Vision tests on spectacle lenses and contact lenses for optical myopia correction: a pilot study

Objective Visual performance and short-term tolerability of different designs of myopia correcting options, including therapeutically relevant bifocal contact lenses (CL) and spectacle lenses with 'defocus incorporated multiple segments (DIMS)' technology were compared. Methods and analysis In myopic volunteering subjects (n=8; spherical equivalent range: -1 to -7 D) visual acuity (VA) using Landolt C and contrast sensitivity (CS) using contrast C were assessed at three different gaze positions (-22 degrees nasal, +22 degrees temporal and 0 degrees central), corresponding to a gaze through the DIMS area or the clear area of the DIMS lens design, respectively, after short-term wear of each of single vision spectacle lenses (SV), DIMS spectacle lenses (DIMS), monofocal soft CL and centre-near multifocal soft CL (MCL). Also, CS was assessed under photopic and mesopic light conditions with and without glare using sinusoidal gratings at 1.5, 3, 6, 12 and 18 cpd. Results Mean VA (Landolt C) was -0.12 to -0.10, -0.05 and 0.10 logMAR (SV, DIMS, CL, MCL) at central gaze (0 degrees). At nasal gaze (-22 degrees), VA differed by 0.12, 0.33, 0.05 and 0.01, and at temporal gaze (+22 degrees) by 0.05, 0.26, 0 and -0.08 compared with central gaze values. Mean CS (Contrast C) was 1.74, 1.73, 1.69 and 1.61 logCS (SV, DIMS, CL, MCL) at central gaze at nasal gaze, CS differed by -0.02 to -0.13, -0.01 and -0.01, and at temporal gaze by -0.02 to -0.16, -0.01 and +0.06 compared with central gaze values. Conclusion When compared with SV, MCL leads to a general decrease in VA and CS, while DIMS did not differ from SV at straight gaze (0 degrees gaze). With DIMS, VA and CS are decreased to a similar level as with the MCL, but only at nasal and temporal gaze.