Effect of Spherical Equivalent Error on Visual Acuity at Various Distances in Eyes With a Trifocal Intraocular Lens

To examine the effect of manifest refraction spherical equivalent error on visual acuity at various distances in eyes that received a trifocal intraocular lens (IOL).

Sixty eyes of 30 patients who underwent bilateral implantation of a trifocal IOL (Alcon PanOptix TFNT00; Alcon Laboratories, Inc., Fort Worth, TX) were enrolled. Corrected visual acuity from far to near distances was measured using an all-distance vision tester after simulating the spherical equivalent error by adding spherical lenses with refractive powers of +1.00, +0.50, 0.00, -0.50, and -1.00 diopters (D); addition of a plus lens simulates myopia, whereas addition of a minus lens simulates hyperopia.

Mean visual acuity at all distances differed significantly among the spherical lens added groups (P ≤ .0374). Mean distance visual acuity at infinity, 5, and 3 m was significantly worse in all lens added groups (+1.00, +0.50, -0.50, and -1.00 D) than in the no lens group (P < .0001). Mean intermediate visual acuity at 1 and 0.7 m did not differ significantly between each of the lens added groups and the no lens group. Mean near visual acuity at 0.3 m was significantly better in the +1.00 and +0.50 D groups and significantly worse in the -0.50 and -1.00 D groups than in the no lens group (P ≤ .0044).

A manifest spherical equivalent error of slight myopia significantly improved near visual acuity but worsened distance visual acuity, whereas that of slight hyperopia worsened both distance and near visual acuity in eyes with trifocal IOLs, suggesting that slight myopia is a better target refraction than slight hyperopia, although emmetropia is the optimum target. [J Refract Surg. 2019;35(5):274-279.].