Clinical Optometry (Feb 2024)
Peripheral Eye Length Evaluation in Myopic Children Undergoing Orthokeratology Treatment for 12 Months Using MRI
Abstract
Yu Chen Low,1 Bariah Mohd-Ali,1 Mizhanim Mohamad Shahimin,1 Norhani Mohidin,1 Hamzaini Abdul-Hamid,2 Siti Salasiah Mokri3 1Optometry and Vision Science Program and Research Centre for Community Health (REACH), Faculty of Health Sciences, UKM Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia; 2Department of Radiology, Faculty of Medicine, UKM, Cheras, Kuala Lumpur, Malaysia; 3Department of Electrical, Electronics and Systems, Faculty of Engineering and Built, UKM, Bangi, Selangor, MalaysiaCorrespondence: Bariah Mohd-Ali, Optometry and Vision Science Program and Research Centre for Community Health (REACH), Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, 50300, Malaysia, Tel +603-92897602, Email [email protected]: To investigate changes in peripheral eye length (PEL) in myopic children undergoing orthokeratology (Ortho-K) treatment for 12 months using MRI. The results were compared to single vision spectacle wearers (SVS).Patients and Methods: A total of 70 children with myopia (aged 8– 9 years old) were recruited. A total of 45 children were fitted with Ortho-K, and 25 were fitted with SVS. The PEL and axial length (AL) were measured by using MRI 3-Tesla, whereas central and peripheral refraction (PR) measurements were conducted at ± 30 degrees horizontally with nasal (N) and temporal (T) intervals of 10°, 20°, and 30° and with an open field autorefractometer (WAM-5500 Grand Seiko). All the measurements were conducted at the baseline and 12 months.Results: The MRI analysis indicates that at 12 months, the SVS group showed more elongation of the PEL and AL at all eccentricities than the Ortho-K group did (p < 0.05). The Ortho-K group only showed significant PEL elongation beyond 20 degrees at N20, N30, T20, and T30 (p < 0.05); however, a significant reduction in the AL was detected in the center AL, N10, and T10 (p < 0.05). All eccentricities in the relative PR of the Ortho-K group were significantly more myopic than at the baseline (p < 0.05), whereas in the SVS group, all eccentricities in the relative PR were shown to be significantly more hyperopic than at the baseline (p < 0.05). The PEL and PR showed negative correlations at 12 months in the Ortho-K group.Conclusion: MRI analysis can be utilized to describe changes in PEL in myopic children. It appears that as myopia progressed in Ortho-K lens wearers, the PEL increased by a greater amount than the AL did; thus, the retina was reshaped to become increasingly oblate and to display peripheral myopic defocus.Keywords: myopia, peripheral eye length, peripheral refraction, children
