Contact Lens Fitting and Long-Term Management for the Boston Keratoprosthesis

Causes of Corneal Melt After the Boston Keratoprosthesis Type I: The Chinese People's Liberation Army General Hospital Experience

PURPOSE

The purpose of this study was to evaluate the long-term incidence, risk factors, and the management of corneal melt following Boston type I keratoprosthesis (B-KPro I) implantation.

METHODS

This is a retrospective observational case series. Data were collected regarding demographics, preoperative characteristics, incidence, and outcomes of corneal melt in 102 patients who underwent B-KPro I in the Chinese PLA General Hospital between 2011 and 2018, with a follow-up period ranging from 4 to 11 years.

RESULTS

Chemical burn was the most common indication for B-KPro I (n = 56; 53.8%), followed by ocular trauma (n = 26; 25.0%). During the follow-up period (107 ± 25.7 months), corneal melt occurred in 60 cases among 37 eyes (35.6%), with an incidence of 20.2% at 1 year after surgery. Fourteen cases presented with recurrent corneal melt. Patients with multiple corneal allograft failures had a higher risk of corneal melt. Thermal burns, compared with alkali burns, significantly elevated the odds ratio (OR) of corneal melt (OR, 5.11; 95% confidence interval, 1.05-24.86; P = 0.043).

CONCLUSIONS

Corneal melt significantly reduced the retention time of KPro ( P < 0.01), and its coexistence with other complications further shortened the retention time. A specific pattern of corneal melt occurrence was identified, with a peak incidence at 1 year postoperatively. Our findings suggest variations in the risk of corneal melt among different indications, with thermal burns carrying the highest OR. Moreover, each previous failed keratoplasty doubled the risk of corneal melt after B-KPro I.

Use of PROSE for long-term ocular surface support in patients with a permanent keratoprosthesis

Purpose

To describe the long-term outcome of the use of a specialized scleral lens known as a prosthetic replacement of the ocular surface ecosystem (PROSE) device to support the ocular surface in patients with a Boston Keratoprosthesis (KPro) Type I. All patients in this series were unable to pursue continuous wear of a bandage soft contact lens (BSCL) - a critical aspect of post KPro implantation management intended to protect the corneal carrier tissue from desiccation and stromal melting.

Observations

Four eyes of four patients with a Boston KPro Type I were included. All four had failed BSCL wear and were instead treated with PROSE device wear. All four patients had underlying diagnoses associated with a diseased ocular surface (Stevens-Johnson Syndrome [one patient], prior failed penetrating keratoplasty associated with herpes zoster-related neurotrophic keratopathy [one patient], and prior failed penetrating keratoplasty associated with severe dry eye disease [two patients]). Causes of failure of BSCL wear included poor retention, discomfort, and poor vision. PROSE device wear was initiated on average seven and a half (range four to 14) months post-KPro implantation. The wear schedule varied and ranged from waking-hour wear only to 24-h wear. The average duration of device wear was 59.3 (range 28-103) months. Two patients exhibited persistent corneal epithelial defect formation with waking-hour wear, which resolved within 10 days with 24-h device wear. All patients exhibited improvement in vision with PROSE compared to baseline, averaging six and a half (range six to eight) lines of improvement in Snellen acuity, and all patients reported increased comfort. There was no incidence of microbial keratitis, KPro device instability, or other complication throughout the duration of device wear.

Conclusions and Importance

This report offers a novel alternate approach to long-term support of the ocular surface in patients with a Boston KPro who fail standard continuous BSCL wear.

Candida Colonization on the Surface of Contact Lenses in Long-Term Wearers and Boston Type 1 Keratoprosthesis Patients Presenting as White Mulberry-Shaped Deposits

PURPOSE

To report Candida colonies on the surface of the contact lens in long-term contact lens wearers and patients with Boston type 1 keratoprosthesis (KPro I).

METHODS

A retrospective study was performed based on analyzing cultures from bandage contact lenses with small whitish mulberry-shaped deposits on their surface.

RESULTS

Eight samples (from seven patients) were positive for Candida. Seven of the eight were positive for Candida parapsilosis.

CONCLUSIONS

The whitish deposits on contact lenses are often Candida colonies that colonize the surface but do not cause an active infection in the eye. C. parapsilosis is well-known for colonizing prosthetic devices. We underline the importance of including Candida species in the differential diagnosis of lens deposits, especially in susceptible patients such as keratoprosthesis carriers.

