Astigmatic outcomes of temporal versus nasal clear corneal phacoemulsification

Purpose: To compare the astigmatic outcomes of phacoemulsification cataract surgery using temporal versus nasal clear corneal incisions. Methods: In a clinical trial, consecutive patients with senile cataracts underwent phacoemulsification and implantation of a hydrophobic acrylic foldable intraocular lens through a horizontal clear corneal incision (temporal in right and nasal in left eyes). Outcome measures included keratometric astigmatism and surgically induced astigmatism (SIA) calculated by the vector analysis method using the Holladay-Cravy- Koch formula. Results: The nasal and temporal groups consisted of 20 eyes each. Mean preoperative keratometric astigmatism was 0.63±0.48 D and 0.38±0.39 D in the temporal and nasal incision groups respectively (P=0.09). Data on 10 eyes in each study group was available for the six-month analysis. Mean keratometric astigmatism was as follows in the temporal and nasal groups respectively: 0.85±0.47 D versus 1.95±0.45 D at 1 week (P<0.001), 0.73±0.46 D versus 1.79±0.55 D at 4 weeks (P<0.001), and 0.63±0.30 D versus 1.05±0.56 D at 6 months (P=0.053) after surgery. SIA at the same follow-up intervals was 0.71±0.20 D versus 1.80±0.22 D (P<0.001), 0.63±0.20 D versus 1.65±0.31 D (P<0.001) and 0.26±0.46 D versus 0.92±0.36 D (P=0.002) in the temporal versus nasal incision groups respectively. Conclusion: Temporal clear corneal phacoemulsification induces significantly less astigmatism as compared to similar surgery using the nasal approach.