Visual outcomes of topography-guided excimer laser surgery for treatment of patients with irregular astigmatism

Abstract

The aim of this study was to evaluate the efficacy, safety, and predictability of topography-guided treatments to enhance refractive status following other corneal surgical procedures. In a prospective case series study, 28 consecutive eyes of 26 patients with irregular astigmatism after radial keratotomy, corneal transplant, small hyperopic and myopic excimer laser optical zones, and corneal scars were operated. Laser-assisted in situ keratomileusis (LASIK) (n = 8) and photorefractive keratectomy (PRK) (n = 20) were performed using the ALLEGRETTO WAVE excimer laser and topography-guided customized ablation treatment software. Preoperative and postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest and cycloplegic refraction, and corneal topography with asphericity were analyzed in 12 months follow-up. Uncorrected visual acuity (UCVA) changed from 0.2 ± 0.2 or (20/100 ± 20/100) to 0.51 ± 0.31 or (20/40 ± 20/60) in the LASIK group (P = 0.01) and from 0.34 ± 0.16 or (20/60 ± 20/120) to 0.5 ± 0.23 or (20/40 ± 20/80) in the PRK group (P = 0.01). Refractive cylinder decreased from -3.2 ± 0.84 diopters (D) to -2.06 ± 0.42 D in the LASIK group (P = 0.07) and from -2.25 ± 0.39 D to -1.5 ± 0.23 D in the PRK group (P = 0.008). Best corrected visual acuity did not change significantly in either group. Topography-guided treatment is effective in correcting the irregular astigmatism after refractive surgery. Topography-guided PRK can significantly reduce irregular astigmatism and increase the UCVA and BCVA.

<p>Topography-Guided Refractive Astigmatism Outcomes: Predictions Comparing Three Different Programming Methods</p>

“…Topography-guided corneal refractive surgery has historically been used as a "repair procedure" for the treatment of eyes with naturally-occurring corneal irregular astigmatism, 1,[12][13][14] complications of corneal refractive surgery, 1,[15][16][17][18][19][20][21][22] corneal transplants, 16,18,20,23,24 and other corneal conditions. 1,16,18 Topography-guided PRK has also been used for the treatment of corneal ectatic disorders in conjunction with corneal crosslinking with riboflavin and ultraviolet light [25][26][27] and to prevent hyperopic regression following hyperopic LASIK. 28 Topography-guided LASIK also produces excellent outcomes for the treatment of refractive errors in otherwise normal eyes.…”

<p>Main Complications of Photorefractive Keratectomy and their Management</p>

“…Ghoreishi et al agree that topography-guided PRK can significantly reduce irregular astigmatism and increase the uncorrected visual acuity (UCVA) and distance corrected visual acuity (DCVA). In a study published in 2014, in which 28 consecutive eyes of 26 patients with irregular astigmatism after radial keratotomy, corneal transplant, small hyperopic and myopic excimer laser optical zones, and corneal scars were operated, UCVA improved significantly and refractive cylinder decreased greatly 47. Reinstein et al studied the transepithelial-PTK technique and state that it can be a safe and effective method of reducing stromal surface irregularities by taking advantage of the natural masking effect of the epithelium.…”

Decentration of Optical Zone Center and Its Impact on Visual Outcomes Following SMILE

“…1 Fixation errors in patients can influence the actual profile of removed corneal tissue during the treatment and result in a statically decentered ablation profile and induction of higher-order aberrations (HOAs). At present, improvements in more detailed ablation patterns such as topographicguided, 4 wavefront-guided, 5 wavefront-optimized, 6 and Q-factor customized patterns are being used. At present, improvements in more detailed ablation patterns such as topographicguided, 4 wavefront-guided, 5 wavefront-optimized, 6 and Q-factor customized patterns are being used.…”