I read with great interest the article by Uji and Yoshimura on new and original observations of microarchitecture of the vitreous body. The authors wrote: “these findings are consistent with the theory proposed by Zinn in 1780, which states that the vitreous is arranged in a concentric, lamellar configuration, similar to that observed in a cut onion.” This statement has been made previously. Johann Gottfried Zinn (1727–1759) published his treatise “Descriptio anatomica oculi humani,” considered to be the first complete description of the eye’s anatomy, in 1755, with a second edition in 1780.

Other sources credit Samuel Moritz Pappenheim (1811–1882) with priority for this observation. According to William Bowman, “Pappenheim appears to have been the first to call attention to the fact that evidence may be obtained of an internal artificial arrangement of parts. He announced that the vitreous body, treated with a solution of carbonate of potass, exhibited a succession of concentric layers, something like those of an onion.” Moreover, Duke-Elder wrote that Zinn “considered that the vitreous was a tissue in the true sense, made up of a cellular framework,” but “Pappenheim (1842) with potassium carbonate detected an onion structure.”

In Zinn’s treatise, I was not able to find comparison of the vitreous structure to that of an onion. Thus, the true nature of Zinn’s original descriptions should be elucidated in future historical analysis.