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April 1995

Grating Visual Acuity With Teller Cards Compared With Snellen Visual Acuity in Literate Patients

Author Affiliations

From the University of Wisconsin Hospital and Clinic (Dr Kushner) and Davis-Duehr Eye Associates (Dr Lucchese and Ms Morton), Madison. The authors have no proprietary interest in the Teller Acuity Cards or in VisTech Inc.

Arch Ophthalmol. 1995;113(4):485-493. doi:10.1001/archopht.1995.01100040107035

Objective:  To determine the usefulness of Teller Acuity Cards for detecting three levels of vision deficit, the cutoff for amblyopia (20/40 or poorer), vision impairment (20/70), or legal blindness (20/200).

Design:  We compared grating visual acuity with the Teller cards with Snellen visual acuity (our gold standard) in 69 literate patients with amblyopia or other cause of vision loss in a prospective masked study.

Results:  Teller card visual acuity and distance Snellen visual acuity correlated significantly (r=.508, P<.001); however, Teller card visual acuity explained only 26% of the variation in distance Snellen visual acuity. Teller card visual acuity had a low sensitivity for detecting vision deficit of 20/40 or poorer (58%), vision deficit of 20/70 or poorer (39%), or legal blindness (24%), but somewhat more accurately reflected near Snellen visual acuity than distance visual Snellen acuity. Teller cards had a higher positive predictive value—80% for 20/70 visual acuity and 43% for legal blindness, as determined by near Snellen visual acuity. Specificity of Teller cards was 88% for detecting visual acuity loss of 20/70 and 98% for legal blindness. Negative predictive value of Teller cards for detecting visual acuity loss of 20/70 was 50% and for legal blindness was 71%.

Conclusions:  Teller Acuity Cards may underestimate the presence of amblyopia of all types, legal blindness, and a specified level of vision impairment (20/70). Even in the presence of normal visual acuity measurements with Teller cards, significant visual loss as assessed by standard Snellen optotypes may be anticipated in many patients.