Scleral tattooing including blindness, of the procedure and warns that it should not be performed without a professional. Scleral tattooing is still a new body modification, and potential longterm effects have therefore still not manifested themselves. In 2009 the Oklahoma Senate passed Senate Bill 844, filed by Oklahoma Senator Cliff Branan and supported by the Oklahoma Academy of Ophthalmology, to make it illegal to tattoo the sclera of the eye. Scleral tattooing Scleral tattooing is the practice of tattooing the sclera, or white part of the human eye. The dye is not injected into the tissue, but between two layers of the
Cooperative eye hypothesis sclera, and irises. Human eyes are also larger in proportion to body size, and are longer horizontally. Among primates, humans are the only ones where the outline of the eye and the position of the iris can be clearly seen. The cooperative eye hypothesis was first proposed by H. Kobayashi and S. Khoshima in 2002 and was subsequently tested by Michael Tomasello and others at the Max Planck Institute for Evolutionary Anthropology in Germany. Researchers examined the effect of head and eye movement on changing gaze direction in humans and great apes. A human experimenter, observed by either a human