Elsevier

Ophthalmology

Volume 116, Issue 4, April 2009, Pages 640-651
Ophthalmology

Original article
The Boston Type I Keratoprosthesis: Improving Outcomes and Expanding Indications

Presented at: American Academy of Ophthalmology Annual Meeting, November 2008.
https://doi.org/10.1016/j.ophtha.2008.12.058Get rights and content

Purpose

To report the usefulness of the Boston type I keratoprosthesis (Massachusetts Eye and Ear Infirmary, Boston, MA) in the management of corneal opacification, corneal limbal stem cell failure, or both in a large single-surgeon series.

Design

Retrospective review of consecutive clinical case series.

Participants

All patients undergoing keratoprosthesis implantation by a single surgeon (AJA) between May 1, 2004, and May 31, 2008.

Methods

Data were collected regarding the preoperative characteristics of each eye undergoing keratoprosthesis implantation, the surgical procedure(s) performed, and the postoperative course. Statistical analysis was performed to identify factors influencing the incidence and severity of postoperative complications.

Main Outcome Measures

Interval visual acuities, keratoprosthesis retention, and significant postoperative complications.

Results

Fifty-seven keratoprosthesis procedures were performed in 50 eyes of 49 patients. The primary indication for surgery was repeat corneal transplantation failure (68%), although no prior corneal surgery had been performed in 16% of eyes. Preoperative visual acuity was 20/200 or worse in all eyes, with 88% of eyes having preoperative vision of counting fingers, hand movements, or light perception. The percentage of eyes with postoperative visual acuity of 20/100 or better was 67% at 6 months (n = 45), 75% at 1 year (n = 28), 69% at 2 years (n = 13), and 100% at 3 years (n = 7). In the 31% of patients in whom preoperative vision in the contralateral eye was 20/50 or better, the postoperative vision in the operative eye improved to 20/50 or better in 47% at the last follow-up (average, 18 months; range, 4–49 months). The overall keratoprosthesis retention rate was 84% at an average follow-up of 17 months (79 person-years of follow-up), with 100% retention in 8 eyes with no history of prior corneal transplantation (14.8 person-years of follow-up). The most common postoperative complications were retroprosthetic membrane formation (22 eyes) and persistent epithelial defects (19 eyes). No cases of infectious endophthalmitis were encountered, and only 1 patient with a history of glaucoma required additional glaucoma surgery during the postoperative period.

Conclusions

The Boston type I keratoprosthesis is an effective means of managing repeat corneal graft failure and corneal limbal stem cell failure with or without corneal opacification in patients with both unilateral and bilateral visual impairment.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Patients and Methods

A retrospective review was performed of all keratoprosthesis procedures performed by a single surgeon (AJA) between May 1, 2004, and May 31, 2008. Informed consent was obtained from each patient for the collection and analysis of preoperative and postoperative data. Study approval was granted by the institutional review board at The University of California, Los Angeles (nos. 04-11-058-01, 04-11-058-02, 04-11-058-03, and 04-11-058-04).

Demographic Features

A total of 57 Boston type 1 keratoprostheses were implanted in 50 eyes of 49 patients (1 patient underwent bilateral implantation). Twenty-five patients were male and 24 were female, with a mean patient age of 63.8 years (range, 21–95 years). Two eyes (2 patients) were excluded from the analysis of postoperative visual acuity outcomes because 1 patient died within 3 months of surgery, preventing an adequate assessment of postoperative visual recovery, and in another patient, the type I

Visual Acuity

Two-thirds or more of patients who received the Boston type I keratoprosthesis had a visual acuity of 20/20 to 20/100 at each of the specified follow-up time points. In fact, the percentage of eyes with visual acuity from 20/20 to 20/50 actually increased at each follow-up time point, from 27% at 6 months to 86% at 3 years. This is not because of the avoidance of patients with preoperative diagnoses known to be associated with a higher risk of postoperative complications for the initial cases

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    Manuscript no. 2008-797.

    Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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