Boston type 1 keratoprosthesis is a viable option for patients with repeated graft failure, even for those with challenging diagnoses such as ocular burns and autoimmune syndromes.

Purpose: To analyse how primary diagnosis and complications affect the evolution of post-operative visual acuity (VA). Methods: We performed retrospective chart analysis on 59 eyes in 57 patients with various diagnoses, most of which were non-standard indications for Boston type 1 keratoprosthesis (Kpro) implantation. The follow-up period was at least 3 months. Patients were classified based on the evolution of post-operative VA: group A demonstrated stable VA improvement, group B lost VA improvement and group C no significant VA improvement. Results: We assigned 46% of our cases to group A with stable VA improvement, 32% to group B with lost VA improvement, and 22% to group C with no VA improvement. The number of graft failures before Kpro implantation did not influence VA outcome. Except for the relatively good VA outcome in chemical burn and radiation injury patients, there seems to be no association between primary diagnosis and positive or negative VA outcome. Only 9% of patients with posterior segment complications and 20% with infections and associated pathologies were assigned to group A. Conclusion: Most cases (78%) showed improvement in VA after Boston type 1 Kpro (groups A and B). Posterior segment complications and infections mostly resulted in persistent loss of vision. These complications should be prevented and carefully treated.