1. A technique to salvage big-bubble deep lamellar keratoplasty after inadvertent full- thickness trephination Siamak Zarei-Ghanavati 1, MD and Mehran Zarei-Ghanavati 1, MD Mashhad University of Medical Sciences (MUMS), Mashhad, Iran The authors have no financial interest in the subject matter of this poster.

2. Herein, we describe a technique to salvage deep anterior lamellar keratoplasty after large DM perforation during trephination. Purpose

3. When we notice inadvertent full-thickness laceration [Fig1] during trephination of the recipient cornea by Hessburg-Barron suction trephine, the full-thickness wound is secured with one partial- thickness X-type 10-0 nylon suture. [Fig 2] Surgical Technique

4. Fig1 Fig2

5. A bent 27-gauge needle attached to a 2 ml syringe filled with air is inserted into stroma,air is gently injected which caused corneal emphysema. Then, anterior keratectomy is done, sparing area around suture. [Fig3] Another air injection from inferior part of the trephination groove is done through the thin stromal layer that formed a small “big bubble” detached DM from the stoma. [Fig4] Surgical Technique

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7. This “big bubble” is not expanded by air to avoid bubble collapse through the site of DM perforation. Surgical Technique

8. Then, a needle attached to an OVD syringeis introduced into the bubble and OVD injected progressively to separate DM from stoma. After small puncture of residual stoma (bubble roof) with 15-degree blade, thin layer of stroma is cut into quarters with scissors. [Fig5] Any remained attachment of DM is released gently by the OVD injection into the pocket created between DM and stroma. [Fig6] Surgical Technique

9. Fig4 Fig5 Fig6

10. Then X-type nylon suture is removed. The donor cornea is prepared and DM is peeled off with a forceps. Graft is secured 10-0 nylon sutures. One suture in site of DM perforation is full thickness to attach DM to stroma. AC is completely filled with air through limbal paracentesis for 5 minutes. At the end of surgery, half of the air is replaced by BBS.[Fig7] Figure 8 shows our first case two months after surgery. Surgical Technique

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12. A 19-year-old woman and a 22-year-old man with keratoconus underwent deep anterior lamellar keratoplasty using this modified big-bubble technique. Both of them had uncomplicated postoperative course such that no double chamber was detected, postoperatively. Follow up time was 6 and 3 months, respectively. At the last follow up visit, visual acuity was 20/40 in the first and 20/03 in the second case. Endothelial cell count was 2961 and 2994 cell/mm2, respectively. Results