Comparison of logMAR ETDRS chart and a new computerised staircased procedure for assessment of the visual acuity of children.

The validity and repeatability of visual acuity measures are particularly important in the detection and monitoring of childhood visual anomalies such as amblyopia. The repeatability and sensitivity of a new computerised visual acuity test, 'Staircased Procedure' is compared with the now gold standard visual acuity test, the early treatment of diabetic retinopathy study (ETDRS). Twenty-seven visually normal children (mean age: 6.7 +/- 1.1 years) and 27 children with amblyopia (mean age: 6.1 +/- 0.7 years) were tested with the ETDRS and Staircased Procedure. A retest was administered 4-5 weeks later and 30 min later for the visually normal and the amblyopic children, respectively. The staircased procedure produced significantly better visual acuity than the ETDRS for visually normal and amblyopic children. Repeatability was similar for both tests (ETDRS: 0.11 log units; staircased procedure: 0.13 log units). In conclusion, the Staircased Procedure was an acceptable test with high repeatability and validity.