Impact of Screen Brightness on Static and Dynamic Aspects of Accommodation among Digital Eye Strain Subjects

Abstract

Purpose: This study examined the impact of screen brightness on an OLED display, investigating the accommodation and pupillary responses of individuals with pre-existing digital eye strain. The hypothesis was that screen brightness would influence the dynamics of accommodation and pupillary response.

Design: Prospective, quasi-experimental study

Methods: This study was conducted in a single hospital setting. A total of 324 patients were screened for digital eye strain using a validated questionnaire. Forty-six participants who met the inclusion criteria were enrolled, comprising young subjects with no history of binocular vision anomalies or ocular problems contributing to binocular vision or digital eye strain. The dynamic accommodative response and pupillary motility of the participants dominant eye were continuously measured using an automatic refractometer as they read text passages under three different screen brightness settings: 200 lux, four hundred lux, and six hundred lux, each for two minutes. The study was conducted under preferred four hundred lux office room illumination, with text size kept constant at 12-point size and 100% letter contrast. Participants viewed the text from a fixed distance of 50 cm.

Results: Repeated-measures ANOVA revealed that screen brightness settings significantly affected both pupillary dynamics and accommodation response, with statistical significance at p < .001. Specifically, a screen brightness of four hundred lux, equal to the room illumination, was associated with acceptable accommodation latencies and ideal pupil responses. In contrast, the 200-lux screen brightness setting resulted in higher accommodation latencies, while the 600-lux screen brightness setting led to lower accommodation latencies but towards the lead of accommodation.

Conclusion: Maintaining adequate brightness settings on digital displays may improve eye function for people with digital eye strain. A screen brightness equal to the surrounding ambient illumination can help the eye to focus and minimize the need for constant adjustment. This may reduce their symptoms of digital eye strain, as accommodation lag is a major cause of this condition. Low screen brightness increases eye strain because it results in higher accommodation lag. Conversely, high screen brightness may cause a lead of accommodation and exacerbate digital eye strain symptoms. Optimizing the screen brightness to match the ambient illumination while working can be an important way to manage digital eye strain.