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

Abstract

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.

Figure 1.

OCT segmentation. The star scan was acquired using OCT and the anterior (yellow line) and posterior (green) choroidal boundaries were detected using semiautomated routines. Subfoveal choroidal thickness and choroidal area were calculated from the boundaries in each of the six scans. Regional area was calculated using the appropriate part of each B-scan in each of the regions shown.

Figure 2.

Choroidal thickness maps. Baseline choroidal thickness for all participants (A), and the change in choroidal thickness from baseline by treatment group after 2 weeks of study contact lens wear (B). MFCL, multifocal contact lens.

Figure 3.

Modelled choroidal thickness and overall area after study contact lens wear was initiated. Significant differences were observed between the +2.50 D MFCL and SVCL groups at all visits, with no differences seen between or within other groups at any visit. Models controlled for the initial thickness/area before initiating study contact lens wear, clinic site, sex, age, randomized treatment group, baseline photopic pupil size, and baseline axial length. The asterisk and bars connect groups within a visit that were significantly different from one another. SVCL, single vision contact lens. Error bars show the SEM.

Figure 4.

Modelled changes in choroidal thickness and overall area after study contact lens wear was initiated. Significant differences were observed between the +2.50 D MFCL and SVCL groups at all visits. Models controlled for the initial thickness before initiating study contact lens wear, clinic site, sex, age, randomized treatment group, baseline photopic pupil size, and baseline axial length. Error bars show the SEM.

Figure 5.

Modelled regional changes in choroidal area after study contact lens wear was initiated. Models controlled for the initial area before initiating study contact lens wear, clinic site, sex, age, randomized treatment group, baseline photopic pupil size, and baseline axial length. Error bars show the SEM.

Figure 6.

Modelled change in subfoveal choroidal thickness (µm) 2 weeks after initiating study contact lenses vs. the 3-year change in axial length (mm) by the assigned treatment group, after adjusting for treatment group, visit, clinic site, sex, age group at randomization, baseline photopic pupil size, and axial length at baseline. Slope and 95% confidence intervals are shown for each group.

Figure 7.

Modelled change in choroidal area (mm²) 2 weeks after initiating study contact lenses vs. the 3-year change in axial length (mm) by the assigned treatment group, after adjusting for treatment group, visit, clinic site, sex, age group at randomization, baseline photopic pupil size, and axial length at baseline. Slope and 95% confidence intervals are shown for each group.

Figure 8.

Modelled 3-year change in axial length (mm) vs. subfoveal choroidal thickness at the 3-year visit (µm) by the assigned treatment group, after adjusting for treatment group, visit, clinic site, sex, age group at randomization, baseline photopic pupil size, and axial length at baseline. Slope and 95% confidence intervals are shown for each group.

Figure 9.

Modelled 3-year change in axial length (mm) vs. choroidal area at the 3-year visit (mm²) by the assigned treatment group, after adjusting for treatment group, visit, clinic site, sex, age group at randomization, baseline photopic pupil size, and axial length at baseline. Slope and 95% confidence intervals are shown for each group.