrutiny. An magnetic resonance imaging scan was advised, which uncovered a large arachnoid cyst in the right frontal, temporal, and parietal regions, exerting a significant mass effect on the brain. He was then urgently referred to a neurologist. Surgical intervention was promptly undertaken on May 18, 2024. Surgical intervention (craniotomy) successfully removed the cyst, leading to complete clinical recovery. This case underscores the importance of not missing visual field abnormalities that can be critical indicators of intracranial pathology, and their presence should prompt further investigation to avoid missing potentially serious diagnoses.