A study recently published in Eye & Contact Lens led by a team of researchers from the Shandong University of Traditional Chinese Medicine evaluated the efficacy of orthokeratology (ortho-k) for slowing myopia progression in pediatric patients over the course of 2 years.
Talk about the study.
Investigators conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) across databases such as PubMed, Embase, Cochrane Library, Clinical Trials, CNKI, SinoMed, and Wanfang Data.
In total, seven RCTs and 655 eyes were included in the study.
Subsequently, the study authors pooled the weighted mean difference (WMD) between the ortho-k and control groups for axial length (AL) elongation as well as the odds ratio (OR) for rates of adverse events and dropout.
Findings?
Significant differences were observed in the effects of ortho-k versus control in slowing AL elongation, as shown below:
- -0.11 mm (95% confidence interval [CI], -0.13 to -0.08, P<0.01) at 6 months
- -0.16 mm (95% CI, -0.18 to -0.13, P<0.01) at 12 months
- -0.23 mm (95% CI, -0.29 to -0.18, P<0.01) at 18 months
- -0.28 mm (95% CI, -0.38 to -0.19, P<0.01) at 24 months
Researchers concluded that ortho-k reduced AL elongation of myopia most effectively in children within 6 months, with an enduring effect observed up to 24 months.
Go on…
Further, investigators noted a decline in the myopia control rate over time:
- 64% at 6 months
- 53% at 12 months
- 50% at 18 months
- 47% at 24 months
What else?
No statistical significance for adverse events between ortho-k and control groups was recorded (OR=2.63, 95% CI, 0.72 to 9.61, P=0.11).
Within a subgroup analysis, researchers highlighted that Caucasian children received more benefits than East Asian children at 12 months.
Additionally, pediatric patients with high myopia experienced more benefits than children with low to moderate myopia at 6 and 12 months.
Expert opinion?
The study authors noted that, while ortho-k was designed as an optical correction mainly for correcting low to moderate myopia, “it can also be used in high myopia children for myopia control and have better results.”
They added: “The mechanism of myopia progression is still needed to further elucidate the potential biological mechanisms of ortho-k for myopia control.”
Take home.
Ultimately, the research team observed that long-term efficacy and acceptability of ortho-k requires additional long-term research to confirm the data.
As such, while ortho-k continues to be an effective therapy for slowing myopia progression in pediatric patients, this study shows that the efficacy of myopia control can decrease with time.