Abstract

Pupil Size and Axial Length Growth in Myopic Children with Orthokeratology

Brittany Garrett, B.S.1; Xiaoyan Yang, M.D., Ph.D.2; Bin Zhang, M.D., Ph.D.3

1 Dr. Kiran C. Patel College of Allopathic Medicine, Davie FL, USA;

2. Tianjin Eye Hospital, NanKai University. Tianjin, China.

3. College of Optometry, Nova Southeastern University, Davie, FL USA

 

Introduction: It has been suggested that axial length growth (ALG) in myopic children treated with orthokeratology (OK) is negatively associated with their pupil sizes. However, a more recent study showed that ALG in children is significantly correlated with summed relative corneal refractive power shift (RCRPS) with the central 2mm area. Therefore, we test the hypothesis that ALG in such children is correlated with the summed RCRPS within the pupil rather than the pupil diameter itself.

 

Methods: 119 myopic children aged 12 were recruited from the eye clinics of the Tianjin Eye Hospital, Nankai University. The mean baseline spherical equivalent (SE) was -3.19±1.45 D. The orthokeratology lens used was a Dreamlite lens made using Boston XO material with a four-curve design. Axial length was measured using an ocular biometer baseline and 12-month visits. Corneal topography was taken at these visits, and pupil size was measured from the topographic maps. Multiple linear regression was applied to test the association between ALG and summed RCRPS, pupil diameter (PD), and SE. A P-value of <0.05 was considered statistically significant.

 

Outcomes: The mean ALG was 0.19±0.17 mm, the mean PD was 3.24±0.32 mm, and the mean RCRPS was 4.75±11.90 D.  ALG was negatively correlated with RCRPS (r=-0.26, p<0.001), but not for PD (p=0.73). In multiple regression with the presence of SE, ALG was significantly associated with RCRPS (p=0.0145), not PD (p=0.813).

 

Discussion: ALG in myopic children treated with OK correlates with the summed RCRPS within the pupil rather than the pupil size itself.