The survey of a population of 7 patients with malignant glaucoma, whose 3 were bilateral, showed that the total length of these eyes was weaker, the corneal radius shorter, the anterior chamber more shallow and the insertion of the lens more anterior than that of eyeballs with angle-closure glaucoma on the whole. These latter, we must remind, are already smaller than normal eyes. But this lessening of size does not affect the corneal diameter which remains always normal. And the lens, which is greater than normally in the angle-closure glaucoma, in the contrary is normal or smaller in the malignant glaucoma. The authors think that this little size of the lens allows it to be dislocated anteriorly through the limbal ring after the operation, and so is the cause of the post-surgical malignant glaucoma.