JMIR Publications

ABSTRACT

Background:

As digital and AI-enabled learning become embedded in children’s education, the relevant health question is not only how much screen time children accumulate, but whether the optical viewing environment can be redesigned. Conventional tablets are generally viewed at short distances and require sustained accommodation and convergence. Earlier distant-image systems were predominantly fixed desktop devices, limiting storage, portability, and deployment in homes and schools. A foldable display that preserves distant-image viewing could alter the optical exposure associated with digital learning without changing course content.

Objective:

To compare short-term ocular responses after an identical 40-minute digital learning task delivered through an S1 foldable distant-image display or a conventional tablet in children.

Methods:

This single-center, prospective, parallel-group randomized controlled trial enrolled 48 children aged 6 to 16 years and allocated them in a 1:2 ratio to a conventional tablet group (n=16) or an S1 group (n=32). Both groups viewed the same online course and video content for 40 minutes. The tablet was viewed at approximately 40-50 cm; the S1 presented the visual content as a virtual image at approximately 6 m. The primary outcome was the change in noncycloplegic spherical equivalent (SE). Key secondary outcomes were changes in subfoveal choroidal thickness and a 1-to-5 visual fatigue composite score adapted from 16 Computer Vision Syndrome Questionnaire symptom domains. Exploratory outcomes were logMAR visual acuity and short-term axial length. Baseline-adjusted linear models included age and used HC3 heteroskedasticity-consistent standard errors.

Results:

The mean ages were 11.1 (SD 2.6) years in the tablet group and 10.2 (SD 2.2) years in the S1 group. Mean SE changed by -0.27 D after tablet viewing and +0.10 D after S1 viewing; the adjusted between-group difference was +0.38 D (95% CI 0.27-0.49; P<.001). Mean choroidal thickness decreased by 11.1 μm in the tablet group and increased by 11.2 μm in the S1 group; the adjusted difference was +22.0 μm (95% CI 14.8-29.2; P<.001). Visual fatigue increased by 0.69 points in the tablet group and decreased by 0.22 points in the S1 group; the adjusted difference was -0.62 points (95% CI -0.87 to -0.38; P<.001). The adjusted differences in logMAR visual acuity and axial length were -0.049 (95% CI -0.072 to -0.026; P<.001) and -0.012 mm (95% CI -0.023 to -0.001; P=.041), respectively. No device-related adverse events occurred.

Conclusions:

During a single 40-minute digital learning task, the foldable distant-image display produced more favorable short-term SE, choroidal, and visual-fatigue responses than a conventional near-viewed tablet. These findings provide randomized mechanistic evidence that desktop distant-image optics can be translated into a foldable display modality for viewing-centered digital learning. They do not establish long-term myopia prevention, control of axial elongation, or full functional equivalence to a tablet computer. Clinical Trial: Chinese Clinical Trial Registry, ChiCTR2100047059; registered June 7, 2021;