Varying amounts of peripheral defocus reported in previous studies are likely due to whether peripheral defocus is measured while turning the eyes or the head. Contact lenses (CLs) lag when viewing objects in peripheral gaze, so future studies ought to measure peripheral defocus while turning the head to measure defocus through the peripheral add power.PURPOSE
Soft multifocal CL peripheral defocus studies report varying results. To determine whether soft multifocal CL lag when turning the eyes could affect the measurement of peripheral defocus, we measured how much CLs move when looking in different gazes.METHODS
The distance between limbus and CL edge was measured with a slit-lamp reticle magnifier. Centration was measured as the distance between CL edge and limbus at the superior, inferior, nasal, and temporal location of the CL while in primary gaze. Decentration of the CL equals the difference of the distance between the CL edge and limbus while looking centrally and 20 degrees in each direction. All measurements were performed while subjects wore habitual and Proclear Multifocal CL.RESULTS
The average ± SD age of the 40 subjects was 27.8 ± 8.4 years, 65% were female, and SE refractive error was −4.43 ± 2.05 diopters. The soft multifocal CLs decentered 0.09 ± 0.03 mm temporal (P = .006). The soft multifocal CLs lagged 0.49 ± 0.28 mm while looking down (P < .001), 0.24 ± 0.36 mm while looking up (P = .008), 0.58 ± 0.20 mm while looking nasal (P < .001), and 0.35 ± 0.21 mm while looking temporal (P < .001).CONCLUSIONS
Soft multifocal CLs center temporally in primary gaze, and they lag significantly while looking in every direction, but 0.50 mm or more when looking down or nasal, which could affect measurement of peripheral defocus when subjects turn their eyes instead of their head.