Outcomes of the Boston keratoprosthesis in jordan

Long-term outcomes of Boston keratoprosthesis type I: the Chinese People's Liberation Army General Hospital experience

PURPOSE

To report the long-term outcomes of Boston keratoprosthesis type I (B-KPro type I) implantation in the management of severe ocular surface disorders.

METHODS

Retrospective case series. Patients who underwent B-KPro type I implantation at the People's Liberation Army General Hospital were enrolled between March 2011 and September 2019. Data regarding visual acuity (VA), B-KPro type I retention and postoperative complications were recorded and analysed.

RESULTS

A total of 103 eyes of 100 patients who underwent B-KPro type I implantation were included. The main indications were chemical burn (59.2%), ocular trauma (25.2%), herpetic keratitis (11.7%) and autoimmune diseases (3.9%). The percentage of eyes with postoperative VA of 10/200 or better was 82.7% at 6 months, 82.8% at 12 months, 77.9% at 2 years, 72.4% at 3 years, 71.1% at 4 years, 69.4% at 5 years, 58.9% at 6 years, 56.8% at 7 years and 42.9% at 8 years. Preoperatively, 8.7% eyes were diagnosed with new-onset glaucoma. Retroprosthetic membrane formation occurred in 19.4% eye. Corneal melting occurred in 18.4% eyes. Sterile vitritis was diagnosed in 4.9% eyes and infectious endophthalmitis in 2.9% eyes. Retinal detachment occurred in 0.9% eyes.

CONCLUSIONS

In a Chinese patient group, B-KPro type I is a viable option for treating severe ocular surface disorders in eyes where conventional keratoplasty would have a poor prognosis, especially in patients with chemical and thermal burns. Improved visual outcomes and high retention rate can be achieved and maintained in most cases.

Artificial corneas versus donor corneas for repeat corneal transplants

BACKGROUND

Individuals who have failed one or more full thickness penetrating keratoplasties may be offered repeat corneal surgery using an artificial or donor cornea. An artificial or prosthetic cornea is known as a keratoprosthesis. Both donor and artificial corneal transplantations involve removal of the diseased and opaque recipient cornea (or the previously failed cornea) and replacement with another donor or prosthetic cornea.

OBJECTIVES

To assess the effectiveness of artificial versus donor corneas in individuals who have had one or more failed donor corneal transplantations.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2019, Issue 11); Ovid MEDLINE; Ovid Embase; LILACS (Latin American and Caribbean Health Sciences Literature database); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 4 November 2019.

SELECTION CRITERIA

Two review authors independently assessed reports from the electronic searches to identify randomized controlled trials or controlled clinical trials. Any discrepancies were resolved by discussion or consultation.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. For discussion purposes, we summarized findings from relevant comparative case series. We performed no data synthesis.

MAIN RESULTS

We did not identify any randomized controlled trials or controlled clinical trials comparing artificial corneas with donor corneas for repeat corneal transplantations.

AUTHORS' CONCLUSIONS

The optimal management for those individuals who have failed a conventional corneal transplantation is unknown. Currently, in some centers, artificial corneal devices are routinely recommended after just one graft failure, while in other centers, they are not recommended until after multiple graft failures, or not at all. To date, there have been no controlled trials comparing the visual outcomes and complications of artificial corneal devices (particularly the Boston type 1 keratoprosthesis, which is the most commonly implanted artificial corneal device) with repeat donor corneal transplantation, in order to guide surgeons and their patients. Such a trial is needed and would offer significant benefit to an ever-increasing pool of people with visual disability due to corneal opacification, most of whom are still in productive stages of their lives.

