MEASUREMENT OF TONIC ACCOMMODATION AS A FUNCTION OF WAVELENGTH

Purpose Tonic accommodation contributes to the refractive state of the human eye in the absence of any visual stimulation. As the power of t he eye, tonic accommodation level should be a function of wavelength a nd its variation should constitute a measure of longitudinal chromatic aberration of the eye. Methods The level of tonic accommodation was m easured with a vernier optometer on a sample of 10 subjects (21-39 yea rs). Five monochromatic filters of wavelengths 450, 486, 550 600, 656 nm have been used. Results Results show a tonic accommodation variatio n with wavelength. The sample mean of longitudinal chromatic aberratio n (left eye) resulting from the variation of tonic accommodation as a function of wavelength is 1.42 +/- 0.08 D between 450 and 656 nm and 0 .96 +/- 0.06 D between 486 and 656 nm. Conclusion These results lit th e predictions from theorical models and question previous results.