Patients have been receiving plaquenil 400 mg for years (especially SLE patients ) and with usual standard of follow up, the cited retinopathy complication of 2-20% is far beyond anything I have seen in my patient population, many of which have been on drug for 20 years. That said, I recently reduced dosing to 6.5 mg/kg. Would there not be better value in ascertaining blood levels as per recommendations of Dr. Petri, especially in SLE patients, where subtherapeutic levels are associated with increased disease activity?