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Ortho-K shows promise as alternative treatment for severe myopia
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A recently published study found that partial-reduction orthokeratology effectively slowed myopic progression in highly myopic subjects.
“While a number of reported studies have shown the effectiveness of orthokeratology for myopic reduction and control in low to moderate myopia, fully correcting high myopes can be challenging,” Jessie Charm, MPhil, said in an interview with Primary Care Optometry News. “One option is to partially correct high myopes using overnight orthokeratology combined with spectacle wear to correct their residual refractive errors in the daytime. This is a novel wear modality, and the effectiveness of myopic control using this combination was unknown. Our study showed that this method is effective.”
The single-masked randomized study included 28 highly myopic children, 12 who underwent partial-reduction (PR) ortho-K and 16 who were controls. Subjects in the PR ortho-K group were fitted with custom made four-zone ortho-K lenses with target reduction of 4.00 D for both eyes. Residual refractive errors were corrected with single-vision spectacles for clear vision in the daytime. Control subjects were fully corrected with single-vision spectacles only.
Upon completion of the 2-year study, the study authors observed a 4.50-D median reduction and a mean increase in axial length of 0.19 mm in the PR ortho-K group and 0.51 mm in the control group (P = .005). This showed a 63% slower elongation of axial length in the PR ortho-K group compared with the group corrected with spectacles only.
“Slowing axial elongation can help to reduce potentially sight-threatening complications, such as retinal detachment, macular degeneration or glaucoma,” Charm said.
“Subjects in the study group initially had at least 6 D of myopia,” Charm said. “After using ortho-K, there was still residual myopia of at least 2 D.”
“The main limitation to this study is the relatively small sample size due to high dropout rates,” she said. “For the orthokeratology subjects, the reason for dropout was the use of stringent protocol and only one lens design. For the control subjects, anxious parents were concerned about the myopic progression in their children and they did not wish to continue as controls, seeking myopic control treatment elsewhere.”
However, the results remain promising, according to Charm.
“Children with high myopia and alarming progression rates now have a promising, safe and feasible option for myopia reduction and control,” she said. “The results of this study represent a big leap in alternatives for high myopes.” – by Daniel R. Morgan