Efficacy of high add soft bifocal contact lenses in myopia control at a five-year follow-up

Introduction . Myopia is a widespread and growing public health concern. The impact of soft contact lenses (MCLs), which create a relative myopic peripheral defocus with an add power of +1.5 to +2.00 D, on slowing myopia progression has been widely studied in short- and long-term studies. However, studies lasting more than three years that evaluate the effect of high add multifocal soft contact lenses (MFCLs) on ocular growth and refractive error dynamics are limited. Purpose: to evaluate the effect of bifocal soft contact lenses (BFCLs) Prima BIO Bi-focal with an add power of +4.00 D on the dynamics of refractive error and axial eye length in patients with progressive myopia over a prolonged period of wear. Materials and methods. Twenty-eight patients (28 eyes) with bilateral myopia, with a spherical equivalent (SE) refractive error between –0.75 and –5.5 D, astigmatism <1.25 D, and anisometropia up to 1.00 D, were included in this study conducted from 2018 to 2023. The mean age of the participants was 10 years. Based on the degree of myopia, the patients were divided into two groups: the first group consisted of 13 patients with mild myopia (–0.75 to –3.00 D), while the second group consisted of 15 patients with moderate myopia (–3.25 to –5.50 D). Cycloplegic refraction, visual acuity, and axial eye length were evaluated at the initial examination and follow-up visits at 12, 24, 36, 48, and 60 months. Patients in both groups wore BFCLs Prima BIO Bi-focal with an add power of +4.00 D on a monthly regimen for at least 10 hours per day. Results. After 60 months of wearing high add BFCLs, the change in refractive error from baseline was 0.25 (0; 0.75) D in the first group and 1.25 (0.5; 1.5) D in the second group. The increase in axial eye length after 60 months compared to baseline was 0.14 (0.03; 0.24) mm in the group with mild myopia, and 0.48 (0.21; 0.55) mm in the group with moderate myopia. Conclusion. The data indicate a stabilizing effect of high add BFCLs on the progression of both mild and moderate myopia. A greater antimyopic effect, in terms of refractive error dynamics and axial elongation, was observed in the group with mild myopia. Further research is needed to explore the correlation between the antimyopic effect of BFCLs and the degree of myopia.