Multifocal effect of against-the-rule myopic astigmatism in pseudophakic eyes

In monofocal intraocular lens (IOL) implants we can sometimes obtain a certain degree of pseudoaccommodation. The use of a slight myopic astigmatism is proposed for postoperative refraction to achieve a significant increase in the depth of field and to reestablish a certain degree of pseudoaccommodation in pseudophakic eyes.

Eighty-one eyes with against-the-rule myopic astigmatism were evaluated in 50 patients who underwent IOL implant surgery. We selected patients with corrected monocular visual acuity greater than or equal to 20/30 and with a refraction ranging from +0.50 to -1.25 diopters sph, from -0.50 to -2.75 D cyl, ax from 55 degrees to 140 degrees.

Monocular uncorrected distance visual acuity in 68% of eyes was 20/40 or better, while binocular uncorrected distance visual acuity in 84% of eyes was 20/40 or better and in 66% of eyes was 20/30 or better. Monocular uncorrected near visual acuity in 67% of eyes was J3 or better, while binocular uncorrected near visual acuity in 82% of eyes was J3 or better and in 68% was J2 or better. Sixty-four percent of patients never wear glasses for distance, while 34% use them occasionally and only 2% always wear them. Fifty-four percent of patients never wear glasses for near, 32% use them occasionally, while 14% always wear them.

These data show that with a low against-the-rule simple myopic astigmatism (about -1.50 D cyl x 90) we can often offer pseudophakic patients a rewarding independence from glasses both for distant and near vision.