Line-by-line visual acuity scoring equivalence with letter-by-letter visual acuity scoring

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Visual acuity measurement is crucial in eye care.
• Standardizing visual acuity scoring methods ensures reliable patient data.
• Current methods for scoring line visual acuity vary, impacting data consistency.

Purpose of the Study:

• To compare different line visual acuity scoring criteria against traditional letter-by-letter scoring.
• To determine the most accurate and least variable method for visual acuity assessment.
• To evaluate scoring criteria under both normal and blurred vision conditions.

Main Methods:

• 32 subjects' visual acuity was tested using high-contrast charts at 4.88 meters.
• Logarithm of the Minimum Angle of Resolution (logMAR) visual acuity was measured under normal and +1.50D blur conditions.
• Four scoring criteria were applied: letter-by-letter, and line criteria of three-or-more, four-or-more, or five correct letters.

Main Results:

• The
• three-or-more
• letters correct criterion showed minimal significant difference compared to letter-by-letter scoring (p ≥ 0.18).
• Under normal and blur conditions, significant differences in visual acuity scores were observed across criteria (p < 0.001).
• The
• three-or-more
• letters correct criterion demonstrated the lowest test-retest variability under best-corrected conditions.

Conclusions:

• The
• three-or-more
• letters correct scoring criterion is a reliable and accurate method for visual acuity testing.
• This criterion offers comparable results to letter-by-letter scoring, even with visual defocus.
• It provides the most consistent visual acuity measurements, reducing variability in clinical practice.