Proposed mechanism for retinal tears after LASIK: an experimental model.

Objective: To demonstrate axial length changes associated with anterior shift of the lens/iris diaphragm and anterior vitreous base in human cadaver eyes during suction ring application preceding Moria LASIK, and to propose that these changes may be associated with anterior retinal tears.

Design: Human eye study.

Materials: Eight human eye bank eyes ranging in age from 65 to 73 years. Two eyes had a history of intraocular surgery involving cataract extraction and intraocular lens implantation.

Intervention: Measurements of intraocular pressure via internal manometer and Tono-Pen, anterior chamber depth, and axial length before and after application of a Moria LASIK suction ring.

Main Outcome Measures: Change in anterior chamber depth and axial length after Moria LASIK suction ring application.

Results: Axial length increases (mean change = 1.125 mm, P = 0.02) after application of the suction ring, whereas anterior chamber depth shows no significant difference (mean change = -0.01 mm, P = 0.98), suggesting anterior movement of the vitreous base resulting in traction on the anterior retina.

Conclusion: Axial length increase with anterior displacement of the vitreous base during suction ring placement might predispose susceptible eyes to anterior retinal tears during and after LASIK.