[Comparative study on in vitro optical characteristics between refractive and other types of extended depth of focus...

Objective: To investigate the differences in optical performance between the novel refractive extended depth of focus (EDof) intraocular lens (IOL), other types of EDof IOLs, and conventional IOLs. Methods: Experimental study. Three non-diffractive EDof IOLs (refractive EDof IOL, wavefront-shaped EDof IOL, rotationally asymmetric regional refractive EDof IOL), an enhanced monofocal IOL, and a monofocal IOL with a power of 20.0 D were included. Using an in vitro IOL optical performance tester, the modulation transfer function (MTF) at far, intermediate and near foci was measured under 3.0 mm and 4.5 mm pupil apertures, different spatial frequencies and corneal spherical aberration models. United States Air Force (USAF) resolution tests were performed, and simulated visual acuity (logarithm of the minimum angle of resolution) was calculated. Results: At 3.0 mm aperture and 50 line pairs (lp)/mm spatial frequency, the far-focus MTF values in descending order were: monofocal IOL (0.73), enhanced monofocal IOL (0.61), rotationally asymmetric regional refractive EDof IOL (0.43), refractive EDof IOL and wavefront-shaped EDof IOL (both 0.36). The intermediate-focus MTF values in descending order were: rotationally asymmetric regional refractive EDof IOL and wavefront-shaped EDof IOL (both 0.15), enhanced monofocal IOL (0.13), refractive EDof IOL (0.06) and monofocal IOL (0.06). At 4.5 mm aperture, the far-focus MTF values in descending order were: monofocal IOL (0.66), enhanced monofocal IOL (0.61), refractive EDof IOL (0.60), wavefront-shaped EDof IOL (0.36), rotationally asymmetric regional refractive EDof IOL (0.22). The far-focus MTF peak of the refractive EDof IOL was higher at 4.5 mm than at 3.0 mm aperture. The intermediate-focus MTF values in descending order were: rotationally asymmetric regional refractive EDof IOL (0.14), wavefront-shaped EDof IOL (0.09), enhanced monofocal IOL (0.07), refractive EDof IOL (0.06), monofocal IOL (0.02). USAF resolution test showed that at 3.0 mm aperture, the far-focus image clarity was the best in the monofocal IOL and enhanced monofocal IOL groups, followed by rotationally asymmetric regional refractive EDof IOL, while refractive EDof IOL and wavefront-shaped EDof IOL were similar; the intermediate-focus image clarity was the best in the wavefront-shaped EDof IOL group. At 4.5 mm aperture, the far-focus image clarity was the best in the monofocal IOL and enhanced monofocal IOL groups, followed by refractive EDof IOL; the intermediate-focus image clarity was the best in the wavefront-shaped EDof IOL and rotationally asymmetric regional refractive EDof IOL groups. Simulated visual acuity analysis showed that at 3.0 mm aperture, the distance visual acuity of the three EDof IOLs was similar, and the intermediate visual acuity of wavefront-shaped EDof IOL and rotationally asymmetric regional refractive EDof IOL was better. At 4.5 mm aperture, the distance visual acuity of refractive EDof IOL was significantly improved and higher than that of the other two EDof IOLs. The MTF of refractive EDof IOL and wavefront-shaped EDof IOL remained stable under decentration and tilt, and refractive EDof IOL showed better stability at 5° tilt. When the simulated visual acuity was 0.2, the depth of focus of monofocal IOL was -2.33 D, and the depth of focus of all three EDof IOLs increased by more than 0.5 D compared with the monofocal IOL, while the intermediate-focus (-1.5 D) visual acuity was higher than 0.2. Conclusions: The three non-diffractive EDof IOLs exhibit differential optical performance under different pupil diameters and defocus conditions, all meeting the minimum visual requirements for EDof IOLs proposed by the American Academy of Ophthalmology. The refractive EDof IOL provides stable distance vision unaffected by pupil size and maintains favorable distance image clarity even under large corneal spherical aberration.