KPro Implantation Research Articles

Five year outcomes of Boston type I keratoprosthesis as primary versus secondary penetrating corneal procedure in a matched case control study.

Despite improved retention and reduced complication rates paving the way for the current expansion of applications and surge in prevalence for the Boston type I Keratoprosthesis (KPro), the most frequent indication for its implantation today remains prior graft failure. The purpose of this study is to evaluate the long-term outcomes of primary KPro and compare to secondary implantation in a matched cohort study. This study included patients who underwent KPro implantation in a single center by two surgeons between July 2008 and October 2014. All eyes with KPro implantation as the primary procedure with a minimum follow up of 12 months were matched with eyes with same preoperative diagnoses that underwent secondary KPro implantation. Main outcomes included visual acuity and device retention. A total of 56 eyes were included with 28 eyes in each group. Mean follow up was 5.0 years for both groups. Twenty-nine percent (8) of the eyes in the primary group had a diagnosis of chemical or thermal injuries, 25% (7) aniridia, 18% (5) autoimmune disease, 4% (1) infectious keratitis/neurotrophic cornea, 7% (2) gelatinous corneal dystrophy, 7% (2) ectrodactyly ectodermal dysplasia/limbal stem cell deficiency, and 11% (3) uveitis/hypotony. Sixty-one percent (17) of the eyes in the primary group and 39% (11) in the secondary group maintained a final best-corrected visual acuity of 20/200 or better at a mean follow up of 5.0 years; the probability of maintaining best-corrected vision is 0.83 and 0.49 for primary and secondary groups at 5.0 years (p = 0.02). There is no statistically significant difference between groups in device retention (p = 0.22) or postoperative complication rates (p >0.05). This study demonstrates that Boston KPro implantation may be successful as a primary procedure in patients at high risk of failure with traditional penetrating keratoplasty. The device has a good long-term retention rate and visual outcomes are promising however a larger study is needed for more definitive results.

Long-term outcomes of the aphakic snap-on Boston type I keratoprosthesis at the Bascom Palmer Eye Institute.

PurposeTo determine the indications, long-term clinical and visual outcomes, and complications of the aphakic snap-on type I Boston keratoprosthesis (KPro).DesignRetrospective, non-comparative case series.MethodsForty-five eyes of 43 patients with type I aphakic snap-on KPros with at least 1 year of follow-up were included. The past medical histories, preoperative indications, best-corrected visual acuities (BCVAs), postoperative complications, and retention rates were analyzed.ResultsThe most common indication for KPro implantation was a failed corneal graft (89%). The mean preoperative BCVA was count fingers–hand motion (2.14±0.45 logarithm of minimum angle of resolution [logMAR]), which initially improved to 20/200 (1.04±0.85 logMAR; P<0.0001). At the last examination, 24 eyes (53%) maintained some visual gain, 22% retained their preoperative visual acuity, and 24% lost vision due to postoperative events and underlying ocular comorbidities. Postoperative complications included retroprosthetic membranes (8/45, 18%), corneal melts (5/45, 11%), glaucoma progression (6/45, 13%), and endophthalmitis or sterile vitritis (6/45, 13%). The KPro retention rate was 89%, with a mean follow-up of 51 months. The mean BCVA at the last visit was 20/1,400 (1.82±0.92 logMAR).ConclusionMost patients experienced improved visual acuity after the implantation of the aphakic, snap-on type I KPro; however, the visual gains were not sustained over time, correlating with the onset of postoperative complications.

Experience with keratoprosthesis at a tertiary eye care center: A report from North-East India

Aim: To evaluate the preservation of visual acuity (VA) and the development of complications after keratoprosthesis (KPro) implantation (Boston KPro and Auro KPro) over a long follow-up period at a tertiary eye center in North-East India. Materials and Methods: This was a single-center retrospective case series. The records of all patients who underwent KPro implantation between March 2013 and August 2017 were analyzed. The preoperative characteristics, postoperative outcomes, complications, its management, and retention rates were reviewed. Results: Ten cases were included in the study. Preoperative VA ranged from counting finger close to face to hand movement close to face. The cause for KPro implantation included multiple graft failures (5 eyes, 50%), chemical injury (3 eyes, 30%), and Stevens–Johnson syndrome (2 eyes, 20%). Mean follow-up duration was 26.9 months (range, 12–54 months). At 1-month follow-up, eight patients had a vision ≥6/60 (80%). At 1-year follow-up, eight patients had a VA ≥6/24. Glaucoma was newly diagnosed in three eyes (30%); progression was noted in one eye (10%). Glaucoma drainage device was implanted in one eye (10%). Retroprosthetic membrane formed in seven eyes (70%) and one eye (10%) underwent KPro replacement. The initial KPro was retained in nine eyes (90%). Conclusions: KPro is an effective and a viable option for treating end-stage corneal diseases for salvaging vision. A significant number of patients lose vision following KPro implantation due to glaucoma and corneal melts. Our study reiterates the importance of regular and long-term follow-up and a comprehensive team approach for management of postoperative complications.

