J Korean Ophthalmol Soc.  2020 Aug;61(8):897-904. 10.3341/jkos.2020.61.8.897.

Long-term Effect of Orthokeratology Lenses on Axial Length Elongation in Myopia: 2-3 Years Follow-up Study

• Jun SY
• Kim HK
• Kim CW
• Lee SM

• KMID: 2505309
• DOI: http://doi.org/10.3341/jkos.2020.61.8.897

Abstract

Purpose
To evaluate the effect of orthokeratology lenses on axial length elongation and associated factors in eyes treated withorthokeratology lenses for 2-3 years.
Methods
Thirty-four eyes of 20 patients treated with orthokeratology lenses for more than 22 months were enrolled into the orthokeratology(OK) group. Uncorrected distant visual acuity, spherical equivalent, axial length, and high-order aberrations of theanterior cornea at baseline and during the follow-up period were analyzed retrospectively. Spectacle-wearing patients matchedwith the OK group patients by sex, age, refractive error and follow-up period were selected as a control group. To adjust for follow-upperiod differences, the 24-month conversion axial length changes were calculated and compared between the two groups.
Results
The 24-month conversion mean axial length change showed significant differences (0.50 ± 0.23 mm in the OK groupversus 1.00 ± 0.28 mm in the control group; p< 0.001). For the OK group, the age at starting OK lens (r = -0.572, p= 0.001)showed statistically significant correlation with axial elongation. The anterior corneal spherical aberrations (SA) and coma with 6mm pupil at last follow-up (SA: r = 0.543, p= 0.001; coma: r = 0.420, p= 0.017) and the total SA and total coma changes (ㅿSA:r = 0.518, p= 0.002; ㅿcoma: r = 0.420, p= 0.017) also showed a statistically significant correlation. The initial age and axiallength, the anterior corneal SA and ㅿSA values were identified as factors significantly correlated with axial length elongation bymultiple regression analysis.
Conclusions
The OK lens effectively suppressed axial length elongation during a 2-3 years treatment period. However, whenthe age of starting OK lens was younger and the anterior corneal spherical aberration during the follow-up period was larger, therisk of axial elongation was higher.

Keyword

Axial length; Corneal wavefront aberration; Myopia; Orthokeratology