Corneal higher order aberrations after intrastromal corneal ring segment implantation for keratoconus

• Main Authors: Mohamed Y.S Saif, Mostafa A Saeed, Mohamed A Mekky
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2020-01-01
• Series: Delta Journal of Ophthalmology
• Subjects: higher order aberrations; intrastromal corneal ring segment implantation; keratoconus; pentacam
• Online Access: http://www.djo.eg.net/article.asp?issn=1110-9173;year=2020;volume=21;issue=1;spage=19;epage=24;aulast=Saif

Background Keratoconus is the most common primary corneal ectatic disease. It is a progressive, noninflammatory, and localized paraxial stromal thinning of the cornea, which often results in bilateral and asymmetrical corneal distortion and anterior corneal protrusion. Patients with corneal protrusion often develop high myopia and irregular astigmatism, resulting in significant impairment of visual acuity. Purpose The aim of this study was to assess changes of higher order aberrations (HOAs) induced by the implantation of intrastromal corneal ring segments (ICRS) in keratoconus. Patients and methods In the current study, a prospective analysis of HOAs, measured by using Pentacam, before and after ICRS implantation was done in a nonrandomized consecutive series of 20 eyes having progressive grade II/III keratoconus (Amsler-Krumeich classification). Results At 1 month postoperatively, a statistically highly significant reduction was found in keratometric readings. The flattest keratometric reading (K1) improved from 46.42±3.08 D preoperatively to 43.25±3.45 D postoperatively, which is highly significant (P<0.01). The steepest keratometric reading (K2) improved from 49.96±3.29 D preoperatively to 46.04±3.15 D postoperatively, which is highly significant (P>0.01). The total HOA root mean square improved from 1.55±0.54 preoperatively to 1.26±0.38 postoperatively, with a statistically significant difference (P<0.05). Primary coma improved from 1.27±0.54 preoperatively to 0.87±0.27 postoperatively, which is highly significant (P>0.01). In addition, astigmatism root mean square changed from 2.42±1.52 preoperatively to 1.98±1.31 postoperatively. Trifoil and quadrifoil showed nonsignificant changes (P>0.05). Conclusion ICRS (Keraring) implantation using femtosecond laser is an effective method for improvement and stabilization of optical, keratometric, and aberrometric measures in keratoconic eyes. Most of the improvement in HOAs was achieved after 1 month and nearly locked up or changed insignificantly till the third month.