Related Experiment Video
Updated: Sep 21, 2026
Subjective Refraction Test Using a Smartphone for Vision Screening
Published on: October 18, 2024
Short-term effects of distant-image screen and myopic defocus on choroidal thickness in children: a randomized pilot
Xingyi Guo1,2,3, Chuanli Zhang1,2,3, Yiyuan Wu1,2,3
1Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China.
Purpose:
This study aimed to characterize the changes in choroidal thickness (ChT) in response to optical approaches using the distant-image screen (DIS) device and defocus-incorporated multiple segments (DIMS) lenses.
Design:
This is a prospective, randomized, controlled, crossover trial.
Participants:
A total of 40 children (8-13 years of age) with spherical equivalent refraction (SER) ranging from -0.50 to -6.00 diopters (D) were recruited and randomized into 4 groups: children who watched videos using either a DIS or a tablet computer (TC) and those wearing DIMS or single-vision lenses (SVL).
Methods:
In their assigned groups, children watched videos for 90 min in stage I, followed by a 3-7-day recovery period. After this recovery period, the children in the TC group were crossed over to the DIS group, and those in the DIS group were crossed over to the TC group for an additional 90 min in stage II. The SER was measured before and after watching videos using an open-field autorefractor. The ChT in the central (1 × 1 mm), superior, inferior, nasal, and temporal regions in 1-3 mm (S3, I3, N3, and T3) and 3-6 mm (S6, I6, N6, and T6) were measured before and after watching videos using full-range swept-source optical coherence tomography (SS-OCT).
Main Outcome Measures:
The main outcome measure was the changes in regional ChT.
Results:
After 90 min of video watching, the SER in the TC group significantly increased after viewing 90-min videos (-2.14 ± 1.15 D vs.-2.26 ± 1.16 D, p = 0.036), whereas no significant difference was observed in the DIS group. Among the participants wearing SVL, the ChT changes in the DIS group were significantly higher than those in the TC group at I3 (p = 0.036) and T3 (p = 0.032), and the changes in other regions were not significantly different between the two groups. For participants using TC, the DIMS group showed greater ChT thickening at C (9.54 ± 3.19 μm, p = 0.005), I3 (6.44 ± 3.04 μm, p = 0.043), N3 (9.10 ± 3.17 μm, p = 0.007), and T3 (8.00 ± 3.17 μm, p = 0.017) than the SVL group. The combination of DIMS and DIS exhibited greater ChT thickening at I3 (11.23 ± 4.07 μm, p = 0.009) compared to the SVL and TC groups.
Conclusion:
Short-term long-distance working mode and myopic defocus may exert beneficial effects on choroidal variation in myopic children.
Clinical Trial Registration Number:
https://www.chictr.org.cn/showproj.html?proj=184978, Identifier ChiCTR2200065741.
