Effectiveness of defocus lenses with multi-zone positive optical defocus design versus high aspheric micro-lens design in controlling myopia

Objective To compare the effectiveness of Defocus Incorporated Multiple Segments (DIMS) and High Aspheric Lenslet (HAL) defocus lenses in controlling myopia.

Methods A total of 214 children and adolescents who were fitted with defocus lenses (DIMS or HAL) in our hospital from January to June 2023 were selected, including 100 cases in DIMS group and 114 cases in the HAL group. Changes in parameters such as spherical lens power, cylindrical lens power, spherical equivalent (SE), corneal curvature (K), axial length (AL), binocular accommodative response (BCC), positive/negative relative accommodation (PRA/NRA), distance/near latent phoria (DLP/NLP), and accommodative convergence to accommodation ratio (AC/A) were compared between the two groups before wearing and after wearing the lenses for 6 months, and the effectiveness of myopia control between DIMS and HAL was further compared.

Results After wearing the lenses (DIMS or HAL) for 6 months, the average increase in axial length was (0.09±0.14) mm, the average increase in spherical lens power was (-0.11±0.23) D, the average increase in astigmatism was (-0.07±0.16) DC, and the average increase in spherical equivalent was (-0.15±0.24) D, with statistically significant differences observed for all these changes (t=9.24, -7.27, -6.60, -9.03, respectively, P < 0.001). Compared with parameters before wearing the lenses, statistically significant differences were noted after wearing for 6 months in spherical lens power, cylindrical lens power, SE, BCC, PRA, DLP, average K, and AL (P≤0.001), except for NRA (t=-0.12, P>0.05), NLP (t=-0.28, P>0.05), and AC/A (t=0.33, P>0.05). The differences in parameters between the two groups after wearing the lenses for 6 months showed a statistically significant difference only in the AL difference (t=4.38, P≤0.001), with no statistically significant differences observed for other parameter differences (P>0.05).

Conclusion Wearing defocus lenses has a positive effect on controlling myopia, delaying axial length elongation, and maintaining binocular visual function balance.