Efficacies of preoperative prism adaptation test and monocul
The efficacies of prism adaptation test (PAT) and monocular occlusion (MO) and their optimal test durations to detect the maximum angles of deviation at near and distance in eyes with intermittent exotropia (IXT) were assessed and compared.

Researchers retrospectively reviewed the medical records of 72 patients with IXT. All the patients had undergone the initial strabismus surgery and had been preoperatively tested by both PAT and MO performed on different days for 30 and 60 min. Near and distance deviations after 30 and 60 min of PAT and MO were compared to their baseline measurements obtained immediately after prism wear and before occlusion by alternate prism cover test.

--Compared with the baseline, the near deviation by PAT significantly increased after 30 and 60 minutes but not the distance deviation. However, the increase after 30 min was not significant.

--By MO, neither near nor distance deviation showed a significant difference from the baseline after 30 and 60 min.

--PAT showed a significantly larger near deviation than MO at 30 and 60 min, but a larger distance deviation by PAT was only observed at 30 min.

Finally, a 30-minute PAT appears to be more helpful than MO in disclosing the greatest angle of deviation before strabismus surgery in individuals with basic and convergence insufficiency kinds of IXT.

Source: https://bmcophthalmol.biomedcentral.com/articles/10.1186/s12886-021-02060-9