P-14 Apparent Absence of a Surgical Plane During Attempted Stromal Peeling for DALK in a Post-Rotational Autokeratoplasty Eye Suggests Role of Migration of Host Keratocytes in the Development of the Natural Pre-Descemetic Plane of Separation

Case A 58-year-old female was referred to our clinic for corneal scarring in the left eye. She previously underwent ipsilateral rotational autokeratoplasty (IRA) for herpetic keratitis in 2001. Day to day visual acuity was 0.74 logMAR and best corrected visual acuity was 0.40 logMAR. Slit lamp exam showed significant stromal scarring in the visual axis. The peripheral cornea was otherwise clear. Deep anterior lamellar keratoplasty (DALK) using the stromal peeling technique described by Bovone et al was attempted. The donor was prepared with a microkeratome (Moria SA, Antony, France) with a 400 µm head. A 9.0 mm adjustable depth vacuum trephine (Moria SA, Antony, France) was applied to the cornea to a depth of 450 microns. After repeated attempts to open a pre-descemetic plane with no success, the surgery was electively converted to a 2-piece microkeratome-assisted mushroom keratoplasty with 9 mm anterior lamella secured with 16 interrupted 10–0 nylon sutures and a 6 mm posterior lamella. At 6 months postoperatively, the graft was clear. Unaided visual acuity was 0.50logMAR improving to 0.10logMAR with correction. Topographic astigmatism with sutures in situ was 5.4D. The postoperative course was otherwise uneventful. The apparent absence of a pre-descemetic plane in an old IRA adds evidence that formation of this plane is dependent on the allogeneic stimulation of host keratocytes. Our working theory is that host keratocytes migrate to the pre-descemet layer of an allogeneic PK graft, thereby allowing stromal peeling in post-PK eyes along a natural pre-descemetic plane of separation.