Inhibitory effect of a distant-image screen on nearwork-induced transient myopia in children

Objective  To investigate whether a distant-image screen display has an inhibitory effect on children’s nearwork-induced transient myopia (NITM).

Methods  A prospective self-controlled study was conducted.From March 2022 to March 2023, 120 pediatric volunteers, aged 4 to 12 years, with a mean age of (5.0±2.2) years, were recruited at Tianjin Eye Hospital.Subjects with refractive errors underwent tests wearing corrective lenses.Subjects were categorized based on accommodative response into three groups: accommodative lead (16 subjects, 32 eyes), accommodative equivalent (48 subjects, 96 eyes), and accommodative lag (56 subjects, 112 eyes). Subjects were also divided by myopia status into myopic (20 subjects, 40 eyes) and non-myopic (100 subjects, 200 eyes) groups.Using a random number table, the subjects were assigned to first view video images for 30 minutes on either an iPad or a distant light screen display.After a two-hour rest between the two sessions, the viewing modality was switched.Visual acuity, refractive power, lens thickness, NITM degree, and NITM recovery time were recorded before and after viewing videos via both modalities.Visual acuity, lens thickness, NITM degree, and recovery time following video viewing via the two modalities across different accommodation types and refractive types were compared.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Tianjin Eye Hospital (No.2022099), and all guardians of the subjects provided informed consent for this study.

Results  The NITM degree and recovery time after watching videos on a distant-image screen display were (0.00±0.36)D and (25.33±15.48) seconds, respectively.The NITM degree and recovery time after watching videos on an iPad were (-0.20±0.40)D and (33.33±17.68) seconds, respectively.Compared with watching videos on an iPad, watching videos on a distant-image screen display resulted in better immediate distance vision, lower myopic refractive power, thinner lens thickness, lower NITM degree, and shorter recovery time, with statistically significant differences ( t=-7.688, 7.842, -4.210, 2.331, -2.887; all P<0.05). After viewing the distant-image screen display and iPad, there was no significant difference in the overall comparison of visual acuity change, lens thickness change, NITM degree and NITM recovery time among the accommodative lead, accommodative equivalent and accommodative lag groups ( H=0.584, 4.923, 1.514, 2.634; all P>0.05. H=3.265, 1.884, 1.606, 1.922; all P>0.05), and there was also no significant difference between the myopic and non-myopic groups ( Z=-1.555, -1.700, -0.254, -2.336; all P>0.05. Z=-1.125, -0.446, -1.033, -0.759; all P>0.05).

Conclusions  The use of a distant-image screen display can reduce the NITM caused by near viewing and shorten the NITM recovery time, which is effective for children with different refractive states and accommodative types.