Treatment of duck-phenotype keratoconus using asymmetric intrastromal corneal ring-segments with hybrid technique

Objective: To evaluate the safety and efficacy of using asymmetric intrastromal corneal ring-segments (ICRS) for the treatment of duck-phenotype keratoconus through an hybrid technique. Methods: A retrospective study was performed in a private clinic of Cordoba City (Argentina), evaluating patients with duck-phenotype keratoconus, implanted with one segment of Keraring AS6 (Mediphacos, Belo Horizonte, Brazil). Uncorrected distance visual acuity (UDVA), manifest refractive spherical equivalent (MRSE), manifest refractive astigmatism, and topographic parameters were evaluated before and six months after the procedure. Results: 31 eyes of 27 patients received Keraring AS6 implants, attaining a reduction in median UDVA from 0.7 to 0.3, mean keratometry from 47.39 ± 2.75 D to 45.45 ± 2.97 D, median refractive astigmatism from -5.00 D to -2.50 D and MRSE from -5.25 D to -2.62 D. All effects were statistically significant (p < 0.01). Conclusions: In the present series, Keraring AS6 implantation by hybrid technique was effective and safe for correcting corneal irregularities secondary to duck-phenotype keratoconus, improving UDVA, MRSE, manifest astigmatism, and topographic parameters.