Abstract
Purpose: :
Correction of peripheral defocus in myopes with traditional spectacle lenses results in foveal blur when eyes move away from the optical centre of the lens. To avoid this optical blur, peripheral vision can be corrected by taking advantage of the longitudinal chromatic aberration of the eye though colored filters that cut-off wavelength that are not focused on the retina. This study measured the influence of mono- and bi-colored lenses on lag of accommodation and pupil diameter.
Methods: :
Accommodation and pupil diameter measurements were carried out on 10 emmetropic or contact lens corrected subjects at 33cm using a Grand Seiko WAM-5500 autorefractor. Data was recorded continuously at approximately 5Hz in 3 sessions and averaged over 10 seconds with 6 different plano lenses: transparent, red (T=37%), blue (T=32%), yellow (T=88%), transparent centre with blue periphery and yellow centre with blue periphery.
Results: :
The average lag of accommodation with transparent lenses was 0.53±0.42D. Lag of accommodation increased significantly with blue lenses (0.67±0.35D, p<0.01), but not with the other lenses (yellow: 0.61±0.37, red: 0.51±0.39, transparent/blue: 0.63±0.37, yellow/blue: 0.51±0.47). Pupil diameter increased significantly with blue (3.4±0.7mm, p<0.05) and red (3.5±0.8mm, p<0.05) lenses compared to transparent lenses (3.2±0.7mm), but not with the other lenses.
Conclusions: :
Uniformly colored red and blue lenses affected lag of accommodation and/or pupil diameter while uniformly yellow lenses and lenses with chromatic peripheral correction (blue periphery) did not. These results indicate that lag of accommodation and pupil diameter, which are commonly supposed to be involved in myopia progression, are not affected by chromatic peripheral correction.
Keywords: myopia • accomodation • chromatic mechanisms