This retrospective study underscores the possibility of good, long-term visual outcomes following Boston Keratoprosthesis type 1 (KPro) implantation, even in patients with complicated ocular issues who otherwise have limited options for visual rehabilitation.
Of the 52 patients (59 eyes) reviewed in this single-center study, the primary indication for surgery was failed corneal transplantation (46 eyes) while the remaining eyes underwent primary KPro implantation. Overall, 88% experienced improved vision after surgery. However, the likelihood of maintaining postop vision declined with each year, decreasing to 71% at year 1, 59% at year 2 and 48% at year 3.
Glaucoma appeared to be the primary reason for failure to maintain best-ever visual acuity after surgery, as well as failure to improve vision after surgery. More than 50% of postop vision loss was attributed to glaucoma or glaucoma surgery-related issues. Prior trabeculectomy was associated with a higher rate of glaucoma-related vision loss (P =.04), likely because it's indicative of more advanced disease, according to the authors.
Additionally, they found that some pathologies – Stevens-Johnson syndrome, mucous membrane pemphigoid, atopic keratoconjunctivitis, neovascularization and scarring in chronic uveitis – were associated with a 3-fold higher risk of losing vision after primary KPro implantation compared with KPro after penetrating keratoplasty.
While the authors say that this study does not fully address the question of which clinical features best predict KPro success or under which circumstances KPro implantation is preferable over donor graft, it does highlight the importance of glaucoma management in these patients. Also, patients with certain pathologies, such as Stevens-Johnson syndrome and mucous membrane pemphigoid, need to be counseled on their more guarded long-term prognosis.