The author made many experiments in regard to the changes in corneal curvature following sections made with lances of various curvatures. He also measured the astigmatism following glaucoma and cataract operations. Sections made with the Graefe knife were not considered on account of the unavoidable irregularity in puncture and counterpuncture. Of 112 cases of glaucoma in which a lance 6-9 mm broad was used, it was found that in the meridian dividing the wound the refraction sank 0.5-2.5 D, while in the meridian at right angles it rose 0.5-3 D. On an average, the astigmatism produced was 2.76 D.
A look at the past . . .. Arch Ophthalmol. 2000;118(1):73. doi:10.1001/archopht.118.1.73