New infusion cannula for prevention of retinal damage by infusion air during vitrectomy.

Abstract

Postoperative visual field defects are sometimes found after macular hole surgery. We have previously shown that damage to the retina by air infusion from an infusion cannula is a causative factor. To minimize such damage, we modified the infusion cannula and examined its effects experimentally. An infusion cannula with a closed tip and openings on four sides was created. Experimentally, a vitrectomy was performed in rabbit eyes using this new infusion cannula or a conventional cannula. After fluid-air exchange at an air pressure of 40 mmHg, eyes were removed and processed for histologic examination. The areas of the retinal damage caused by air infusion were evaluated. The area of retinal damage created by the new cannula was reduced significantly when compared with damage from conventional cannula use. This new cannula, designed for the purpose of scattering the air infusion, can reduce retinal damage, which leads to less frequent postoperative visual field defects.