A synthetic, absorbable suture (Vicryl), was investigated for its usability in eye-muscle surgery. In experimental investigations on animals and strabismus surgery in humans, properties of the suture were compared with those of plain catgut. Histological investigations after modified strabismus surgery on rabbits clearly showed a smaller degree of tissue reaction around the hydrolytically dissolvable synthetic suture than around plain catgut. After implantation of Vicryl or catgut into the anterior chamber of rabbit eyes, within the first eight days both cause infective reactions which were somewhat stronger with Vicryl, which caused more scarring over the iris, than with catgut. One-hundred and eighty strabismus operations on man showed that the synthetic suture handles better and rips less markedly than plain catgut, whereas duration and amount of postoperative irritations are similar. Overreactions and granuloma were rare.