Abstract
Purpose :
Dual-focus contact lenses (DF) imposing myopic defocus on the peripheral retina have been verified effective for myopia control. A within-subject, between-eye analysis was conducted in a one-year prospective clinical trial to investigate the impact of DF decentration on peripheral refraction and myopia progression among Chinese children.
Methods :
30 children aged 8 to 12 years (myopia, -4.00 D to -0.75 D; astigmatism <1.00 D) were recruited to wear DF (Misight® 1 day, CooperVision) binocularly for 1 year. Peripheral refraction (PR) with and without DF of each eye was measured by multispectral refraction topography (MRT) (MSI C2000, Thondar), and difference maps were derived. With the subject’ head and eyes still, MRT obtains PR of a circular field of 53° in several seconds. The margin of the central correction zone was manually fitted with a circle using imageJ and the macular fovea was set as the reference point. 1-year changes in axial length (AL) and spherical equivalent refraction (SER) of the eye with larger DF horizontal decentration (LHD) were compared with the eye with smaller horizontal decentration (SHD) within each subject using paired t-tests. Relative peripheral refraction (RPR) is calculated as PR minus the absolute refraction on the macular fovea. The relationship between decentration and change in RPR of the right eyes was analyzed using Pearson’s correlation.
Results :
28 children (F/M, 17/11) with a mean (SD) age of 9.4 (1.1) years completed the study. Change in RPR was significantly associated with horizontal decentration (r=0.746, P<0.001). The mean growth in AL in LHD was 0.23 (0.13) mm and the SHD had reduced mean axial elongation by 0.06 mm (95% CI, 0.04 to 0.08; P<0.001). However, there was no significant difference in change in SER between the two eyes of one subject (95% CI, -0.002 to 0.171; P=0.054). The changes in SER were -0.37 (0.37) D in the SHD and -0.45 (0.30) D in the LHD.
Conclusions :
The smaller the decentration of DF is, the more myopic the RPR changes after wearing DF. Growth in AL was less in eyes with smaller decentration. The decentration of DF impacts axial elongation, most likely through alteration of RPR. Further research is needed to clarify what causes the results different from orthokeratology, which is more effective in myopia control with larger decentration.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.