When driving in high-glare conditions the visibilities of objects are reduced, and lowcontrast objects may be rendered invisible. A major cause of the problems associated with glare is that light is scattered within the eye onto the retina (veiling glare) thus reducing the contrast of the retinal image. This reduction of contrast is called disability glare.  

The main indicator of driving safety that was used was the safety margin at the point when the driver initiated the turn. This safety margin can be thought of as the amount of time that would be leftover if the driver made the turn: a safety margin of +2 seconds means that the driver could finish their turn and leave the intersection 2 seconds before the oncoming car entered the same intersection (a safe situation) while a safety margin of 0 seconds means the back bumper of the driver's car would clear the intersection at the exact instant the oncoming vehicles' front bumper entered the intersection (a very unsafe situation). A smaller safety margin in this context increases the likelihood of a collision with the oncoming vehicle. Of particular interest was whether the safety margin used by drivers for turns changed in the presence of glare and whether this change was effected by the used of blue-light filtering IOLs. 

Across the two studies a total of 67 patients (mean age of 72 years) previously implanted with IOLs developed by Alcon Laboratories were evaluated. There were two blue light-filtering groups: 17 patients implanted with blue-light filtering, acrylic IOLs (AcrySof Model SA60AT) and 18 patients implanted with blue-light filtering, toric IOLs (AcrySof Models SN6ATT or SN60TT). The control groups (a total of 32 patients) were implanted with IOLs without UVonly filtering (AcrySof Model SA60AT). 