Improving management and outcomes of the Boston type 1 keratoprosthesis: lessons learned from available evidence

Abstract

Boston Keratoprosthesis type I (KPro) surgery is a relatively novel treatment for severe corneal blindness in the context of recurrent graft failure and high-risk conditions such as cicatrizing disease, aniridia, herpetic keratitis or chemical burns. Recently, modifications in design, surgical techniques and postoperative management have increased the success rate and popularity of the Boston KPro. Complication rates have decreased substantially in the last decade making the Boston KPro a safe therapeutic alternative to certain corneal pathologies. However, certain comorbidities such as glaucoma and late-onset fungal infections remain a problem. This article will review recent evidence about management and outcomes of the Boston KPro type I.

Keywords:

• Boston KPro
• endophthalmitis
• glaucoma
• keratoprosthesis
• penetrating keratoplasty
• retinal detachment
• retroprosthesis membrane
• sterile keratolysis

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• With new advances in design, such as the addition of holes in the back plate, a threadless and click-on model and new titanium back plate manufacturing, the Boston keratoprosthesis (KPro) has witnessed a rise in its success rates.

• Lifelong use of broad-spectrum topical antibiotics such as vancomycin and fluoroquinolones has decreased rates of Gram-positive endophthalmitis. However, new antibiotic resistance and long-term risk for Gram-negative and fungal infections are emerging as new challenges.

• Retroprosthetic membrane is by far the most common complication in KPro eyes. Early treatment with Nd:YAG laser can be effective in most cases. However, surgical management is sometimes inevitable.

• Sterile keratolysis is an important risk factor for KPro failure, leading to devastating complications such as extrusion and endophthalmitis, often warranting device replacement. New studies are showing promising results with collagen cross-linking as a prophylactic and therapeutic modality.

• Sterile vitritis is an idiopathic inflammation that can often be confused with endophthalmitis. New studies have demonstrated that this entity is not as harmless as previously thought. Prompt recognition and appropriate treatment are crucial.

• KPro eyes are highly susceptible to glaucoma. Challenges in IOP monitoring have made this entity a major threat for the success of KPro. Drainage tubes are frequently required either along with KPro implantation or afterward.