The Boston Keratoprosthesis-The First 50 Years: Some Reminiscences

Millions of people worldwide are bilaterally blind due to corneal diseases including infectious etiologies, trauma, and chemical injuries. While corneal transplantation can successfully restore sight in many, corneal graft survival decreases in eyes with chronic inflammation and corneal vascularization. Additionally, the availability of donor cornea material can be limited, especially in underdeveloped countries where corneal blindness may also be highly prevalent. Development of methods to create and implant an artificial cornea (keratoprosthesis)may be the only option for patients whose eye disease is not suitable for corneal transplantation or who live in regions where corneal transplantation is not possible. The Boston keratoprosthesis (B-KPro) is the most commonly implanted keratoprosthesis worldwide, having restored vision in thousands of patients. This article describes the initial design of the B-KPro and the modifications that have been made over many years. Additionally, some of the complications of surgical implantation and long-term care challenges, particularly complicating inflammation and glaucoma, are discussed. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

CLEAR - Medical use of contact lenses

The medical use of contact lenses is a solution for many complex ocular conditions, including high refractive error, irregular astigmatism, primary and secondary corneal ectasia, disfiguring disease, and ocular surface disease. The development of highly oxygen permeable soft and rigid materials has extended the suitability of contact lenses for such applications. There is consistent evidence that bandage soft contact lenses, particularly silicone hydrogel lenses, improve epithelial healing and reduce pain in persistent epithelial defects, after trauma or surgery, and in corneal dystrophies. Drug delivery applications of contact lens hold promise for improving topical therapy. Modern scleral lens practice has achieved great success for both visual rehabilitation and therapeutic applications, including those requiring retention of a tear reservoir or protection from an adverse environment. This report offers a practical and relevant summary of the current evidence for the medical use of contact lenses for all eye care professionals including optometrists, ophthalmologists, opticians, and orthoptists. Topics covered include indications for use in both acute and chronic conditions, lens selection, patient selection, wear and care regimens, and recommended aftercare schedules. Prevention, presentation, and management of complications of medical use are reviewed.

Resolution of an exposed pars plana Baerveldt shunt in a patient with a Boston keratoprosthesis type 1 without surgery

Patients with a keratoprosthesis often develop complications including glaucoma, requiring glaucoma drainage devices. In most of these patients, glaucoma drainage devices have been shown to be safe and effective. However, occasionally, a glaucoma drainage device in the setting of a keratoprosthesis can lead to conjunctival erosion with mechanical trauma. While repeat surgical intervention may appear necessary, we report a case of a patient who had improved conjunctival erosion and glaucoma drainage device exposure after refitting of a therapeutic contact lens. Therapeutic contact lenses can be used to maintain hydration and decrease exposure while improving cosmesis and refractive error. Complications following keratoprosthesis surgery are an understudied area, particularly regarding glaucoma drainage devices, and we seek to show that careful fitting of therapeutic contact lenses may avoid the risks of repeat surgical intervention.

[Boston-keratoprosthesis : Preliminary experiences in 13 high-risk eyes from the Department of Ophthalmology of the University of Cologne]

BACKGROUND

Corneal transplantation in high-risk eyes remains a challenge. The Boston keratoprosthesis (B-KPro) is a final option for patients with end-stage corneal disease and a poor prognosis with conventional penetrating keratoplasty. In this article the results of the first 13 eyes that received a B-KPro type I at the Department of Ophthalmology, University of Cologne, Germany are reported and the usefulness of postoperative slit-lamp optical coherence tomography (SL-OCT) for control purposes is evaluated.

MATERIAL AND METHODS

All recipients of a B-KPro type I between September 2013 and May 2015 were included in the study. The feasibility of the operation, clinical outcomes, complications and revision surgery were investigated. The visualization of wound healing by SL-OCT was analyzed.

RESULTS

The age of the patients ranged from 26 to 92 years (mean 57.3 ± 20.9 years). In all 13 eyes from 12 patients (6 males and 6 females) dense corneal opacification with vascularization and sometimes also conjunctivalization was present. Preoperative visual acuity was reduced and ranged from mere light perception up to a maximum of 1/35 eye chart. All 13 eyes could be supplied with a B-KPro type I without any intraoperative complications, in 6 eyes no significant postoperative complications occurred, whereas in 7 eyes various additional surgical interventions were required and 1 B-KPro could not be preserved. Postoperative visual acuity ranged from light perception to 20/32 and was significantly improved in 85 % of the treated eyes. The use of SL-OCT reproducibly allowed the postoperative assessment of stromal thinning.

CONCLUSION

The B-KPro provides the possibility of visual rehabilitation in high-risk eyes that could never be achieved without artificial cornea replacement. Despite higher complication rates this technique represents a significant progress in the surgical treatment of complex corneal pathologies. Regular and intensive postoperative controls are necessary to achieve good long-term results.

