Axial growth and meridian modulation of cornea power in children wearing orthokeratology lenses of different back optic zone diameters

Muhan Sun; Mengdi Li; Hua Bi; Ting Wang; Shuxian Zhang; Xiaoyan Yang; Bin Zhang; Lihua Li

doi:10.1016/j.ajo.2025.07.009

Axial growth and meridian modulation of cornea power in children wearing orthokeratology lenses of different back optic zone diameters

Am J Ophthalmol. 2025 Jul 10:S0002-9394(25)00362-9. doi: 10.1016/j.ajo.2025.07.009. Online ahead of print.

Authors

Muhan Sun¹, Mengdi Li², Hua Bi³, Ting Wang², Shuxian Zhang², Xiaoyan Yang², Bin Zhang⁴, Lihua Li⁵

Affiliations

¹ Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital Optometric Center, Tianjin, China; College of Optometry, Nova Southeastern University, Davie, FL, United States.
² Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital Optometric Center, Tianjin, China; Nankai University Optometry Institute, Tianjin, China.
³ College of Optometry, Nova Southeastern University, Davie, FL, United States.
⁴ College of Optometry, Nova Southeastern University, Davie, FL, United States. Electronic address: bz52@nova.edu.
⁵ Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital Optometric Center, Tianjin, China; Nankai University Optometry Institute, Tianjin, China. Electronic address: lilihua5081@vip.sina.com.

PMID: 40651782
DOI: 10.1016/j.ajo.2025.07.009

Abstract

Purpose: To evaluate the effect of orthokeratology lenses with different back optical zone diameters (BOZD) on relative corneal refraction power shift (RCRPS) and explore its association with axial length growth (ALG).

Design: A randomized, double-blinded, controlled clinical trial.

Methods: Subjects aged between 8 and 15 years, with the refraction of -1.0 to -4.00 D. Participants were randomly assigned to two groups, wearing a BOZD_5.0mm or a BOZD_6.2mm lenses. Axial length (AL) was measured at baseline and 12 months after lens wear, and ALG and age-adjusted ALG (aALG) were calculated. A differential map comparing the 12-month and baseline corneal topography was used to analyze the RCRPS, summed within the central 4 mm diameter. The RCRPS subset was divided into eight meridians at 45-degree intervals. Linear and stepwise multiple linear regression were performed to assess the associations between ALG and RCRPS.

Results: There was no significant difference in baseline parameters, including age, spherical equivalent, and AL (all P > 0.05). Over 12 months, children wearing BOZD_5.0mm lens demonstrated significantly slower ALG (0.15 ± 0.13 mm) than those wearing BOZD_6.2mm lenses (0.24 ± 0.17 mm, P = 0.04). aALG was also significantly slower in BOZD_5.0mm group (-0.10 ± 0.12 mm vs. -0.001 ± 0.16 mm, P = 0.01). The summed RCRPS within the central 4mm area was significantly greater in children wearing BOZD_5.0mm lenses (92.31 ± 43.21 D) when compared to children wearing BOZD_6.2mm lenses (70.04 ± 41.64 D, P = 0.04). The summed RCRPS only demonstrated significant differences between the groups on 0-, 45-, and 90-degree meridians (all P < 0.01). The association between aALG and summed RCRPS was analyzed on eight different meridians. Only the 0-,45-, and 90-degree meridians demonstrated significant associations.

Conclusions: Children wearing orthokeratology lenses with smaller BOZD had slower ALG. This difference in ALG was associated with greater RCRPS in the nasal-superior quadrant of the cornea.

Keywords: axial length growth; back optic zone diameter; corneal power distribution; orthokeratology.