Rasch Analysis Of Eq-5D-5L And Ivi Instruments In Cataract-Related Quality Of Life Assessment

Cataract impairs visual function and quality of life (QoL). Both generic and vision-specific instruments are used to assess patient-reported outcomes, but their comparative performance in primary care settings is unclear. This study examined the correlation between the EQ-5D-5L and the Impact of Vision Impairment (IVI) questionnaire and compared their measurement performance among cataract patients.

Primary care settings

A cross-sectional study was conducted among cataract patients attending a primary healthcare facility. Presenting visual acuity (VA) was measured, and QoL data were collected through interviewer-administered EQ-5D-5L and IVI questionnaires. Spearman’s rho (ρ) assessed correlations between instruments and with VA. Rasch analysis evaluated measurement precision and targeting. Analyses included total scores and IVI subscales: mobility (M), reading (R), and emotional well-being (E).

Ninety-eight patients were included. Mean presenting VA was 0.85 ± 0.68 logMAR (better eye) and 1.92 ± 0.58 logMAR (worse eye). Moderate positive correlations were observed between EQ-5D-5L and IVI total scores (ρ = 0.572, p < 0.001) and across all subscales. A significant correlation with better-eye VA was found only for the reading (R) subscale of both instruments. Rasch analysis showed high precision for the IVI (person separation reliability > 0.70), whereas the EQ-5D-5L demonstrated poor precision (0.08). The IVI reading subscale showed the best targeting.

Both instruments captured cataract-related QoL, with moderate correlation. The IVI demonstrated superior precision and targeting, especially for reading. Using both tools may provide a comprehensive assessment of vision-specific and general QoL in cataract patients.