DISPERSION AND LONGITUDINAL CHROMATIC ABERRATION OF THE CRYSTALLINE LENS OF THE AFRICAN CICHLID FISH HAPLOCHROMIS-BURTONI

Dispersion and longitudinal chromatic aberration (LCA) of the crystall ine lens of the African cichlid fish Haplochromis burtoni were measure d with laser lights of four wavelengths: 457, 488, 515, and 633 nm. LC A and spherical aberration, as an indicator of image quality, were det ermined from the back vertex distances of laser beams deflected by the lens. In the green range between 488 and 515 nm, dispersion is almost constant in the entire lens. In the blue and the red ranges (457-488 and 515-633 nm, respectively), dispersion of lens material increases a pproximately linearly with increasing refractive index from the periph ery to the center of the lens. Spherical aberration and thus monochrom atic image quality are independent of the wavelength of light. Dispers ion and LCA of the lens are lower than expected from the dispersive pr operties of ocular media measured in other vertebrate species. Since t he lens in fish sets the limit on optical performance, reduction of ch romatic aberration of the crystalline lens improves the image quality of the eye. (C) 1996 Optical Society of America.