Physical Assessment of Keratometric (k1.k2)Outcomes after Crosslinking Followed by Intrastromal Ring Implantation by using Femtosecond Laser in Patients with Keratoconus

Abstract

Background: Keratoconus is a disorder involving the cornea, presenting with central or paracentral corneal thinning progressively, the steepened cornea causes irregular astigmatism. For progressive cases of keratoconus, the primary treatment consists of corneal collagen cross-linking (CXL), this minimal invasive procedure aims to stabilize the coning by inducing stiffness of corneal stroma through fashioning of more cross-link bonds between the stromal collagen fibers. However, in order to correct the visual acuity, additional options should be sought, that includes refractive surgeries like intra-corneal rings segment (ICRS). Aims: To physically assess the changes in corneal curvature (K readings) after 3 months of the cross-linking procedure and then after 3 months of intrastromal corneal segment ring implantation by femtosecond laser in a sample of Iraqi patients with keratoconus. Methodology: The study was done in Dar Alsalam Private Hospital in Iraq/ Baghdad from 1-September-2019 to 1-October-2020. The study enrolled 40 patients (40 eyes) with keratoconus who had under gone corneal crosslinking then followed-up for three months, then had underwent intra-stromal corneal Keraring implantation with the aid of femtosecond laser, then followed-up for another three months, and after each time-interval the assessment included changes in corneal curvatures (K1 and K2).
Results: The mean age of participants was 25.58± 6.08 years, with 18 (45%) males and 22 (55%) females. There was a statistically significant difference decrease in K1 and K2 reading following CXL by 0.5% (0.24 D) and 0.53% (0.28 D), respectively, while three
months after ICRS K1 and K2 significantly decreased by 1.28% (0.60 D) and 8.69% (4.57 D). Conclusions: Collagen crosslinking offered significant stabilization of corneal curvature and refraction and prevent further progression of the condition. Femtosecond laser can effectively create corneal incisions on corneas that had collagen crosslinking before three months. Intra stromal corneal rings (Keraring) can safely be done after collagen crosslinking with excellent outcomes regarding keratometry and refraction.