To evaluate the various forms of clinical presentation, the potential of growt h, the risk of functional loss and the possibility of malignant transformation o f optic disk melanocytomas in European patients. Retrospective observational cas e control study. Evaluation of 37 cases of optic disk melanocytomas identified i n the computer files of the ocular oncology unit of Jules Gonin Hospital to dete rmine the clinical presentation of these tumors and the risk of complications. T he tumor was asymptomatic in 28 cases. Visual acuity was normal in 26 cases, sub normal in 10 cases, and in one case it was reduced to 0.1. Visual field defects were observed in 19 cases; the size and extent of the tumor and the degree of pa pilledema appeared to influence the severity of the visual field defect. Tumor g rowth was demonstrated in 6 of the 9 cases in which follow-up was for at least six years. In two cases there was presumed malignant transformation that was tre ated by accelerated proton beam radiotherapy. Melanocytomas in white Europeans a nd those of European derivation are rarely symptomatic, have only a moderate eff ect on visual function and show a low rate of progression over long observation. The risk of tumor progression, although sometimes occurring as much as several years after the initial diagnosis, justifies a cautious approach with long-term regular surveillance of these patients. To evaluate the various forms of clinical presentation, the potential of growt h, the risk of functional loss and the possibility of malignant transformation of optic disk melanocytomas in European patients. Evaluation of 37 cases of optic disk melanocytomas identified in the computer files of the ocular oncology unit of Jules Gonin Hospital to dete rmine the clinical presentation of these tumors and the risk of complications. T he tumor was asymptomatic in 28 cases. Visual acuity was normal in 26 cases, sub normal in 10 cases , and in one case it was reduced to 0.1. Visual field defects were observed in 19 cases; the size and extent of the tumor and the degree of pa pilledema Taken to influence the severity of the visual field defect. Tumor g rowth was demonstrated in 6 of the 9 cases in which follow-up was for at least six years. In two cases there was treaned by accelerated proton beam r adiotherapy. Melanocytomas in white Europeans a nd those of European derivation are rarely symptomatic, have only a moderate effct on visual function and show a low rate of progression over long observation. The risk of tumor progression, although since as as as much as several years after the initial diagnosis, justifies a cautious approach with long-term regular surveillance of these patients.