comparison of the effect of different types of experimental anisometropia on stereopsis measuredwith titmus, randot and tno stereotests

Purpose: to assess the effect of experimental anisometropia and monovision on stereopsis using the titmus, randot, and tno stereoacuity tests. methods: sixty adult volunteers were enrolled in the present study. four different types of anisometropia—myopia, hyperopia, and astigmatism (both 90° and 45°)—were induced by placing trial lenses over the dominant eye (from 3 to 1 d). stereoacuity was measured using the titmus, randot, and tno tests. results: in all the anisometropia types, stereopsis deteriorated with increase in anisometropia in the three stereoacuity tests performed (p < 0.001). the largest decrease in stereopsis was attributed to 3 d myopic anisometropia—6.51 ± 2.10, 6.59 ± 2.35, and 7.36 ± 1.89 arc seconds in titmus circles, randot circles, and tno, respectively. minimal change in stereopsis was observed in 1 d astigmatism of 45°. conclusion: any type of anisometropia may reduce stereoacuity; this reduction is most noticeable with myopic anisometropia, especially in the tno test, probably due to the lack of monocular cues.