The explosion of Boston keratoprosthesis (KPro) surgery over the last 10 years has revolutionised the field of cornea and ocular surface disease. Options for patients with severe inflammation of the corneal and conjunctival surface were limited prior to the development of the KPro surgical technique by Dohlman et al.1 The Type 1 KPro, which is most frequently used, has a collar button design consisting of two plates joined by a stem, which forms the optical portion (see Figure 1). A fresh donor graft is used as a carrier for the device and a soft contact lens is placed over the ocular surface. The Type 2 Boston KPro is similar in design except that the 2 mm optical portion protrudes through a tarsorrhaphy.2
The Boston KPro allows for dramatic and rapid visual improvement in patients whose ocular disease is confined to the anterior segment.3 In the past, vision loss following Boston KPro could result from a number of complications including infection, corneal melting and retinal detachment. Modifications in device design and post-operative management have reduced the occurrence of these problems. At present, glaucoma is the most important threat to long-term preservation of vision following Boston KPro surgery.4–6 Appropriate diagnosis and management of glaucoma following Boston KPro is vital to ensure the best outcomes.
Pre-operative Glaucoma
Many patients who are candidates for Boston KPro surgery have pre-existing glaucoma. Previous case series from multiple institutions have shown a prevalence of pre-operative glaucoma of between 36 and 76 %.5–10 This is not surprising since patients who need a Boston KPro have often had multiple prior corneal surgeries or have diseases that cause intraocular inflammation, necessitating topical, subtenon or systemic glucocorticoids.2 Steroid-response ocular hypertension is prevalent among these patients, which can contribute to the development of glaucoma.11
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