Intermittent exotropia met the following criteria : ( 1 ) IXT at distance OR constant exotropia at distance and either IXT or exophoria at near ; ( 2 ) exodeviation ( tropia or phoria ) of at least 15 prism diopters ( PD ) at distance or near by prism and alternate cover test ( PACT ) ; and ( 3 ) exodeviation of at least 10 PD at distance by PACT .