Abstract
Purpose :
To assess visual function by visually evoked potentials in adults with orbital and other primary brain tumors affecting the optic pathway from a tertiary hospital in Brazil.
Methods :
In this retrospective case-control series, patients with orbital (intraconal and extraconal) or midline/chiasmatic tumors were included. Visually-evoked potentials (VEP) using pattern-reversal (PRVEP) and flash (FVEP) stimuli were performed according to international standards. Outcome measures were VEP parameters of amplitude (microvolts) and peak times (milliseconds) measured both for the P100 component (PRVEP) and the N2-P2 complex (FVEP). Kruskal-Wallis analysis of variance, followed by Dunn post-test, was adopted to analyze VEP parameters of amplitude and peak-time from affected, fellow and control eyes. Statistical significance was determined by p ≤.05.
Results :
Participants were 21 patients (17 females; 81.0 %; mean age= 49.2± 11.9 years) and 21 age and sex-matched healthy controls (17 females; mean age=49.7±13.1 years). Tumor location was intraconal (6 meningiomas, 3 hemangiomas, 1 glioma), extraconal (6 meningiomas) and midline (3 pituitary adenomas, 2 hypothalamic/chiasmatic low-grade gliomas). Abnormal fundus (76%), abnormal pupillary reflexes (71%), reduced visual acuity (62%), strabismus (48%) and proptosis (38%) were major ophthalmic features. VEPs abnormalities were found in at least one eye of all cases . Affected eyes had significantly reduced amplitudes (mean 15'=8.4±4.1; mean 60'=7.3±3.1 µV) and prolonged latencies (mean 15'=119.3±24.3; mean 60'= 116.6±24.4 ms) for PRVEP and significantly reduced amplitudes (8.5±3.7 µV) for FVEP when compared to controls (amplitude - mean 15'=12.7±3.0; mean 60'=11.4±2.7; mean FVEP=15.0±4.9 µV; peak-time mean 15'=95.5±3.7; mean 60'=95.1±4.8; mean FVEP=116.9±16.7 ms). Results from fellow and control eyes were comparable for both PRVEP and FVEP. However, In 6 fellow eyes of 16 unilateral orbital tumors, abnormally prolonged latencies were found for PRVEP.
Conclusions :
VEP abnormalities were found in all adult patients with orbital and other visual pathway primary tumors, even in some of the fellow eyes, suggesting a more widespread and insidious abnormality of the visual pathways in this condition. VEP can be used as an ancillary non-invasive test to characterize and monitor visual function in subjects with these neoplastic lesions.
This is a 2020 ARVO Annual Meeting abstract.