Corneal biomechanics and refractive outcomes after cataract surgery
Reviewed by Anju Kadyan

The authors aimed to study a range of corneal properties and correlate them with refractive outcomes after phacoemulsification. Outcomes were reviewed in a fairly small group of 40 patients (including only right eyes) operated by two surgeons using clear corneal incisions (CCI) of either standard 2.75mm small incision cataract surgery (SICS) or 1.7 and 2.2mm width for co-axial micro-incision cataract surgery (MICS) as per surgeon preference. Corneal thickness increased on day one with corresponding decrease in corneal hysteresis (CH), both recovering to preoperative values at one month. The Corneal Resistance Factor (CRF) showed a significant change from baseline but was reduced more with direct than constructed 3-plane corneal incisions. Surgically induced astigmatism (SIA) was higher in the SICS group and correlated positively with incision width and negatively with CH and CRF (multivariate regression generated equation developed). All higher order aberrations (HOA) increased initially and regained preoperatively value by day 30 except third order trefoil. Literature has not consistently shown a decrease in SIA and HOA with smaller incision size and this study results emphasise the existence of other factors like corneal biomechanics. The findings suggest 3-step CCI are better as they do not weaken corneal resistance and taking the preoperative CH into account helps to better predict the final refractive result.

Influence of corneal biomechanical properties on surgically induced astigmatism in cataract surgery.
Denoyer A, Ricaud X, Van Went C, et al.
JOURNAL OF CATARACT AND REFRACTIVE SURGERY
2013;39:1204-10.