Russian Keratoprosthesis in Stevens-Johnson Syndrome

PURPOSE

To evaluate the efficacy and safety of Moscow Eye Microsurgery Complex in Russia (MICOF) keratoprosthesis (KPro) implantation in patients with Stevens-Johnson syndrome (SJS).

METHODS

This was a retrospective case series. Fourteen eyes of 13 patients with SJS underwent KPro implantation at the Chinese People's Liberation Army General Hospital between April 1, 2000, and December 24, 2014. The visual outcome, KPro retention rate, and incidence of postoperative complications and their management were recorded and investigated.

RESULTS

The mean age and follow-up duration were 61.5 ± 17.3 years (range: 27-87 yrs) and 62 ± 39.1 months (range: 13-144 mo). Thirteen eyes (92.9%) achieved a best-corrected visual acuity of 20/200 or better, and 8 eyes (57.1%) achieved a best-corrected visual acuity of 20/40 or better after surgery. However, 71.4% (10/14) experienced visual decline because of different postoperative complications. Common complications included corneal melting, glaucoma, vitritis, superficial tissue overgrowth, and retroprosthetic membrane, and the incidence of these complications was 71.4%, 28.6%, 35.7%, 14.3%, and 28.6%, respectively. After repair and autoauricular cartilage reinforcement, all cases had stable anatomical retention at the last visit.

CONCLUSIONS

The MICOF KPro improved vision of patients with SJS, but lifelong surveillance is necessitated because of a high rate of postoperative complications. Corneal melting was the main reason for KPro failure. Infectious endophthalmitis and glaucoma were the main risk factors for visual loss.

Boston Type 1 Keratoprosthesis for Gelatinous Drop-Like Corneal Dystrophy

PURPOSE

To report the outcomes of Boston type 1 keratoprosthesis in the management of advanced gelatinous drop-like corneal dystrophy (GDLD).

METHODS

A retrospective, noncomparative, interventional case series was conducted at Ramathibodi Hospital, Bangkok, Thailand. Four eyes of three siblings with molecularly and histologically confirmed GDLD from a Thai family underwent an uneventful Boston type 1 keratoprosthesis implantation for visual rehabilitation. Clinical data were obtained from a review of the medical records. Visual acuity, device retention, and postoperative complications were the main outcome measures. The follow-up ranged from 8 to 96 months.

RESULTS

One eye received keratoprosthesis surgery as a primary penetrating procedure. The other three eyes had the surgery as a secondary procedure after graft failure. Best-corrected visual acuity was favorably improved from counting fingers to 20/25 in two eyes, from hand movement to 20/20 in one eye, and from hand movement to counting fingers at 2 feet in one eye caused by severe amblyopia. The improved vision was maintained for 8 months to 6.2 years after surgery. Postoperative complications included disease recurrence in the donor graft (N = 3), manageable retroprosthetic membrane (N = 3), intraocular pressure elevation responded to antiglaucoma drugs (N = 2), and Pseudomonas keratitis with severe corneal melting requiring device removal (N = 1). All of our patients failed to have a comfortably well-fitting contact lens after surgery.

CONCLUSIONS

Boston type 1 keratoprosthesis could be considered as a reasonable option in the management of advanced GDLD. However, patients remain at risk for sight-threatening postoperative complications as long as the keratoprosthesis is retained. The use of Boston keratoprosthesis implantation needed to be individualized on a case-by-case basis.

Corneal graft dellen in a patient implanted with a Boston keratoprosthesis type 1

The purpose of this study was to report a case of corneal dellen in a patient implanted with a Boston type 1 keratoprosthesis (KPro), which rapidly appeared after the loss of the large-diameter soft contact lens. This study is an observational case report of a 56-year-old man who underwent KPro implantation in his right eye in November 2010. In March 2014 during a follow-up visit, two areas of corneal dellen were observed. The patient had lost his bandage contact lens. With the application of a new soft contact lens, the thinned areas recovered completely within 5 days. After keratoprosthesis implantation, it is necessary to maintain uninterrupted wear of a bandage contact lens as it allows for adequate ocular surface hydration and prevents consequent complications. This case report highlights the need to provide proper instructions to such patients, in order to minimize the risk.

Boston type 1 keratoprosthesis from patient selection through postoperative management: a review for the keratoprosthetic surgeon

For the anterior segment surgeon, the implantation of Boston type 1 keratoprosthesis is a multistep process that begins with careful patient selection. Success depends on thorough preoperative evaluation, detailed surgical planning, and frequent postoperative follow-up. New practice patterns have emerged for each of these phases as the international experience with keratoprosthesis grows. This review details special considerations that can improve outcomes and also allow surgeons to consider its use in challenging patient populations at each step.