Castroviejo's square corneal grafts.

The evolutionary history of the modern day keratoplasty technique is filled with numerous attempts to implant all manner of material using very creative surgical techniques. Many different shapes of incisions were tried. Castroviejo introduced a square shaped keratoplasty technique which had considerable success. He also introduced new surgical instruments which made the procedure easier to perform. This technique remained popular until the 1950s when improved instrumentation along with the demand for the most cosmetically pleasing result displaced the square keratoplasty technique as the keratoplasty procedure of choice.