Glaucoma after penetrating keratoplasty and keratoprosthesis.

PURPOSE: To compare visual and glaucoma outcomes in patients with known glaucoma after a penetrating keratoplasty (PKP) or a Boston Keratoprosthesis Type 1 (KPro) as a second corneal replacement procedure. DESIGN: Retrospective interventional case series. PARTICIPANTS: Charts of 141 eyes that underwent either a PKP or KPro at the Centre hospitalier de l'Université de Montréal after one failed PKP from 2008 to 2020 were reviewed. Forty-six eyes with preoperative glaucoma were included. METHODS: Data collected included demographics, indication for the initial surgery, best corrected visual acuity (BCVA), concurrent ocular disorders, number of glaucoma medications, need for glaucoma surgery, cup-to-disc ratios (CDRs), mean RNFL thickness, and visual field (VF) characteristics. Primary outcomes were glaucoma progression trends. Secondary outcomes were visual outcomes and need for additional procedures. RESULTS: Mean follow-up was 4.7 years for the PKP and 7.3 for the KPro group (P<0.007). 30.6% of PKP compared to 70.5% of KPro patients were diagnosed with glaucoma preoperatively. Glaucoma worsened similarly in both groups; this is based on an analysis of the number of glaucoma medications, CDR, need for glaucoma surgery, and characteristic VF changes. Patients in the PKP group required significantly more regrafts than patients in the KPro group (31.8 vs. 8.3%; P=0.045). CONCLUSIONS: A preoperative diagnosis of glaucoma does not preclude KPro implantation. In glaucomatous eyes, the disease progressed similarly in both groups. Since both procedures increase the risk of worsening glaucoma, close follow-up is recommended. KPro may decrease the need for further corneal transplantation surgery.

[Long-term visual outcomes of Boston type I keratoprosthesis in Canada]. / Résultats à long terme de la kératoprothèse de Boston de type I au Canada.

BACKGROUND/PURPOSE: To evaluate long-term visual outcomes of Boston type I keratoprosthesis (KPro) surgery and identify risk factors for visual failure. METHODS: Single surgeon retrospective cohort study including 85 eyes of 74 patients who underwent KPro implantation to treat severe ocular surface disease, including limbal stem cell deficiency, postinfectious keratitis, aniridia and chemical burns. Procedures were performed at the Centre hospitalier de l'Université de Montréal from October 2008 to May 2012. All patients with at least 5 years of follow-up were included in the analysis, including eyes with repeated KPro. Main outcome measures were visual acuity (VA), visual failure, defined as a sustained VA worse than the preoperative VA, postoperative complications, and device retention. RESULTS: Mean follow-up was 7.2±1.3 years (±SD). Mean VA was 2.1±0.7 (logarithm of minimal angle resolution) preoperatively and 1.9±1.2 at last follow-up. In total, 2.4% of patients had VA better than 20/200 preoperatively vs. 36.5% at last follow-up. Maintenance of improved postoperative VA was seen in 61.8% of eyes at 7 years. Preoperative factors associated with visual failure were known history of glaucoma (HR=2.7 [1.2 to 5.9], P=0.02) and Stevens-Johnson syndrome (HR=7.3 [2.5 to 21.4], P<0.01). Cumulative 8-year complication rates were 38.8% retroprosthetic membrane formation, 25.9% hypotony, 23.5% new onset glaucoma, 17.6% retinal detachment, 8.2% device extrusion and 5.9% endophthalmitis. The majority (91.8%) of eyes retained the device 8 years after implantation. CONCLUSION: Nearly two-thirds of patients exhibited improved VA 7 years after KPro implantation. Preoperative risk factors for visual failure were known glaucoma and Stevens-Johnson syndrome.

[Boston keratoprosthesis type 1]. / La kératoprothèse de Boston type 1.

