The Potential of Self-Controlled Focus for Myopia Prevention: A Pilot Study Using a Mobile Phone

Purpose The purpose of this study was to determine the short-term impacts of reading through self-controlled focus. Methods Thirteen near-emmetropes performed a 30-minute reading task under unrestricted working distance on a mobile phone while wearing either (1) a self-adjusted eyeglass (SAG) or (2) a plano eyeglass (PE), equipped with an integrated Time of Flight (ToF) distance sensor. The ocular impacts of the self-controlled focus on spherical equivalent refraction (SER), axial length (AxL), and choroidal thickness (ChT) were tested before and after reading. Temporal dynamics of dioptric correction, reading distance, and speed were tracked to assess the behavioral impact of the defocus correction. Results Our results show a significant reduction in hyperopic retinal defocus (mean difference = −1.12 diopter [D] ± 1.00 D, P < 0.005) accompanied by larger working distance (mean difference = 75.96 mm ± 33.88 mm, P < 0.05) under self-adjusted focus, as compared with the healthy controls. This behavioral change showed no significant influence on reading performance, as estimated by reading speed, but affected ocular responses: as expected, reduced hyperopic retinal defocus in SAG resulted in reduced AxL elongation (mean difference: 9 µm ± 4 µm, P < 0.05) and SER (mean difference = −0.17 D ± 0.078 D, P < 0.05). On the other hand, ChT exhibited a significant association with dioptric dynamics (P < 0.001), but not lens correction, suggesting the potential role of visual dynamics. Conclusions Self-controlled defocus has a significant impact on short-term eye changes under reading. Further work is necessary to understand the long-term impact of this solution and its interaction with individual behavioral responses. Translational Relevance Self-controlled defocus has the potential to reduce hyperopic retinal defocus for myopia prevention and control in schoolchildren.