Endophthalmitis remains one of the most damaging and challenging complications following Boston keratoprosthesis type 1 (KPro) surgery. The authors reviewed the literature from 2001 onward to identify cases of endophthalmitis following KPro surgery and present an additional case of endophthalmitis in a patient with Stevens Johnson syndrome. The prevalence of endophthalmitis between 2001 and 2011 was 5.4%. Gram-positive bacteria are the most common agents responsible for endophthalmitis in this patient population while gram-negative bacteria and fungi are emerging pathogens. Risk factors for endophthalmitis include preoperative diagnosis of cicatricial disease and postoperative infectious keratitis, glaucoma drainage device erosion and non-compliance with antibiotic prophylaxis. Additional studies on the prevention and treatment of endophthalmitis are required to improve the overall prognosis of these patients.

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.

This review assesses different clinical aspects of the various known drug-induced corneal deposits, based on the corneal layer involved (epithelium, stroma and/or endothelium), and based on the drug class. The most well-known condition caused by drug deposits is vortex keratopathy, or corneal verticillata, which is a whorl-like opacity in the corneal epithelium. Vortex keratopathy is commonly caused by certain cationic amphiphilic drugs such as amiodarone, antimalarials, suramin, tamoxifen, chlorpromazine and non-steroidal anti-inflammatory drugs. These deposits usually occur once a certain dose of the drug is reached. Most cases present with mild to moderate symptoms with minimal visual impairment. Most of these deposits resolve automatically, after months to years of drug cessation. Notably, other drug classes can cause deposits in all three layers of the cornea. Chlorpromazine, gold, rifabutin, indomethacin and tyrosine kinase inhibitors can cause stromal deposits, with reduced visual acuity when the anterior stroma is involved. Chlorpromazine and rifabutin can also cause deposits in the endothelial layer of the cornea. Regardless of the type of corneal deposit, local therapies such as topical lubricants or corticosteroids may help improve symptoms. Drug cessation or modification can also be helpful but should be weighed against the systemic risks of the underlying disease.

This study aims to determine whether frozen corneas can be successfully used as carriers of the Boston keratoprosthesis (KPro). Prospective study of 37 patients undergoing KPro surgery with fresh or frozen corneas as carriers. Patients were randomized to receive either a fresh corneal graft or a frozen corneal graft during implantation of the Boston KPro. The randomization depended on availability of fresh versus frozen corneas offered by the local eye bank. All surgeries were performed by the same experienced surgeon. Outcome measures included retention of the device, level of preoperative and postoperative visual acuities (VAs), and complications. The indication for Boston KPro was corneal graft failure in 24 eyes; 13 patients had KPro as a primary procedure. The assembly of the Boston KPro and surgery were uneventful in all cases. Mean follow-up was 9.65 months. Median preoperative VA was counting fingers (range, 20/100 to light perception) in the fresh cornea group (19 eyes) and hand motions (range, 20/150 to light perception) in the frozen cornea group (18 eyes). Median postoperative VA were 20/150 (range, 20/30 to hand motions) and 20/150 (range, 20/40 to counting fingers) in the fresh and frozen cornea groups, respectively. Inflammation and retroprosthetic membrane formation were the most common complications with similar rates between the 2 groups. The device retention rate was 100% at the end of the follow-up period. Frozen and fresh corneal donors seem equally efficient and safe as carriers of the Boston KPro with similar recuperation of VA and no untoward complications, such as melt, leaks, or endophthalmitis.

Purpose: To determine the presentation, risk factors, and outcomes of keratolysis after Boston type I keratoprosthesis (B-KPro). Methods: Retrospective chart review. Results: A total of 16 (14%) of the 110 eyes (96 patients) which underwent B-KPro implantation developed keratolysis at an average 20 ± 11 months. Retroprosthetic membrane (RPM), infectious keratitis, and corneal dellen were identified in 31%, 25%, and 13% of corneal melts, respectively. Five eyes had keratolysis without a readily identifiable cause. RPM (odds-ratio, OR = 4.4, p = 0.02) and infectious keratitis (OR = 17.6, p<0.0005) were confirmed as significant risk factors. Retinal detachment (p = 0.001) and choroidal detachment (p = 0.003) were more common in eyes with keratolysis. Management included B-KPro removal or exchange (n = 7), amniotic membrane transplantation (n = 1), tectonic corneal transplantation (n = 2), medical treatment (n = 4), and observation (n = 2). Conclusions: The risk of keratolysis following B-Kpro increases with the development of RPM and infectious keratitis. Patients with keratolysis had higher complication rates and should receive rigorous monitoring.