Here's a brief review of how eyetracking has evolved:
First generation - simple eye tracking using a static image with no interaction between the respondent and the image being viewed. There is little or no use of virtual reality technology. Useful output is restricted mainly to findability metrics.
Second generation - utilizes VR to provide a more realistic shopping experience but requires two separate sessions on the part of respondents, the first session is a VR shopping study followed up by a second session, the eye tracking component, that measures what the respondent is looking at. The two-part nature of this study make it nearly impossible to obtain a single integrated view of show the respondent is shopping. Attempts to overlay the two datasets are performed manually and are subject to analyst interpretation. Output includes gaze trails, dwell times and incidence of views along with separate tables of items purchased or rejected.
Third generation - integrates eye tracking and virtual shopping into a single session that is being driven by the respondent in a dynamic VR environment. The key distinction that true integration brings to shopper marketing studies is that robust statistical analysis can be applied to the data being collected. Gaze trails have now been replaced with regression models that can be used to project the findings of the studies into nationally reliable sales numbers.
The latest developments in technology are seeing new biometrics being captured to augment the insights gained from eye tracking. For example, brainwave measurements captured at the same time with eye tracking can pinpoint the portions of the brain that are stimulated during key periods of VR shopping. Researchers can now measure how emotionally involved the respondent is during the shopping experience which may lead to the ability to manipulate the very nature of the decision-making process itself!