Normative Values, Testability, and Validity for a New Preferential Looking Stereoacuity Test

Area of Science:

• Ophthalmology
• Pediatric Vision
• Stereopsis Assessment

Background:

• Existing age norms for the Preschool And School-age Stereotest (PASS) III are limited to children aged 3-5 years.
• The PASS III stereotest has been validated using a pointing response in older children.
• There is a need for normative data and testability assessments in younger children and those with special needs.

Purpose of the Study:

• To expand normative data for the PASS III stereotest to children as young as 6 months.
• To assess the testability of the PASS III in infants, toddlers, and children with special needs.
• To evaluate the validity of the PASS III as a preferential-looking test for young children and those with special needs.

Main Methods:

• The PASS III was administered to 68 control children, 362 children with eye conditions, and 167 children with special needs.
• Testability percentages were calculated for children with and without special needs.
• Normal tolerance limits were determined, and test validity was assessed by comparing results to established norms and gold standard stereoacuity tests.

Main Results:

• Mean PASS III stereoacuity improved with age in controls, from 371 arcsec at 12 months to 87 arcsec at 36 months.
• Testability was high: 81% at 12 months, 87% at 24 months, 97% at 36 months, and 92% in children with special needs.
• The PASS III demonstrated 89% accuracy compared to gold standard stereoacuity tests, supporting its validity.

Conclusions:

• Preferential-looking tests using the PASS III are a sensitive and specific method for measuring stereoacuity.
• The PASS III exhibits high testability in young children and those with special needs.
• The PASS III is a valid tool for assessing stereoacuity across a broad pediatric age range.