Management Of Keratoconus With Snowman Phenotype: Comparative Outcomes Of Symmetric And Asymmetric Intracorneal Ring Segments

To evaluate the effectiveness of different intracorneal ring segment (ICRS) implantation strategies in keratoconus with the Snowman phenotype, comparing the outcomes of two symmetric versus two asymmetric segments

Cornea department Zaldivar Institute

A total of 10 eyes diagnosed with Snowman phenotype keratoconus were included in the study. Patients underwent femtosecond-assisted implantation of intracorneal ring segments (ICRS), receiving either: 2 symmetric ICRS segments, or 2 asymmetric ICRS segments with variable thickness and base width.

Both groups showed statistically significant improvements in UDVA and CDVA postoperatively, Corneal flattening was more pronounced in the asymmetric segment group, with a greater reduction in the steepest keratometric values. Coma-like aberrations significantly decreased in both groups, but the asymmetric segment group exhibited superior regularization of the anterior corneal surface (P < 0.05). No severe complications, such as segment migration or extrusion, were observed in either group.

For patients with keratoconus and Snowman phenotype, both symmetric and asymmetric ICRS implantation proved to be effective in improving corneal regularization and refractive outcomes. While asymmetric segments allowed for greater customization due to their variable thickness and base width, symmetric segments also provided significant visual and topographic benefits. The choice of approach should be tailored to each patient’s corneal morphology and refractive needs to optimize postoperative results.