Penetrating keratoplasty is the most commonly performed tissue transplant in the world. However, its success depends on the health of the ocular surface and the intact immune privilege of the eye. In the absence of these two conditions, corneal transplants have an increased failure rate and result in corneal blindness. For more than two hundred years, researchers have been trying to find the best design of the artificial cornea in order to address these cases of severe corneal blindness. Despite previous difficulties, interest in the field has recently been revived, and considerable progress has been made over the last 20 years, to the point where the keratoprosthesis is now considered a primary procedure for some indications and is no longer always a surgery of last resort. In this review, we describe the global and personal experience with Boston keratoprosthesis type 1. It is a relatively new treatment for severe corneal blindness in the context of multiple failed corneal transplants and high-risk conditions. In the last decade, changes in the design, surgical technique, and postoperative management have increased the success rate and popularity of the Boston keratoprosthesis and decreased its complications substantially, making it a safe and effective alternative for certain corneal pathologies. However, some complications persist and require management to improve the visual prognosis of patients with corneal blindness.

Pars plana vitrectomy through the Boston Keratoprosthesis type 1.

PURPOSE: To ascertain the feasibility of pars plana vitrectomy (PPV) through a permanent Boston Keratoprosthesis type 1 (KPro) without the use of a temporary KPro. METHODS: A retrospective interventional case series. Eyes implanted with Boston KPro type 1 between 2008 and 2011 requiring PPV for vitreoretinal complications were included. Feasibility of PPV through the KPro, its anatomical and functional success were studied. RESULTS: Five out of 70 patients required PPV for vitreoretinal complications post-KPro surgery resulting in an incidence of 7%. PPV was feasible through the Boston KPro with no deleterious effects on the corneal carrier or the KPro itself. Repeat PPV was necessary in some cases. Although anatomical repair of the vitreoretinal complications was achieved in most cases, post PPV visual acuity remained poor in the majority. CONCLUSION: Our study suggests that although PPV through the Boston KPro is a viable approach for vitreoretinal disease repair, visual rehabilitation remains poor.

Diffuse lamellar keratitis: incidence, associations, outcomes, and a new classification system.

PURPOSE: To evaluate the incidence, associations, and visual outcomes in patients with diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK). SETTING: University-based refractive surgery center, Boston, Massachusetts, USA. METHODS: This retrospective review comprised 2711 eyes that had LASIK between September 1996 and September 1999. All eyes that developed DLK after LASIK were included. They were divided into type I DLK (center sparing) or type II DLK (center involved) and then subdivided into A (sporadic-DLK not diagnosed in other patients treated on the same day) or B (cluster-other patients identified with DLK). Type IA corresponded to center sparing, sporadic; type IB, center sparing, cluster; type IIA, center involved, sporadic; and type IIB, center involved, cluster. The main outcome measures were incidence of DLK after LASIK, time to diagnosis, time to resolution, and changes in best spectacle-corrected visual acuity (BSCVA). Unpaired t tests were used for statistical analyses. RESULTS: Thirty-six eyes (1.3%) developed DLK. Type I occurred in 58.3% of cases (type IA, n = 18; type IB, n = 3) and type II, in 41.7% (type IIA, n = 10; type IIB, n = 5). The mean time to diagnosis was not statistically significantly different between type I (1.8 days) and type II (1.1 days). Fourteen eyes (38.9%) developed DLK after an epithelial defect, representing an odds ratio of 13 times. The association with an epithelial defect was statistically significantly greater with type I (11/21 eyes, 52.4%) than with type II (3/15 eyes, 20.0%; P =.05). The mean time to resolution was 3.5 days in type I (type IA = 3.6 days; type IB = 2.7 days). This was significantly shorter than in type II, which had a mean time to resolution of 12.1 days (type IIA = 9.3 days; type IIB = 10.2 days) (P =.001). Loss of 2 or more lines of BSCVA occurred in 2 of 5 patients with type IIB and in no patients with types IA, IB, or IIA. CONCLUSIONS: Epithelial defects after LASIK increased the risk of DLK occurrence, especially type I. Type II DLK was associated with a prolonged time to resolution and carried a significantly higher risk of BSCVA loss than type I.