Preoperative and posteroperative visual acuities for Landolt ring targets and for a grating target of comparable retinal illuminance produced by two-beam interference were assessed in patients with anterior segment disease. Good preoperative interferometric acuities (6/12 or better) were found in over half of the cases in which Landolt acuities were 6/90 or worse. In general, good preoperative interferometric acuities were predictive of good postoperative Landolt acuities. However, poor interferometric acuities in patients with opacified media did not preclude good Landolt acuities postoperatively. We conclude that interferometric acuity testing can provide valuable information about potential macular resolution capacity in some cases. Both the strengths and weaknesses of interferometric acuity testing must be appreciated for successful application.