Intra Corneal Inlays For Presbyopic Correction

Intra corneal Inlays for presbyopic correction

Introduction to corneal InlaysCorneal inlays are small artificial implants that are inserted into the eye via either a femtosecond laser-created pocket or corneal flap to improve near vision Three types of inlays are available :-1. KAMRA (Acufocus)

2.. Raindrop (formely Vue +PresbyLens , ReVision optics)

3.Flexivue Micro-lens (Presbia)

The Raindrop Inlay (corneal reshaping inlay) - It is a 2mm hydrogel corneal implant - Based on principle of multifocality- A 30 micron thick implant is placed under a 130-150 micron LASIK flap to change the corneal curvature of one eye to add near and intermediate focusing power .- This procedure is reversible and the implant can be removed.

How the raindrop in lay works

MicroLens Flexivue Hydrogel corneal microlens implanted after creating a

femtosecond flap. It is transparent , biocompatible and mimics a healthy

cornea made of hydrophilic polymer. Removal with reversible vision. Base on the multifocal (bifocal) principle 3mm wide , 15 micron thick , 0.15mm opening in the center to allow nutrient and fluid flow. Implanted in cornea at depth of 280-300 microns.

The bifocal design produces two images at fovea -One image results from combined refractive effects of area of cornea that surrounds the lens and central zone of lens -One image from peripheral zone of lensDisadvantage – pupil smaller than 3.0 mm = peripheral plus power of lens obstructed by iris.

KAMRA INLAY It utilizes a small aperture optics to increase the depth

of focus to allow only focused light rays to enter the eye .

It is 3.8 mm in diameter , 5 microns thick , 1.6 mm central aperture

The annulus is incorporated with black carbon particles and has 8,400 perforations of various sizes ,

This is designed to counter diffraction issues under mesopic settings and yet allow nutrient flow.

KAMRA inlay can provide up to 2.00 D of presbyopic correction.

Design of KAMRA implant

The KAMRA inlay is placed unilaterally in the patients non dominant eye in a corneal pocket and is centered over the visual axis.

Since the inlay works based on small aperture optics rather than a change in refractive power , improved near vision results remain immune to the progression of presbyopia , offering patients a lifetime of benefits.

Exclusion criteria

Prior corneal procedures (except LASIK and PRK)KeratoconousCataractMacular degenerationAmblyopia or strabismus Corneal degeneration or dystrophySevere dry eyePatient with unrealistic expectations

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