Abstract
Purpose :
Non-coaxial, multizone optical designs have been incorporated into soft contact lenses for myopia control to disrupt the inverse relationship between efficacy and vision quality seen with coaxial designs. Commercial optical lens analyzers are available to measure power profiles of contact lenses, but limitations have been identified in their application to multizone designs (Kim et al. JOptom 2016;9:126). This study evaluated the capability of the NIMO TR1504 (Lambda X, Belgium) in assessing the optics of a commercially available soft contact lens for myopia control (ACUVUE® Abiliti™ 1-Day, Johnson & Johnson MedTech, Jacksonville, FL).
Methods :
Radial and tangential power profiles of the lenses were measured with the NIMO TR1504. Five lenses of each power from -1D to -5D in 1D steps were stored in buffered saline solution for at least 12h at 20°C, then measured in a wet cell and converted to equivalent power in air. Add power was calculated as the difference between the minimum power in the first distance zone and the maximum power for each treatment zone. Add powers for the -3D lens were also calculated using ray tracing simulation by manual optimization of the geometric spot size in Zemax (Ansys, Canonsburg, PA).
Results :
The add power was averaged across all labelled distance powers. Both power profiles showed a small central high plus zone, surrounded by alternating annular distance and treatment zones. The add power (mean ± SD) of the radial power profiles were lower (5.56D ± 0.33D centrally, 1.52D ± 0.09D and 0.73D ± 0.29D for first and second treatment zones) than the tangential profiles (9.43D ± 0.52D centrally, 6.00D ± 0.24D and 6.00D ± 0.88D for first and second treatment zones), and both were lower than add powers from ray tracing calculations of the -3D lens (+10.34D centrally, +6.92D and +6.83D in the first and second treatment zones). The tangential power profiles showed artificial sharp drops in lens power at the zone margins.
Conclusions :
The NIMO TR1504 failed to accurately render the lens design, underestimating power in both central and annular zones. This reinforces previously documented challenges of optical lens analyzers in the optical characterization of small central or non-coaxial zones. Proprietary, custom equipment and software are needed to accurately represent the optics of more complex designs such as Abiliti™ 1-Day.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.