Basic issues in the performance of the multifocal technique VERIS™ compared to RETIscan™

After the remarkable success of VERIS™ (1991), which is the pioneer in multifocal analysis in clinical ophthalmology and visual electrophysiology, new products of this type are being developed and are being put on the market. Among them is the RETIscan™ (1997), the first competitor to VERIS™. VERIS™ maintains a primary focus on nonlinear analysis derived from mathematical properties of the m-sequence. On the other hand, RETIscan™ modifies this focus to make the recording process more convenient. In spite of many applications for the multifocal technique, there is still some confusion in interpreting the results of testing with this technique due to lack of understanding of how it works. Review of the VERIS™ and RETIscan™ products should help bring about better comprehension of these multifocal techniques among ordinary users in the clinic.