Some 10-0 monofilament nylon (Ethilon) (22.1μ diameter), 9-0 and 8-0 silk, and 7-0 collagen sutures were tied to the corneas of germfree guinea pigs to determine the effects of suture toxicity in a controlled environment. Of the sutures tested, 10-0 nylon demonstrated the mildest reaction and 8-0 silk the most severe inflammatory reaction.
McMaster PRB, Aronson SB, Moore TE. Suture Toxicity in the Germfree Guinea Pig. Arch Ophthalmol. 1970;84(6):776-782. doi:10.1001/archopht.1970.00990040778017