Prophylactic sclerotherapy for varices.

cutaneous malignancy is complex. Current models suggest, however, that ozone depletion may cause a more rapid increase in melanoma than in non-melanoma skin cancer.10 This is because short episodes of intense and burning ultraviolet exposure are linked to melanoma, whereas nonmelanoma skin cancer is associated with the lifetime build up of exposure to ultraviolet. To quantify changes in incidence and risk of skin cancer caused by the depletion of ozone is clearly important, but changes in holiday and clothing habits may make it impossible to attribute a percentage of the increased cancers to this depletion. What action is required? Firstly, more nations should set up monitoring equipment at various locations to record ultraviolet changes through the entire ultraviolet A, ultraviolet B, and ultraviolet C portions of the spectrum. Secondly, those who have recently spent a long time in Antarctica should be observed for cutaneous malignancies. The outdoor protection needed in the Antarctic may well, however, have effectively protected people against ultraviolet." Resident fauna such as the Emperor penguins may show ocular damage induced by ultraviolet and might merit a field study. Plankton in the surface waters around Antarctica may for the first time in their evolutionary history experience ultraviolet B or ultraviolet C. Lastly, the Montreal convention, signed last September, should be strengthened. 2 The convention aims at reducing the production of chlorofluorocarbons by halfby the end of the 1990s. This is too little and too late. A drastic reduction of chlorofluorocarbon production is needed as soon as possible to prevent an environmental problem becoming an environmental catastrophe. RONA M MAcKIE Professor of Dermatology, University of Glasgow, Glasgow GIl 6NU MICHAEL J RYCROFT Head, Upper Atmospheric Sciences Division, British Antarctic Survey, Cambridge CB3 OET