A study recently published in Ophthalmology and Therapy sought to evaluate the efficacy of using concurrent orthokeratology (ortho-k) and low-concentration atropine to control myopia in pediatric patients.
Give me some background first.
While ortho-k and low-dose atropine monotherapies have been proven to aid in myopia correction, the study authors noted that younger children and those with lower myopia are more likely to experience rapid axial length (AL) elongation with mono-treatment.
Now talk about the study.
In this retrospective study, investigators analyzed the medical records of baseline and follow-up visits for pediatric patients between the ages of 7 and 14 over the course of 24 months to establish if the treatment results were long-term in nature.
How were the treatments compared?
The study included 68 children who received ortho-k monotherapy and 68 children who received 0.01% atropine in tandem with ortho-k (AOK).
Participants underwent comprehensive baseline ophthalmic testing and had their AL measured every 6 months to assess the efficacy of the treatments.
No significant differences were noted in baseline characteristics between the treatment groups.
Findings?
The AL significantly increased over time in both groups.
At the 2-year mark, the AL elongation for the combination therapy group was 0.16 mm lower than the ortho-k group (0.28 mm + 0.22 mm vs. 0.44 mm + 0.34 mm, p = 0.001)—a 36% decrease from the mono-treatment group.
Go on…
The research team observed significant AL elongation suppression rates in the atropine and ortho-k combination therapy group for the initial 1.5 years of treatment:
- 0-6 months: 62.5%
- 6-12 months: 33.3%
- 12-18 months: 38.5%
Anything else?
Additionally, a multiple regression analysis demonstrated an important relationship between age and treatment effect:
Investigators found a reduced treatment effect for older children, indicating that a 1-year age decrease was associated with a 0.06 mm increased delay in AL elongation in the atropine/ortho-k group.
Expert opinion?
The study authors noted that one potential explanation for this decreased treatment effect is that “the muscarinic receptors might be exhausted after a long time of binding with atropine, causing a reduction in efficacy.”
Further, based on their regression analyses, they hypothesized that “the combined effect of atropine and [ortho-k] would decrease as age increased and might not be significant in children older than 10.”
Take home.
Prescribing a combination therapy of low-dose atropine and ortho-k for pediatric patients demonstrated a stronger suppression effect on AL elongation than ortho-k monotherapy alone.
However, the add-on effect of 0.01% atropine with ortho-k only occurred in the first 1.5 years of treatment.
The results of the study also illustrated that younger children benefited more from combination therapy to control myopia.