Analysis of the vergence facility test using different prismatic dioptric powers

Area of Science:

• Optometry and Vision Science
• Pediatric Optometry
• Binocular Vision Assessment

Background:

• The vergence facility (VF) test is a crucial component of optometric examinations.
• Optimal prismatic power combinations for the VF test, particularly in children, remain debated.

Purpose of the Study:

• To evaluate the vergence facility (VF) test using three distinct prismatic power combinations.
• To determine the most effective prismatic power combination for the VF test across different age groups.

Main Methods:

• Assessed the VF of 122 healthy individuals across four age groups.
• Utilized three prismatic flipper combinations: 8Δ base-in/8Δ base-out (8BI/8BOΔ), 3BI/12BOΔ, and 5BI/15BOΔ.
• Measured vergence facility in cycles per minute (cpm) for both near and distance vision.

Main Results:

• Vergence facility (VF) performance, measured in cpm, increased with age.
• Youngest participants (mean age 6.69 years) exhibited the lowest cpm values, while adults (mean age 28.67 years) showed the highest.
• Near vision testing consistently yielded higher cpm values than distance vision testing across all age groups and prism combinations.

Conclusions:

• Vergence facility (VF) improves with age, with optimal performance observed in adults.
• The 3BI/12BOΔ prismatic power combination demonstrated superior results for both near and distance vision across all tested age groups.
• Near vision assessments provide higher vergence facility (VF) values compared to distance vision assessments.