A new trifocal corneal inlay for presbyopia

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.

Optical Evaluation of New Designs of Multifocal Diffractive Corneal Inlays

Purpose. To assess the imaging properties of two different designs of a new concept of corneal inlays whose working principle is based on diffraction. Methods. The quality of the retinal images provided by Diffractive Corneal Inlays (DCIs) was evaluated theoretically in comparison with Small Aperture Corneal Inlay (SACI). ZEMAX OpticStudio software was employed for the simulations in an eye model with different pupil diameters (3.0 mm and 4.5 mm). The employed merit functions in the analysis were the Modulation Transfer Function (MTF), the area under the MTF (MTFa), and the Point Spread Function (PSF). Comparison was made with the SACI at different defocus conditions. Results. The bifocal nature of the DCIs was demonstrated in a model eye for the first time. It was shown that the intensity of the near focus depends on the radius of the central zone. Retinal image quality of the DCI was equal to or exceeded the SACI in the majority of visual conditions as was demonstrated with simulated images. Conclusions. A new customizable type of corneal inlays has been evaluated using objective numerical simulations. Improvements in imaging of near objects and in light throughput compared with the popular small aperture inlays were demonstrated. These findings open a new technical branch of minimally invasive surgical solutions for the treatment of presbyopia.

A 3-year follow-up study of a new corneal inlay: clinical results and outcomes

PurposeHere, we report the results of a 3-year follow-up analysis of the outcomes of the Flexivue Microlens corneal inlay.PatientsNon-dominant eyes (n=31) of emmetropic presbyopic patients (spherical equivalent: −0.5 to 1.00 dioptre).MethodsA Flexivue Microlens corneal inlay was implanted after the creation of a 300 μm deep stromal pocket using a femtosecond laser. Patients were followed up according to a clinical protocol involving refraction, anterior segment imaging analysis (Oculyser), optical quality analysis (OPD-Scan), monocular binocular uncorrected and corrected visual acuity tests, contrast sensitivity measurements (photopic and mesopic), satisfaction questionnaire results and adverse event reporting.ResultsThirty patients were examined at the 3-year follow-up in this ongoing study. The mean uncorrected near visual acuity improved to Jaeger 1 in 76.9% of eyes treated with the inlays (vs 87.1% at the 1-year follow-up). All eyes improved four lines in all visits, except for four patients for whom the inlay was explanted. Patients reported that their near vision was good or excellent in 73.3% of cases (vs 90.3% in the first year). The UDVA remained stable over time. Three patients were explanted due to blurred vision for near-point and far-point distances. One patient developed a superficial corneal ulcer after 20 months. Two patients underwent cataract removal. Four patients underwent inlay exchange to increase near power correction.ConclusionsThe Presbia Flexivue Microlens provided presbyopia treatment by improving near vision. Manageable complications may occur over the long term.Clinical trial registration numberU1111-1185-5684 and 0310451200000550.