Abstract
Purpose :
To determine light discomfort thresholds quantitatively using a new clinical device on a large sample of healthy adult humans, reliability and relationship with biometric and optical parameters.
Methods :
A total of 489 healthy subjects with ages ranging from 20 to 70 years (241 men, 248 women), were examined with the LUMIZ™ 100 (Essilor Intl., France), a new handheld, portable, clinical device for the determination of light discomfort thresholds. Instructions were given by means of a recorded video to ensure homogeneity in the explanations. A mock-up test was carried out prior to measurement. Two thresholds, “just perceptible” and “really disturbing” discomfort, were determined for three light presentation protocols (Continuous warm, Continuous cold, and flashing warm), using two different LED sources (Warm:4000°K, and Cold:6500°K). Iris color and skin pigmentation level were classified, and subjective manifest refraction was also determined.
Results :
Discomfort thresholds are well distributed across the range of intensities. Intrasession intraclass correlation coefficients were higher than 0.80 for all thresholds. First measurement was representative of the median of three. There was no effect of age on discomfort thresholds (r2<0.1, p=0.30), nor affected reliability of the measurements (p=0.368). For the considered population, women have lower discomfort thresholds than men (p<0.001). Subjects with high self-perceived light sensitivity tend to have lower discomfort threshold and vice versa (p<0.001). No effect on discomfort thresholds was found for ametropia (p=0.45), nor was any link with pupil size, axial length or wavefront aberrations in this sample. There was no significant representation of iris color or skin tone to allow for statistical significance of the effect, although a trend for green eyes to have lower thresholds was observed.
Conclusions :
The new device is reliable for the clinical determination of light discomfort thresholds on healthy subjects. Nor age, refractive error, or biometric parameters seem to have an effect on discomfort thresholds. Women tend to have lower thresholds than men. The new device is useful for the quantitative determination of light discomfort in healthy subjects. Applications in diseased eyes and filter treatments are to be explored.
This is a 2021 ARVO Annual Meeting abstract.