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Intraoperative Optical Coherence Tomography–Guided Femtosecond Laser–Assisted Deep Anterior Lamellar Keratoplasty

Liu, Yu-Chi, MD*,†,‡; Wittwer, Valéry V., MD§; Yusoff, Nur Zahirah M., Bte BSc*; Lwin, Chan Nyein, MBBS*; Seah, Xin Yi, BSc*; Mehta, Jodhbir S., MBBS*,†,‡; Seiler, Theo, MD, PhD§

doi: 10.1097/ICO.0000000000001851
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Purpose: To describe the feasibility and outcomes of intraoperative optical coherence tomography (OCT)–guided, femtosecond laser–assisted deep anterior lamellar keratoplasty in which the lamellar and tunnel cuts were completed by laser.

Methods: The Ziemer Z8 system was used to scan the corneas intraoperatively and guide the stromal lamellar and tunnel cuts created by the laser. Thirty porcine eyes and 3 human cadaver globes were used to evaluate the accuracy of laser-created intrastromal tunnels and the feasibility of achieving big-bubble pneumatic dissection. The tunnel distance above the Descemet membrane (Dt-dm) was set at 100 and 130 μm, and the accuracy of laser cut was assessed by anterior segment OCT and histological sections. Fourteen patients with keratoconus or corneal scars were then included to evaluate the clinical outcomes.

Results: The deviation from the targeted Dt-dm was 5.5% to 8.6% and 0.7% to 9.8% for the 100 and 130 μm groups, respectively. The achieved thickness had a significantly and positively strong correlation with the targeted thickness (r = 0.86; P < 0.001). In all cases, the anterior stromal lamella was removed without difficulty, except in the patients with corneal scars in whom some remaining stromal fiber attachments were observed. A type 1 big bubble was successfully achieved in all patients.

Conclusions: We present the accuracy and clinical outcomes of femtosecond laser–assisted, intraoperative OCT–guided deep anterior lamellar keratoplasty, in which controlled lamellar and tunnel cuts at desired depths were performed by laser in one step, and a successful big bubble was achieved.

*Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore;

Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore;

Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Medical School, Singapore; and

§The Institute for Refractive and Ophthalmic Surgery, (IROC), Zurich, Switzerland.

Correspondence: Jodhbir S. Mehta, MBBS, Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751 (e-mail: jodmehta@gmail.com).

Supported by the Singapore National Research Foundation under its Translational and Clinical Research (TCR) programme (NMRC/TCR/1021 -SERI/2013).

The authors have conflicts of interest to disclose.

Y. C. Liu and V. V. Wittwer contributed equally to this work and should be regarded as equivalent authors.

Received September 27, 2018

Accepted November 02, 2018

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