Are fenestrations in peripheral pre-Descemet’s layer the route for intracameral air bubble migration during femtosecond LASIK?

Abstract

Femtosecond laser assisted in situ keratomileusis (FS-LASIK) is associated with the creation of cavitation gas bubbles in the stromal dissection plane. Intraoperative intracameral migration of these air bubbles is a rare complication observed during the procedure. At present, it is postulated that the air bubbles created during the photodisruptive process migrate into the anterior chamber via the Schlemm’s canal and trabecular meshwork. This theory; however, does not explain the extremely rare occurrence of this complication. Recently, the pre-Descemet’s layer (PDL) and the presence of fenestrations in its periphery have been described in literature. We present an alternative pathomechanism for intracameral air bubble migration during FS-LASIK based on the anatomical relationship of fenestrations in the peripheral PDL and the termination of Descemet membrane. We propose that the air bubbles migrate directly from the laser dissection plane into the anterior chamber via the fenestrations in the peripheral PDL in cases where the Descemet membrane terminates proximal to the fenestrations. The anatomical variability in the termination of the Descemet membrane in relation to the fenestrations in the peripheral PDL may explain why the complication is not observed in a significant proportion of cases where the LASIK flap border lies in close proximity to the limbus.