Ament JD, Tilahun Y, Mudawi E, Pineda R. Role for Ipsilateral Autologous Corneas as a Carrier for the Boston Keratoprosthesis: The Africa Experience. Arch Ophthalmol. 2010;128(6):795-797. doi:10.1001/archophthalmol.2010.79
Copyright 2010 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.2010
We report the use of the Boston Keratoprosthesis (KPro) with ipsilateral autologous corneas in 4 eyes of 3 patients in Ethiopia and Sudan. Currently, surgery with the KPro is performed using an allograft donor cornea sandwiched between 2 polymethyl methacrylate plates during assembly. Autologous corneas have been used with the Cardona “nut and bolt” prosthesis,1 but to our knowledge no reports on its use with the Boston KPro exist.
This approach is especially important in nonindustrialized nations, where the availability of corneal allograft tissue, operational costs, and high corneal graft failure rates remain significant challenges. Ipsilateral autologous corneas would make the KPro more accessible in these regions. Even without a formal cost-effective analysis, the savings are markedly apparent.
Specific patient selection criteria in nonindustrialized nations are outlined in the international Boston KPro protocol.2 Additional requirements exist when considering autologous grafts. Patients were not appropriate candidates for anterior lamellar keratoplasty due to severely scarred eyelids or full-thickness central corneal scars.
Inclusion criteria included the following: bilateral blindness per World Health Organization criteria3; clinically normal peripheral endothelium by specular reflection; and limited stromal thinning after trephination (<30%). Exclusion criteria were as follows: uncontrolled glaucoma; extensive anterior synechiae; and evidence of corneal perforation.
All patients received an aphakic KPro with a 16-hole polymethyl methacrylate backplate and a titanium locking ring assembled around an 8.5-mm trephinated ipsilateral autologous cornea. An extracapsular cataract extraction was performed on all patients through the corneal trephination opening.
Postoperative data from 5 to 20 months are reported, including compliance, visual outcomes, complications, and results from quality-of-life surveys. Disabilities in activities of daily living were evaluated by interview using standardized scales.4 The human studies committee at the Massachusetts Eye and Ear Infirmary granted a waiver of informed consent and granted Health Insurance Portability and Accountability Act authorization for medical record review.
Surgery in 3 eyes was uneventful. In 1 eye, intraoperative vitreous loss was effectively managed with Weck-Cel vitrectomy. Patient characteristics and follow-up data are presented in the Table. Corneal pathologic findings included advanced ocular trachoma and previous measles keratitis. Uncorrected visual acuity improved in all of the eyes. All patients adhered to the protocol, retained their contact lenses, and successfully administered their medications. Based on a culturally sensitive 14-item Visual Function Index survey,5 patients experienced substantial improvement in activities of daily living such as regaining the ability to wash clothes and manage transportation needs.
There has been growing global interest in use of the KPro for the treatment of corneal conditions not effectively treated by penetrating keratoplasty. Despite this and the overwhelming incidence of blindness due to corneal pathologic abnormalities, use of the KPro in nonindustrialized countries remains equivocal and rare.
The use of an ipsilateral autologous cornea as the skirt in transplantation of the KPro mitigates costs and eliminates corneal allograft storage. This also avoids graft rejection and allocates available donor corneal tissue for suitable keratoplasty patients.
Concerns regarding the postoperative management and complications of international KPro surgery include inadequate follow-up, poor compliance, infection, contact lens loss, retroprosthetic membrane formation, glaucoma, retinal detachment, and extrusion.6 Nevertheless, in our small sample of ipsilateral autologous KPro recipients, retention is 100% without postoperative complications and visual acuity improved in all patients to 20/60 or better.
There are inherent weaknesses with this study. We discuss a small sample with limited postoperative follow-up. Many common complications such as glaucoma and endophthalmitis often manifest later in the postoperative period. Additional follow-up will help elucidate the long-term success of this procedure.
In summary, the use of ipsilateral autologous corneas for assembly of the KPro in certain populations appears feasible, practical, and cost saving as shown in this small group of patients from nonindustrialized countries with limited resources.
Correspondence: Dr Ament, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles St, Boston, MA 02114-4724 (firstname.lastname@example.org).
Author Contributions: Drs Ament and Pineda had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Financial Disclosure: The authors do not have any commercial or proprietary interest in the Boston KPro, nor do they have any financial interest or receive payment as a consultant, reviewer, or evaluator. Dr Ament is a clinical research fellow under Claes Dohlman, MD, PhD, creator of the Boston KPro. Dr Dohlman has no financial interest in the Boston KPro. He makes no profit from its sales. All proceeds support continuing research and medical missions to Africa and other nonindustrialized nations.
Role of the Sponsor: Dr Dohlman was not involved in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.
Additional Contributions: Through a research and development fund, Dr Dohlman donated the KPro devices and provided support for the medical trips. Khalil Lakho, MD, an administrator in Sudan, provided logistical support, clinic time, operating room time, and coordination of efforts with ophthalmology staff and residents. Tania Marie Ament, BS, modified and conducted activities of daily living, instrumental activities of daily living, and quality-of-life surveys.