Keratoprosthesis: Current global scenario and a broad Indian perspective

Keratoprosthesis (Kpro) forms the last resort for bilateral end-stage corneal blindness. The Boston Type 1 and 2 Kpros, the modified osteo-odonto Kpro and the osteo-Kpro are the more frequently and commonly performed Kpros, and this review attempts to compile the current data available on these Kpros worldwide from large single-center studies and compare the indications and outcomes with Kpros in the Indian scenario. Although the indications have significantly expanded over the years and the complications have reduced with modifications in design and postoperative regimen, these are procedures that require an exclusive setup, and a commitment toward long-term follow-up and post-Kpro care. The last decade has seen a surge in the number of Kpro procedures performed worldwide as well as in India. There is a growing need in our country among ophthalmologists to be aware of the indications for Kpro to facilitate appropriate referral as well as of the procedure to enable basic evaluation during follow-ups in case the need arises, and among corneal specialists interested to pursue the field of Kpros in understanding the nuances of these surgeries and to make a judicious decision regarding patient and Kpro selection and more importantly deferral.

Boston keratoprosthesis type 1 for limbal stem cell deficiency after severe chemical corneal injury: A systematic review

PURPOSE

To systematically review the published literature on outcomes of Boston keratoprosthesis type 1 for the treatment of limbal stem cell deficiency secondary to severe chemical corneal injury.

METHODS

Literature searches were conducted in MEDLINE (Ovid), Embase, Web of Science, and the Cochrane Central Register. The main outcome measures assessed were the proportion of eyes with best-corrected visual acuity (BCVA) ≥ 20/200 and the proportion retaining their original keratoprosthesis, both at the last recorded visit.

RESULTS

We identified 9 reports in which outcomes of Boston keratoprosthesis type I implantation after severe chemical injury could be determined, encompassing a total of 106 eyes of 100 patients. There were no randomized controlled studies. The median pre-operative BCVA was hand motion. Vision improved to ≥20/200 in 99/106 (93.4%) eyes after implantation. With a mean follow-up of 24.99 ± 14 months, 68/106 (64.1%) eyes retained BCVA ≥ 20/200 at the last examination. Therefore, 68/99 (68.7%) of those who improved to > 20/200 maintained at least this acuity. The originally implanted device was retained in 88/99 (88.9%) recipients for whom retention was reported. The mean time to failure was 22.36 ± 17.2 months. Glaucomatous optic neuropathy was the most common cause for BCVA <20/200 in eyes that retained the keratoprosthesis (18/27, 66.7%)..

CONCLUSIONS

Implantation of a Boston keratoprosthesis type I in eyes with corneal blindness after severe chemical ocular injury leads to functional vision in the majority of recipients. Evidence was limited by variability in outcome reporting and an absence of controlled studies..

Vitreoretinal complications of the Boston Keratoprosthesis

The Boston Keratoprosthesis has allowed for visual restoration in patients with corneal blindness; however, vitreoretinal complications remain a significant cause of ocular morbidity. Retroprosthetic membranes, infectious endophthalmitis, sterile vitritis, vitreous hemorrhage, vitreous opacities, retinal detachment, cystoid macular edema, choroidal detachments, retinal vascular occlusion, and epiretinal membrane have all been described, may require the intervention of a vitreoretinal specialist, and are reviewed herein. A strong familiarity with associated posterior segment complications is important to maximizing patient outcomes.

Medium-term outcomes of boston type 1 keratoprosthesis implantation in Bangkok, Thailand

PURPOSE

The aim of this study was to investigate the medium-term outcomes after Boston type 1 keratoprosthesis surgery in patients with poor prognosis for standard keratoplasty.

METHODS

A prospective study of a case series was conducted at a university-based referral center from 2006 to 2013. Forty-two eyes of 40 patients with a minimum follow-up of 4 years were recruited. The main outcome measures included best spectacle-corrected visual acuity (BSCVA), keratoprosthesis retention, and complications.

