A pilot study examining density of suppression measurement in strabismus

Area of Science:

• Ophthalmology
• Vision Science
• Clinical Research

Background:

• Suppression density measurement is crucial for understanding and managing strabismus.
• The Sbisa bar, Bagolini filter (BF) bar, and neutral density filter (NDF) bar are commonly used tools.
• Equivalence and reliability of these filters require thorough investigation.

Purpose of the Study:

• To establish the equivalence and test-retest reliability of Sbisa, BF, and NDF bars for measuring suppression density.
• To determine if measurement equipment or testing conditions alter suppression density.
• To provide insights into the clinical utility of these filters.

Main Methods:

• A pilot study involved 10 adult subjects with childhood-onset strabismus.
• Density of suppression was measured repeatedly under varying conditions (light, light source intensity).
• Data were analyzed for test-retest reliability, equivalence, and impact of altered testing conditions.

Main Results:

• Test-retest reliability issues were identified for the BF bar (median 6 filter change) and NDF bar (median 5 filter change).
• Suppression density measurements were not affected by changes in environmental illumination or fixation light intensity.
• NDF bar measurements yielded higher suppression density values compared to the BF bar.

Conclusions:

• Potential test-retest reliability issues exist for the BF and NDF bars, which are still manufactured.
• Testing conditions do not significantly influence results if the same filter bar is used consistently.
• Further research in pediatric strabismus patients undergoing amblyopia treatment is recommended.