Background/aims To compare the complications leading to best-corrected visual acuity (BCVA) loss in patients with Boston keratoprosthesis type 1 (KPro) and glaucoma drainage device (GDD) and those with KPro alone.

Methods Retrospective case series of all patients who underwent KPro surgery at the Centre Hospitalier de l'Université de Montréal between 2008 and 2011. Preoperative diagnoses, BCVA and complications were tabulated and analysed.

Results KPro surgery was performed in 96 eyes: 18 eyes (19%) had KPro and GDD while 78 eyes (81%) had KPro only. Median BCVA at postoperative 6 months was 20/150 in both groups. Seven eyes (39%) with KPro and GDD experienced vision loss due to complications such as glaucoma progression (three eyes, 22%), tube occlusion (four eyes, 22%) and choroidal haemorrhage (three eyes, 17%). Vitreous incarceration was the most common cause of tube occlusion. Vitreoretinal, glaucoma and infectious complications caused BCVA loss in 16 eyes (21%) with KPro alone (p=0.13).

Conclusions Glaucoma progression is a major cause of visual decline post-KPro. However, GDD implantation should only be performed in carefully selected patients. Because of a high risk of vitreous incarceration within the tube, a complete pars plana vitrectomy should be performed prior to GDD implantation.