Impact of multifocal gas-permeable lens designs on short-term choroidal response, axial length, and retinal defocus profile

Abstract

Aim: To investigate the impact of multifocal gas permeable contact lens (MFGPCL) in various add power and distance/near area allocation on short-term changes of choroidal thickness (ChT), axial length (AL), and retinal defocus profile in young adults.

Methods: Seventeen young adults (2 males and 15 females; age 23.17±4.48y) were randomly assigned to wear two designs binocularly with a one-week washout period in between. Total of four MFGPCL designs were assessed. All designs were distance-center that varied in two add power (+1.50 and 3.00 D) and/or two distance zone (DZ) diameters (1.50 and 3.00 mm; design A: DZ 1.5/add 3.0, B: DZ 1.5/add 1.5, C: DZ 3.0/add 3.0, D: DZ 3.0/add 1.5). ChT, AL, and peripheral refraction data were collected on each subject at baseline, on days 1 and 7 of MFGPCL daily wear. ChT was assessed in four quadrants using a spectral-domain optical coherence tomography.

Results: AL was shortened by -26±44 µm with lens C, -18±27 µm with lens D, -13±29 µm with lens A, and -8±30 µm with lens B (all P<0.05). A significant overall increase in ChT was observed with all 4 designs (lens A: +6±6 µm, B: +3±7 µm, C: +8±7 µm, and D: +8±7 µm). Temporal and superior choroid exhibited more choroidal thickening associated with MFGPCL. All designs induced significant relative peripheral myopia (RPM) beyond the central 20° across the horizontal meridian in both nasal and temporal fields (P<0.05).

Conclusion: MFGPCLs show a significant influence on ChT and AL, which are associated with significant increase in RPM after short-term wear. The reliability and feasibility of quantifying short-term changes in ChT support its use as a promising marker for the long-term efficacy of myopia-controlling treatments.

Keywords: axial length; choroid; gas-permeable contact lens; myopia; retinal defocus.

Figure 1. Schematic diagrams of optical zones geometries of multifocal gas-permeable contact lens designs.

Figure 2. Change from baseline in AL following 1 and 7d of multifocal gas-permeable contact lens daily wear

Error bars represent standard error of the mean. AL: Axial length; DZ: Distance zone diameter; Add: Addition power.

Figure 3. Change in ChT in each quadrant following 1 and 7d of multifocal gas-permeable contact lens daily wear

Error bars represent standard error of the mean. ChT: Choroidal thickness; DZ: Distance zone diameter; Add: Addition power.

Figure 4. Scatter plot demonstrating the association between the change in subfoveal ChT and change in AL in response to MFGPCLs

AL: Axial length; ChT: Choroidal thickness; MFGPCLs: Multifocal gas-permeable contact lens.

Figure 5. Change in relative peripheral refraction across the horizontal visual field in baseline (without lens) and four experimental MFGPCL designs

Error bars represent standard error of the mean. MFGPCLs: Multifocal gas-permeable contact lens. DZ: Distance zone diameter; Add: Addition power.

Figure 6. The correlation between the baseline refraction and the amount of RPR at 25 degree in the nasal and temporal retina at baseline without a lens (r=-0.44, P<0.001; represented by the black squares and black line), MFGP design A lens (r=0.42, P=0.05; represented by the red diamonds and red solid line), design B (r=0.65, P<0.001; represented by the blue diamonds and blue solid line), design C (r=0.70, P<0.001; represented by the red circles and red dashed line) and lens design D (r=0.75, P<0.001; represented by the blue circles and blue dashed line)

RPR: Relative peripheral refractive; DZ: Distance zone diameter; Add: Addition power.