Ultrastructure of the Internal Limiting Membrane Removed During Macular Hole and Diabetic Macular Edema Surgery

ABSTRACT

PURPOSE: To evaluate retinal damage following internal limiting membrane (ILM) peeling in macular hole and diabetic macular edema (DME) surgeries. METHODS: Forty-five eyes with macular holes and thirty-five eyes with DME underwent pars plana vitrectomy with ILM peeling. The structures of the ILM were investigated using transmission electron microscopy, and the grades of retinal tissue damage were analyzed. We additionally observed the clinicopathologic association of retinal damage with the development of retinal hemorrhage during ILM peeling and that seen with indocyanine green (ICG) staining. RESULTS: In all specimens, cellular fragments were observed on the retinal side of the ILM in both macular hole and DME patients. The thickness of the ILM in DME significantly increased (3.13+/-1.12 micrometer compared with that in patients with macular holes (2.41+/-0.77 micrometer, p=0.002). The frequency of minute retinal bleeding during ILM peeling was higher in macular hole patients (46.7%) than in those with diabetic macular edema (22.9%m p=0.028). Twenty-two eyes of 45 macular hole patients (48.9%) and 16 eyes of 35 DME patients (45.7%) had relative retinal damage. Overall, ILM performed in eyes which had minute bleeding during the peeling had more retinal damage (62.1%) than did those without hemorrhage (39.2%, p=0.049). ICG staining did not appear to influence retinal damage (p=0.81). CONCLUSIONS: ILM peeling can cause minor, but demonstrable, damage of the adjacent retina.