A new trifocal corneal inlay for presbyopia

Abstract

Corneal inlays (CIs) are the most recent surgical procedure for the treatment of presbyopia in patients who want complete independence from the use of glasses or contact lenses. Although refractive surgery in presbyopic patients is mostly performed in combination with cataract surgery, when the implantation of an intraocular lens is not necessary, the option of CIs has the advantage of being minimally invasive. Current designs of CIs are, either: small aperture devices, or refractive devices, however, both methods do not have good performance simultaneously at intermediate and near distances in eyes that are unable to accommodate. In the present study, we propose the first design of a trifocal CI, allowing good vision, at the same time, at far, intermediate and near vision in presbyopic eyes. We first demonstrate the good performance of the new inlay in comparison with a commercially available CI by using optical design software. We next confirm experimentally the image forming capabilities of our proposal employing an adaptive optics based optical simulator. This new design also has a number of parameters that can be varied to make personalized trifocal CI, opening up a new avenue for the treatment of presbyopia.

Review of Presbyopia Treatment with Corneal Inlays and New Developments

“… 40 While trifocal corneal inlays may allow for improved visual quality at near, intermediate, and distance, these inlays face similar concerns that past synthetic corneal inlays faced such as reaction to a foreign body and epithelial remodeling that does not reverse with removal of the implant. 44 Pharmacologic therapies such as pilocarpine drops are inexpensive, non-invasive, and effective. However, they come with complications such as headache, reduced distance vision especially at night, and as noted earlier have rare associated complications such as retinal detachments.…”

“…Trifocal intraocular lenses are a well-established (albeit premium) IOL typically used for patients following cataract removal. 44 However, to our knowledge, corneal inlays are yet to venture into the trifocal design. In their 2021 paper, Furlan et al proposed the first trifocal corneal inlay (TCI) design.…”

“… 45 The total area of the lens is 5.5mm 2 compared to the 8.0mm 2 and 9.3mm 2 of the Flexivue and KAMRA lenses. 44 A summary of the device properties and mechanism of action can be found in Table 2 .…”

“…The authors’ initial analysis suggests it does not compromise DVA. 44 In a follow up analysis of their TCI, they evaluated how spherical aberration effects visual results. They found that spherical aberration extends the focal depth of the intermediate focus which may allow for customized focal distribution that fits the needs of each patient.…”

“…However, the dramatically decreased total area of the lens combined with the micro-drilled holes and advances in biocompatible material may mitigate the host reaction to the material. 44 Since the material for the device is not native corneal tissue, the concern remains that it may lead to a foreign body reaction causing corneal haze or other adverse reactions similar to the TCI’s bifocal counterparts. While the TCI is still in the experimental stages, it offers an interesting technology that may improve how we treat presbyopia in the coming years.…”