New Glaucoma Questionnaire Shows High Validity, Reliability

The newly designed 40-item Glaucoma Visual Functioning Questionnaire (GVFQ-40) shows good validity and reliability, and it can be used to assess the effect of glaucomatous damage on visual acuity (VA), according to a study in the British Journal of Ophthalmology. 

A number of tools have been developed to examine vision-related quality of life, restrictions in participants, and symptoms of eye diseases. However, there remains an urgent need for an appropriate and standardized questionnaire to capture the influence of glaucoma on visual ability and to assess intervention efficacy, according to the research.   

The cross-sectional, observational study (Clinicaltrials.gov Identifier: NCT04722861) included 84 glaucoma suspects (controls) and 270 patients with glaucoma. Participants were enrolled from the Glaucoma Clinic at Zhongshan Ophthalmic Center, in Guangzhou, China, between January 2021 and August 2021. All participants completed the GVFQ-40 and the validated National Eye Institute Visual Functioning Questionnaire-25 (NEI VFQ-25) on the same day during a routine clinical visit. Researchers evaluated the discriminant, criterion-related and construct validity of the GVFQ-40. To determine test-retest reliability, a subset of participants completed the GVFQ-40 twice. 

The mean age of all participants was 41.21±13.28 years (age range: 18–83 years) and a little more than half were men (51%). Of the 270 patients with glaucoma, 91 had mild visual field (VF) loss, 84 had moderate VF loss, and 95 had severe VF loss. Compared with controls, domain-specific and total GVFQ-40 scores were significantly higher (worse visual ability) in patients with glaucoma (all P <.001). Researchers found statistical significance in all pairwise subgroup comparisons except for the ’mobility’ domain comparison between the mild VF loss and control groups (P =.189). They observed significant differences between the two groups in only 2 of the 12 dimensions on the NEI VFQ-25.

GVFQ-40 results showed strong correlations with better-eye mean deviation and VF Index (glaucoma severity measures). Exploratory factor analysis tended to confirm a three-domain structure, according to the study. The test-retest intraclass correlation coefficients were greater than 0.927 for each domain score and total GVFG-40 scores.

“The GVFQ-40 possesses good validity and reliability, supporting its use in evaluation of the visual ability of Chinese patients with glaucomatous vision impairment,” the researchers report. “It could be useful in elucidating the impact of glaucomatous damage on a patient’s visual function, even when VA remains good.”

Study limitations include the single-center design and the absence of healthy controls.

Disclosure: This research was supported by multiple sources. Please see the original reference for a full list of disclosures.

Reference

Huang H, Lin J, Luo M, et al. Development and validation of the 40-item Glaucoma Visual Functioning Questionnaire. Br J Ophthalmol. Published online April 4, 2022. doi:10.1136/bjophthalmol-2021-320985