Abstract
Purpose:
To investigate the utility of Intraoperative Optical Coherence Tomography (iOCT) in Deep Anterior Lamellar Keratectomy (DALK).
Methods:
We retrospectively reviewed data from 10 patients from 2 surgeons who underwent attempted DALK between 1/11/2012 and 11/19/2012. Seven of 10 patients had keratoconus. Three of 10 had visually significant corneal scarring. We obtained iOCT images utilizing the Bioptigen Envisu Spectral Domain Ophthalmic Imaging System. iOCT images were analyzed at various points in the surgery. Specifically, we examined depth and location of post-host trephination, pre-big bubble cannula tunnel, post-big bubble, post-stromal dissection and post suturing of the donor graft.
Results:
Four of 10 patients had successful big bubble and completed DALK. Two of 10 had partially successful big bubble with additional manual dissection and completed DALK. Four of 10 had rupture of Descemet’s membrane during attempted big bubble and required conversion to penetrating keratoplasty (PKP). From the successful big bubble cases we captured image examples of post-host corneal trephination, pre-big bubble cannula placement prior to air injection, post-big bubble injection, post-stromal bed dissection/bare Descemet’s membrane and post-suturing of donor graft. In addition, from the partially successful big bubble cases we obtained images of the residual stromal bed during manual dissection. In cases of Descemet’s rupture, we captured images of the defects in Descemet’s membrane.
Conclusions:
iOCT is a useful tool for gauging tissue planes at various steps in DALK surgery. Namely, it is helpful in measuring depth of trephination, position of the cannula, location of the big bubble, post-dissection residual stromal bed, alignment of the graft-host junction. In particular, assessment of the cannula position prior to air injection on attempted big bubble may prove to be a useful application of this modality in improving the success rate of achieving big bubble. Additionally, in cases when a complete big bubble is not achieved, iOCT can be useful in assessing residual stromal bed depth. When Descemet’s membrane is violated, the areas of ruptured can be identified. These applications of iOCT may lead to a greater percentage of successful DALK surgeries and a smaller conversion rate to PKP.
Keywords: 479 cornea: clinical science •
550 imaging/image analysis: clinical