We propose a new method for assessing and quantifying compliance with contact lens care regimens. We recommend two separate procedures: one in which trained interviewers examine the actual lens care techniques used by typical, experienced patients and another in which clinicians rate each step in a lens care regimen as to the level of risk to the patient's comfort and safety if noncompliance with that step occurs. When combined, these steps quantify compliance with the regimen under investigation. The method can be used to assess the incidence of compliance with the regimen in question, and to compare compliance across dissimilar care systems. In our investigation, we applied the method to a multi-purpose solution regimen which has been marketed as being simple to use and, therefore, the correct care procedures are more likely to be complied with. However, we found that patient compliance with this regimen was equivalent to that found in an earlier study of an oxidative (hydrogen peroxide) care system, with noncompliance posing significant risks to both safety and comfort. The results indicate that 91% of patients were noncompliant with one or more of the steps in the lens care regimen that were judged to be clinically significant safety risk factors. Factors which posed significant risks to comfort were less likely to induce noncompliance. Only 34% of patients failed to follow one or more of the steps judged to provide clinically significant risks to comfort. The authors conclude that multi-purpose or simplified regimens are not acceptable substitutes for careful patient training and frequent follow-up.