In vitro and schematic model eye assessment of glare or positive dysphotopsia-type photic phenomena: Comparison of a new material IOL to other monofocal IOLs.

PURPOSE

To compare the glare-type photic phenomena for a new intraocular lens (IOL) to other monofocal IOLs, and to investigate how IOL design features might affect these phenomena.

SETTING

Alcon Laboratories, Inc., Fort Worth, Texas; John A Moran Eye Center, University of Utah, Salt Lake City, USA.

DESIGN

Schematic model eye evaluation and in vitro study.

METHODS

Five monofocal IOL models (Clareon CNA0T0, Tecnis ZCB00, enVista MX60, Eternity W-60, and Vivinex XY1) were used to evaluate glare or positive dysphotopsia-type phenomena. Optical simulations of incoming light were generated using nonsequential ray-tracing software based on a collimated light source for various off-axis angles of illumination. The simulation analyses were verified using a laboratory in vitro bench-top glare measurement system.

RESULTS

The Clareon and Vivinex IOLs produced focused off-axis images with negligible peripheral glare characteristics. The Tecnis and enVista IOLs produced dispersed images with additional glare characteristics at 45 degrees of off-axis illumination and higher. The Eternity IOL showed the highest edge-reflected glare characteristic, likely because of its straight optic edge geometry. The laboratory bench images and glare intensity profiles were consistent with the simulation data.

CONCLUSIONS

In vitro and nonsequential ray-tracing evaluations showed that straight optic edges and peripheral nonimaging optic geometry might contribute to positive dysphotopsia. The IOL designs with optic edge curvature and full functional optics demonstrated the lowest level of glare-type photic phenomena. Only clinical studies can confirm whether the differences observed between the IOLs in vitro are clinically significant.