RESULTS

The mean follow-up was 64.9 ± 15.2 months (range, 48-88 months). At 1 week, 90.5% had an improvement in BSCVA by ≥2 lines compared with that in preoperative BSCVA. The best-ever vision was reached by the end of 6 months. Nevertheless, 39.5% (15/38) could not maintain the improved vision. The major etiology of visual deterioration after initial gains was glaucoma (60%). The initial keratoprosthesis retention rate was 80.9%, corresponding to a failure rate of 4 per 100 eye-years or 0.04/eye-year. Autoimmune diagnosis was the independent risk factor for keratoprosthesis failure (hazard ratio, 5.68; 95% confidence interval, 1.41-22.85; P = 0.014). The common postoperative complications were glaucoma, retroprosthetic membrane, corneal melting, infectious keratitis, and endophthalmitis.

CONCLUSIONS

Boston type 1 keratoprosthesis is an alternative for patients who are not candidates for corneal transplants. However, there was a trend toward visual loss over time most commonly because of progressive glaucoma. Therefore, appropriate patient selection, lifelong follow-up, and early aggressive treatment of complications are recommended.

Boston keratoprosthesis - Clinical outcomes with wider geographic use and expanding indications - A systematic review

Over 2 decades of research, several design modifications, and improvements in post-operative management have made Boston keratoprosthesis (B-KPro) a viable option for patients with corneal blindness for whom traditional keratoplasty procedure has a very low probability of success. In this systematic review, we examined the indications, visual outcomes, complications and retention rate of the literature published in the past 10 years (2005–2014). While most of the studies report smaller datasets (typically <50 eyes), some of the recent multicenter studies have reported large datasets (up to 300 eyes). Most of the literature is published from the US; however, last few years have witnessed some papers reporting the successful use of B-Kpro from developing countries or arid climatic conditions (such as the Kingdom of Saudi Arabia). Due to differences in the causes of corneal blindness in different geographic regions, newer indications for B-Kpro are emerging (e.g. trachoma). Additionally, improving clinical outcomes and increasing surgeon confidence have also expanded indications to include cases of unilateral visual impairment and paediatric age. We observed that there is growing body of evidence of successful clinical use of B-KPro; however, financial challenges, lack of trained surgeons, shortage of donor corneas must be overcome to improve accessibility of B-KPro.

Artificial corneas versus donor corneas for repeat corneal transplants

BACKGROUND

Individuals who have failed one or more full thickness penetrating keratoplasties (PKs) may be offered repeat corneal surgery using an artificial or donor cornea. An artificial or prosthetic cornea is known as a keratoprosthesis. Both donor and artificial corneal transplantations involve removal of the diseased and opaque recipient cornea (or the previously failed cornea) and replacement with another donor or prosthetic cornea.

OBJECTIVES

To assess the effectiveness of artificial versus donor corneas in individuals who have had one or more failed donor corneal transplantations.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2013, Issue 10), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2013), EMBASE (January 1980 to November 2013), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to November 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 27 November 2013.

SELECTION CRITERIA

Two review authors independently assessed reports from the electronic searches to identify randomized controlled trials (RCTs) or controlled clinical trials (CCTs). We resolved discrepancies by discussion or consultation with a third review author.

DATA COLLECTION AND ANALYSIS

For discussion purposes, we assessed findings from observational cohort studies and non-comparative case series. No data synthesis was performed.

MAIN RESULTS

We did not identify any RCTs or CCTs comparing artificial corneas with donor corneas for repeat corneal transplantations.

AUTHORS' CONCLUSIONS

The optimal management for those individuals who have failed a conventional corneal transplantation is not known. Currently, in some centers, artificial corneal devices routinely are recommended after just one graft failure, and in others, not until after multiple graft failures, or not at all. To date, there have been no controlled trials comparing the visual outcomes and complications of artificial corneal devices (particularly the Boston type 1 keratoprosthesis which is the most commonly implanted artificial corneal device) with repeat donor corneal transplantation, in order to guide surgeons and their patients. It is apparent that such a trial is needed and would offer significant benefit to an ever-increasing pool of people with visual disability due to corneal opacification, most of whom are still in productive stages of their lives.