Major eligibility criteria for the trial included children ages 9 to 17 years, exodeviation at near at least 4Δ greater than at far, a receded near point of convergence (NPC) break (6 cm or greater), and insufficient positive fusional vergence at near (PFV) (convergence amplitudes) (i.e., failing Sheard’s criterion [PFV less than twice the near phoria] (30 ) or minimum PFV of ≤15Δ base-out blur or break), and a CI Symptom Survey (described in Outcome Measures section below) score of ≥16. Because patients with symptomatic CI often have an associated accommodative insufficiency (12 (link)), patients with symptomatic CI associated with accommodative insufficiency were included in the study. However, children with monocular accommodative amplitudes <5D were excluded because the severity of their accommodative insufficiency may indicate an organic etiology. Table 1 provides a complete listing of eligibility and exclusion criteria.
A refractive correction was prescribed for patients if a significant refractive error was present or a significant change in refractive correction was found. A significant refractive error/change was defined as ≥1.50 D hyperopia, ≥0.50 D myopia, ≥0.75 D astigmatism, ≥0.75 D anisometropia in spherical equivalent or ≥1.50 D anisometropia in any meridian (based on cycloplegic refraction). For hyperopes the investigator had the discretion to reduce the prescription up to 1.25 D. For myopia full correction was required. After wearing the glasses for at least two weeks, eligibility testing was repeated to determine if the patient still met the eligibility criteria. Thus, the CI Symptom Survey and eligibility testing were always performed with appropriate refractive correction in place.
A refractive correction was prescribed for patients if a significant refractive error was present or a significant change in refractive correction was found. A significant refractive error/change was defined as ≥1.50 D hyperopia, ≥0.50 D myopia, ≥0.75 D astigmatism, ≥0.75 D anisometropia in spherical equivalent or ≥1.50 D anisometropia in any meridian (based on cycloplegic refraction). For hyperopes the investigator had the discretion to reduce the prescription up to 1.25 D. For myopia full correction was required. After wearing the glasses for at least two weeks, eligibility testing was repeated to determine if the patient still met the eligibility criteria. Thus, the CI Symptom Survey and eligibility testing were always performed with appropriate refractive correction in place.
