Depending on the location and extent of DR, and if the vitreous is too clouded with blood, another treatment must be used. In this, a surgical procedure, called a vitrectomy, the blood-filled vitreous is removed from the eye and replaced with a clear, artificial solution. The timing of this procedure for each patient depends on the extent of damage to the eye and to the condition of the other eye. Since then, researchers have come to suspect that it plays an important role in controlling sleep, and may be help- ful in correcting certain sleep problems, such as jet lag. Melatonin secretion is inhibited by bright light, and drowsiness occurs when levels are high.
Production is highest in childhood and gradually decreases after puberty.
By age 60, people produce very little. Melatonin supplements can be purchased in some pharmacies and health food stores. But taking them for insomnia is ill-advised because little is known about the hormone s general effect. Melatonin products are unregulat-ed and can vary considerably in quality. W e all expect a lot from our health professionals, hospitals, and health plans.