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Updated: Oct 5, 2025
Author Spotlight: Advancements in Refractive Surgical Correction for Presbyopia and Exploring Postoperative Visual Acuity
Published on: September 20, 2024
Intrastromal corneal ring segments followed by PRK for postkeratoplasty high astigmatism: prospective study
Pedro Bertino1, Renata Soares Magalhães, Carlos José de Souza
1From the University of São Paulo, São Paulo, Brazil (Bertino, Santhiago); INOB Eye Hospital, Brasília, Brazil (Bertino, Santhiago); Hospital de Base, Brasília, Brazil (de Souza); Hospital Oftalmológico de Brasília, Brasília, Brazil (Rocha).
Purpose:
To evaluate refractive and topographic results of the association of intrastromal corneal ring segments (ICRS) with photorefractive keratectomy (PRK) for the correction of high (>6.0 diopters [D]) postkeratoplasty astigmatism (PKA).
Setting:
University of São Paulo, São Paulo, Brazil.
Design:
Prospective interventional study.
Methods:
Postpenetrating keratoplasty patients, intolerant to contact lens fitting, and with corneal astigmatism higher than 6.0 D were treated by the combination of ICRS and PRK from January 2017 to June 2019. First, patients underwent femtosecond laser-assisted ICRS implantation to reduce and regularize corneal astigmatism, and 3 months later, submitted to PRK for the residual astigmatism. Outcomes were obtained 12 months after PRK.
Results:
The study comprised 30 eyes of 29 patients. Mean uncorrected distance visual acuity (logMAR) changed from 1.16 ± 0.37 in the preoperative to 0.69 ± 0.40 after ICRS ( P < .0001) and to 0.34 ± 0.29 12 months after PRK ( P < .0001). Mean spherical equivalent decreased from -5.19 ± 4.81 D in the preoperative to -3.38 ± 4.51 D after ICRS ( P < .0001) and to -2.30 ± 2.84 D after PRK ( P = .132). Mean topographic astigmatism decreased from 7.88 ± 2.13 D in the preoperative to 5.47 ± 2.29 D after ICRS ( P < .0001) and to 4.12 ± 2.93 D after PRK ( P = .003). Mean refractive astigmatism decreased from 7.10 ± 1.13 D in the preoperative to 4.61 ± 1.61 D after ICRS ( P < .0001) and to 2.58 ± 1.49 D after PRK ( P < .0001). After PRK, the mean correction index (CI) for corneal astigmatism was 0.77 ± 0.36. The ICRS/PRK combination resulted in a higher CI than ICRS only, both for corneal and refractive astigmatism. 2 eyes (8%) presented clinically significant opacification. Other complications were endothelial rejection (n = 1, 4%), infectious keratitis (n = 1, 4%), and ICRS extrusion after corneal melting (n = 1, 4%).
Conclusions:
The association of ICRS and PRK was effective for treating high PKA. This strategy improved visual acuity, spherical equivalent, topographic and refractive astigmatism and resulted in a high CI. Safety questions remain open and must be balanced against benefits.
