Título

Intrastromal Corneal Ring in a Post-Keratoplasty Patient: a prospective study

Objetivo

To assess the clinical outcomes after the implantation of a new 340-degree arc length corneal ring segment aided by femtosecond laser in post-keratoplasty patients after 12-month follow-up.

Método

Twenty eyes of 18 patients with previous keratoplasty who underwent an intrastromal corneal ring segment (ICRS) implantation assisted by femtosecond laser were included in this study. Primary outcome measure was the change in uncorrected distance visual acuity (UCVA) at 12 months postoperatively. The secondary outcome measures were corrected distance visual acuity (CDVA), refraction outcome, and corneal tomography 1,3, 6 and 12 months after surgery. The astigmatism results were analyzed using vector analysis through the Double-Angle polar plot.

Resultado

Seven (38.9%) patients were male and 11 were female. The mean UCVA of patients before implantation was 20/250 (1.15 logMAR), and after the last follow-up was 20/70 (0.54 logMAR) (P<.001). Mean CDVA improved from 20/35 (0.26 logMAR) to 20/25 (0.10 logMAR) (P<.001). The mean spherical equivalent and astigmatism components were significantly reduced after ICRS implantation. The mean corneal astigmatism decreased from 5.55 ± 2.29 D preoperatively to 3.92 ± 1.82 D postoperatively (P<.001). Best-corrected visual acuity remained the same or improved in 19 of 20 eyes and decreased by 1 line in 1 patient. There were no surgical complications. Table 3 shows the manifest distribution of the refractive error before and 12 months after ICRS implantation. There was a large reduction in blur strength after surgery (P<.001). Figure 3 shows the double-angle plots of the preoperative and postoperative keratometric astigmatism. The astigmatism component of the power vector, represented as a 2-dimentional vector (J0 and J45), is plotted in Figure 4. The coordinates at the origin (0, 0) represent as astigmatism-free eye.

Conclusão

A new intrastromal corneal ring with a 340-degree arc length was effective in treating post-keratoplasty eyes with improvement in visual acuity and reduced corneal astigmatism.