Intrastromal corneal ring segments followed by PRK for postkeratoplasty high astigmatism: prospective study

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 Sao Paulo, Sao 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. Copyright (C) 2022 Published by Wolters Kluwer on behalf of ASCRS and ESCRS

Automated summary

The association of ICRS and PRK is effective for treating high PKA, resulting in improved visual acuity, spherical equivalent, topographic and refractive astigmatism. However, safety concerns need to be balanced against the benefits.