Abstract
Purpose :
To evaluate the impact of visual dysfunction on vision-related quality of life (VRQoL) in pseudoxanthoma elasticum (PXE)
Methods :
As part of the baseline visit of the PROPXE study (NCT05662085), a prospective, non-interventional, natural-history study, the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) was administered and both eyes were evaluated for best-corrected visual acuity (BCVA) and contrast sensitivity function (CSF). Additionally, multi-locus dark adaptometry was measured at 8°, 15°, 30°, and 46° in the eye with better visual acuity (or the right eye in case of equal acuity). To identify predictors of VRQoL, we applied cross-validated LASSO regression due to the high correlation among explanatory variables (i.e., among the visual function measures).
Results :
A total of 40 eyes of 20 patients with a median [IQR] age of 55.6 years [41.5; 59.7] were included in the analysis. At baseline, the median BCVA was -0.07 logMAR [-0.07; 0.11] for the better eye (BE) and 0.015 logMAR [-0.07; 0.59] for the worse eye (WE). The VRQoL composite score was impaired, with an average of 78.0 points [70.2; 89.0].
The four predictors with highest impact on the VRQoL composite score selected by LASSO regression were: BE contrast sensitivity at 1.5 cycles per degree (+8.11 units/log10(CS)), WE contrast sensitivity at 1.5 cycles per degree (+2.55 units/log10(CS)), and the dark adaptometry S2 slope at 15° eccentricity (-65.16 units/[LogUnits/min]), and at 30° eccentricity (-13.53 units/[LogUnits/min]).
Similarly, BE and WE contrast sensitivity at 1.5 cycles per degree and the S2 slope at 15° eccentricity with the addition of the final rod threshold at 8° were in the final model for the distance activities subscore. For near activities, no specific predictor with an impact on the VRQoL was identified and the intercept-only model provided the predictive performance.
Conclusions :
Patients with PXE experience a considerably reduced VRQoL. Contrast sensitivity at low spatial frequencies and the rate of rod-mediated dark adaptation outside of the macula are stronger predictors of VRQoL than BCVA in PXE patients. These findings emphasize the importance of prioritizing functional tests with high impact on VRQoL, such as dark adaptometry, in PXE that are reflective of the underlying Bruch’s membrane alterations.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.