Ehrich W
Albrecht Von Graefes Arch Klin Exp Ophthalmol. 1978 Mar 7;205(4):237-43. doi: 10.1007/BF00413452.
After implantation of a disc (thickness: 0.25 mm, diam: 1.5 mm) of PUR in the anterior chamber of rabbits through a lancet incision, the reactions of iris, aqueous, and cornea were observed for six months at regular intervals using slit-lamp photography. 'Steeping' materials were as compatible as nonsteeping materials. At the place where the disc touched the iris one could see during a half-year period hyperemia iridis and foreign-substance granuloma of the iris. The cause of these reactions is a toxin in the PUR. Mechanical irritants as a cause could be excluded through the method utilized in the experiment.