Outcomes of Boston keratoprosthesis type 1 reimplantation: multicentre study results

ObjectiveTo investigate the visual and anatomical outcomes of Boston keratoprosthesis (Kpro) type 1 reimplantation. DesignSubgroup analysis of multicentre prospective cohort study. ParticipantsOf 303 eyes that underwent Kpro implantation between January 2003 and July 2008 by 1 of 19 surgeons at 18 medical centres, 13 eyes of 13 patients who underwent reimplantation of Boston Kpro type 1 were compared with 13 eyes of 13 diagnosis-matched patients who underwent initial implantation. MethodsForms reporting preoperative, intraoperative, and postoperative parameters were prospectively collected and analyzed. Main outcome measures were Kpro retention and logMAR visual acuity. ResultsAfter a mean follow-up time of 17.1 ± 17.6 months, the retention of both initial and repeat Kpro implantation was 92.3% (12/13 in both groups), and 62% of initial implantation and 58% of repeat implantation eyes achieved visual acuity better than 20/200. Vision worse than 20/200 was often due to glaucoma or posterior segment pathology. Best-recorded logMAR visual acuity was significantly improved postoperatively in both groups (p < 0.001), and there was no statistically significant difference in final logMAR visual acuity between the 2 groups (p = 0.89). Sterile keratolysis (n = 4) and fungal infection (n = 5) were the most common causes of initial Kpro failure in the repeat Kpro group. The single failure in the repeat Kpro implantation group was due to fungal keratitis, and in the control group it was related to Kpro extrusion. ConclusionsRepeat Kpro implantation is a viable option after failed initial Kpro, with visual and anatomical outcomes comparable to those of initial procedures.

Retroprosthetic Membrane Formation in Boston Keratoprosthesis: A Case-Control-Matched Comparison of Titanium Versus PMMA Backplate.

Retroprosthetic membrane (RPM) formation is the most common complication after Boston type 1 keratoprosthesis (KPro) implantation. It affects visual acuity and can predispose to corneal melt. Two KPro backplate materials are available: titanium and polymethyl methacrylate (PMMA). This study investigates the influence of the KPro backplate material on visually significant RPM formation. A retrospective case-control-matched study involving 40 patients; 20 eyes implanted with a titanium backplate KPro were case-matched with 20 eyes implanted with a PMMA backplate KPro between 2007 and 2015 with 1-year minimum follow-up. The mean follow-up duration was 28.1 ± 8.9 and 53.6 ± 24.3 months in the titanium and PMMA groups, respectively. At 12 months postoperatively, 7 eyes with titanium and 6 eyes with PMMA backplates developed a visually significant RPM. By the end of the study, a total of 11 eyes with titanium and 9 eyes with PMMA KPros developed a visually significant RPM. There was no statistically significant difference between both groups. Three of 11 eyes with titanium KPros that had a visually significant RPM required surgical membranectomy, whereas all eyes with PMMA KPros were successfully treated with the yttrium-aluminum-garnet laser. Recurrence of RPMs was found in 7/11 eyes in the titanium group and 2/9 eyes in the PMMA group with no statistical significance. Titanium backplate KPros do not significantly reduce RPM formation compared with PMMA backplate KPros in a case-control-matched setting. A larger prospective study is warranted to evaluate comparative long-term performance and guide newer designs.

Long-Term Visual Outcomes, Complications, and Retention of the Boston Type I Keratoprosthesis.

To report the long-term outcomes of the Boston type I keratoprosthesis (KPro). Data were collected regarding preoperative characteristics, surgical procedure(s) performed, and postoperative outcomes of patients who underwent KPro implantation from May 1, 2004, to May 1, 2011, and were followed for 5 years after surgery. Seventy-four KPro procedures were performed in 58 eyes (55 patients), with more than 1 KPro implanted in 10 eyes. The mean follow-up duration was 82.8 ± 20.5 months (range 57-145 months), and the most common indication for keratoprosthesis implantation was corneal transplant failure (50%). Preoperative corrected distance visual acuity (CDVA) was ≥20/200 in 5%; between 1 and 8 years after surgery, the percentage of eyes with CDVA ≥20/200 varied between 57% (4 years) and 82% (8 years). Nineteen (25.7%) KPros implanted were removed (retention failure rate 0.047/eye-year), although a KPro was retained at final follow-up in 55 eyes (94.8%). The most common postoperative complication was retroprosthetic membrane formation in 51.7% of eyes. The incidence of each postoperative complication decreased significantly over the first 10 years after surgery. The KPro provides significant visual improvement in most eyes, with more than 50% regaining and maintaining 20/200 CDVA each year through 8 years after surgery. The incidence of each postoperative complication decreases significantly over the first 10 years after surgery. Although almost one-quarter of implanted keratoprostheses were removed, over 90% of eyes reaching 5 years of follow-up retain a keratoprosthesis at final follow-up.

