To evaluate aberrometric changes in corneas in patients with keratoconus 3-month after intrastromal corneal segment (Keraring 355) implantation.

A prospective interventional study including 16 eyes of 16 keratoconic patients who underwent KeraRing 355 implantation. After three months, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive outcomes, Orbscan finding and corneal abberrations were assessed.

Three months postoperately, the mean UDVA(logMAR) improved significantly from 0.74±0.34 to 0.35±0.24 (p=0.002).The mean CDVA improved (from .29±.18 to .23±.17) but it is not statistically significant. There was not statistically significant improvement in mean spherical refractive error (from -1.48±1.55 to -.52±2.39) but both spherical equivalent and the mean cylindrical refractive error decreased significantly from -3.49±1.61 to -1.52±2.77 (p=0.024) and -4.02±.99 to -2.02±1.38(p<0.001) respectively. Also, the mean keratometry value decreased from 47.61±2.03 to 42.5±2.76 (p<0.001). in regard to aberrometry, a statistically significant increase in quatrefoil, secondary coma, spherical aberration and secondary spherical was found. No statistically significant changes were detected in total RMS, trefoil, secondary trefoil and coma. Low order aberration(defocus and astigmatism) and secondary astigmatism decreased significantly postoperatively.

KeraRing 355 implantation provided significant improvement in UDVA, spherical equivalent, keratometry results and low order aberrations.but it is not effective in decrease of HOA.