gms | German Medical Science

102. Jahrestagung der DOG

Deutsche Ophthalmologische Gesellschaft e. V.

23. bis 26.09.2004, Berlin

Inverse mushroom-shaped non-mechanical penetrating keratoplasty using a femtosecond laser

Meeting Abstract

  • corresponding author B. Seitz - Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen; website: www.kornea.org
  • H. Brünner - Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen; website: www.kornea.org
  • A. Viestenz - Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen; website: www.kornea.org
  • C. Hofmann-Rummelt - Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen; website: www.kornea.org
  • U. Schlötzer-Schrehardt - Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen; website: www.kornea.org
  • A. Langenbucher - Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen; website: www.kornea.org

Evidenzbasierte Medizin - Anspruch und Wirklichkeit. 102. Jahrestagung der Deutschen Ophthalmologischen Gesellschaft. Berlin, 23.-26.09.2004. Düsseldorf, Köln: German Medical Science; 2004. Doc04dogP 038

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dog2004/04dog529.shtml

Published: September 22, 2004

© 2004 Seitz et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Objective

Non-mechanical corneal trephination creating a self-sealing donor/host apposition without the necessity of sutures is a vision of cornea surgeons. The purpose of this study was to demonstrate the feasibility of an inverse mushroom-shaped corneal trephination using a femtosecond laser in a non-contact automated manner.

Methods

In this laboratory study 10 PMMA blocks and 10 pig corneas were treated with a commercially available femtosecond laser source (Ti:Sapphire Amplifier Laser System, type "Hurricane-i" - kindly provided by Spectra-Physics), which was adapted to a rapid beam delivery system (wave length 800 nm, 2 to 20 microJ, 5 kHz, 150 to 400 fs). All electronic components were custom-made or individualized for this system. The beam was expanded to the maximum aperture of the mirror (20 mm) and focussed with a f-theta 100 mm telecentric optic. The trephination profile consisted of (1) a 7 or 6 mm diameter cylinder from the anterior chamber, (2) a transversal plane in the mid-stroma and (3) a concentric 5 mm diameter cylinder upwards beyond the epithelium. Following the laser action PMMA blocks were examined by a transmission microscope and corneas were fixed in 10% buffered formaldehyde solution and processed for PAS light and transmission electron microscopy (TEM).

Results

Creation of inverse mushroom-shaped trephinations took less than 60 s. In PMMA blocks, the thickness of the outer ('stipe') and inner part ('cap') of the "inverse mushroom" could be varied. Histology in pig corneas displayed trephination edges marked by partly confluent gas bubbles (10 to 40 microm) with tissue bridges in between. By TEM, the gas bubbles were lined by a delicate, electron-dense layer (5 to 40 nm in width) and essentially normal adjacent collagen fibers without any evidence of thermal damage.

Conclusions

Femtosecond laser technology seems to offer a promising approach towards minimally invasive self-sealing "no-stitch keratoplasty". Further studies have to focus on the improvement of the laser setup.