Inclusion/exclusion criteria

Inclusion criterion was patients with diabetic fibrovascular membranes that threaten the macula. Threat to the macula was considered as fibrovascular membranes close to the avascular foveal zone inside and over the vascular arcade. Assessment of macula-threatening lesion was made by clinical examination and noted routinely by the same experienced surgeon (FH) before the operations. The exclusion criteria included history of prior vitrectomy, glaucoma filtration surgery, intractable glaucoma, and vitreous hemorrhage (VH) without fibrovascular proliferation. All patients received anterior segment examination, intraocular pressure measurement with applanation tonometry, a best-corrected Snellen visual acuity measurement, and biomicroscopic evaluation with fundus noncontact lenses. All eyes without visualization of fundus underwent B-scan ultrasonography. All Snellen visual acuities were converted into logarithm of the minimum angle of resolution units. Intraocular pressure levels ≥21 mmHg were accepted as elevated intraocular pressure.