Clinical Efficacy of Periphheral Defocus Versus Single Vision Spectacles in Myopia Progression Control

BACKGROUND: This study investigates whether the myopia control efficacy of Peripheral Defocus spectacle lenses (PDL), as established in controlled trials, holds true in a real-world clinical environment.

PATIENTS AND METHODS: This single centre, retrospective study analysed clinical records from the University Eye Hospital Basel (2019 - 2024). Patients included had myopia diagnosis, had undergone at least three axial eye length measurements (approximately at 6, 12 and 18 months after starting therapy), and were treated with either PDL or Single Vision (SV) spectacle lenses exclusively, with no concurrent myopia treatments (e.g., atropine or contact lenses). Axial elongation and spherical equivalent (SE) were compared using independent t-tests. Statistical significance was set at p < .05.

RESULTS: Of 177 patients, 30 were treated with PDL and 37 with SV lenses. Compared to SV lenses, PDL lenses significantly reduced axial elongation over 6, 12, and 18 months. At 6 months, average axial elongation in the left eye was 0.024 mm (CI: 0.007 - 0.041) in the PDL group compared to 0.101 mm (CI: 0.082 - 0.140) in the SV group (p = 0.005); in the right eye, - 0.003 mm (CI: - 0.040 - 0.034) vs. 0.112 mm (CI: 0.081 - 0.143) (p < 0.001). At 12 months, average axial elongation in the left eye was 0.088 mm (CI: 0.036 - 0.140) with PDL vs. 0.167 mm (CI: 0.119 - 0.215) with SV (p < 0.05); in the right eye 0.080 mm (CI: 0.029 - 0.131) vs. 0.191 mm (CI: 0.146 - 0.236) (p < 0.005).

At 18 months, left eye elongation was 0.110 mm (CI: 0.028 - 0.192) with PDL vs. 0.229 mm (CI: 0.182 - 0.276) with SV; right eye 0.078 mm (CI: 0.008 - 0.148) vs. 0.254 mm (CI: 0.208 - 0.300) (p < 0.001 for both).

No significant differences in SE were observed at 6 or 12 months. A significant difference in right eye SE was noted at 18 months (p = 0.044); however, no consistent trend emerged.

DISCUSSION: This study confirms that PDL lenses significantly reduce myopic axial elongation compared to SV lenses in a real-world clinical setting. These results reinforce prior controlled trial findings and support the clinical adoption of PDL for effective myopia management.