In 221 consecutive cataract extractions the peroperative epithelial damage was assessed by vital staining with 1% lissamine green, using logarithmic grading (grade 5 more than 10 000 stained dots) on cornea and on the superior, medial, lateral, and inferior conjunctiva. Evenly spread dots were seen on the cornea in 63 per cent of the eyes not subjected to protective treatment. In 35 per cent we observed staining caused by taut suturing of cornea and/or conjunctiva, in 10 per cent horizontal lines due to corneal bending during the extraction. The cornea was protected most effectively by healon (1% instilled once). Saline (4 or 5 instillations during the operation sufficed) protected equally well as gelatin sponge, methylcellulose, polyvinyl alcohol, and a soft contact lens. The inferior conjunctiva was protected only by healon, the superior also by saline, gelatin sponge, and polyvinyl alcohol.