Boston KPro implants appear unsafe for children

Researchers examined visual outcomes and complications of Boston type 1 keratoprosthesis (KPro) implants in a pediatric population.  

Study design 

This retrospective case series included 11 eyes of 11 patients aged 16 years or younger. All patients underwent KPro surgery at 1 of 3 tertiary ophthalmology centers in Canada between 2010 to 2014.   

Before surgery, BCVA ranged from 20/600 to light perception. All 6 patients with concurrent glaucoma received a glaucoma drainage device (GDD) prior to KPro implantation. 

Outcomes 

At the last follow-up (mean 41.8 months; range 6.5 to 85.0 months), 2 eyes retained their preoperative BCVA, and 5 eyes lost light perception. The initial KPro device was retained in only 4 eyes (36.4%). 

The authors observed a high incidence of serious postoperative complications, which included retroprosthetic membrane (9 eyes), corneal melt (5 eyes) retinal detachment (5 eyes), infectious keratitis (3 eyes), endophthalmitis (3 eyes), and GDD erosion (2 eyes).  

Limitations 

This study is limited by its retrospective design and small cohort. Investigators did not address an age when KPro surgery will result in clinical outcomes similar to what has been observed in adults. 

Clinical significance 

Due to the high complication rate, the authors do not recommend KPro implantation in children. All 3 centers involved in this study have stopped offering KPro surgery for children with corneal opacification. 

The findings show that KPro surgery in children is a major undertaking, and can often lead to permanent and irreversible vision loss. Because the distance between the lens and cornea is short in children, the procedure routinely requires lensectomy and anterior vitrectomy and may warrant subtotal iridectomy and GDDs. Therefore, KPro implantation could subject children to lifelong follow-up, long-term use of topical antibiotics, and perpetual risk of sight-threatening complications.