Analysis of stray-light effects related to intraocular lens edge design.
OBJECTIVE
To study the behavior of light rays that impact the frosted, double-square edge of an intraocular lens (IOL).


METHODS
Optical Phisiophatological Department, University of Florence, Florence, Italy.


METHODS
The interaction of light rays as a function of the edge design of a frosted, sharp-edged IOL was evaluated using an experimental eye model and an advanced ray-tracing program. The model simulates the irregularities of the frosted edge by the random overlap of sinusoidal phase gratings that have a random phase, an orientation, and a fixed period.


RESULTS
The reduction in the maximum intensity of the ghost image by frosting the square edge was linked to the period of the microroughness. At a maximum microroughness, when the period is less than 5 microm, the reduction in the value of an unfrosted, square-edged IOL was 17.5%.


CONCLUSIONS
The frosted edge had a small impact on reducing the intensity of the ghost image caused by the reflection of light from the double square edge of the IOL. Furthermore, in optics, the stray light from microroughness is generally considered to be a drawback because it can decrease contrast sensitivity.
Franchini
Alessandro
A
Optical Phisiophatological Department, Eye Institute, University of Florence, Viale Morgagni 85, 50134 Florence, Italy. alessandrofranchini@yahoo.it
Gallarati
Barbara Zamma
BZ
Vaccari
Eleonora
E
D006801:Humans; D007910:Lenses, Intraocular; D008027:Light; D008953:Models, Anatomic; D008962:Models, Theoretical; D011474:Prosthesis Design; D012542:Scattering, Radiation