Aberrometry-Based Intrastomal Corneal Ring Segment Implantation In Moderate To Advanced Keratoconus

To evaluate the short-term clinical outcomes of a novel aberrometric coma‐based nomogram for intrastromal corneal ring segment (ICRS) in patients with advanced versus moderate keratoconus.

monocentric retrospective study

91 eyes of 68 patients (age 21-65y) with moderate and advanced keratoconus were implanted with ICRS according to a novel aberrometric coma‐based nomogram. Visual, refractive, corneal topographic, aberrometric, and pachymetric changes after surgery were evaluated during a 3-month follow-up.

At postoperative month 3, corrected distance visual acuity (CDVA) improved from a mean of 0.39 logMAR to 0.17 logMAR, astigmatism and spherical equivalent decreased from -4.34D and -5.4D to -2.18D and -3.18D respectively (p<0.001). Average and maximal keratometry, and total, higher order, coma and spherical aberrations significantly decreased (p<0.05). Advanced keratoconus with maximal keratometry (Kmax) above 60D had significantly lower keratometric flattening (p=0.04) and coma aberration reduction (p=0.01). Nevertheless, post-operative visual improvement was comparable to patients with Kmax <60D (p=0.29). One case of spontaneous extrusion and one case of ring misalignment were reported.

Aberrometry-based nomogram provides significant refractive and visual improvement in moderate to advanced keratoconus. ICRS implantation may be a less invasive, effective, therapeutic alternative in advanced keratoconus with steep corneas, prior to corneal transplantation.