Test retest values for TNO, Frisby, Lang stereopad and Asteroid stereoacuity tests
Reviewed by Fiona Rowe

This study aimed to determine test-retest variability of four different measurements of stereoacuity including TNO, Frisby, Lang stereopad and Asteroid, and compare stereoacuity values between tests in an adult population. Participants were >18 years of age (mean 38 years, SD 12.7) with no history of ocular disorders and visual acuity better than 0.3logMAR. There were 54 participants; 23 male and 31 female. Mean distance visual acuity was -0.08, SD 0.08 right eye and -0.08, SD 0.11 left eye. Mean near visual acuity was 0.02, SD 0.13 right eye and -0.01, SD 0.12 left eye. Median test and retest values were 60” / 60”, 20” / 20”, 100” / 100” and 79.5” / 81.5” for TNO, Frisby, Lang and Asteroid respectively. Median values (both test and retest) were 1.78, 1.30, 2.00 and 1.90 log respectively. TNO and Frisby had good reliability but could not be used interchangeably. Therefore, stereoacuity tests should be individually consistently used at follow-up visits. Asteroid had good reliability and compared well to TNO. Despite normal visual acuity values, there was varying degrees of agreement for stereoacuity.

Test retest variability in stereoacuity measurements.
Mehta J, O’Connor A.
STRABISMUS
2023;31(3):188–96.