Abstract
Purpose :
To evaluate the quality-of-life (QoL) impact of eye diseases (keratoconus; age-related macular degeneration, AMD; retinal vein occlusion, RVO; and diabetic macular edema, DME) using the Impact of Vision Impairment (IVI) questionnaire, and to determine the relationship between the IVI scores and visual acuity.
Methods :
A cross-sectional study was conducted utilizing the Save Sight Registries data. Rasch analysis was conducted on the IVI data using the Andrich Rating Scale Model. Univariate analysis included Welch’s t-test, one-way ANOVA, and Pearson’s correlation coefficient.
Results :
The IVI was completed by 1693 patients; 336 with keratoconus, 1147 AMD, 150 RVO and 60 DME. 735 (54.2%) patients with retinal conditions had received intravitreal therapy. Participants had a mean ± SD age of 68.0 ± 22.2 years and 842 (49.7%) were female.
The IVI scales (overall; visual functioning, VF; emotional, EM) had robust psychometric properties including well-functioning response categories, unidimensionality (variance explained > 50%, eigenvalue of the first contrast <3.0), excellent measurement precision (person separation index > 2.0) and satisfactory fit statistics (MnSq, 0.7 to 1.3).
In a group-wise analysis, female patients had lower VF (1.8 vs 2.3), EM (2.3 vs 2.7) and overall (1.7 vs 2.1) logits IVI scores (all p < 0.05). The differences in mean VF scores between the diseases were not significant (Keratoconus 2.0, AMD 2.0, RVO 2.1, DME 2.1 logits; p = 0.998). Keratoconus patients had worse mean EM scores (Keratoconus 1.7 vs AMD 2.7, RVO 2.7, DME 2.5 logits; all pairwise p < 0.05). Similarly, keratoconus patients had worse mean overall IVI score in logits (1.7) than AMD (2.0), RVO (2.0), and DME (1.9), however, the differences were not statistically significant (p = 0.06). The IVI overall and subscale scores were similar between retinal conditions (all p > 0.05). Pearson’s correlations of IVI scores were higher with visual acuity in the better eye (VF 0.41, EM 0.27, overall 0.37) than in the worse eye (VF 0.28, EM 0.24, overall 0.28). Correlations with visual acuity were stronger for VF than for EM subscales.
Conclusions :
The IVI was a psychometrically robust QoL questionnaire. Keratoconus patients had worse IVI scores, particularly low EM scores, than patients with retinal diseases. The low strength of correlations between visual acuity and QoL scores, although statistically significant, suggested a complex relationship.
This is a 2021 ARVO Annual Meeting abstract.