The optics of vitreous surgery

We calculated the refractive power of the human eye in the various optical configurations that may occur during vitreous surgery. We found that a biconcave corneal contact lens with an anterior surface refractive power of -63 to -98 diopters allowed the fundus to be seen when the vitreous cavity was filled with air, as did a weak minus lens attached to the bottom of the operating microscope. Our tests showed that the unsymmetrical biconcave lenses were superior.