Minimally invasive keratoprosthesis (mi-KPro) for vision restoration after severe chemical injury.

Abstract

Purpose : Approximately 1.5-2 million patients globally become corneal blind every year, of which a significant proportion is not amenable to standard corneal transplantation. To this end, artificial corneas have become the mainstay of treatment of severe corneal blindness. More than 20,000 eyes have been treated with the most successful FDA approved artificial corneas, the Boston Keratoprosthesis (B-KPro) and the Lucia. However, complications, such as, ocular hypertension, glaucoma, endophthalmitis and retroprosthetic membrane (RPM) formation often compromise long-term outcomes and cause terminal blindness. To overcome these limitations, we developed a minimally invasive KPro (mi-KPro) device, to minimize the aforementioned complications while being amenable for patients with severe ocular pathologies.

Methods : Corneal alkali and acid injury models were employed in rabbits, using 2N NaOH (n=12) or 2N HCl (n=12), respectively. One month after injury, animals underwent either mi-KPro surgery (n=12) or penetrating keratoplasty (PKP) (n=12). Animals were followed with anterior and posterior eye optical coherent tomography (OCT), photography, and intraocular pressure (IOP) with cannulation at baseline and monthly for 12 months. At 12 months, rabbits were euthanized and both the eyes and optic nerves were enucleated for histological analyses.

Results : Eye implanted with the mi-KPro had an excellent anatomic retention for 12 months and minimal complications as compared to standard keratoplasty that exhibited graft rejection within 3 months. None of the mi-KPro implanted rabbits developed ocular hypertension, while retinal thickness and optic nerve cup to disc ratio remained unchanged, as compared to baseline OCT. In contrast, PKP control animals exhibited significant retinal thinning (n=6, p=0.004), and showed significant loss in optic nerve axons (n=6, p=0.01), as compared to KPro implanted eyes.

Conclusions : The mi-KPro achieves excellent anatomic retention for over a year in chemically inured eye and does not lead to post-surgical IOP elevation, glaucoma, PRM, or infection. This translates to preservation of the retina and optic nerve at 1 year after injury suggesting superiority in the treatment of chemically injured eyes, as compared to PKP or historical data from rabbit B-KPro. The pre-clinical safety and efficacy profile of the mi-KPro is exception and supportive of further evaluation in patients.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.