To describe a simple finding that can be used to determine donor tissue orientation in Descemet membrane endothelial keratoplasty (DMEK). This involves the appearance of a highly reflective round curved line from an overlapping graft edge within the anterior chamber using light from an endoilluminator. We here name this Kobayashi sign (K-sign).
Twelve consecutive eyes from 12 patients who underwent DMEK were evaluated for the presence of a K-sign. The presence of Berrospi sign (B-sign), a double-line reflection from the peripheral curls of the Descemet membrane (DM) roll that has been reported to be useful for correct graft orientation, was also evaluated.
Of 12 cases, 3 donors showed a loosely scrolled roll soon after DM donor insertion; all 3 of these showed a positive B-sign only when the endoilluminator was used. Nine donors showed a tightly scrolled DM roll without a B-sign; among these 9 donors, a K-sign was visible in 7 cases only when the endoilluminator was used. The remaining 2 cases with a tight scroll configuration showed no K-sign even with the use of endoillumination, indicating that the roll edge was located completely downward; rotation of the roll using a small jet of fluid from paracentesis revealed K-sign in these cases.
This technique is useful for determining the correct orientation of a tightly scrolled DM roll, subsequently enabling rapid DMEK surgery. For loosely scrolled DM roll, endoillumination enhanced B-sing is proven useful.