Yoshinori Nakai*, Osamu Hieda, and Shigeru Kinoshita Department of Ophthalmology

1. Relation Between the Progression of Myopia, Growth of Axial Length, and Ocular Wavefront Aberrations in Ethnic Japanese School Children Yoshinori Nakai*, Osamu Hieda, and Shigeru Kinoshita Department of Ophthalmology Kyoto Prefectural University of Medicine Kyoto, Japan* Presenting author The authors have no financial interest in the subject matter of this poster.

2. Purpose To investigate the relationship between ocular wavefront aberration and myopia progressions, or axial elongation,and the Kerato-value change in ethnic Japanese school children. Subjects & Methods Fifty-nine elementary-school children (28 males, 31 females) were measured annually for 4 years from 7 (or 8) to 11 (or 12) years of age. • IOL master and wavefront sensing • Measured at their elementary school • Two skilled examiners measured all cases • Right eyes were used for analysis

3. Exclusion Criteria(As judged by two ophthalmologists) KR-9000PW（TOPCON） Measurement of Axial Length IOL-Master（Carl Zeiss） Measurement of Aberrations ‣Hartmann-Shack wavefont sensor ‣Zernike polynomials ‣Coma-like, spherical-like, and total higher-order aberrations (HOA) ‣Light interferometer ‣Non contact, safe ‣Quick measurement • Poor fixation • Poor exposure of the pupil or cornea (covered by the eyelid) • Only data to which the analyzer was correctly recognized was adopted.

4. Results 1 ~Myopic Change and Axial Length~ p<0.02 p<0.01 p<0.04 p<0.01 p<0.01 p<0.01 (mm) (D) (measured year)

5. Results 2~Corneal HOA~ (μm) No significant change (measured year)

6. Results 3 ~Ocular HOA~ Results 2 (μm) p<0.02 p<0.03 (measured year)

7. Results 4 ~K-Values~ (D) p<0.01 p<0.01 (measured year)

8. Examination 1 (D) (mm) Relationship between myopic change and axial elongation over a 3-year period

9. Examination 2 ~P-Value*~ AL: Axial length; SE: spherical equivalent; Ks: steep K ; O/C: Ocular/Corneal *statistically significant (p< .05) Of the elements included in the 1st-year medical examination, only axial length and spherical equivalent were directly related to axial elongation, myopic change, and a steep K-value change.

10. Examination 3 ~P-Value*~ Ks: steep K-value; O/C: Ocular/Corneal *Statistically significant (p< .05) Change of corneal higher-order aberrations (z4 and total) were correlated with a steep K-value change over a 3-year period

11. Summary • Axial elongation and myopic change were found to be correlated, and increased in the children during each year of elementary school. • 1-mm axial elongation resulted in approximately 2.2-diopter of myopia. • Ocular coma-like aberration, ocular total higher-order aberration, and the steep K-value were increased with axial elongation, but these elements of the 1st-year examinations were not the primary reasons for the near-term axial elongation and myopic change. • The amount of corneal higher-order aberration change (spherical-like and total) was correlated with a steep K-value change over a 3-year period.

12. Conclusions • In children of elementary-school age, long axial length during the 1st year is the primary risk factor for near-term myopic progression, and strong myopic error during the 1st year is the primary risk factor of axial elongation. • In this study, we found no relationship between any HOAs and axial elongation or myopic change, but some elements of the ocular HOAs were increased with myopic progression, and some elements of corneal HOAs were changed and correlated with strong K-value change over a 3-year period. • Measurement of axial length and HOAs should be included in the yearly medical examinations of children of elementary-school age.