FEASIBILITY AND OUTCOMES OF CONCOMITANT ENDOSCOPY-ASSISTED TOTAL PARS PLANA VITRECTOMY IN BOSTON KERATOPROSTHESIS TYPE 1

Vitreoretinal complications after Boston keratoprosthesis type 1 (Boston KPro) lead to severe visual loss but can be decreased with total pars plana vitrectomy (PPV) at the time of Boston KPro implantation. However, anterior hyaloid peeling during PPV is challenging without endoscopy. The purpose was to report on the feasibility of the first-ever case of total PPV, with anterior hyaloid peeling assisted by endoscopy, performed at the time of Boston KPro surgery.

Centre hospitalier de l’Université de Montréal (CHUM), Montreal, Canada

First case of Boston KPro and endoscopy-assisted anterior hyaloid peeling performed as part of a prospective, interventional study. Clinical and surgical reports from before and after surgery were reviewed, including history, best-corrected visual acuity (BCVA), intraocular pressure (IOP) by digital palpation, optical coherence tomography (OCT), and B-scan ultrasonography, over a 2-month period. Intraoperative observations and results were reported. A thorough review of the literature was also performed.

A 60-year-old male, with a history of two previously failed penetrating keratoplasties after ocular perforation with plugged iris in his left eye, was deemed eligible to benefit from both Boston KPro and PPV. Preoperative evaluation was limited through the opaque-diseased cornea. BCVA was light perception (LP), no retinal detachment was seen on B-scan, and IOP=26mmHg on 3 glaucoma drops. On the day of surgery, the unstable intraocular lens was removed and synechiae lysed. A Boston KPro was implanted, and a 3-port 23-gauge PPV was achieved with visualization through the Boston KPro optic and wide-angle viewing system, without a temporary KPro. Anterior hyaloid peeling and removal of capsule remnants were completed using endoscopy. Endoscopic intraoperative assessment revealed severe cupping suggestive of already advanced glaucoma, with the posterior pole, peripheral retina, and retinal vessels within normal limits. A soft contact lens was applied. The patient was put on prednisolone and moxifloxacin drops four times daily. One week later, BCVA was hand motion (HM) and IOP=28mmHg on maximal tolerated medical therapy (MTMT). Two months later, BCVA remained LP, IOP=20 mmHg on MTMT, and the Boston KPro optic remained clear, with no retroprosthetic membrane (RPM), no cells in the anterior chamber, and intact sutures. Preexisting advanced glaucoma was only diagnosed once a clear optic was in place, hence little improvement in BCVA.

Endoscopy at the time of Boston KPro implantation offers a rare in-situ view of the Boston KPro and retroiridal structures, as well as complete removal of the anterior hyaloid. This combined procedure, reported herein for the first time, can be achieved in Boston KPro candidates with vitreoretinal diseases, shortening operative time. By removing such proinflammatory membranes, the incidence of glaucoma progression, retinal detachment and RPM may be decreased and improve visual outcomes for patients.