Impact of type I Boston keratoprosthesis implantation on vision-related quality of life

AimTo determine the impact of type I Boston keratoprosthesis (KPro) implantation on vision-related quality of life (VRQoL).MethodsProspective study in 33 patients (mean age 56±12 years, 67% male) with bilateral corneal...

Visual Outcomes and Complications of Type I Boston Keratoprosthesis in Children: A Retrospective Multicenter Study and Literature Review

To report outcomes and complications of Boston type 1 keratoprosthesis (KPro) implantation in children. Retrospective, multicenter case series. All children 16 years of age or younger who underwent KPro surgery at 3 ophthalmology centers in Canada between January 2010 and November2014. Records of patients having undergone KPro implantation were reviewed. Data on preoperative characteristics, surgical procedure(s) performed, and postoperative outcomes were collected and analyzed. Intraoperative and postoperative complications, device retention, and best-corrected visual acuity (BCVA). The KPro was implanted in 11 eyes of 11 patients 0.9 to 15.5 years of age, with 6 being primary corneal procedures. Best-corrected visual acuity recorded before surgery ranged from 20/600 to light perception (LP), and vision in 2 eyes was fix and follow. All patients had been diagnosed with glaucoma and 6 eyes had glaucoma drainage devices (GDDs) inserted before KPro implantation. At last follow-up (mean, 41.8 months; range, 6.5-85.0 months), 2 eyes retained BCVA of 20/400 or better, whereas 5 eyes lost LP. Postoperative complications included retroprosthetic membrane (9 eyes), corneal melt (5 eyes), infectious keratitis (3 eyes), endophthalmitis (3 eyes), GDD erosion (2 eyes), and retinal detachment (5 eyes). The initial KPro was retained in 4 eyes (36.4%). Boston type 1 keratoprosthesis implantation in children is associated with a substantially higher rate of complications, higher chance of device failure, and worse visual outcomes than observed in adults. In view of these results, the authors do not recommend the use of the KPro in the pediatric population.

Impact of Total Pars Plana Vitrectomy on Postoperative Complications in Aphakic, Snap-On, Type 1 Boston Keratoprosthesis

To determine the impact of total pars plana vitrectomies (PPVs) with peripheral shaving of the vitreous base on the rates of postoperative complications in patients with aphakic, snap-on type I Boston keratoprostheses (KPros). Retrospective, consecutive case series. A total of 48 eyes in 46 patients with implantation of aphakic, snap-on type 1 Boston KPros performed at a tertiary care facility between January 1, 2007, and December 31, 2013, were included. The cumulative incidences of postoperative complications were compared between patients who underwent total PPVs with shaving of the vitreous base (n= 22) and those who had partial PPVs or anterior vitrectomies (AVs) at the time of KPro implantation (n= 26). Rates of complications between patients who underwent total PPVs and partial PPVs or AVs. The rate of total postoperative complications was lower in the total PPV group (P= 0.018, log-rank test). In particular, eyes that underwent total PPVs had lower rates of retroprosthetic membranes (RPMs) requiring intervention (P= 0.049) and less vision loss due to glaucoma progression (P= 0.046). There was also a trend for fewer corneal melts (P= 0.060) and less sight-threatening complications (P= 0.051) in the total vitrectomy group. There was no difference in the rates of KPro extrusion (P= 0.41), endophthalmitis or vitritis (P= 0.15), retinal detachments (P= 0.76), cystoid macular edema (P= 0.83), or timing of complications between the 2 groups. The mean preoperative and postoperative visual acuities were similar between the 2 groups (P= 0.97). The mean follow-up was 49±22 months. Eyes that underwent total PPVs during implantation of aphakic, snap-on, type I Boston KPros had less postoperative complications than eyes with partial PPVs or AVs during the average 4 years of follow-up.

