Clinical

The CONTROL OrthoK Study

September 15, 2021

By Dwight Akerman, OD, MBA, FAAO, FBCLA

In prospective studies of low to moderate myopes, orthokeratology (OrthoK) lenses have been shown to effectively reduce axial elongation compared with controls in Asian (Cho et al. 2005; Kakita et al. 2011; Cho & Cheung 2012; Hiraoka et al. 2012; Swarbrick et al. 2015), Spanish (Santodomingo- Rubido et al. 2012; Paune et al. 2015), and American (Walline et al. 2009) children. However, these studies are heterogeneous in design. Six of the studies reported two-year efficacy, which varied from 32% to 56%.

The variation in myopia prevalence among children worldwide is attributed to both genetic and environmental factors (Lopes et al. 2009; Guggenheim et al. 2012; Williams et al. 2019). Therefore, the efficacy of myopia control treatments may differ between ethnic groups. Thus, Jakobsen and Moller conducted an 18-month randomized controlled trial including Scandinavian (Danish) children with low to moderate myopia assigned to receive either OrthoK lenses or single vision spectacles (SVS). 

Sixty Danish children aged 6–12 years with myopia ranging from 0.5 to 4.75 diopters (D) spherical component and refractive astigmatism ≤2.5 D in both eyes were randomly assigned to either OrthoK or SVS. The primary outcome variables were axial length (AL), measured every six months with the Haag-Streit Lenstar LS900, and adverse events, which were graded with the Efron Grading Scale for Contact Lens Complications.

The authors concluded that orthokeratology lenses reduced AL elongation in myopic Scandinavian children by 59%, with no treatment-requiring or vision-threatening adverse events. The results align with the outcomes of previous clinical trials.

Abstract

Control of Myopia Using Orthokeratology Lenses in Scandinavian Children Aged 6 to 12 Years. Eighteen-Month Data from the Danish Randomized Study: Clinical study Of Near-sightedness; TReatment with Orthokeratology Lenses (CONTROL study)

Trine Moldrup Jakobsen and Flemming Møller

Purpose: To investigate the efficacy of myopia control defined by axial elongation and safety of orthokeratology lenses (OKL) in a Scandinavian (Danish) population.

Methods: Sixty Danish children aged 6–12 years with myopia ranging from 0.5 to 4.75 diopters (D) spherical component and refractive astigmatism ≤2.5 D in both eyes were randomly assigned to either OKL or single-vision spectacles (SVS). The study duration was 18 months. Outcome measures were axial length (AL) measured with Lenstar LS900 (Haag-Streit, Koeniz, Switzerland) and adverse events graded with Efron Grading Scale for Contact Lens Complications.

Results: Nineteen participants completed the 18-month follow-up in the OKL group and 28 in the SVS group. The average AL elongation in the OKL group was 0.24 mm smaller as compared to the SVS group (95% confidence interval 0.12–0.36, mixed model adjusted for baseline sex, age, and AL). There were no fast progressors (>0.75 D/year) in the OKL group during the follow-up period, in contrast to 22% in the SVS group. No treatment-requiring or vision-threatening adverse events were observed.

Conclusion: Orthokeratology lenses reduced AL elongation in myopic Scandinavian children by 59%, with no treatment-requiring or vision-threatening adverse events. The results align with the outcomes of previous clinical trials.

Jakobsen, T. M., & Møller, F. (2021). Control of myopia using orthokeratology lenses in Scandinavian children aged 6 to 12 years. Eighteen-month data from the Danish Randomized Study: Clinical study Of Nearsightedness; TReatment with Orthokeratology Lenses (CONTROL study). Acta Ophthalmologica.

DOI: https://doi.org/10.1111/aos.14911

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