Reliability and Construct Validity of the NEI VFQ-25 in a Subset of Patients With Geographic Atrophy From the Phase 2 Mahalo Study

Am J Ophthalmol. 2018 Jun;190:1-8. doi: 10.1016/j.ajo.2018.03.006. Epub 2018 Mar 10.

Abstract

Purpose: Geographic atrophy (GA) is an advanced form of age-related macular degeneration characterized by progressive, irreversible visual function loss. This analysis evaluates the psychometric properties of the 25-Item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) composite, near activity, and distance activity scores in patients with GA.

Design: Reliability and validity study.

Methods: Reliability and validity were tested with NEI VFQ-25 data collected from 100 subjects with GA from United States' sites of the phase 2 Mahalo study of lampalizumab (ClinicalTrials.gov identifier: NCT01229215).

Results: Strong internal consistency and reproducibility were demonstrated for the NEI VFQ-25 composite (Cronbach's α, 0.95; intraclass correlation coefficient [ICC], 0.86), near activity (Cronbach's α, 0.84; ICC, 0.80), and distance activity (Cronbach's α, 0.84; ICC, 0.84) scores. Convergent validity with the binocular measures, Minnesota Low-Vision Reading Test (MNRead) reading speed and Functional Reading Independence (FRI) index score, was demonstrated for baseline NEI VFQ-25 composite (Pearson correlation [r] = 0.61 and 0.69, respectively), near activities (r = 0.69 and 0.73), and distance activities (r = 0.57 and 0.64) scores. Known-group validity testing for baseline mean NEI VFQ-25 scores (composite, near activities, and distance activities) showed differences between patients with mean maximum MNRead reading speed ≥ 80 vs < 80 words per minute, and between mean FRI index score ≥ 2.5 vs < 2.5 (all P < .0001).

Conclusions: Psychometric evidence supports the NEI VFQ-25 as a reliable and valid cross-sectional measure of the impact of GA on patient visual function and vision-related quality of life.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Aged
  • Cross-Sectional Studies
  • Female
  • Geographic Atrophy / physiopathology*
  • Geographic Atrophy / therapy
  • Humans
  • Immunoglobulin Fab Fragments / therapeutic use
  • Intravitreal Injections
  • Male
  • National Eye Institute (U.S.)
  • Psychometrics
  • Quality of Life*
  • Reproducibility of Results
  • Sickness Impact Profile*
  • Surveys and Questionnaires
  • United States
  • Vision Disorders / physiopathology*
  • Vision Disorders / therapy
  • Vision, Binocular / physiology
  • Visual Acuity / physiology*

Substances

  • Immunoglobulin Fab Fragments
  • lampalizumab

Associated data

  • ClinicalTrials.gov/NCT01229215