Long-term results of intrastromal ring implantation for keratoconus

ABSTRACT Objective: To evaluate refractive and topographic outcomes before and at least 7 years after intrastromal ring segment implantation surgery in patients with keratoconus. Methods: Long-term retrospective longitudinal study carried out with 35 patients (62 eyes) aged 10 to 30 who underwent...

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Main Authors: Henrique Celso Duarte de Rezende Rocha, Bernardo Kaplan Moscovici, Daniel Diniz da Gama, Renato Ambrósio Júnior, Marcos Pereira de Ávila
Format: Article
Language:English
Published: Sociedade Brasileira de Oftalmologia 2025-08-01
Series:Revista Brasileira de Oftalmologia
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Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0034-72802025000100226&lng=en&tlng=en
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Summary:ABSTRACT Objective: To evaluate refractive and topographic outcomes before and at least 7 years after intrastromal ring segment implantation surgery in patients with keratoconus. Methods: Long-term retrospective longitudinal study carried out with 35 patients (62 eyes) aged 10 to 30 who underwent intrastromal ring segment implantation using a manual technique. Different arc rings were analyzed across various keratoconus types. Results: Significant improvements in topographic astigmatism (p = 0.001) and corrected distance visual acuity (p < 0.001) were observed, with no significant changes in keratometry (p = 0.099) and a slight decrease in pachymetry (p = 0.033). Statistically significant improvements in K1 were noted with two 160° arc rings. K2 showed improvements with all arc rings except for one 210° ring. Topographic astigmatism improved notably with two 160° arc rings. No significant changes occurred between six months after surgery and final visits. Conclusion: Long-term follow-up demonstrated favorable outcomes post-intrastromal ring segment implantation, particularly in manifest refraction and corrected distance visual acuity. Vision gain was common, though endothelial cell counts decreased, especially with two-ring segments. Thicker rings reduced astigmatism more significantly, whereas two-ring segments reduced keratometry. Notably, 210° arc rings did not reduce topographic astigmatism but did decrease refractive astigmatism.
ISSN:1982-8551