To report indications, practices, complications, and outcomes from the first multicenter study on the Boston Type 1 keratoprosthesis. Prospective, noncomparative, interventional case series. We analyzed 141 Boston Type 1 keratoprosthesis surgical procedures, from 17 surgical sites, done from January 2003 through September 2005 in 136 eyes of 133 patients. Forms reporting 70 preoperative, intraoperative, and postoperative parameters were collected and analyzed at a central data collection site (Cornea Consultants of Albany, Albany Medical College, Albany, New York). Visual acuity (VA) and keratoprosthesis survival. Common preoperative diagnoses were graft rejection, in 73 eyes (54%) (average prior grafts, 2.24); chemical injury (20 eyes [15%]); bullous keratopathy (19 eyes [14%]); and herpes simplex virus keratitis (9 eyes [7%]). Additionally, 82 eyes (60%) had preoperative glaucoma. Preoperative best-corrected VA ranged from 20/100 to light perception, and was <20/200 in 96% of eyes. At an average follow-up of 8.5 months (range, 0.03-24; standard deviation, 6.1; median, 12), postoperative vision improved to > or =20/200 in 57%. Among eyes at least 1 year after the operation (62 eyes), vision was > or =20/200 in 56% of eyes and > or =20/40 in 23%. At an average follow-up of 8.5 months, graft retention was 95%. Severe visual loss or failure to improve from keratoprosthesis was usually secondary to comorbidities such as advanced glaucoma, macular degeneration, or retinal detachment. The Boston Type 1 keratoprosthesis seems, based on early follow-up, to be a viable option after multiple failed corneal grafts or in some situations of a poor prognosis for primary penetrating keratoplasty.