Refractive extended depth‐of‐focus lens design based on periodic power profile for presbyopia correction

Abstract

PurposeLimitations of existing diffractive multifocal designs for presbyopia correction include discrete foci and photic phenomena such as halos and glare. This study aimed to explore a methodology for developing refractive extended depth‐of‐focus (EDoF) lenses based on a periodic power profile.MethodsThe proposed design technique employed an optical power profile that periodically alternated between far, intermediate and near distances across the pupil radius. To evaluate the lens designs, optical bench testing was conducted. The impact on visual performance was assessed using a spatial light modulator‐based adaptive optics vision simulator in human subjects. Additionally, the effects of pupil size change and lens decentration on retinal image quality were examined. A comparative performance analysis was carried out against a typical diffractive trifocal design and a monofocal lens.ResultsThe proposed design method was found to be effective in uniformly distributing light energy across all object distances within the desired depth of focus (DoF). While trade‐offs between overall image quality and DoF still exist, the EDoF lens design, when tested in human subjects, provided a continuous DoF spanning over 2.25 D. The results also revealed that the EDoF design had a slightly higher dependence on changes in pupil size and lens decentration than the diffractive trifocal design.ConclusionThe proposed design method showed significant potential as an approach for developing refractive EDoF ophthalmic lenses. These lenses offer a continuous DoF but are slightly more susceptible to variations in pupil size and decentration compared with the diffractive trifocal design.

Diffractive multifocal lens design using phase retrieval

“…Based on the focality, premium IOLs can be categorized into multifocal and extended depth of focus (EDoF) types [1]. An EDoF lens provides continuous vision from far to near [2][3][4], whereas a multifocal lens provides clear vision at distinct distances [5,6]. This study focused on multifocal lens designs.…”

“…For simplicity, we assume that a thin phase plate (IOL) is located in the air at the pupil plane. As shown in Figure 1, the wavefront immediately after the phase plate is written as 𝑊(𝜌), where 𝜌 = 𝑟 2 . 𝑟 represents the radial distance from the center of the wavefront.…”

“…where 𝑙 is an integer and 𝑊 0 represents a basic wavefront where the corresponding phase increases by 2𝜋 if 𝜌 increases by 𝑅 2 . 𝑊 0 has a refractive power of 𝜙 0 = 2𝜆 𝑅 2 .…”

“…Figure 3e shows the areaMTF values through the focus for pupil diameters of 3, 4, 5, and 6 mm. The areaMTF values exhibited three peaks at the corresponding foci at -1.10, 0.00 and 1.10 D. In Example 3, 𝑅 was set to be √ 3 2 2 mm, and the targeted foci had 9 equally spaced refractive powers from -0.98 D to 0.98 D, which corresponded to diffraction orders from -4 to +4. Further, 𝑡1 and 𝑡2 were set to be 0.1 and 0.1, respectively.…”