Orthokeratology (ortho-k) is a strong option for myopia management, but higher astigmatism can present design challenges. The case presented in this article describes progressive myopia and significant corneal toricity in a 10-year-old girl who initially experienced halos at night. A targeted lens redesign resolved her symptoms, highlighting the value of customizing treatment zone geometry in astigmatic ortho-k fits. Although the redesign principles were applied to both her right and left orthokeratology lenses, this report will highlight the treatment of the patient’s left eye.
Case Description
A 10-year-old white female patient presented for a myopia management consultation with a history of progressive myopia and high astigmatism. Her chief complaint highlighted frustration with increasing myopia over time and dependence on glasses for academic and recreational activities. The family expressed interest in myopia control and desired a glasses-free lifestyle, making ortho-k a strong candidate for her care plan.
Her presenting spectacle refraction was -3.50 -1.75 x 165, and corneal shape demonstrated significant toricity. After a thorough discussion of risks, benefits, and expectations, the patient was fitted with NightLens (WAVE Eye Care), designed with the WAVE Contact Lens System. The goal was to create a lens with a well-centered treatment zone capable of reducing her myopia and addressing her higher-than-average corneal astigmatism.
Initially, the patient performed well with an over-refraction of +0.75 -0.75 x 172. She reported overall satisfaction with vision during the day but noticed halos and glare with nighttime lighting, particularly while riding in the car. Her visual acuity during the day was 20/20. Over the next several years, as the patient approached driving age, she and her parents were concerned about the nighttime visual disturbances.
Discussion
Topography confirmed an adequate central flattening pattern, but analysis of the treatment zone showed a nearly circular shape, which did not fully account for the difference in power between the principal meridians. It was hypothesized that her halos were due to uncorrected residual astigmatism that were more noticeable in dim lighting, resulting from incomplete neutralization of her corneal toricity.
To resolve the issue, the lens design was modified to incorporate an oval treatment zone, with a longer horizontal axis and a shorter vertical axis. This adjustment leverages the differential hydraulic forces along each meridian and allows for more tailored epithelial redistribution. The result is a peripheral power profile that varies between the horizontal and vertical meridians—effectively better aligning the treatment to her corneal astigmatism.
Following the lens redesign and several nights of wear, the patient reported a significant improvement in night vision symptoms. Topography confirmed a more toric treatment zone, and her over-refraction was +0.50 -0.50 x 170. She was able to maintain clear vision throughout the day and reported no further issues with halos or glare in dim illumination.
Conclusion
This case highlights the importance of understanding how treatment zone geometry affects epithelial redistribution in ortho-k, especially in patients with moderate-to-high astigmatism. Oval treatment zones can be a powerful tool when addressing residual cylinder in cases where a symmetric lens design falls short. Visual needs and demands evolve with patients over time, and those evolving needs can be met with highly customizable lens designs.
To hear Dr. Chapman discuss this case, click here.