Variation of Coma Aberration With Prismatic Soft Contact Lenses

To analyze the variation in vertical coma and the rest of ocular aberrations before and after fitting prismatic soft contact lenses (PSCL).

Thirty-seven eyes of 20 healthy subjects (24.30±2.03 years) were evaluated to analyze the variation in ocular wavefront aberrations before and after fitting PSCL of different base-down prism values (1.0, 1.5, and 2.0 prism diopters [PD]), designed to study its influence in the compensation of vertical coma aberration. A Hartmann-Shack sensor with a wavelength of 780 nm was used, considering a pupil size of 3 mm. In addition, the influence of PSCL in visual function under photopic conditions in terms of high-contrast visual acuity and contrast sensitivity was evaluated.

There was statistically significant differences (P<0.05) in ocular aberrations from first to seventh order after fitting PSCL, but only the differences in vertical tilt, horizontal tilt, defocus, vertical astigmatism, and vertical coma were clinically relevant (Strehl ratio <0.8). The mean of vertical coma (μm) was 0.022±0.030 for control, 0.045±0.064 for 1.0 PD (P=0.645), 0.048±0.053 for 1.5 PD (P=0.037), and 0.074±0.047 for 2.0 PD (P<0.001). The changes in visual function under photopic conditions were not clinically relevant.

PSCL induce a magnitude of vertical coma aberration directly proportional to prism value without affecting the rest of ocular high-order aberrations.