Far and near visual acuity with multifocal intraocular lenses in an optomechanical eye model with imaging capability

Opto-mechanical design of a dispersive artificial eye

We present an opto-mechanical artificial eye that can be used for examining multi-wavelength ophthalmic instruments. Standard off-the-shelf lenses and a refractive-index-matching fluid were used in the creation of the artificial eye. In addition to dispersive properties, the artificial eye can be used to simulate refractive error. To analyze the artificial eye, a multi-wavelength Hartmann-Shack aberrometer was used to measure the longitudinal chromatic aberration and the possibility of inducing refractive error. Off-axis chromatic aberrations were also analyzed by imaging through the artificial eye at two discrete wavelengths. Possible extensions to the dispersive artificial eye are also discussed.

Visual performance with accommodating and multifocal intraocular lenses

AIM

To compare the visual functional outcomes with accommodating and multifocal intraocular lenses (IOLs).

METHODS

Our retrospective comparative study included 51 patients (60 eyes) received implantation of an accommodating IOL (Tetraflex; 16 patients, 20 eyes), a refractive multifocal IOL (ReZoom; 18 patients, 20 eyes), or a diffractive multifocal IOL (ZMA00; 17 patients, 20 eyes). Subjective refraction, visual acuity, contrast sensitivity (CS), intraocular aberration, and subjective photic phenomena were detected at 3mo after surgery.

RESULTS

The spherical equivalent in the three groups was -0.38±0.54 D, 0.14±0.56 D, and 0.35±0.41 D, respectively. No statistically significant differences were found in uncorrected and corrected distance visual acuity and uncorrected intermediate visual acuity among the groups (P=0.39). The ReZoom group had significantly better distance-corrected intermediate visual acuity than the ZMA00 group (P=0.003). The ZMA00 group had significantly better near visual acuity than the other groups (P<0.05). Better contrast sensitivity values were observed in the Tetraflex group under most of the spatial frequencies conditions (P=0.025). The total aberration was lowest in the ZMA00 group (P=0.000), and the spherical aberration was highest in the Tetraflex group (P=0.000). The three groups had similar frequency of ghosting and glare, and the Tetraflex group had a low rate of halos (P=0.01).

CONCLUSION

Both accommodating and multifocal IOLs can successfully restore distance and uncorrected intermediate visual acuities. Tetraflex accommodating IOLs perform better in CS and with less halos of photic phenomena. ReZoom refractive multifocal IOLs have better performance in distance-corrected intermediate visual acuity than ZMA00 diffractive multifocal IOLs, and the latter achieved better near visual acuity and efficiently decreased the optical aberration.

Opto-mechanical artificial eye with accommodative ability

The purpose of this study was to describe the design and characterization of a new opto-mechanical artificial eye (OMAE) with accommodative ability. The OMAE design is based on a second-pass configuration where a small source of light is used at the artificial retina plane. A lens whose focal length can be changed electronically was used to add the accommodation capability. The changes in the OMAE's aberrations with the lens focal length, which effectively changes the accommodative state of the OMAE, were measured with a commercial aberrometer. Changes in power and aberrations with room temperature were also measured. The OMAE's higher-order aberrations (HOAs) were similar to the ones of the human eye, including the rate at which fourth-order spherical aberration decreased with accommodation. The OMAE design proposed here is simple, and it can be implemented in an optical system to mimic the optics of the human eye.