PARENTS OF young children are often attracted to orthokeratology (ortho-k) simply because the lenses are typically worn and cared for at home. But what happens when the child’s prescription is too high for ortho-k?
Partial reduction ortho-k, in which the max amount of treatment is obtained with overnight ortho-k lens wear and daytime vision is enhanced with spectacles or soft contact lenses, is an option. Studies have shown that high myopes treated with partial reduction ortho-k achieve results similar to those undergoing full correction ortho-k (Charm and Cho, 2013; Lyu et al, 2020; Wang et al, 2024).
It is even plausible that partial reduction ortho-k for high myopia may actually achieve better myopia control than full ortho-k for low to moderate myopes because of the increased amount of myopic defocus induced in the peripheral retina (Charm and Cho, 2013). To date, no studies have addressed the potential impact of soft multifocal/dual focus lenses or myopia control spectacles combined with partial reduction ortho-k.
On-label ortho-k can correct up to –6.00D of myopia and up to –1.75D of astigmatism, but there are several off-label designs that can achieve success with much higher prescriptions (Lipson, 2019). Practitioners should practice special caution when considering off-label ortho-k, especially in children, due to the potential impact of more aggressive central pressure and flattening when full correction is attempted.
CASE REPORT
An 8-year-old Asian male presented for a myopia management consult. The parents exhibited a heightened concern about their son’s drastic myopia progression over the past two years, stating that his prescription was increasing every six to eight months. Both parents were high myopes. The child was highly academic, an avid reader, and spent very little time outdoors.
His previous prescription (six months prior) was –7.75 –2.00 x 180 OD and –8.25 –1.50 x 165 OS. Manifest refraction was –8.50 –2.25 x 180 OD and –8.75 –1.50 X 170 OS with keratometry 39.75 @ 176, 41.5 @ 086 OD and 40.50 @ 174, 41.00 @ 084 OS. Axial lengths were 27.80mm OD and 27.92mm OS.
After a thorough discussion of pharmaceutical therapy, soft toric multifocals, and ortho-k, the parents were adamant that partial reduction ortho-k, along with daytime spectacles, was the best option for their son, mainly due to his young age. Anterior and posterior segment health was normal. Best-corrected vision was 20/20 OD/OS/OU.
Lenses were designed with a target of a –4.00D myopia reduction. The reason for this conservative approach was twofold: 1) protecting the patient’s corneal integrity by avoiding aggressive treatment, and 2) unlikelihood of any further treatment being successful due to the patient’s flat K values. After four weeks of consistent overnight wear, the patient was elated with a 50% reduction in his prescription and considerably thinner spectacles (Figure 1). Post-treatment manifest refraction was–4.50 –0.75 x 020 OD and –3.50 DS OS.
He has now worn partial reduction ortho-k for more than 10 years with minimal change in his myopia and considerably reduced axial elongation (Figure 2). He now supplements his daytime vision with single-vision spherical soft lenses.
Although partial ortho-k does not achieve 100% freedom from daytime correction, it can increase a patient’s quality of life by improving uncorrected visual acuity while still providing effective myopia control.
REFERENCES
1. Charm J, Cho P. High myopia-partial reduction ortho-k: a 2-year randomized study. Optom Vis Sci. 2013 Jun;90:530-539.
2. Lyu T, Wang L, Zhou L, Qin J, Ma H, Shi M. Regimen Study of High Myopia–Partial Reduction Orthokeratology. Eye Contact Lens. 2020 May;46:141-146.
3. Lispon M. Contemporary Orthokeratology. 2019. Available at contemporaryorthokeratology.com. Accessed 2024 Jul 11.
4. Wang F, Wu G, Xu X, et al. Orthokeratology combined with spectacles in moderate to high myopia adolescents. Cont Lens Anterior Eye. 2024 Feb;47:102088.
