Bifocal intraocular lenses (BIOLs) reduce image contrast. We measured
contrast sensitivity (CS) to evaluate the clinical significance of the
loss in image contrast. Four groups were compared: 15 patients with a
monofocal IOL, 13 with the True Vista BIOL, 13 with the AcuraSee BIOL
, 11 with the diffractive BIOL. CS was measured using the Mentor B-VAT
II-SG. Distance CS was slightly better in monofocal eyes than in all
bifocal eyes, and distance CS was considerably better than near CS in
eyes with the True Vista or the AcuraSee BIOL. With the diffractive BI
OL, values were about the same at distance and near focus. Our results
demonstrate that BIOLs reduce CS, thereby performing differently: bot
h True Vista and AcuraSee favor distance vision, while the diffractive
BIOL provides about the same contrast at distance and near focus.