A comparison was made between the relative breaking strength of normal sclera, sclera treated with diathermy, and sclera treated with cryosurgical techniques. A device was developed which measured the force necessary to rupture the excised sclera at the treatment site. In each case, when compared to control sclera, the force necessary to penetrate the tissue was markedly reduced after treatment with diathermy while the cryosurgically treated eye showed little or no reduction in strength.