Contact lens correction of presbyopia

Abstract

The contact lens wearing presbyopic population is underserved worldwide. There are several available options, including single vision contact lenses and spectacle overcorrection for near, monovision, rigid gas permeable (GP) multifocal and bifocal lens designs and soft bifocal lens designs. This paper presents an overview of the latest research and clinical experience as it pertains to these forms of correction. Recent comparative studies concluded that contact lens multifocals perform better in many different forms of visual measurements, in some cases performing similar to best spectacle correction, than monovision wearers. The future appears to be very promising for multifocal GP and soft lens modalities.

Temporal multiplexing with adaptive optics for simultaneous vision

“…Each projected image corresponds to a sharp image at a different vergence. Typically, this solution is achieved by multifocal CLs [1,5] or IOLs with refractive [4] or diffractive [4,6] profiles. Success of simultaneous vision relies on the ability of the human brain to select among the superimposed images a primary in-focus image [1], suppressing the blurred out-of-focus image.…”

“…reading the newspaper). Nowadays, there is a wide range of available tools for counteracting presbyopia symptoms [1,4,5], based on different strategies, such as ophthalmic lenses, contacts lenses (CLs), intraocular lenses (IOLs), and surgical techniques. We can distinguish two basic strategies for presbyopia treatment: simultaneous vision and alternating vision.…”

“…Simultaneous vision is based on simultaneous projection of images on the retina at the same time [1,4,5]. Each projected image corresponds to a sharp image at a different vergence.…”

“…The drawback of this strategy is that suppression ability varies among individuals [7]; the out-of focus images, if not suppressed, can generate a great amount of blur and reduce the contrast sensitivity [1,4,8]. Monovision [1,4,5], where one eye receives the correction for far vision and the other for near, can be considered as simultaneous vision if the binocular rivalry between the retinal images generates binocular suppression. Large depth-of-focus (DoF) achieved by using a pinhole in a contact lens [9], in a corneal inlay [10] or near the pupil plane [11], also allows for simultaneous vision.…”

Short-term visual performance of soft multifocal contact lenses for presbyopia

“…The high proportion of presbyopic contact lens wearers prescribed single vision or monovision lenses may be related to the practitioners' common perception that multifocal contact lenses are more challenging to fit to provide acceptable vision and/or the perceived visual performance by the contact lens wearers themselves (4) . Multifocal contact lenses, which use simultaneous imaging, often cause visual disturbances, such as ghosting and haloes, because the optical zones for intermediate-and near-distance focusing are positioned over the pupil (7)(8)(9)(10) . These disturbances can occur at any distance and are often exacerbated in low-contrast or low-illumination conditions.…”