Dynamic pupillometry in patients with visible optic disc drusen: a cross-sectional study.

BACKGROUND

Although often considered asymptomatic, optic disc drusen (ODD) may be associated with subtle changes in visual pathway function. In this study, the ability of dynamic pupillometry to reveal impairment in patients with visible ODD was examined.

METHODS

In this cross-sectional case‒control study, 67 eyes from 39 patients with visible ODD and 60 eyes from 30 controls comparable in age and sex were examined. All participants underwent fundus imaging, optical coherence tomography (OCT), and dynamic pupillometry. The parameters included the maximum and minimum pupil diameter (PD), mean constriction velocity (MCV), mean dilation velocity (MDV), constriction amplitude (CA), and mean mesopic and photopic PD. Fundus autofluorescence (FAF) intensity on the optic disc was graded 1 to 4 according to quadrant involvement. Group comparisons and FAF-grade associations were analyzed using generalized estimating equations (GEE) to account for inter-eye correlation.

RESULTS

The MCV was significantly lower in ODD eyes compared with controls (1.50 ± 0.41 vs. 1.96 ± 0.74 mm/s; β = -0.41, 95% CI: -0.67 to -0.15; Bonferroni-adjusted p = 0.014). Similar findings were obtained in the right-eye sensitivity analysis (p = 0.009). No significant associations were observed between FAF grade and the pupillometric parameters. Average retinal nerve fiber layer (RNFL) thickness was also lower in the ODD group (90.0 ± 11.4 vs. 96.9 ± 10.6 µm; β = -6.33, 95% CI: -11.84 to -0.81; p = 0.024). FAF grade was significantly associated with lower average RNFL thickness (β = -5.49, 95% CI: -7.28 to -3.71; p < 0.001).

CONCLUSIONS

Dynamic pupillometry demonstrated reduced MCV in eyes with ODD, a finding supported by single-eye sensitivity analysis. Although pupillometric parameters were not significantly associated with FAF grade after adjustment for multiple comparisons, higher FAF grades were significantly associated with lower RNFL thickness. These findings suggest altered pupillary dynamics in ODD and a structural association between FAF grade and RNFL thinning.