Abstract
Purpose :
Assessment of intraocular lens (IOL) image quality and mitigation of unwanted visual phenomena, such as glare, are critical for the best optical performance of the implantable device. The purpose of this study is to assess the IOL glare by evaluating off-axis incoming light rays both refracted and reflected by the edge or outer region of the IOL.
Methods :
The methodology employed in this study is a combination of non-sequential ray trace analysis using a schematic model eye and a laboratory bench set-up to evaluate glare phenomena from off-axis illumination for two commonly used IOLs. The simulation analyses were verified using a laboratory glare bench-top measurement system, whereby glare components formed from off-axis illumination of IOLs fitted into an artificial eye model were measured.
Results :
This study is the first to evaluate glare from off-axis illumination of the SN60WF and ZCB00 IOLs using a non-sequential ray trace analysis program along with a laboratory glare bench measurement verification of the simulations. Glare phenomena was determined for off-axis illumination of 0 to 65 degrees. The results from ray trace simulations showed that mid- and higher power SN60WF IOLs produced off-axis focused images with minimal peripheral glare components across a wide range of off-axis angles of incoming illumination. These results also revealed that mid- and higher power ZCB00 IOLs produced dispersed main images at off-axis angles greater than 35 degrees, and glare components at 50 degrees of off-axis illumination and above. Most of the incoming light from off-axis illumination travels through the IOL optic and forms the main image focused at the peripheral retina. Off-axis rays composed of incoming light striking the lens at an oblique angle rather than perpendicularly, is particularly recognized as contributing toward glare phenomena.
Conclusions :
The results from a non-sequential ray trace analysis using a schematic model eye and a laboratory bench set-up confirm that IOL edge and peripheral design has an effect on glare-type photic phenomena. Further studies of photic phenomena in patients following cataract surgery are needed to validate these findings in a clinical setting.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.