Corneal topographic analysis in patients with cataract.

We studied the corneal curvature of 161 eyes in 101 patients, aged from 50 to 80 years (mean: 63 years), with senile cataract using the Topographic Modeling System (TMS) preoperatively. The results revealed that mean surface asymmetry index (SAI) was 0.36 and mean surface regularity index (SRI) 0.79. Simulated keratometry reading (Sim K) was 44.46 D, and 43.56 D. Minimum K reading was 42.60 D. The same patterns of corneal topography in both eyes were 50% in 60 patients who had binocular examination. Astigmatism less than 1 D was 23% in 161 corneas. Corneal patterns included round (21.2%), oval 16.1%), symmetric and asymmetric bow-tie (22.2%), and irregular (40.4%). SRI and SAI of the irregular pattern were statistically higher than those of the round, oval and bow-tie patterns in our patients (P < 0.01 and P < 0.05). The results of our study determined that the cornea of eye with senile cataract preoperatively is not a perfect spherocylinder. It is asymmetrically aspheric, with less curvature peripherally than centrally.