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Vienna 2018 Delegate Registration Programme Exhibition Virtual Exhibition Satellites 2018 Survey


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Progressive thickness intrastromal corneal ring segments (Keraring® AS) implantation for paracentral keratoconus with non-coincident topographic and coma axis (Duck phenotype)

Poster Details

First Author: A.Soares PORTUGAL

Co Author(s):    T. Monteiro   N. Franqueira   F. Faria-Correia   F. Vaz           

Abstract Details


To evaluate the efficacy and safety of implantation of progressive thickness intracorneal ring segments (ICRS) Keraring® AS (Mediphacos®, Brazil) segments for the correction of paracentral keratoconus with non coincident topographic and coma axis.


Hospital de Braga


This retrospective study included patients with paracentral keratoconus with non coincident topographic and coma axis (coma axis between 30° and 60° of the flat topographic axis) submitted to Keraring® AS implantation. Parameters evaluated at preoperative and 6 months after surgery were: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, corneal topography and corneal aberrometry with Pentacam (Oculus®, Germany).


The study included 14 eyes of 13 patients. The mean CDVA preoperatively was 0.35±0.14 and postoperatively was 0.80±0.22 (p=0.002). The mean UDVA preoperatively was 0.10±0.08 and postoperatively was 0.35±0.3 (p=0.03). The subjective refractive cylinder improved from a mean preoperatively value of -2,65±1.11D to -1,124±0.48D after surgery (p=0.00041); topographic cylinder improved from 3.78±1.22 before surgery to 2.10±1.8 after surgery (p=0.14). The value of coma improved significantly from 3.15±0.94 to 1.83±0.86 μm (p=0.018). No intraoperative or postoperative complications occurred; no eyes lost lines of BCVA and 77,8% of eyes gained 2 or more lines of BCVA.


The implantation of progressive thickness intrastromal corneal ring segments (Keraring AS) in eyes with paracentral keratoconus with non coincident topographic and coma axis was safe and effective. They produce a progressive flattening effect, allowing a better customization of the corneal remodelling, specially in patients with significant difference between the flat topographic axis and the coma axis.

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