Evaluation of Criteria of Stereoacuity for Titmus, Randot & TNO Stereotests

ABSTRACT

The commonly used tests for stereopsis are Titmus-fly, Randot, and TNO tests. In this study, 50 normal subjects were tested with these tests in order to set a criterion for normal stereopsis. The value of mean, mode and 75% point of these three tests were derived and compared.These three tests were also performed in 23 intermittent exotropes and 32 accommodative esotropes who showed gross stereopsis in the range of 60 to 400 seconds of arc by Titmus-fly testing. The aim was to obtain standards for clinical applicability and accuracy of these tests.This study cincludes that the appropriate criteria for normal stereopsis are less than 60 seconds of arc for Titmus-fly or Randot test, and 120 seconds of arc fot TNO test. Accurate testing for stereopsis in patients with gross stereopsis requires both Titmus-fly and Randot tests together. TNO test was inferior to the other two tests in terms of the accuracy and clinical applicability.