Topography-guided ablation for the treatment of irregular astigmatism

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.