Multifocal Orthokeratology versus Conventional Orthokeratology for Myopia Control: A Paired-Eye Study

Abstract

We conducted a prospective, paired-eye, investigator masked study in 30 children with myopia (−1.25 D to −4.00 D; age 10 to 14 years) to test the efficacy of a novel multifocal orthokeratology (MOK) lens compared to conventional orthokeratology (OK) in slowing axial eye growth. The MOK lens molded a center-distance, multifocal surface onto the anterior cornea, with a concentric treatment zone power of +2.50 D. Children wore an MOK lens in one eye and a conventional OK lens in the fellow eye nightly for 18 months. Eye growth was monitored with non-contact ocular biometry. Over 18 months, MOK-treated eyes showed significantly less axial expansion than OK-treated eyes (axial length change: MOK 0.173 mm less than OK; p < 0.01), and inner axial length (posterior cornea to anterior sclera change: MOK 0.156 mm less than OK, p < 0.01). The reduced elongation was constant across different baseline progression rates (range −0.50 D/year to −2.00 D/year). Visual acuity was less in MOK vs. OK-treated eyes (e.g., at six months, MOK: 0.09 ± 0.01 vs. OK: 0.02 ± 0.01 logMAR; p = 0.01). We conclude that MOK lenses significantly reduce eye growth compared to conventional OK lenses over 18 months.

The Limited Value of Prior Change in Predicting Future Progression of Juvenile-onset Myopia

“…Previous studies have used a strategy of recruiting only those with faster progression of at least −0.50 D or more in the previous year 26,27 . This strategy of enrolling fast progressors may be more effective in the first year compared with subsequent years.…”

“…Expert panels have recommended against using prior progression as an entry criterion for myopia control clinical trials because of measurement error, bias, and ethical considerations 22,23 . Nevertheless, surveys of pediatric ophthalmologists indicate that a rapid rate of progression (>1 D/y) is the main reason for their initiation of myopia control, and some recent clinical trials have used the previous rate of progression as an entry criterion 24–27 . The results of SCORM provide some support for the use of history of progression.…”

Simultaneous Myopic Defocus for Myopia Control: Effect on Accommodation, Peripheral Refraction and Retinal Image Quality in Non-Presbyopic Patients

“…These optical treatments had a slowing effect on the progression of myopia, but the change in peripheral refraction responsible for this effect is not fully understood. The axial length measured prospectively in a paired-eye study using standard orthokeratology in one eye and multifocal orthokeratology, showed significantly less axial length elongation in the eye fitted with multifocal orthokeratology, but with no significant difference in the peripheral refraction change between the two lenses in children [20]. Additional longitudinal studies have so far not been able to correlate the progression of myopia in humans with a change in the peripheral refraction in children [61,62].…”

“…Another hypothesis regarding optical treatment methods is that exposing the retina to an on-axis simultaneous myopic defocus slows the progression of myopia. This optical method shows good results in slowing the progression of myopia in children [16][17][18][19][20]. On-axis simultaneous myopic defocus is also applied in multifocal contact lenses for the correction of presbyopia [21,22].…”

“…A study using monovision in children showed that the far-correction eye accommodates normally [22]. Additionally, with soft contact lenses [18] and multifocal orthokeratology [20], accommodation is not highly affected in children when a simultaneous defocus is applied. Apart from a slight image degradation that comes with the use of multifocal optics [23], such optical correction methods are well tolerated.…”