This retrospective, interventional case series reported the rate of no light perception (NLP) following Boston Keratoprosthesis (B-KPro) type 1 surgeries.

Investigators at a Canadian university hospital reviewed records from 119 patients who underwent B-KPro implantation over an 8-year period. All surgeries were performed by a single surgeon, and a standardized technique was used. In cases of bilateral surgery, only the first treated eye was included. Patients were followed for a mean of 49 months postoperatively.

A total of 19 eyes (16%) progressed to NLP vision, of which 8 eyes had a preoperative diagnosis of aniridia. Of all aniridic eyes, 35% had NLP vision by end of follow-up, a relative risk of 3.04 (P=0.01). Of note, no eyes with pseudophakic bullous keratopathy resulted in NLP vision. The most common causes of NLP were inoperable retinal detachment, terminal glaucoma and graft-melt complications.

The retrospective nature of the study limits the ability to control for many confounding factors present given the varied underlying diagnoses. The authors also point out the limited number of Stevens Johnson Syndrome (SJS) patients. Only 2 patients with SJS were included, and both ended up with NLP vision. This study emphasizes the need for careful patient selection when choosing the KPro. It also highlights the need for heightened vigilance for complications particularly in high-risk groups such as aniridia.