An automated visual acuity testing computer program using the Apple II system.

We developed an automated visual acuity testing program that uses an E optotype with surrounding confusion bars. The computer software program runs on Apple II equipment and a black-and-white monitor with a five-inch screen. The program is available in response box and joystick versions. The test is suitable for children older than 31/2 to 4 years of age and for adults. A t-test on the same floppy disk as the visual acuity programs is used to test the probability that the differences in test results are greater than chance. Visual acuities of 20 normal subjects were reduced by means of plus lenses. Test-retest acuity correlation coefficients were similar for letter charts and computer-generated E optotypes, suggesting approximately equal reliability under the test conditions employed. Visual acuities of 12 amblyopic eyes were obtained by a Ferris-type letter chart and computer-generated E optotypes. The correlation coefficient was +0.93, suggesting similar test results by these two methods.