Agreement analysis comparing iPad LCVA and Sloan testing in multiple sclerosis patients.

BACKGROUND: Visual symptoms are common in multiple sclerosis (MS). Low-contrast visual acuity (LCVA) testing using Sloan charts has demonstrated increased sensitivity for visual deficits compared to high-contrast acuity testing. Computerized testing of visual acuity may facilitate use in the clinic setting.

OBJECTIVES: To evaluate the agreement between an iPad-based and Sloan testing of LCVA in a cohort of MS patients.

METHODS: A total of 38 patients with relapsing-remitting MS were enrolled after providing informed written consent at Partners MS Center, Brigham and Women's hospital. Monocular LCVA was measured using retroilluminated Sloan chart and iPad-based LogMAR chart. Number of correct letters and agreement between two measurements were assessed for each eye using Bland-Altman analysis and paired t-test.

RESULTS: For both eyes, there was no significant difference in number correct between the two measurements using a paired t-test, and there was high correlation between two measurements (oculus dextrus (OD) r = 0.89, p < 0.001; oculus sinister (OS) r = 0.78, p < 0.001). The limits of agreement were -7.9 to +8.5 letters for the right eye and -10.9 to +11.2 letters for the left eye.

CONCLUSION: An iPad-based LCVA test shows good agreement with Sloan testing in MS patients.