BRIGHT LIGHT SUPPRESSES MELATONIN IN BLIND PATIENTS WITH NEURONAL CEROID-LIPOFUSCINOSES

We studied whether Light information can reach the pineal glands of cl inically blind patients with neuronal ceroid-lipofuscinoses. The suppr ession of melatonin by light was used as an indicator. Seven patients and seven control subjects were exposed to 3,000-lux light for 60 minu tes at the rising phase of the melatonin synthesis. Most patients were not cooperative, and their eyelids were opened by a researcher every 2 minutes for 2 seconds. The control subjects opened and closed their eyes similarly by themselves. Light suppressed melatonin in three of s even control subjects and in all patients. The average postlight level s were 80% (control subjects) and 51% (patients) of the corresponding levels during the dim-light session. Despite degenerated retinas of th e blind patients, light can penetrate their visual system to the hypot halamic and pineal levels and regulate neuroendocrine function.