Corneal anterior and posterior curvature changes in patients who underwent cataract surgery

SUMMARY PURPOSE: To compare the anterior and posterior corneal curvature changes after phacoemulsification surgery METHODS: One hundred and sixty eight eyes of 141 patients who underwent phacoemulsification and intraocular lens implantation with a minumum postoperative follow-up of 3 months were included in our retrospective study. Keratometry values was recorded with autorefractometer; keratometry and axial length values were recorded with IOLMaster, pre-operatively. Anterior, posterior and total corneal astigmatism and keratometry values were measured by Pentacam, pre-operatively and post-operatively first and third month. The anterior, posterior and total surgically induced astigmatism (SIA) were calculated by the vector analysis at the first and the third post-operative months. The effects of main incision site and size, axial length, pre-operative astigmatism on corneal anterior, posterior and total SIA were evaluated. RESULTS: In temporal, oblique and superior site incision performed cases; at the third post-operative month; mean anterior corneal SIA were 0.53±0.34 diopters (D), 0.75±0.52 D, 0.81±0.46 D respectively; mean posterior corneal SIA were 0.23±0.19 D, 0.25±0.19 D, 0.23±0.14 D respectively; mean total corneal SIA were 0.58±0.43 D, 0.79±0.52 D, 0.86±0.52 D respectively. In terms of anterior and total SIA, there was a statistically significant difference , only between temporal and superior site main incision performed groups. Mean posterior corneal SIA differences were not statistically significant among the main incision site groups. In groups with 2.2 mm, 2.4 mm, 2.75 mm and 3.5 mm main incision sizes; at the third month; mean anterior corneal SIA were 0.38±0.17 D, 0.62±0.19 D, 1.05±0.40 D, 1.31±0.67 D respectively; mean posterior corneal SIA were 0.17±0.10 D, 0.24±0.17 D, 0.27±0.23 D, 0.30±0.19 D respectively and mean total corneal SIA were 0.41±0.19 D, 0.68±0.29 D, 1.03±0.42 D, 1.13±0.77 D respectively. When the corneal anterior and total curvature changes were analyzed, no statistically difference was found between the groups with the main incision size of 2.75 mm and 3.5 mm. But statistically significantly compared differences were found in dual analyses of between the other groups. When posterior corneal curvature changes examined; SIA difference was statistically significant, between only 2.2 mm and 3.5 mm incision groups . In temporal main X incision site group, higher SIA was found in cases with a pre-operative astigmatism value of ≥ 2 D. SIA was statistically significantly higher in cases with axial length less than 22 millimeters in temporal and oblique incision groups. Posterior corneal SIA was found statistically significantly higher in cases with a pre-operative posterior astigmatism of ≥ 0.5 D. CONCLUSIONS: When cases are examined in terms of the main incision sizes; the lowest SIA was found in 2.2 mm main incision group that followed by 2.4 mm, 2.75 mm and 3.5 mm main incision groups. In analyses in terms of main incision sites; the lowest SIA was found in temporal incision site group and the highest SIA was found in superior incision site group. SIA was found to be high in cases with an axial lengths of < 22 mm or those with a pre-operative astigmatism values of ≥ 2 D. Posterior corneal SIA was high in cases with a pre-operative posterior corneal astigmatism values ≥ 0.5D. Key words: Cornea, anterior astigmatism, posterior astigmatism, total astigmatism, surgically induced astigmatism,axial lenght, Pentacam