Viewpoint 3

Abstract

type I collagen in the dermis (16,36). These observations demonstrate the role of retinoids in both preventing and reversing the signs of UV-induced skin ageing.In conclusion, despite the vast array of 'antiageing' products now available topical retinoids and sunscreens remain the most tried and tested treatments with long established safety records and proven efficacy in the treatment and prevention of UV-induced skin ageing.Stephanie Ogden, Christopher EM Griffiths 13 Sendagorta E, Lesiewicz J, Armstrong R B. J Am Acad Dermatol 1992: 27: S15-S18. Viewpoint 3Excessive skin exposure to solar UV brings about detrimental histological changes in the skin, which combine with and accelerate the effects of chronological ageing, and which result in the lax, dull and wrinkled appearance of 'old' skin. UV photochemically generated oxidative stressors such as singlet oxygen damage matrix integrity; elastosis-inducing damage to the underlying connective tissue occurs, with interstitial spaces appearing in the matrix caused by loss of collagen volume and fibre binding; the viscosity and quality of the matrix ground substance glycosaminoglycans is reduced; and an inflammatory infiltrate can be identified (1).The elegant idea of using light to repair the damage caused by overexposure to light was heralded by the indication of first the CO 2 and the Er:YAG lasers in the early 1990s, (2-4) and then a system which combined both wavelengths in the one console (5,6). Although still regarded as the 'gold standard' in the rejuvenation of seriously photoaged skin, laser ablative resurfacing is simply a controlled second degree burn of the dermis and is associated with, at best, unpleasant side effects and a long downtime.A non-ablative approach using lasers and intense pulsed light (IPL) systems delivered a zone of controlled dermal photothermal damage under an intact epidermis to 'kickstart' the wound healing process recognized as essential in successful skin rejuvenation. The very good histological evidence of tightening of the typically elastotic dermis failed to be echoed in a younger-looking epidermis, and patient satisfaction with single modality non-ablative skin rejuvenation was extremely low (7-10). The combination of single modality systems based on wavelength-specific photobiological precepts produced much better visible results (11-13).Fractional photothermolysis was next proposed for skin rejuvenation (14,15), to bridge the gap between ablative and non-ablative technologies by delivering controlled microdamage to both the epidermis and dermis. Some good results have been reported, but patient satisfaction has again been fickle with fractional technology on its own,