Refractive bifocal intraocular lens and pupillary diameter

To assess the relationship between pupillary diameter and focusing for distance and near vision with the refractive bifocal intraocular lens (IOL), we studied visual acuity for far and near distance, near point, and depth of focus with normal pupillary movements and after pharmacological miosis and mydriasis (pilocarpine 2% and phenylephrine 10% eyedrops, respectively) in 20 patients implanted with an IOLAB refractive bifocal IOL. Pharmacological miosis and mydriasis did not change far and near visual acuity values from the values with normal pupillary diameter. After pharmacological miosis, the near point position and the width of the depth of focus were unchanged. After pharmacological mydriasis, near point distance was unchanged but depth of focus dropped in a statistically significant manner (P < .01). We concluded that the pupillary diameter alone cannot produce distance or near vision focusing. The choice depends on the brain's preference. Pupillary diameter increases the quality of vision through the blur circles mechanism.