Scleral, lens, and vitreoretinal tissue was incised using CO2 laser radiation in a controlled and predictable fashion without producing untoward effects on neighboring ocular tissue. The penetration depth of infrared radiation into normal human vitreous was measured and was found to be exceedingly small. A quantitative correlation was observed between the CO2 laser power and the depth of penetration in scleral-chorio-retinal wall incisions and in lens tissue from human eyebank eyes. The results of this investigation suggest that the CO2 laser may be useful in intravitreal surgery, full-thickness scleral-chorio-retinal wall resections, transvitreal chorioretinal biopsy, and even dissolution of cataracts.