To the Editor.— The article in the DecemberArchives(113:1667-1670, 1977) by Roenigk and Martin on photochemotherapy of psoriasis was most informative. The authors noted that their patients wore sunglasses that protect against ultraviolet-A (UV-A) for five hours after photochemotherapy is given in the office. I would like to point out that for the two hours prior to receiving the photochemotherapy, the patients should also wear the protective glasses since they do have substantial blood levels of methoxsalen and are receiving UV-A from sunlight. Since we all are concerned about the possibility of retinal and/or lens changes that might occur with this form of treatment, we should take every precaution to minimize the patient's exposure to UV-A while there are detectable blood levels of methoxsalen. Even these measures may not prevent ocular changes, since we do not know whether methoxsalen enters the human lens and, if so, how long it