[Corneal neural paralysis after block excision including the 3 and 9 o'clock meridian]

Corneal innervation is mainly supported by the long posterior ciliary nerves. Anatomically, the long ciliary nerves run with the long ciliary arteries at 3 and 9 o'clock. The aim of this retrospective study was to find out if block excision of anterior uveal tumors or epithelial ingrowth located at the 3 or 9 o'clock position of the limbal circumference causes corneal neuroparalysis.

Between 1980 and May 1999, a total of 151 block excisions were performed in our department (92 block excisions because of anterior uveal tumors and 59 because of cystic epithelial ingrowth to the anterior chamber). In 27 patients, anterior uveal tumors or cystic epithelial ingrowth were located at the 3 or 9 o'clock position of the limbal circumference (14 patients with cystic epithelial ingrowth and 13 patients with anterior uveal tumors). Mean age of all patients was 54.4 +/- 15.7 years at the time of surgery. Mean diameter of the block excision was 10.7 +/- 4.5 mm for tumor-patients and 9.0 +/- 1.2 mm for patients with anterior chamber cysts. Mean follow-up time was 93.6 +/- 43 months.

Only 1 of 27 patients exhibited a moderate neuroparalytic corneal ulcer during the follow-up time. In the remaining 26 patients, no signs of clinically relevant corneal neuroparalysis such as epithelial disorders or neuroparalytic ulcers were found.

Block excision of tumors or cystic epithelial ingrowth located at the 3 or 9 o'clock position of the limbal circumference did not lead to severe neuroparalytic disorders of the host cornea. This may be an important factor in postoperative management of patients undergoing block excision and corneoscleral grafting.