Long-term outcomes of the Boston type I keratoprosthesis in eyes with previous herpes simplex virus keratitis

PurposeTo report the long-term outcomes of the Boston type I keratoprosthesis (Kpro) in eyes with prior herpes simplex virus (HSV) keratitis.MethodsRetrospective review of all Kpro procedures performed by a single...

Russian Keratoprosthesis in Stevens-Johnson Syndrome.

To evaluate the efficacy and safety of Moscow Eye Microsurgery Complex in Russia (MICOF) keratoprosthesis (KPro) implantation in patients with Stevens-Johnson syndrome (SJS). This was a retrospective case series. Fourteen eyes of 13 patients with SJS underwent KPro implantation at the Chinese People's Liberation Army General Hospital between April 1, 2000, and December 24, 2014. The visual outcome, KPro retention rate, and incidence of postoperative complications and their management were recorded and investigated. The mean age and follow-up duration were 61.5 ± 17.3 years (range: 27-87 yrs) and 62 ± 39.1 months (range: 13-144 mo). Thirteen eyes (92.9%) achieved a best-corrected visual acuity of 20/200 or better, and 8 eyes (57.1%) achieved a best-corrected visual acuity of 20/40 or better after surgery. However, 71.4% (10/14) experienced visual decline because of different postoperative complications. Common complications included corneal melting, glaucoma, vitritis, superficial tissue overgrowth, and retroprosthetic membrane, and the incidence of these complications was 71.4%, 28.6%, 35.7%, 14.3%, and 28.6%, respectively. After repair and autoauricular cartilage reinforcement, all cases had stable anatomical retention at the last visit. The MICOF KPro improved vision of patients with SJS, but lifelong surveillance is necessitated because of a high rate of postoperative complications. Corneal melting was the main reason for KPro failure. Infectious endophthalmitis and glaucoma were the main risk factors for visual loss.

Outcomes of bilateral sequential implantation of the Boston keratoprosthesis type 1

ObjectiveTo evaluate the risks and benefits of sequential bilateral Boston type 1 keratoprosthesis (KPro) implantation for bilateral corneal blindness. DesignComparative retrospective study. ParticipantsPatients who underwent a sequential bilateral KPro surgery. MethodsAll 11 patients who underwent sequential bilateral KPro surgery at the Centre Hospitalier de l’Université de Montréal between October 2008 and October 2011 were recruited. Data from the 22 patient eyes in our study were separated in 2 groups based on the first (group 1) or second eye (group 2) implanted with the Kpro. Both groups were then compared for the best corrected visual acuity (BCVA) and complications. Bilateral BCVA following both surgeries and the overall number of complications that affected each patient after both interventions were also analyzed. ResultsAt 24 months, BCVA was 20/150 in group 1 and 20/200 in group 2 (p = 0.67). Throughout the study, there was no significant difference in BCVA between the 2 groups (p > 0.05), and bilateral BCVA was similar. The complication rate was comparable in the 2 groups. Patients had a mean of 2.45 complications following the first surgery and a mean of 5.27 in both eyes combined after the second intervention (p = 0.03). ConclusionsBecause visual gain observed following the second surgery was the same as that with the first and multiple surgeries increased the number of complications for each patient, we recommend saving bilateral KPro implantation for cases in which the first eye with KPro develops a disease limiting its visual potential.

Safety of Concurrent Boston Type I Keratoprosthesis and Glaucoma Drainage Device Implantation

To evaluate the safety of concurrent Boston type I keratoprosthesis (KPro) and glaucoma drainage device (GDD) implantation. Retrospective comparative study of a consecutive cohort of patients. Patients who underwent KPro implantation by a single surgeon (A.J.A.) with or without 1 concurrent Ahmed GDD (New World Medical, Inc., Rancho Cucamonga, CA) implantation between January 1, 2005, and January 31, 2015, were included. Patients with fewer than 3 months of follow-up or a history of previous KPro implantation were excluded. Preoperative, operative, and postoperative data were collected for each procedure. All comparisons were made between KPro procedures performed with or without concurrent GDD implantation. The Fisher exact test (2-tailed) was used to compare proportions, Student t test and Wilcoxon rank-sum test were used to compare means, and the log-rank test was used to compare time-to-outcome events. The primary outcome was frequency of the composite variable, that is, any serious vision-threatening postoperative complication, which included sterile vitreitis, endophthalmitis, hypotony maculopathy, suprachoroidal hemorrhage, retinal detachment, stromal necrosis, and infectious keratitis. Secondary outcomes included intraocular pressure control, worsening of visual acuity, cystoid macular edema, retroprosthetic membrane formation, persistent epithelial defect formation, GDD exposure, and KPro removal. One hundred thirty-seven KPro procedures were performed in 129 patients: 91 (66.4%) KPro alone and 46 (33.6%) KPro plus GDD. There were no statistically significant differences between the 2 groups in terms of the incidence of vision-threatening postoperative complications. None of the 46 GDDs placed at the same time as the KPro became exposed during an average follow-up of 44 months. Compared with KPro alone, GDD placement combined with KPro was not associated with increased postoperative complications.

