[Corneal endothelial damage and its repair after phacoemulsification]

To introduce a grading system for corneal edema after phacoemulsification and to study the corneal endothelial damage and its repair after phacoemulsification.One hundred and five senile cataracts after phacoemulsification were included. Corneal edema was categorized into grades 0 to 4. Endothelial densities at various locations of the cornea were measured with specular microscopy before and three months after surgery.The corneal endothelial cell loss rate was 4.6%, 14.9%, 40.8%, 67.0% and 84.4% in eyes with corneal edema from grades 0 to 4, respectively. Time required for resolution of corneal edema was (2.1 +/- 0.7) days (grade 1), (5.6 +/- 1.9) days (grade 2) and (21.8 +/- 7.1) days (grade 3). The endothelial cell densities at superior, mid and inferior portions of the cornea were (2006 +/- 546) cells/mm(2), (1979 +/- 545) cells/mm(2) and (1754 +/- 543) cells/mm(2) respectively at 3 months after phacoemulsification. Postoperative endothelial cell loss at superior, mid and inferior portions of the cornea was (627 +/- 496) cells/mm(2), (656 +/- 492) cells/mm(2) and (1026 +/- 509) cells/mm(2) respectively. The difference in postoperative endothelial cell densities between the superior and inferior portions of the cornea was statistically significant (P = 0.017), so was the difference between mid and inferior portions of the corneas (P = 0.027). There was no statistically significant difference between the superior and mid portions of the cornea (P = 0.867).The grading system for corneal edema is helpful in evaluating the severity of endothelial damage after phacoemulsification and can be used to predict the outcome of the cornea. The major area of endothelial injury after phacoemulsification occurs at the inferior portion of the cornea.