Catquest-9SF questionnaire: Validation in a Greek-speaking population using Rasch analysis

Area of Science:

• Ophthalmology
• Health Outcomes Research
• Psychometrics

Background:

• Cataract surgery aims to improve vision and daily functioning.
• Validated tools are essential for assessing patient-reported outcomes after cataract surgery.
• The Catquest-9SF questionnaire measures visual disability and limitations in daily activities.

Purpose of the Study:

• To validate the Greek version of the Catquest-9SF questionnaire.
• To assess its psychometric properties in a Greek-speaking population with cataracts.

Main Methods:

• Translation and back-translation of the Catquest-9SF into Greek.
• Administration of the questionnaire to 100 cataract patients pre- and post-surgery.
• Rasch analysis to evaluate psychometric properties (reliability, validity, unidimensionality, precision, targeting).

Main Results:

• The Greek Catquest-9SF demonstrated good reliability (Person Reliability = 0.92) and separation (Person Separation Index = 3.28).
• Unidimensionality was confirmed with acceptable item fit statistics.
• Significant improvement in vision-related quality of life was observed post-surgery, with a large effect size (1.3).

Conclusions:

• The Greek version of Catquest-9SF is a reliable, valid, and responsive measure for cataract patients.
• It exhibits good psychometric properties for assessing vision-related disability and daily functioning.
• Postoperative results indicated potential mistargeting, suggesting tasks became easier after surgery.