Here's a paper showing no help with bifocal to slow down myopia progression.
Pärssinen, O., Kauppinen, M., & Viljanen, A. (2014). The progression of myopia from its onset at age 8-12 to adulthood and the influence of heredity and external factors on myopic progression. A 23-year follow-up study.
Acta ophthalmologica,
92(8), 730–739.
https://doi.org/10.1111/aos.12387
Bifocal treatment, accommodation stimulus and reading distance
At the end of the 3-year treatment, myopic progression was not slowed down by using bifocals or by Reading without spectacles (Pärssinen et al.
1989). Thereafter, the children received ordinary fully corrected spectacles with a recommendation of continuous use. Myopic progression up to Follow-up 5 was −3.67 D ± 1.64 in the continuous-use group, −3.67 D ± 1.97 in the distant-use group and −3.76 D ± 1.85 in the bifocal group, with no significant differences between the groups (p = 0.944). There were also no significant differences in myopic progression between the treatment groups when males and females were analysed separately. Thus, in the analyses of this study, the treatment groups are not taken into account.
When the average reading distance calculated from four measurements at childhood and SE at the end of the 3-year follow-up and at the two adult ages was compared, significant correlations were observed among females, and when both sexes were combined (Table
2), the shorter the reading distance in childhood, the greater the myopia in adulthood. However, the correlation did not hold among males. Among females, the correlations between childhood reading distances and SE at different ages remained significant, also after controlling for the age of myopia onset and body height at the respective ages. However, the less the childhood accommodation stimulus, the greater the myopia in childhood, but accommodation stimulus in childhood did not correlate with SE in adulthood.
