5. Mueller AJ, Bartsch DU, Folberg R, et al. Imaging the micro- vasculature of choroidal melanomas with confocal indocya- nine green scanning laser ophthalmoscopy. Arch Ophthalmol 1998;116:31–9. 6. Mueller AJ, Freeman WR, Schaller UC, et al. Complex micro- circulation patterns detected by confocal indocyanine green an- giography predict time to growth of small choroidal melanocytic tumors: MuSIC Report II. Ophthalmology 2002;109:2207–14. 7. Shields CL, Cater J, Shields JA, et al. Combination of clinical factors predictive of growth of small choroidal melanocytic tumors. Arch Ophthalmol 2000;118:360 – 4. Blue Light Exposure and Uveal Melanoma Dear Editor: It was with great interest that we read Shah et al’s article. 1 The study was very well conducted and represented an interesting epidemiological examination of the potential risk factors involved in uveal melanoma. The major conclusion of the study was that, of all potential ultraviolet light expo- sures, the only one that significantly increased the risk of developing uveal melanoma was prolonged exposure to welding. However, we propose that the results suggest a minimal role for ultraviolet light in the development of uveal melanoma and invite further research regarding the specific reason why welding appears to increase the risk of developing uveal melanoma. Okuno et al 2 evaluated various light sources for blue light hazard. Among these sources, arc welding was found to have extremely high effective radiance, with correspond- ing permissible exposure times of only 0.6 to 40 seconds, suggesting that viewing this light source is very hazardous to the retina. There is evidence suggesting that the major culprit is not ultraviolet light, but blue light exposure. Manning et al 3 induced an ocular melanoma in a rat exposed to half- amplitude band pass fluorescent blue light (434 – 475 nm). We did an in vitro study to investigate the effect of blue light on the proliferation rates of melanoma cell lines. Cells were exposed to blue light with and without the presence of ultraviolet light–absorbing or blue light–filtering intraocular lenses (IOLs). The proliferation rate of the cells relative to a control was then assessed (Fig 1 [available at http:// aaojournal.org]). Cells exposed to blue light showed a sig- nificant increase in proliferation. Those exposed to blue light through a standard IOL showed a smaller increase in proliferation, whereas those exposed with a blue light– filtering IOL showed no increase in proliferation in 3 of the 4 cell lines. Our data provide evidence regarding the role of blue light in the oncogenesis of uveal melanoma. BRUNO F. FERNANDES, MD JEAN-CLAUDE A. MARSHALL, MSC MIGUEL N. BURNIER,JR, MD, PHD Montreal, Canada References 1. Shah CP, Weis E, Lajous M, et al. Intermittent and chronic ultraviolet light exposure and uveal melanoma. A meta-analysis. Ophthalmology 2005;112:1599 – 607. 2. Okuno T, Saito H, Ojima J. Evaluation of blue-light hazards from various light sources. Dev Ophthalmol 2002;35:104 –12. 3. Manning WS Jr, Greenlee PG, Norton JN. Ocular melanoma in a Long Evans rat. Contemp Top Lab Anim Sci 2004;43:44 – 6. Author reply Dear Editor: Dr Fernandes et al present data that suggest blue light is involved in the proliferation of certain human uveal mela- noma cell lines, concluding that blue light may have a role in the oncogenesis of uveal melanoma. Although these preliminary data are interesting, the relationship between blue light and uveal melanoma remains inconclusive. Some studies on the epidemiology of uveal melanoma explore the role of blue light. Although Okuno et al found arc welding to have a high blue light effective radiance, they also report similar findings for sunlight. 1 Therefore, if our reported association between arc welding and uveal mela- noma were due to blue light, one would also expect an association between sunlight and uveal melanoma. How- ever, as shown in our meta-analysis, there were no epide- miological associations between uveal melanoma and out- door leisure activities, occupational sunlight exposure, or birth latitude, each a surrogate for sunlight exposure. 2 To the best of our knowledge, there are no published studies that specifically examine blue light and uveal mel- anoma. However, Ohara et al have studied the role of blue light in B16 mouse cutaneous melanoma cells. They report opposite results, with findings that blue light cytostatically inhibits the proliferation of melanoma cells. 3 These results may be due to differences between uveal and cutaneous melanoma cell lines. A study directly examining the 2 melanoma cell lines may prove interesting. Furthermore, research studying the transformation of melanocytes into uveal melanoma by blue light, and not merely the proliferation of melanoma cells, would strengthen the argument implicating blue light in the oncogenesis of uveal melanoma. Presently, the literature does not support a significant role for sunlight—which includes blue light—in the onco- genesis of uveal melanoma. We welcome further research that builds upon the work of Fernandes et al in examining the role of blue light. CHIRAG P. SHAH, MD, MPH EZEKIEL WEIS, MD, MPH MARTIN LAJOUS, MD, SM JERRY A. SHIELDS, MD CAROL L. SHIELDS, MD Philadelphia, Pennsylvania References 1. Okuno T, Saito H, Ojima J. Evaluation of blue-light hazards from various light sources. Dev Ophthalmol 2002;35:104 –12. 2. Shah CP, Weis E, Lajous M, et al. Intermittent and chronic ultraviolet light exposure and uveal melanoma. A meta-analysis. Ophthalmology 2005;112:1599 – 607. 3. Ohara M, Kawashima Y, Katoh O, Watanabe H. Blue light inhibits the growth of B16 melanoma cells. Jpn J Cancer Res 2002;93:551– 8. Ophthalmology Volume 113, Number 6, June 2006 1062