Abstract
Purpose: :
Preschool vision screenings often include refractive error or visual acuity (VA) testing to detect amblyopia as well as eye alignment testing to detect strabismus. The Vision in Preschoolers (VIP) Study Group recently reported that tests of refractive error and VA performed best in identifying preschool children with ≥1 targeted vision conditions. The purpose of this report is to determine the effect on sensitivity of combining screening for eye alignment with screening for refractive error or VA.
Methods: :
Over 3 years, 4,040 preschool children were screened in the VIP Study, with a different array of screening tests each year. Examinations (which included assessment of threshold VA, cycloplegic refractive error and eye alignment) were performed by masked examiners on each child to identify amblyopia, strabismus, or significant refractive error. The best tests for detecting children with any targeted condition (non–cycloplegic retinoscopy [NCR], Retinomax, SureSight, and LEA Symbols and HOTV VA tests) were paired with the best tests for detecting strabismus (cover–uncover testing, Random Dot E [RDE], MTI Photoscreener, and StereoSmile II). The change in sensitivity that resulted from combining a test of eye alignment with a test of refractive error or VA was determined with specificity set at 90% and 94%.
Results: :
Addition of the cover–uncover test, MTI, or StereoSmile II generally resulted in increased sensitivity for the detection of strabismus (increases ranged from 6% to 31%), with the greatest increases in sensitivity for cover–uncover test. Test combinations performed better at detecting constant than intermittent strabismics and performed worst at detecting exotropia. Sensitivity for detection of ≥ 1 targeted conditions was generally not changed significantly by the addition of a test of eye alignment.
Conclusions: :
While sensitivity for detection of ≥ 1 targeted conditions is generally not significantly changed by combining a screening test of eye alignment (cover–uncover, MTI, or StereoSmile II) with a screening test of refractive error or VA (NCR, Retinomax, SureSight, Lea, or HOTV), the detection of strabismus may be increased. The decision of whether or not to include a test of alignment should be based upon the screening program’s goals (e.g. targeted visual conditions) and resources.
Keywords: screening for ambylopia and strabismus • refraction • visual acuity