Psoralens and ocular effects in man and animals: in vivo monitoring of human ocular and cutaneous manifestations.

Optical spectroscopy (fluorescence, phosphorescence, and electron spin resonance) has demonstrated the presence of 8-methoxypsoralen (8-MOP) and its potential for photobinding (to DNA and proteins) in human and animal ocular lenses. Similar photobinding in other ocular tissues, particularly the retina, has also been shown to occur in the young eye (lens has not yet developed as an effective UVA filter) and in aphakic and pseudophakic eyes. Skin biopsies were performed on a series of patients before, during, and following psoralen photochemotherapy (PUVA). High-resolution phosphorescence spectroscopy of PUVA patients enabled us to monitor the presence of 8-MOP in the skin and blood samples. These data indicated that significantly higher levels of 8-MOP accumulate within the psoriatic skin compared with uninvolved areas and demonstrated the feasibility of monitoring 8-MOP metabolism by this method. A second series of patients who had been on chronic PUVA therapy for many years were also evaluated by this technique and all patients' eyes were monitored by UV slit-lamp densitography with respect to determining lenticular photodamage in "unprotected eyes" compared with protected and untreated controls. The latter data have delineated at least 3 cases of presumptive PUVA cataracts. Phosphorescence assays on lens matter derived from individuals with a clinical diagnosis of PUVA cataracts demonstrated a photoproduct identical with the previously reported triplet noted in the lenses from experimental PUVA-treated animals.