Deep Anterior Lamellar Kertaoplasty with a femtosecond assisted zig-zag cut
The fresh pre-cut donor corneal button was inspected through its clear packaging for its suitableness for the transplant procedure. The accompanying paperwork was also reviewed for acceptable endothelial cell count and laser cut characteristics. After suitable preoperative medication, and confirmation of informed consent and current health status, the patient was brought to the laser suite. A surgeon's time out was performed to re-affirm the correct patient, surgical site, and surgery to be performed. Peripheral corneal thickness previously determined by Visante OCT pachymetry was reviewed. The thinnest value was determined, and the depth of the posterior side-cut was set to be 70 microns more superficial. The remainder of the parameters were inserted and double-checked in the software. The correct eye was again verified. The sterile patient interface was then applied, with the suction ring centered on the cornea. The femtosecond laser then performed the incision. At the completion of the laser procedure, additional topical antibiotic was instilled and a shield was placed over the eye. The patient was then transported directly into the operating suite.
An additional surgeon's time out was performed to re-affirm the correct patient, surgical site, and surgery to be performed. Anesthesia was administered as mentioned above. The eye was then prepped with Betadine and an incise drape placed, cut to cover the lashes and meibomian glands when the Schott lid speculum was placed. The donor button, pre-cut in a pattern matching the laser incision of the patient, was set aside under protection with corneal storage medium protecting the endothelium.
The laser incision in the patient cornea was fully opened with a Sinskey hook and blunt dissection. The lamellar stromal cut was identified and a bent 30-gauge needle on a 5 cc syringe filled with air was inserted bevel down along the lamellar cut into midcorneal stroma and air was injected, baring Descemet membrane. Next, a 15-degree blade was used to make a small midperforation into the big bubble created and OVD injected into this space to protect Descemet membrane. The right-handed and left-handed corneal scissors were used on a bevel to remove the remainder of the posterior stroma respecting the angle of the laser-created posterior lip. Descemet membrane remained intact.
The fresh pre-cut donor corneal button's endothelium was wiped off using a Weck-Cel. The donor stroma was placed on the eye epithelial side up, and 8 interrupted 10-0 nylon sutures were placed at the laser-created radial incision marks, taking care to distribute the tissue evenly and align the donor and host layers. Then the incision closure was completed via 16-bite running suture. Subconjunctival lidocaine followed by antibiotics and steroids were injected inferiorly. The speculum was then removed and topical antibiotic was placed in the eye. A patch and shield were placed over the eye. The patient left the operating room in satisfactory condition, having tolerated the procedure well.
Visual impairment secondary to corneal pathology
Donor cornea was cut in a zig-zag C pattern, patient also had a similarly cut zig-zag C pattern done by femtosecond laser
Dissection of the anterior portion of the cornea was made prior to Descemet's membrane
DALK offers better recovery and outcomes while zig-zag pattern has also been shown to also have better visual recovery and long-term outcomes (1).
Fungal infection of the cornea (rare)
Dr. Marjan Farid has co-developed the scissors used in this video.
No Other Conflicts of Interest for Authors to Disclose
Many thanks to the staff and faculty at the Gavin Herbert Eye Institute
1. Gaster RN, Dumitrascu O, Rabinowitz YS. Penetrating keratoplasty using femtosecond laser-enabled keratoplasty with zig-zag incisions versus a mechanical trephine in patients with keratoconus. Br J Ophthalmol. 2012;96(9):1195–1199. doi:10.1136/bjophthalmol-2012-301662