Figure 2.

Comparison of postoperative outcomes between adult (Group A) and pediatric (Group B) groups after 6 months, including (A) uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA); (B) sphere, cylinder, and SE; (C) keratometry readings (K1, K2, Kaverage, and Kmax); and (D) Q-ant and Q-post. Abbreviations: Postop, postoperative at 6 months; Preop, preoperative values; Sphere, spherical component of refractive error; Cylinder, cylindrical component of refractive error; SE, spherical equivalent of refractive error calculated as sphere + 1/2 cylinder; K1, front keratometry in flat meridian; K2, front keratometry in steep meridian; Kaverage, front mean keratometry; Kmax, front maximum keratometry; Q-ant, asphericity of the anterior corneal surface; Q-post, asphericity of the posterior corneal surface. Note: Group (A), Adult group included patients aged ≥ 18 years with intolerance to spectacles and gas permeable contact lenses (GPCL), stable keratoconus for at least one year (Kmax remained < 1 diopter [D]), grade 1 and 2 Amsler – Krumeich classification (A-K; Kaverage ≤ 48 D with < - 5 D myopia and astigmatism, 48 – 53 D with 5 – 8 D myopia and astigmatism, respectively) [13]. The cone asymmetry was type 1 and type 2 (100% and 80% of the cones were on one side of the steepest meridian, respectively), and the thinnest corneal thickness (TCT) should be > 380 μm; Group (B), Pediatric group included patients aged 14 – 17 years with intolerance to spectacles and GPCL, grade 1 and 2 A-K classification [13], type 1 and 2 cone asymmetry, TCT > 380 μm, and SE worse than - 4 D