To provide satisfactory treatment in patients with heterotropia, it is necessary to get an accurate measurement of the deviation in distance and near fixation. In this study, we compared ocular deviation before occlusion, after one hour patch test and the prism adaptation test (PAT) at near(0.33 m), distance (6m) and far distance (12m) through prism alternate cover test (PACT) in patients with concomitant horizontal strabismus. Our study analyzed 30 subjects (14 esotropic and 16 exotropic) which were categorized into three groups: Non-Responders, Patch test responders and PAT responders. Mean esodeviation and exodeviation measurements were found maximum after PAT followed by patch test and minimum after traditional PACT. Following patch test and PAT test, an increase in the angle of deviation was seen in 70% and 76.67% patients at 1/3 m, in 50% and 66.67% patients at 6 m and in 43.33% and 63.33% patients at 12 m respectively. Comparing the maximum angle of deviation, 20 patients were found to be as responder either to patch test or PAT or both. Through this study, we concluded that PAT is useful in determining the largest exotropic and esotropic angle and superior to patch test to estimate the target angle preoperatively.