Abstract
Background. To evaluate the change in corneal astigmatism after intrastromal corneal ring segment (ICRS) implantation in keratoconus patients with previous deep anterior lamellar keratoplasty (DALK). Design was a longitudinal, retrospective, interventional study. The study included 25 eyes of 24 patients with keratoconus who had DALK performed at least two years prior to ICRS implantation. All patients had a clear corneal graft with up to 8.00 D of corneal astigmatism and intolerance to contact lenses. The studied parameters were age, sex, corrected distance visual acuity (CDVA), maximum keratometry (K1), minimum keratometry (K2), spherical equivalent, and astigmatism. There was a statistically significant decrease in the postintervention analysis as follows: 3.5 D reduction in K1 (p < 0.001); 1.53 D in K2 (p = 0.005); and 2.52 D (p < 0.001) in the average K. The spherical equivalent reduced from −3.67 D (±2.74) to −0.71 D (±2.35) (p < 0.001). The topographic astigmatism reduced from 3.87 D preoperatively to 1.90 D postoperatively (p < 0.001). The CDVA improved from 0.33 (±0.10) to 0.20 (±0.09, p < 0.001). ICRS implantation is a useful option for the correction of astigmatism after DALK as it yields significant visual, topographic, and refractive results.
Highlights
Keratoconus is a noninflammatory, progressive ectatic disease characterized by thinning and protrusion of the cornea
This study evaluated the use of intrastromal corneal ring segments implanted using a femtosecond laser as a surgical option for treating patients undergoing deep anterior lamellar keratoplasty (DALK) due to keratoconus
It is commonly accepted that the average postoperative cylinder after keratoplasty varies from three to five diopters; [18] about 10–27% of patients undergoing corneal transplantation evolve with high astigmatism, and for high astigmatism, it is understood as the refractive cylinder of more than four diopters (D) [19]
Summary
Keratoconus is a noninflammatory, progressive ectatic disease characterized by thinning and protrusion of the cornea It causes progressive myopia and irregular astigmatism, decreasing the quality of vision [1]. Correction is achieved by wearing glasses, followed by the fitting of rigid gas permeable contact lenses (RGPCL). When these methods fail, surgery is indicated to improve the corneal surface. To evaluate the change in corneal astigmatism after intrastromal corneal ring segment (ICRS) implantation in keratoconus patients with previous deep anterior lamellar keratoplasty (DALK). ICRS implantation is a useful option for the correction of astigmatism after DALK as it yields significant visual, topographic, and refractive results
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