Three-Year Change in Subfoveal Choroidal Thickness and Area With Multifocal Contact Lens Wear in the Bifocal Lenses in Nearsighted Kids (BLINK) Study.

Purpose: To evaluate changes in subfoveal choroidal thickness and area in children wearing soft multifocal contact lenses (MFCLs) for myopia control. Methods: Analyses included 281 myopic children aged 7 to 11 years in the Bifocal Lenses in Nearsighted Kids (BLINK) Study randomly assigned to wear single vision contact lenses (SVCLs), +1.50 D add, or +2.50 D add center-distance MFCL. Subfoveal choroidal thickness and choroidal area were measured using spectral-domain optical coherence tomography before and after 2 weeks of lens wear, and then annually for 3 years. Repeated measures linear regression was used to determine the effect of contact lens wear on the choroid and test the association between choroidal changes and axial elongation. Results: After initiating contact lens wear, mean ± SE subfoveal choroidal thickness and choroidal area increased in the +2.50 D MFCL group compared with the SVCL group by 8 ± 3 µm (P = 0.003) and 0.07 ± 0.02 mm2 (P = 0.002), a difference maintained throughout the 3-year study (P ≥ 0.55). Increased choroidal thickness and area after 2 weeks in the +2.50 D MFCL group vs. SVCL group were associated with less axial elongation over 3 years (β = -0.0058 mm/µm and -0.947 mm/mm2; P = 0.02 and P = 0.006; 20% and 29% of total treatment effect, respectively). Conclusions: The choroid increased in subfoveal thickness and area after 2 weeks of +2.50 D MFCL wear, which was maintained for 3 years and was associated with slower axial elongation. However, only a portion of the treatment effect can be accounted for by the choroidal parameters.