96th DOG Annual Meeting, 1998



T. Walkow1, N. Anders1, S. Klebe2

Background: In order to reduce the resulting astigmatism after cataract surgery, the position of the surgical access can be varied. A lateral corneoscleral section has been found to reduce the induced astigmatism in eyes with a preoperatively "against-the-rule" astigmatism. In the study presented here we investigated, whether the location of the 7mm corneoscleral tunnel incision, which is widely used in phacoemulsification, as well as additionally intra- and preoperative parameters have an influence on the total or localized endothelial cell loss.

Patients and Methods: Fifty patients without ocular pathologies scheduled for routine cataract surgery (mean age 73 years) were elected prospectively for this clinical trial. Preoperatively, the anatomical parameters axial length, anterior chamber depth, lens thickness and astigmatism were measured. Time and relative energy of phacoemulsification, as well as total operation time were recorded additionally. Using a specular microscope (Noncon Specular Microscope, Robo CA), endothelial cell counts of the cornea were determined centrally, superiorly and temporally preoperatively, six weeks, six month and twelve month postoperatively.

Results: Concerning intraoperative parameters phako-time (0.9 min vs 0.9 min), relative intensity of phako (42.9% vs 46.5%) and operation time (12.3 min vs 11.7min) there were no significant differences between superior and temporal surgical approach. There was no significant difference neither in the central endothelial cell loss nor in the area localized in the quadrant of the different positions of the corneal surgical access. In the superior access group there was a central endothelial cell loss of 8.0% after six weeks, 8.4% after six month and 8.4% after twelve month versus 7.0%, 7.7% and 8.1% in the temporal access group (p>0.05 for all time-matched pairs). For the former group the temporal cell loss was 13.9 %, 13.4% and 12.7% versus 10.8%, 10.9% and 11.2% in the temporal access group (p>0.05). There was also no significant difference between both groups concerning the superior cell loss 11.9%, 11.5% and 11.5% versus 9.5%, 9.8% and 10.9% after twelve month. The only risk factors found to be significant for higher endothelial cell loss were shorter bulbus length and shallow anterior chambers (p<0.05).

Conclusions: The location of 7-mm corneoscleral access for phacoemulsification can be chosen according to the preoperative astigmatism without causing additional adverse effects on the corneal endothelium. Shorter eyes with a shallow anterior chamber have a significant higher risk for enhanced endothelial cell loss.

1 Dept. of Ophthalmology, Humboldt-University of Berlin, Charité; D-13353 Berlin

2 Dept. of Ophthalmology, Flinders University; South Australia, SA-5042 Adelaide