Purchase this article with an account.
Yuankai Tao, Michael LaBarbera, Justis P Ehlers, Sunil K Srivastava, William J Dupps; Image-Guided Modified Deep Anterior Lamellar Keratoplasty (DALK) Corneal Transplant Using Intraoperative Optical Coherence Tomography. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):1966.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Deep anterior lamellar keratoplasty (DALK) has become a popular alternative to penetrating keratoplasty (PK). One conventional DALK technique (modified ‘big bubble technique’) begins by performing a trephination of approximately 80% stromal thickness, as measured by pachymetry. These procedures are inherently difficult and intraoperative rates of Descemet’s membrane perforation between 4-39% have been reported. Optical coherence tomography (OCT) provides high-resolution images of tissue microstructures in the cornea, including Descemet’s membrane, and allows quantitation of corneal layer thicknesses. Here, we use cross-sectional OCT measurements of corneal thickness during surgery and a novel micrometer-adjustable biopsy punch to precision-cut the stroma down to Descemet’s membrane.
Modified DALK procedures were simulated on cadaveric porcine eyes using a prototype microscope-mounted intraoperative OCT (iOCT) system for guidance of corneal stroma dissection. The micrometer-adjustable biopsy punch consists of a blunt-tipped cannula attached to a manual micrometer with 1 μm precision and a disposable 1 mm diameter biopsy punch. Corneal thicknesses up to the pre-Descemet’s space measured on iOCT were scaled using a mean measured corneal refractive index and used to set the biopsy punch cut-depth. Once a dissection plane was established, a blunt cannula was used to inject air or viscoelastic to further dissect across the plane, creating a space between Descemet’s membrane and the corneal stroma (Fig. 1).
iOCT-guided modified DALK procedures were performed on 47 cadaveric porcine eyes by non-experts and achieved a perforation rate of ~5% with a mean corneal dissection time <18 minutes. The procedure was also successful performed on a human donor eye without perforation.
iOCT-guided modified DALK allows blind dissection of corneal stroma down to Descemet’s membrane. iOCT measurements of corneal thickness and use of a micrometer-adjusted biopsy punch provides reproducible cut-depths with reduced surgical complexity and corneal endothelium perforation rates. Our data shows the potential for iOCT-guided precision anterior segment surgery without variability as a result of tremor and improvements to standard clinical care.
This PDF is available to Subscribers Only