First Author: D.Siedlecki POLAND
Co Author(s): A. J A. Hill Bator
Purpose:
Chromatic aberration of the optical system of an eye is a consequency of the optical properties of tissues which form the elements of this system: the cornea, aqueous humor, lens, vitreous body. Significant amount of chromatic aberration typical for the human eye is likely to be used by the visual system to control accommodation. Extracting the natural lens, intransparent because of cataracts, and replacing it with an artificial implant changes seriously the size of chromatic aberration. Knowledge of the value of chromatic aberrations can be important when analyzing the quality of vision in the eye with an artificial lens implanted.
Setting:
: A group of patients of Ophthalmology Clinic, Medical University of Wroclaw, who underwent cataract surgery to remove the crystalline lens and implant artificial intraocular lens (IOL) were investigated. As a reference group people with normal or corrected vision, with no visual problems were selected.
Methods:
For measurement of chromatic aberration in vivo we used specially adapted visual refractometer (Rodenstock). White light illuminator was replaced by three LED's emitting red light (lambda = 660±20 nm), green light (lambda = 525± nm) and blue light (lambda = 470±20 nm) respectively. Comparison of refraction measured for each of these wavelengths enabled to plot the longitudinal chromatic aberration curve.
For comparison, we calculated chromatic aberrations of the eye with natural lens or with different types of artificial intraocular implants (made of different materials) using the software package for optical design ZEMAX. Optical and geometrical parameters of the eye was in accordance with the Dubbelmann eye model; optical and geometrical parameters of the selected types of IOL was taken from the available literature sources.
Results:
In most cases, the curve of the longitudinal chromatic aberration in the eyes of the artificial lens, has a shape similar to the analogous curve for healthy eyes. There was slight difference in maximum value of aberration – the one in the eyes with IOL being slightly smaller.
We observed also several cases in which form of the aberration curve was similar to the case of achromatic correction, however secondary spectrum was significant.
Conclusions:
So far our investigations does not allow to draw univocal conclusion about the chromatic aberration in the eye with an artificial lens. However, it appears that in most cases, implantation of the IOL does not significantly alter the nature of this aberration.
Further research will probably help in establishing the relationship between the IOL type and the magnitude of the eye chromatic aberration.
The work was done in the framework of the Research Project N N518 414138 funded by Polish Ministry of Science and Higher Education
Financial Disclosure:
None
