Topography-guided ablation for the treatment of irregular astigmatism

Abstract

# Purpose Refractive surgery promotes good quality of vision without optical correction in most cases. Conventional ablation has reduced effectiveness in irregular corneas, where custom ablations are usually a better option. We have evaluated the results of visual acuity and refraction in patients undergoing custom topography-guided ablation. # Setting Oftalmocentro, Porto Alegre – RS – Brazil. # Design This is a case series, retrospective, non-comparative study. # Methods We studied 60 eyes from 48 patients who underwent topography guided customized refractive surgery, from October 2013 to September 2017, performed with excimer laser Schwind Amaris 750. # Results Mean age was 44.2 years, being most men (56.6%). Patients with penetrating keratoplasty (PKP) encompassed 36.6% (n = 22), previous radial keratotomy (RK) 20.0% (n = 12), previous deep anterior lamellar keratoplasty (DALK) 16.6% (n = 10) and 26.5% (n = 16) with other diagnoses. Topo-guided surgeries were trans-photorefractive keratectomy (trans-PRK) (41.5%), femto laser-assisted in situ keratomileusis (femto-LASIK) (35.0%), laser-assisted in situ keratomileusis (LASIK) (11.6%) and photorefractive keratectomy (PRK) (11.6%). Cylinder refraction decreased from −3.91 D (±2.00) to −1.45 D (±1.43) (p < 0.01). The spherical equivalent (SE) decreased from −2.04 D (±1.85) to −0.65 D (±1.03) (p < 0.01). Best spectacle-corrected visual acuity (BSCVA) improved in 65% of eyes, from 0.55 (±0.23) to 0.69 (±0.24) (p < 0.01). Follow-up of 40 eyes from 30 patients demonstrated that the effect of the procedure was maintained during the studied period (24,45 ± 14,14 months). # Conclusion Topography-guided ablation is safe and effective in reducing corneal irregularities, leading to an improvement in visual acuity in 2/3 of cases.