The eye has a relatively simple optical design with incredible functionality; only two lenses, the cornea and crystalline lens, set the physical rules for image-forming onto the retina. However, the eye is not the perfect optical system we would like it to be since imperfections, irregularities, and misalignments in the cornea and/or crystalline lens induce focusing errors and image degradation. While keratoconus degrades the corneal shape, presbyopia and cataracts are conditions related to aging that affect the crystalline lens and consequently vision.

Standard refractive treatments and cataract surgery have evolved over the years, including wavefront-guided laser corneal surgery, combined solutions, image-guided planning systems, and an increasing number of intraocular lens designs now commercially available. Furthermore, the past years have seen a growth in research on novel technologies that allow predicting, measuring, and manipulating the wavefront aberrations of the eye. This, in turn, would not only enable further exploration of the limits of adaptation to aspherical, toric, and multifocal designs, but also allow incorporation of novel optical concepts aiming at customized solutions to go beyond the correction of conventional refraction in prevalent ocular conditions, such as cataracts, presbyopia, keratoconus, and myopia.

These developments are opening up a new era in anterior segment treatments, allowing surgeons to make evidence-based decisions and affording more predictable outcomes in refractive and cataract procedures. The goal of this special issue is to attract manuscripts in this multidisciplinary area of ophthalmology and visual optics and to provide a broad scope covering clinical, experimental, and theoretical studies. Submissions could include original research and targeted reviews, with the hope that this issue will be of use to ophthalmologists.

Potential topics include but are not limited to the following:

• Novel intraocular lens designs
• Clinical, experimental, and theoretical outcomes of multifocal intraocular lenses, multifocal contact lenses, or small apertures
• Visual performance and clinical outcomes of toric intraocular lenses
• Influence of intraocular lens design and positioning on visual quality
• Safety, efficacy, clinical outcomes, and visual function of phakic intraocular lenses
• Advances in the correction of keratoconus
• New insights on corneal refractive surgery
• Impact of wavefront-guided laser corneal ablation and combined treatments in regular and irregular corneas
• Instruments to measure and/or manipulate optical aberrations and their applications in myopia, presbyopia, and cataract