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Updated: Nov 30, 2025
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Published on: November 12, 2015
Five-year long-term outcomes of intrastromal corneal ring segment implantation using the manual technique for
Jorge Vasco Costa1, Tiago Monteiro, Nuno Franqueira
1From the Cornea and Refractive Surgery Department, Ophthalmology Department, Hospital de Braga, Braga, Portugal (Costa, Monteiro, Franqueira, Faria-Correia, Alfonso, Vaz); Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal (Costa, Monteiro, Franqueira, Faria-Correia, Alfonso); Fernandez-Vega Ophthalmological Institute, Oviedo, Spain (Alfonso); Surgery Department, School of Medicine, University of Oviedo, Oviedo, Spain (Alfonso).
Purpose:
To evaluate the long-term effectiveness, safety, and stability of Ferrara-type intrastromal corneal ring segments (ICRS) by manual surgery implantation in patients with keratoconus.
Setting:
Ophthalmology Department, Hospital de Braga, Braga, Portugal.
Design:
Retrospective cohort study.
Methods:
This study included 124 eyes that had ICRS implantation using the manual technique with a follow-up of 5 years. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), subjective refraction, keratometry, aberrometry, and pachymetry maps were evaluated preoperatively and at 6 months, 1 year, and 5 years postoperatively. A secondary analysis of all variables was performed comparing 2 subgroups of patients: a group younger than 30 years and a group of 30 years or older.
Results:
At 5 years, both mean UDVA and CDVA improved significantly (P < .0001) from a preoperative value of 0.91 ± 0.36 to 0.46 ± 0.32 logMAR and 0.40 ± 0.27 to 0.22 ± 0.20 logMAR, respectively. Spherical equivalent, refractive cylinder, and all topography values significantly decreased postoperatively (P < .0001). No regression was observed in any visual or topographic parameter during the entire follow-up. Regarding the subgroup analysis, both younger and older patients demonstrated similar and stable results from the preoperative to the 5-year visit, except for minimum pachymetry value change over time.
Conclusions:
Ferrara-type ICRS implantation significantly improved visual acuity, refractive error, and topographic values; the improvement was stable throughout a 5-year follow-up period. This study confirms that ICRS implantation surgery for keratoconus is a stable procedure in a long-term follow-up, regardless of the preoperative patient's age.
