Resumen de Measurement validity of the Low Vision Independence Measure (LVIM)

Theresa M. Smith, Shilpa Krishnan, Ickpyo Hong, Timothy Reistetter

• OBJECTIVE. This study’s objective was to test the psychometrics of Smith’s (2013) Low Vision Independence Measure (LVIM) using the Rasch model.

  METHOD. A cohort design was used with 93 participants receiving occupational therapy for low vision. Confirmatory factor analysis (CFA) with a parceling approach was used to test the LVIM factors and Rasch analysis to examine item-level psychometrics.

  RESULTS. Participants’ average age was 78.9 yr (standard deviation = 12.1), and the majority were female (72.8%) with macular degeneration (62.3%). The CFA revealed two measurement factors: visual field or scotoma (n = 28) and visual acuity (n = 24). We removed six misfitting items, and the two factors of the revised LVIM demonstrated good rating scale function, good internal consistency (person reliability: visual field, .87; visual acuity, .90), good precision (person strata: visual field, 3.91; visual acuity, 4.40), no ceiling or floor effects, and no differential item functioning.

  CONCLUSION. The revised LVIM demonstrates good psychometrics on the Rasch model and can be used as a valid outcome measure in low vision rehabilitation.