Usefulness of critical flicker fusion frequency measurement and its laterality for evaluating compressive optic neuropathy due to pituitary neuroendocrine tumors

PurposeCritical flicker fusion frequency (CFF) is a short but sensitive method for evaluating optic nerve function. We measured CFF in patients with pituitary neuroendocrine tumors (Pit-NETs) to assess its usefulness.MethodsData from 184 patients with nonfunctioning Pit-NETs, who had been treated with transsphenoidal surgery and had no medical history of eye diseases, was used in this retrospective study. Visual acuity decline (VAD) was defined as > 0.10 reduction in logMAR visual acuity and CFF decline (CFD) was defined as CFF value ResultsContact between the optic nerve or chiasma and the tumor was present and absent in 161 and 23 patients, respectively. In patients showing contact, the difference in CFF between the left and right eyes was larger (P = 0.0008), and the optimal cut-off value using the receiver operating characteristic curve was 3 Hz. Therefore, ≥ 3 Hz was considered positive for CFF laterality (CFL), the most prevalent condition. Tumor height was lower in patients with CFL positivity compared to those with VAD or VFD (P ConclusionChanges in CFL permit early detection of Pit-NETs. Our results indicate that CFF laterality can be seen in the early stages of compressive optic neuropathy due to Pit-NET.