Repeatability and Validity of the VAA-2000 Automated Self Vision Tester

PURPOSE: To evaluate the test-retest reliability and validity of the VAA-2000 Self Vision Tester. METHODS: A total of 108 eyes of 108 adults (55 men and 53 women) who visited Seoul National University Bundang Hospital from March to December 2015 and who had best corrected visual acuities of 20/200 or better, according to both Hahn's visual acuity test (using numbers and Landolt rings) and the VAA-2000 Self Vision Tester, were included. The test-retest reliability and validity of the VAA-2000 Self Vision Tester were assessed and compared with Hahn's visual acuity test performed using numbers and Landolt rings. The intraclass correlation, Pearson correlation, Bland-Altman plots, and Deming regression between the different tests were analyzed. RESULTS: The average best corrected visual acuity was 0.12 ± 0.17 logMAR measured with the VAA-2000 Self Vision Tester, and was 0.08 ± 0.20 logMAR with Hahn's visual acuity test using numbers and 0.08 ± 0.30 logMAR using Landolt rings. The VAA-2000 Self Vision Tester demonstrated high test-retest reliability (intraclass correlation coefficient = 0.903, p < 0.001) and acceptable validity when compared with Hahn's visual acuity test using numbers (r = 0.767, p < 0.001) and Landolt rings (r= 0.727, p < 0.001). CONCLUSIONS: The VAA-2000 Self Vision Tester possesses good reliability and acceptable validity when compared to Hahn's visual acuity test using numbers and Landolt rings.

A Case of Trochlear Nerve Schwannoma Presenting with Binocular Diplopia

PURPOSE: To report a case of unilateral trochlear nerve schwannoma in a patient without neurofibromatosis. CASE SUMMARY: A 58-year-old male presented with acute onset of diplopia which developed 10 days prior. Alternate prism cover test, ductions and versions and Bielschowsky three-step test were compatible with left superior oblique muscle palsy. High-resolution magnetic resonance imaging showed a 6-mm-sized lobulated mass in the cisternal segment of the left trochlear nerve passing lateral to the brainstem. An additional thin-section gadolinium-enhanced orbit magnetic resonance imaging showed definite enhancement in the entire portion of the lobulated mass, compatible with a trochlear nerve schwannoma. Diplopia was managed conservatively with prism glasses and regular follow-up examinations were recommended without further treatment. CONCLUSIONS: A trochlear nerve tumor should be considered in adults who develop diplopia associated with acquired superior oblique muscle palsy.