Allotex Allogenic Corneal Inlays: A New Frontier in Presbyopia Correction

A Modern Solution to a Widespread Problem

Presbyopia affects nearly 1.8 billion people globally, reducing quality of life by impairing near vision in people over 45. For emmetropic presbyopes or those with minor refractive errors the challenge is unique: they enjoy good distance vision but find near tasks increasingly difficult. Traditional options like reading glasses, monovision LASIK, multifocal contact lenses, and refractive lens exchange all have drawbacks for this particular group of people. Glasses offer a solution but not independence. Monovision LASIK compromises binocular function. Multifocal IOLs can have a long adaptation period in the emmetropic presbyope with a clear crystalline lens. Corneal laser options like PresbyLASIK may be irreversible in require significant myopia in the non-dominant eye to achieve good near vision.

Now, Allotex offers a transformative alternative: the allogenic corneal inlay, a biological, minimally invasive implant that restores near vision without sacrificing distance acuity or resorting to intraocular surgery.

A Safe, Proven Biological Approach

Allotex builds on the proven safety and efficacy of allogenic corneal tissue used in procedures like CAIRS (corneal allogenic intrastromal ring segments) for keratoconus. These ring-shaped allogenic implants have demonstrated excellent outcomes in reshaping the cornea and improving visual acuity with minimal complications. Compared to synthetic intrastromal rings, CAIRS show lower rates of inflammation, haze, and long-term complications due to their biologic compatibility.

This success supports the broader use of allogenic corneal implants in refractive surgery. Unlike synthetic inlays previously marketed for presbyopia, which were ultimately withdrawn due to complications, Allotex inlays are made from decellularised, radiation-sterilised donor corneal collagen. This material integrates well with host tissue, avoiding adverse immune reactions or metabolic disturbances and ensuring greater long-term stability and safety.

Design and Placement

The Allotex inlay is a transparent, 30-micron-thick, 2.6 mm-diameter disc, shaped using an excimer laser and implanted under a femtosecond-created LASIK flap in the non-dominant eye. Its curvature and optical properties are designed to increase depth of focus (DoF) by introducing specific higher-order spherical aberrations. This enhances near and intermediate vision while preserving distance acuity, functioning similarly to extended depth-of-focus intraocular lenses but without entering the eye.

The surgical procedure involves creating a LASIK flap approximately 120 microns thick. The flap is lifted, and the inlay is positioned directly over the pupil on the stromal bed. After positioning, the flap is repositioned, encapsulating the inlay beneath the surface. There is no ablation of corneal tissue (unless combined with an excimer laser ablation), no lenticule extraction, and no change to the natural lens. The procedure is entirely additive and reversible.

Reversibility

The Allotex corneal implant is reversible.  In the very rare event that a patient does not adapt to the visual result, the inlay can be removed. Removal is performed by lifting the LASIK flap and gently irrigating away the inlay. In the very few reported cases of dissatisfied patietns, visual acuity returned to preoperative baselines quickly, with no permanent changes or scarring once the implant was removed.

Who Benefits Most

Allotex inlays are particularly well-suited to:

·       Emmetropic presbyopes who wish to regain near vision without glasses

·       Patients with low levels of hyperopia or myopia not warranting lens surgery

·       Those intolerant of monovision corrections

·       Individuals wary of permanent or intraocular solutions

This demographic has previously had limited satisfactory options. Allotex fills that niche by offering a solution that preserves distance vision, avoids intraocular risks, and can be removed if desired.

Clinical Outcomes: 3-Year Data

A prospective 3-year study published in the Journal of Cataract and Refractive Surgery (Keskin Perk et al., 2023) evaluated 25 patients (50 eyes) who underwent implantation of Allotex inlays in their non-dominant eyes. The study provides strong evidence of efficacy, safety, and stability.

Key Results

·       Near Visual Acuity (UNVA): Mean UNVA in treated eyes improved significantly to 0.10 logMAR (approx. J2), compared to 0.56 logMAR in untreated eyes.

·       Distance Visual Acuity (UDVA): No significant difference between treated and untreated eyes. Mean UDVA was 0.07 logMAR vs. 0.03 logMAR, respectively.

·       Corrected Distance Visual Acuity (CDVA): Minimal change in CDVA. 6 out of 25 eyes lost one line of CDVA, mostly attributed to dry eye.

·       Depth of Focus: Treated eyes achieved 2.8 D of DoF compared to 1.1 D in untreated eyes.

·       Spectacle Independence: 22 of 25 patients reported complete freedom from reading glasses at 3 years.

·       Complications: No cases of corneal haze, rejection, or epithelial ingrowth. No inlays required explantation due to medical complications.

These results suggest the Allotex inlay significantly improves near vision and DoF without compromising distance vision, and does so safely over a multi-year period.

Comparison to Other Presbyopia Solutions

Monovision LASIK adjusts one eye for near and one for distance. While effective for some, it can reduce stereopsis and cause adaptation difficulties. The Allotex inlay, by enhancing DoF in one eye without inducing significant myopia, preserves distance acuity and binocular function.

Refractive Lens Exchange (RLE) replaces the natural lens with a multifocal or EDOF IOL.  Whilst overall this is a very successful procedure the outcomes for emmetropic presbyopes has always been less predictable than for those with hyperopia or significant lens opacity.    Allotex offers a non-invasive alternative that retains the natural lens.

PresbyLASIK reshapes the cornea to create a multifocal surface. It is irreversible and may affect night vision and contrast. Allotex achieves a multifocal-like effect through spherical aberration without tissue ablation.

Pharmacological Drops such as pilocarpine provide temporary pupil constriction to improve near vision. These offer limited duration, require ongoing application, and may cause brow ache or reduced night vision. Allotex offers a stable, long-term effect in a one-time procedure.

Patient Experience and Visual Quality

Patients report a high degree of satisfaction. The treated eye retains usable distance vision with improved intermediate and near acuity. Binocularly, most patients function with excellent vision at all ranges. Depth perception is maintained, and night vision disturbances are rare due to the inlay’s optical clarity and matched refractive index.

Adaptation time varies, but most patients adjust within weeks. Counselling and setting expectations are crucial. The reversible nature of the procedure provides peace of mind.  Achieving good distance vision involved epithelial remodelling which can take up to 6 months.

Clinical Integration and Workflow

For practices already performing LASIK, integrating Allotex requires minimal change. The femtosecond laser and flap creation process are familiar. The inlay is provided sterile and ready-to-use. Postoperative care mirrors LASIK: short-term antibiotics and anti-inflammatory drops.

Patient selection is key. Ideal candidates are:

·       Aged 45–65

·       Motivated for spectacle independence

·       Free of ocular surface disease or keratoconus

·       With a stable refraction and healthy corneas

Preoperative measurements should include topography, aberrometry, and pupil evaluation under different lighting. Dominance testing helps select the correct eye. Educating patients on the expected benefits and adaptation phase improves satisfaction.

Summary

Allotex allogenic corneal inlays offer a new, biocompatible solution for presbyopia in emmetropic and mildly ametropic patients. Key benefits include:

·       Significant improvement in near vision and DoF

·       Preservation of distance vision and stereopsis

·       Reversibility and minimal invasiveness

·       Excellent biocompatibility and long-term safety

These features make Allotex an attractive option for both patients and eye care providers seeking a balanced, low-risk presbyopia solution.

Learn More

Visit Allotex.com to explore more clinical data.