Abstract
Purpose :
The evaluate the efficacy of a high add power soft multifocal contact lens prototype to control axial length growth on a young myopic population.
Methods :
This is a prospective,randomized, clinical cross-over study. 24 subjects (aged 8-12) were recruited. They were myopic (0.50 to 6D) and progressing of at least 0.50D in the last year. Refractive astigmatism was <0.75D. Clinical assessment includes cycloplegic refraction, contrast visual acuity, binocular vision assessment, corneal topography, aberrometry, axial length, pupil measurement, fundus examination and slit lamp evaluation.
Participants were randomly fitted on one eye with a soft bifocal lens, designed with a +5.00D add power surrounding a central zone correcting a refractive error at distance. Transition and central distance zone size were customized for every patient. The second eye was fitted with a spherical lens as a control. Lenses must be worn minimally five days a week for 8h00 per day. After six months, lenses were crossed-over. This means that the first eye was refitted with the control lens and the second one with the test lens.
Results :
The clinical population is made of 14 girls and ten boys, average age of 10.5 + 1.2 y.o. Seven participants were excluded for the final analysis (3 drop-outs, 4 for compliance issues). Baseline refraction was -3.44 + 1.40 D evolving to -3.61 + 1.43 D after 6 months for the test eye compared with -3.29 + 1.26 evolving to -3.62 + 1.19 D for the control. Axial length went from 24.75 + 0.61 to 24.88 + 0.72 on the test eye and from 24.70 + 0.69 to 24.86 + 0.72 mm on the control. There is a significant difference between test and control based on myopia evolution. For axial length, there is a significant difference for those who were fitted with the control first and the test lens in the following 6 months, AL limiting its elongation when wearing multifocal lenses. Reported on an annual basis, the efficacy of this prototype lens was established at 60% vs control. Finally, there is a moderate correlation between the treatment zones and myopia progression, the smaller distance zones being associated with lower myopia progression (r=0.414).
Conclusions :
It is possible to fit soft bifocal lens with high add power and be effective to control myopia progression, without impacting vision at distance. This prototype may be considered as a valuable device for myopia management in the future.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.