Correlation of Surgically Induced Astigmatism From 2.4 mm Clear Corneal Incision and Corneal Biomechanical Parameters
To determine if there is a relationship between the biomechanics of the cornea and the amount of astigmatism induced by a temporal 2.4 mm incision placed during cataract surgery.
Retrospective chart review of single eyes from patients undergoing uncomplicated phacoemulsification surgery using 2.4 mm temporal clear corneal incision at Stein Eye Institute by single surgeon. Exclusion criteria included previous corneal surgery, corneal scarring, keratoconus, significant ocular surface disease, intraoperative or postoperative corneal procedures, poor quality topographic imaging. Data collected included pre- and post-operative topographic astigmatism (Orbscan), and 39 biomechanical parameters (2nd Gen Ocular Response Analyzer). Cohort 1 included eyes with SIA of <= 0.5D. Cohort 2 included eyes with SIA of > 0.5D. Statistics were performed using T test. Statistical significance was noted at the p < 0.05 level.
Thirty-seven eyes in Cohort 1 and 35 eyes in Cohort 2 were analyzed. There was no statistically significant difference between age and gender between the 2 cohorts. There was a statistically significant difference between the 2 groups with respect to the following parameters, all from the first peak of the ORA signal: aspect1 (p=0.02) , uslope1 (p=0.0006), dive1 (0.01), mslew1 (0.03), slew1 (p=0.0004), and uslope11 (p=0.001).
There are measureable, significant differences in the corneal biomechanics of eyes with large SIA compared to eyes with small SIA following 2.4 mm temporal clear corneal cataract surgery. Further elucidation of this relationship may assist cataract surgeons in achieving optimal control over induced astigmatism, leading to more favorable refractive outcomes.