Topography-Guided Photorefractive Keratectomy for Postkeratoplasty Astigmatism: Long-Term Outcomes

Abstract

Purpose: To evaluate the long-term efficacy and safety of topography-guided photorefractive keratectomy (TG-PRK) for postkeratoplasty refractive error correction. Methods: A retrospective interventional case series of 54 eyes of 50 patients who underwent previous corneal transplants. Unaided distance visual acuity (UDVA) and best corrected visual acuity (CDVA), manifest refraction, mean central keratometric value, mean keratometric astigmatism, and postoperative complications were reviewed. Results: Final follow-up was at mean 31 (±17) months. Sixteen point seven percent of eyes underwent more than 1 surface ablation. Mean UDVA improved from 0.96 ± 0.06 logarithm of the minimum angle of resolution (LogMAR) preoperatively to 0.46 ± 0.05 LogMAR of resolution at the final follow-up (Bonferroni, P < 0.0001). Mean UDVA improved by 4.4 Snellen lines. Improvement in CDVA was not significant, although a significant improvement was noted when eyes with preoperative CDVA <20/40 were analyzed separately (t test, P = 0.005). Mean astigmatism improved from −4.4 ± 0.26 D preoperatively to −2.4 ± 0.26 D at the final follow-up (Bonferroni, P < 0.0001), whereas mean SEQ improved from −2.5 ± 0.39 D preoperatively to −1.1 ± 0.25 D (Bonferroni, P = 0.02). In total, 9% at the preoperative visit and 55% at the final visit had less than 2 D of astigmatism, respectively. Keratometric astigmatism decreased from 5.24 ± 0.36 D preoperatively to 2.98 ± 0.34 D at the final follow-up (t test, P < 0.0001). No eyes developed clinically significant haze, 14.8% developed regression, and 13% had a reduction of 2 or more CDVA lines. Conclusions: Postkeratoplasty topography–guided photorefractive keratectomy has good long-term efficacy and safety, resulting in significant UDVA, refractive, and keratometric improvement. Regression can occur after the first year of treatment, emphasizing the importance of long-term follow-up.

Topography-Guided Trans-Epithelial No-Touch Photorefractive Keratectomy for High Irregular Astigmatism After Penetrating Keratoplasty: A Prospective 12-Months Follow-Up

“…The significant improvement of UDVA is supported by previous case series or retrospective studies using the same surgical technique. 11 , 31 However, final UDVA values between studies are hardly comparable due to the different refractive characteristics at enrollment, where our patients presented higher values of SRAST, SimK, and SEQ and worse UDVA and CDVA at T0. Consequently, when comparing between studies mean UDVA values at the final follow-up, our cohort obtained a worse visual acuity without the use of spectacles; conversely, when comparing UDVA changes, the observation of a mean improvement of 5.67±2.93 lines in our study is consistent with previous literature and in some cases even more conspicuous.…”

“…Consequently, when comparing between studies mean UDVA values at the final follow-up, our cohort obtained a worse visual acuity without the use of spectacles; conversely, when comparing UDVA changes, the observation of a mean improvement of 5.67±2.93 lines in our study is consistent with previous literature and in some cases even more conspicuous. 14 , 31 In addition, it should be noted that our patients were selected among those who were intolerant to spectacles and/or CLs, and not among those who were likely to reach emmetropia. However, the significant improvement of CDVA is consistent with Sorkin et al 29 probably due to highly irregular astigmatism (mean >6D) at enrollment, which could have curtailed the effect of the correction with spectacles or CLs before intervention.…”

Aberrometric, Keratometric, and Visual Outcomes After Trans-Epithelial Topography-Guided Phototherapeutic Keratectomy for the Treatment of Irregular Corneas

“…Furthermore, HOAs (mean SA and mean coma) significantly reduced at the 6-month visit. Sorkin et al 10 found a statistically significant improvement in the analyzed aberration parameters measured including total RMS, HOA RMS, defocus, coma, trefoil, and spherical aberration in 13 eyes.…”

“…Many studies have demonstrated the effectiveness in TG-treatments for the treatment of corneal irregular astigmatism 2–6 , 8 , 10–14 , 17–21 with most of these being done in patients with irregular astigmatism secondary to keratoplasty, RK or post-refractive decentered/small zone ablations. Lains et al 20 reported a retrospective case series of 31 eyes with irregular astigmatism after PKP treated with TG-PRK.…”

“…[1][2][3][4][5][6][7] Most cases of irregular astigmatism are secondary to corneal causes, and TG treatments have been used in these cases with satisfactory results. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]20,21 When the aberrations exist at the level of the cornea, the information provided by the topographer is then transferred to a laser platform, which subsequently plans a treatment based on the specific irregularity and higher order aberrations of that specific cornea. The regularizing procedure itself may induce some refractive shift that will further need to be corrected.…”