Refractive And Topographic Outcomes Following Progressive Intracorneal Ring Segment Implantation In Keratoconus

To evaluate the refractive and topographic outcomes of progressive intracorneal ring segment (ICRS) implantation in keratoconus patients, with morphological phenotype of duck-shape and snowman topographic pattern.

Refractive surgery department, Research institute of ophthalmology, Giza, Egypt

In this prospective study, 30 eyes with keratoconus were enrolled and classified into duck-shape and snowman patterns. All eyes underwent preoperative tomographic analysis to assess corneal curvature, thickness, and morphological pattern. Progressive AJL Pro+ ICRS implantation was performed, with decisions guided by a nomogram and surgical experience to optimize corneal regularization. Pre- and postoperative assessments included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, and tomographic  analysis.

Following progressive ICRS implantation, mean UDVA improved from 0.2 ± 0.1 to 0.6 ± 0.2, while mean CDVA improved from 0.4 ± 0.1 to 0.9 ± 0.1. Mean steep keratometry decreased from 54.0 ± 2.5 D to 46.0 ± 2.0 D. Duck-shape corneas demonstrated greater anterior surface regularization, whereas snowman morphology exhibited more pronounced keratometric flattening. No major complications or explantations were reported.

Progressive ICRS implantation, guided by preoperative tomographic analysis, nomogram, and surgical experience, is a safe and effective method for improving visual acuity and corneal shape in keratoconus. Morphology-specific responses highlight the importance of individualized surgical planning.