In vivo assessment of multifocal contact lens fitting using anterior segment optical coherence tomography

Multifocal contact lenses (MCLs) are designed to provide near vision functionality in presbyopia. They rely on the correct deployment of the multifocal power profile on the cornea and on the optical interactions between the MCL and the eye. The contact lens profile on the eye and the potential conformity to the cornea was evaluated using custom-developed spectral anterior segment Optical Coherence Tomography (OCT). OCT images were obtained from one eye of 13 subjects (age: 35.7 ± 13.8 years) with naked eyes and with MCLs on the eye. All eyes were measured with the same MCLs: 1-Day Acuvue® Moist Multifocal with low, medium, and high additions. Images were processed using custom routines for segmentation, fan distortion correction, 3D model construction and quantification. The radius of curvature of the anterior and posterior surfaces of the MCLs (RAL and RPL, respectively) and the anterior surface of the naked cornea (RAC) were obtained within a 3-mm diameter central area (addition area) and within a 3-6 mm peripheral ring. The power profile was also obtained by a ray-tracing analysis. RAC ranged from 7.5 to 8.2 mm across subjects (mean 8.02 ± 0.22 mm). RAC was correlated with RPL and RAL in the periphery (r > 0.80, p < 0.05) and in the addition (r > 0.79, p < 0.05) areas for the three MCL additions. The average power profile exhibited a slightly lower addition than that reported by the manufacturer (1.32, 1.36, and 1.83 D for low, medium, and high additions), but similar to other off-eye reports in the literature. OCT equipped with quantification tools allows to study the fitting of MCLs to the eye in vivo. It was found that, overall, soft MCLs conform to the underlying cornea, in both the central and the peripheral areas, and the central near add is provided as expected.