Chiasmal decussation in tilted disc syndrome PVER in tilted disc

Abstract

The tilted disc syndrome is a benign congenital abnormality of the optic nerve head. Since it can be confused with papilledema and chiasmal lesions, differential diagnosis is important. The tilting anomaly may be associated with other abnormalities along the optic nerve. Visual field defects may be similar to those in chiasmal lesions. In order to determine whether the normal crossover of nerve fibers at the chiasm is altered, the crossed and the uncrossed fibers were investigated using the pattern visual evoked responses (PVER) test. Thirtyfour eyes of 17 patients diagnosed with tilted disc syndrome were evaluated for refraction, keratometry, color vision with Ishihara, visual field, and PVER. The presence of abnormal nerve fiber decussation was determined by recording PVER from the electrodes mounted on the scalp of both hemispheres. The amplitude and latency differences between the 'crossed' and 'uncrossed' fibers were not statistically significant (p>0.05). As a result, the tilting abnormality of papilla was found to be without chiasmal abnormal decussation.