Femtosecond Thin-flap laser assisted in situ keratomileusis for Correction of Post- Penetrating Keratoplasty Ametropia: Long-Term Outcome

Abstract

Purpose: To evaluate the long-term clinical outcomes of femtosecond thin-flap LASIK (femto-LASIK) for correction of refractive error after penetrating keratoplasty in keratoconus-affected eyes. Setting: a private ophthalmology clinic Design: Prospective interventional case series Methods: This prospective interventional case series enrolled 22 eyes of 22 patients who underwent femto-LASIK for the management of post-penetrating keratoplasty ametropia. The refractive error, uncorrected (UDVA), and corrected (CDVA) distance visual acuities and vector analysis were reported in short-term and long-term period after surgery. Results: The mean age was 32.7 ± 7.5 years (range, 23 to 47 years) at the surgery time. The average time between PK and femto-LASIK was 42.5 ± 31.7 months. The average follow-up duration after femto-LASIK was 81.2 ± 18.6 months. The mean preoperative UDVA significantly improved from 0.47 ± 0.15 to 0.35 ± 0.14 at 12 months (P=0.048) and 0.4 ± 0.17 at final follow-up exam (P= 0.007). CDVA was 0.22 ± 0.1 at baseline which improved to 0.18 ± 0.15 and 0.15 ± 0.1 logMAR at 12 and 81 months, respectively. (Ps= 0.027, 0.014). The mean cylinder before surgery was -5.04 ± 1.4D which significantly decreased to -1.5 ± 0.8 D at 12 months postoperatively. (P< 0.001). There was a significant increase in refractive astigmatism from 12 months to 81 months postoperatively (-3.1±2.0, P=0.002). Conclusions: Our findings suggest that femtosecond thin-flap LASIK was an effective and safe procedure to correct refractive error after penetrating keratoplasty. However, some regression was observed at the final exam compared to results achieved immediately postoperatively.