Comparison of Excimer Laser Versus Femtosecond Laser Assisted Trephination in Penetrating Keratoplasty: A Retrospective Study
To compare the impact of non-mechanical excimer-assisted (EXCIMER) and femtosecond laser-assisted (FEMTO) trephination on outcomes after penetrating keratoplasty (PK).
In this retrospective study, 68 eyes from 23 females and 45 males (mean age at time of surgery, 53.3 ± 19.8 years) were included. Inclusion criteria were one surgeon (BS), primary central PK, Fuchs’ dystrophy (FUCHS) or keratoconus (KC), no previous intraocular surgery, graft oversize 0.1 mm and 16-bite double running suture. Trephination was performed using a manually guided 193-nm Zeiss Meditec MEL70 excimer laser (EXCIMER group: 18 FUCHS, 17 KC) or 60-kHz IntraLase™ femtosecond laser (FEMTO group: 16 FUCHS, 17 KC). Subjective refractometry (trial glasses) and corneal topography analysis (Pentacam HR; Casia SS-1000 AS-OCT; TMS-5) were performed preoperatively, before removal of the first suture (11.4 ± 1.9 months) and after removal of the second suture (22.6 ± 3.8 months).
Before suture removal, mean refractive/AS-OCT topographic astigmatism did not differ significantly between EXCIMER and FEMTO. After suture removal, mean refractive/Pentacam/AS-OCT topographic astigmatism was significantly higher in the FEMTO (6.2 ± 2.9 D/7.1 ± 3.2 D/7.4 ± 3.3 D) than in the EXCIMER patients (4.3 ± 3.0 D/4.4 ± 3.1 D/4.0 ± 2.9 D) (p ≤ 0.005). Mean corrected distance visual acuity increased from 0.22 and 0.23 preoperatively to 0.55 and 0.53 before or 0.7 and 0.6 after suture removal in the EXCIMER and FEMTO groups, respectively. Differences between EXCIMER and FEMTO were only pronounced in the KC subgroup.
Non-mechanical EXCIMER trephination seems to have advantages regarding postoperative corneal astigmatism and visual acuity compared with FEMTO trephination, especially in KC. A bigger sample size and longer follow-up are needed to evaluate the long-term impact of EXCIMER and FEMTO trephination on postoperative topographic and visual outcomes.
KeywordsAstigmatism Excimer Femtosecond Laser Ophthalmology Penetrating keratoplasty Visual acuity
We hereby thank all the participants of the study.
No funding or sponsorship was received for this study or publication of this article. The Rapid Service Fee was funded by the University of Saarland.
Medical Writing Assistance
Language editing and assistance for this article were provided by San Francisco Edit (San Francisco, USA) and funded by the University of Saarland.
All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship for this article, take responsibility for the integrity of the work as a whole, and have given their approval for this version to be published.
Gábor Tóth, Nóra Szentmáry, Achim Langenbucher, Elina Akhmedova, Moatasem El-Husseiny and Berthold Seitz have nothing to disclose.
Compliance with Ethics Guidelines
The study was approved by the Ethics Committee of Saarland University, Germany (no. 201/11). All procedures performed in our study involving human participants were in accordance with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent for participation and publication of patient data was obtained from all individual participants included in the study.
The data sets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.