Visual Acuity and Over-refraction in Myopic Children Fitted with Soft Multifocal Contact Lenses

Abstract

Significance: Practitioners fitting contact lenses for myopia control frequently question whether a myopic child can achieve good vision with a high-add multifocal. We demonstrate that visual acuity is not different than spectacles with a commercially available, center-distance soft multifocal contact lens (MFCL) (Biofinity Multifocal "D"; +2.50 D add).

Purpose: To determine the spherical over-refraction (SOR) necessary to obtain best-corrected visual acuity (BCVA) when fitting myopic children with a center-distance soft MFCL.

Methods: Children (n = 294) aged 7 to 11 years with myopia (spherical component) of -0.75 to -5.00 diopters (D) (inclusive) and 1.00 D cylinder or less (corneal plane) were fitted bilaterally with +2.50 D add Biofinity "D" MFCLs. The initial MFCL power was the spherical equivalent of a standardized subjective refraction, rounded to the nearest 0.25 D step (corneal plane). An SOR was performed monocularly (each eye) to achieve BCVA. Binocular, high-contrast logMAR acuity was measured with manifest spectacle correction and MFCLs with over-refraction. Photopic pupil size was measured with a pupilometer.

Results: The mean (±SD) age was 10.3 ± 1.2 years, and the mean (±SD) SOR needed to achieve BCVA was OD: -0.61 ± 0.24 D/OS: -0.58 ± 0.27 D. There was no difference in binocular high-contrast visual acuity (logMAR) between spectacles (-0.01 ± 0.06) and best-corrected MFCLs (-0.01 ± 0.07) (P = .59). The mean (±SD) photopic pupil size (5.4 ± 0.7 mm) was not correlated with best MFCL correction or the over-refraction magnitude (both P ≥ .09).

Conclusions: Children achieved BCVA with +2.50 D add MFCLs that was not different than with spectacles. Children typically required an over-refraction of -0.50 to -0.75 D to achieve BCVA. With a careful over-refraction, these +2.50 D add MFCLs provide good distance acuity, making them viable candidates for myopia control.

Trial registration: ClinicalTrials.gov NCT02255474.

Figures

Figure 1

Frequency distribution of spherical over refraction values for each eye (588 eyes of 294 subjects).

Figure 2

Binocular best-corrected distance visual acuity with best spectacle correction and with +2.50 D add center-distance soft multifocal contact lenses with spherical over-refraction (n = 294). Error bars represent SD.

Figure 3

Frequency distribution of binocular, high-contrast distance visual acuity (logMAR) when wearing best spectacle correction (gray bars) and with +2.50 D add center-distance soft multifocal contact lenses with spherical over-refraction (black bars; 294 subjects per distribution).