Base-in Prism Spectacles for Intermittent Exotropia

Inclusion Criteria

• •Intermittent Exotropia meeting all of the following criteria:
• •Age 3 to 13 years
• •Mean distance control score of ≥2.00 points with at least 1 measure of 3, 4, or 5 points (i.e, spontaneous tropia) from the 3 assessments during the exam
• •A near control score ≤4 on at least 1 of 3 assessments (cannot have score of 5, 5, 5)
• •Distance exodeviation between 16 Prism Diopters (Δ) and 35 Δ (inclusive) by PACT
• •Near exodeviation between 10 Δ and 35 Δ (inclusive) by PACT
• •Near deviation does not exceed distance deviation by more than 10 Δ by PACT (i.e., convergence insufficiency-type IXT excluded)
• •Refractive error between -6.00 Diopters (D) spherical equivalent (SE) and +2.50 D SE (inclusive) (based on a cycloplegic refraction performed within 7 months but prior to the day of enrollment)
• •Refractive correction (must be worn for at least 1 week if refractive error meets any of the following (based on a cycloplegic refraction performed within 7 months but prior to the day of enrollment):
• •* SE anisometropia ≥1.00 D
• •* Astigmatism ≥1.00 D in either eye
• •* SE myopia ≥-0.50 D in either eye
• •If spectacles have been prescribed and are worn, they must meet the following pre- enrollment criteria:
• •* SE anisometropia corrected to within 1.00 D of full SE anisometropic difference
• •* Astigmatism corrected to within 1.00 D of full magnitude; axis within 10 degrees if astigmatism ≤1.00 D and axis within 5 degrees if astigmatism \>1.00 D