Visual acuity and over-refraction in myopic children fitted with soft multifocal contact lenses in the BLINK Study

Abstract

Purpose : To determine the over-refraction necessary to achieve best-corrected visual acuity (BCVA) when fitting myopic children with a center-distance soft multifocal contact lens (MFCL) with a +2.50 D add.

Methods :
Myopic children (n = 294) ages 7 to 11 years were fitted OU with a center-distance soft MFCL (Biofinity “D” with +2.50 D add; CooperVision). All children had myopia (spherical component) of -0.75 D to -5.00 D (inclusive) and 1.00 D cylinder or less (corneal plane). The initial CL power chosen was based on the spherical equivalent (after referencing each meridian to the corneal plane) of a most plus/least minus subjective refraction that provided BCVA. Initial CL powers were rounded to the nearest 0.25 D step. A spherical over-refraction (OR) was performed for each eye to achieve BCVA. High-contrast logMAR acuity was measured binocularly with full manifest spectacle correction and with best-corrected MFCLs. Photopic pupil size OD was measured with a VIP-200 Pupillometer (NeurOptic, Inc.). A t-test was used to compare the difference in BCVA between correction types to zero, and a correlation analysis was used to evaluate whether there was a relationship between pupil size and BCVA with MFCLs.

Results : The mean age (±SD) and spherical equivalent refraction at the corneal plane (OD / OS) were 10.3 ± 1.2 years and OD: -2.57 ± 1.07 D / OS: -2.53 ± 1.07 D, respectively. The mean (±SD) spherical OR needed to achieve BCVA was OD: -0.61 ± 0.24 D / OS: -0.58 ± 0.27 D. Binocular high-contrast BCVA (logMAR) with spectacles was -0.01 ± 0.06 (range: -0.20 to +0.16) and with best-corrected MFCLs was -0.01 ± 0.07 (range: -0.20 to +0.10). There was no significant difference in BCVA between correction types (p = 0.59). The mean (±SD) photopic pupil size was 5.4 ± 0.7 mm (range: 3.1 to 7.2 mm). There was no correlation between photopic pupil size and logMAR BCVA with MFCLs (p = 0.30).

Conclusions : Children achieved visual acuity with MFCLs with a +2.50 D add that was not different compared to spectacle correction. Most children required an over-refraction of between a -0.50 D and -0.75 D to achieve best vision. With a careful over-refraction, the +2.50 D add MFCLs provide good distance visual acuity, making them viable candidates for myopia control in children.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.