The Change of Corneal Shape after Cataract Operation Analysed by Slit Scan Cornea Tomography/Pachymetry System(ORBSCAN TM)

Yang, Hong Seok; Ahn, Jae Hong; Lew, Ho Min

Abstract

We used slit scan cornea tomography/pachymetry system(ORBSCAN TM)to analyze corneal topographical changes in 44 eyes of 35 patients who had phacoemulsification and posterior chamber lens implantation. The patients were divided into 3 groups;6.0 mm superior scleral tunnel incision with double vertical sutures(group A, n=20), 4.0 mm superior scleral tunnel incision with no suture(group B, n=15), 3.0 mm temporal clear corneal incision(group C, n=9). ORBSCAN TM was performed once preoperatively and at the 1st day, the 1st week, the 1st month and, the 2nd month postoperatively and we checked if our findings showed differences in corneal surface elevation, thickness, and change of refractive power between the three groups. At the four postoperatve time intervals, there was no statistically significant elevation of anterior corneal surface. However, there was a statistically significant elevation of posterior corneal surface(3.0 mm distant from center to the incision)and increase of corneal thickness in 3 groups. At the first operative day, the mean elevation of posterior corneal surface was -145 micrometer in group A, -159 micrometer in group B and, -262 micrometer in group C. These significant elevations were resolved at postoperative 1 month for group A and C, but 1 week group B. At the postoperative day, the mean increase of central corneal thickness was 30.2 micrometer in group A, 85.8 micrometer in group B, 77.3 micrometer in group C and the mean increase of peripheral corneal thickness was 92.8 micrometer in group A, 100.0 micrometer in group B, 217.0 micrometer in group C. In all three groups, the peripheral thickness(near the incision site)showed higher increase than central thickness. After 1 week, central corneal thickness regained its preoperative thickness and peripheral thickness regained its preoperative thickness after 1 month. At the first postoperative day, there was peripheral flattening and central steepening in the suture group. The mean of refractive power change was decreased according to time interval and stabilized between first and second month postoperatively. The results showed that there was no statistically significant difference between the three groups.