The Measurement of Visual Acuity: Comparison of Teller Acuity Cards with Snellen and MBL Results

Abstract

In the past several years, new methods have been developed to estimate the visual acuity of pre-verbal and non-verbal patients. The newest and least time consuming of these is the Teller acuity card (TAC) method. Acuity card results have been equated with methods for determining visual acuity in verbal patients, but this comparison can be misleading. In this study, verbal patients were tested with Teller acuity cards, Snellen line charts, and modified Bailey-Lovie acuity charts to determine the relationship among these three tests. The results demonstrated that visual acuities measured by Teller acuity cards generally appear to be better than the acuities measured by Snellen or MBL testing. Although TAC testing can be useful in assessing visual acuity in nonverbal or pre-verbal patients, the results must be interpreted carefully, particularly in terms of translation into Snellen equivalents.

• visual acuity
• Snellen charts
• Teller acuity cards
• Bailey-Lovie charts
• amblyopia