Self-assessed visual function outcome in cataract surgery: minimum important difference of the Catquest-9SF...

Area of Science:

• Ophthalmology
• Health Outcomes Research
• Psychometrics

Background:

• Cataract surgery aims to improve visual function.
• The Catquest-9SF is a patient-reported outcome measure used to assess visual function.
• Determining the minimum important difference (MID) is crucial for interpreting changes in scores.

Purpose of the Study:

• To determine the minimum important difference (MID) of the Catquest-9SF questionnaire in the context of cataract surgery.
• To provide a reliable measure for assessing meaningful visual function improvement after surgery.

Main Methods:

• A nationwide multi-center prospective randomized study was conducted.
• 400 patients completed the Catquest-9SF pre- and post-surgery, with an anchor question assessing self-perceived change.
• Rasch analysis was used to analyze questionnaire data, dichotomizing patients based on preoperative scores to calculate MID using anchor and distribution-based methods.

Main Results:

• Analysis included 231 patients.
• For patients with better preoperative visual function, the anchor-based MID was -0.5 and the effect size-based MID was -1.07.
• For patients with worse preoperative visual function, the anchor-based MID was -1.80 and the effect size-based MID was -1.46.

Conclusions:

• This study provides detailed knowledge of the Catquest-9SF's MID.
• These findings enable more accurate high-quality evaluation of cataract surgery outcomes and benefits.
• The established MIDs can be applied globally for consistent assessment of surgical impact.