Spherical Soft Contact Lens Designs and Peripheral Defocus in Myopic Eyes

Abstract

Purpose: Peripheral retinal defocus has been implicated in myopia progression. The effect of commercially available spherical soft contact lenses (SCLs) on peripheral defocus of adult myopic eyes was investigated.

Methods: Twenty-five young adults with spherical equivalent (SE) refractions between -0.50D and -6.00D were enrolled. Cycloplegic autorefraction (right eye) was measured centrally and ±20°, ±30°, and ±40° from the line of sight along the horizontal meridian using an autorefractor. Four commercially available spherical SCLs (Biofinity, Acuvue2, PureVision2, and Air Optix Night & Day Aqua) were evaluated. SE defocus (M) was used to calculate relative peripheral defocus (RPD) while wearing each SCL and relative peripheral refraction of the uncorrected eye. Spherical aberration (SA) changes caused by each SCL were measured along the line of sight by aberrometry. Peripheral defocus was analyzed using repeated-measures analyses of variance (RM-ANOVA). The association between changes in axial SA and the change in peripheral defocus was evaluated using linear mixed models.

Results: The mean age (±SD) and central SE refractive error were 24.0 ± 1.3 years and -3.45 ± 1.42D, respectively. PureVision2 did not change RPD (P = .33). Significant myopic shifts on the temporal retina were found with three lenses: Acuvue 2 (-0.29D at 30°; -0.80D at 40°; both P ≤ .01), Biofinity (-1.21 D at 40°; P = .02), and Air Optix Night & Day Aqua (-0.23D at 20°, -0.48D at 30°, and -1.50D at 40°; all P < .004). All SCLs caused a negative change in SA. SCLs inducing less negative (more positive) SA changes were associated with a less hyperopic change in RPD.

Conclusions: Spherical SCL design can influence the peripheral defocus profile experienced by a myopic eye. Several, but not all, SCLs reduced peripheral hyperopia. Differences in how SCL types influence peripheral defocus may have implications for myopia progression.

Figure 1

Relative peripheral defocus (M) while wearing each of the four soft contact lenses and relative peripheral refraction with no lens on the eye. Positive values represent hyperopic defocus and negative values represent myopic defocus. Error bars represent the SEM.

Figure 2

Relative peripheral J₀ astigmatism with the four soft contact lenses and with no lens on the eye. Error bars represent the SEM.

Figure 3

Relative peripheral J₄₅ astigmatism with the four soft contact lenses and with no lens on the eye. Error bars represent the SEM.

Figure 4

Change in relative peripheral defocus averaged across the four soft contact lenses split by contact lens power. Positive defocus represents a hyperopic image shift and negative defocus represents a myopic image shift. The asterisks denote eccentricities at which the two groups are significantly different from one another. Error bars represent the SEM.

Figure 5

Slope estimates from linear mixed model showing the influence of eccentricity on the dioptric change in defocus per 1 micron (µm) change in on-axis spherical aberration (SA) due to the contact lens. Error bars represent the SEM.