Retroprosthetic Membrane Formation After Boston Keratoprosthesis: Is It Truly a Benign Complication?

Advances in Boston type 1 keratoprosthesis (K-Pro) technology and postoperative management have led to a decrease in postoperative complications and expanded indications in recent years. However, several challenges still remain, including the post-implantation development of fibrous tissue behind the device known as a retroprosthetic membrane (RPM). Herein, we review the epidemiology, pathophysiology, detection, treatment, prevention, and sequelae of RPM formation after keratoprosthesis implantation. Among postulated risk factors, device indication has been found to be a significant predictor of RPM formation. However, the etiology is likely multifactorial and probably involves both pathologic wound healing triggered by the device and host-specific factors. Anterior segment optical coherence tomography is emerging as a useful tool in the detection and monitoring of RPM formation. Once diagnosed, most RPMs affecting vision are responsive to therapy. However, attempts to reduce the burden of RPM formation including the utility of intracameral corticosteroid prophylaxis at the time of surgery have shown limited effect. Beyond visual impairment, evidence suggests that membrane extension behind the back-plate and into local intraocular structures may contribute to significant morbidity. Indeed, recent reports of RPM-related sequelae include sterile keratolysis and K-Pro extrusion, angle closure and glaucoma development, and, in some cases, tractional retinal detachments. RPM formation after K-Pro implantation compromises the stability of the device and long-term patient outcomes. Accordingly, further investigations are needed to understand RPM etiology in order to inform the development of more effective strategies for prophylaxis and treatment.

Boston Keratoprosthesis Outcomes in Severe Ocular Chemical Burns in Southern China: A Retrospective Study.

The objective of this study was to report clinical outcomes (functional and anatomic) of Boston keratoprosthesis (KPro) after severe chemical burns in Southern China. Nineteen patients (19 eyes) that sustained severe chemical injuries in Southern China were enrolled in this retrospective study in our hospital between May 2009 and June 2015. KPro implantation in these patients was performed by a single experienced surgeon (Jiaqi Chen). The parameters evaluated in this study included diagnosis, comorbidity, preoperative and postoperative visual acuity (VA), complications, KPro retention, histological and immunohistochemical results of retroprosthetic membrane (RPM) and mucous membrane over the optic cylinder. The mean age of the patients was 42.7±11.3years (range 29-62years). All patients were male. Of the 19 included eyes, nine had acid burns, and 10 had alkali burns. Ten patients had previously undergone failed penetrating keratoplasty. The mean follow-up time was 41.3±5.5months (range 36-56months). Preoperatively, the VA of the patients ranged from hand movement to light perception. Postoperatively, 17 patients (89.4%) achieved at least 20/200 once, and 7 patients (36.8%) achieved at least 20/200 and maintained this acuity until the last follow-up. The initial KPro was retained in 14 (73.6%) eyes and successfully replaced in one eye. Postoperative complications included RPM in 10 eyes, glaucoma in 6 eyes, retinal detachment in 2 eyes, corneal melting in 5 eyes, ischemic optic neuropathy in 1 eye, and overgrowth of the mucous membrane over the optical cylinder in 2 eyes. The histological and immunohistochemical results of the RPM showed granulomatous disorders and mucous membrane over the optic cylinder of conjunctival origin. KPro surgery can restore useful vision in patients suffering from severe chemical burns. However, postoperative VA declined with the development of complications, and ocular surface disorders caused by the chemical burns were associated with a greater incidence of KPro retention failure. The retention rate was comparable in patients using ipsilateral autologous corneal tissue with allograft corneal tissue. Science and Technology Foundation of Guangdong Province of China, Grant Number 2014A020212714.

Effect of Penetrating Keratoplasty and Keratoprosthesis Implantation on the Posterior Segment of the Eye.

PurposeTo compare the effects of post-penetrating keratoplasty (PK) and post-keratoprosthesis (KPro) surgery-related inflammation on the posterior segment of the eye and to assess inhibition of tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL-1β) on these effects.MethodsBALB/C (syngeneic) or C57BL/6 (allogeneic) corneas were transplanted onto BALB/C host beds as part of PK or miniature KPro (m-KPro) implantation. Intraocular pressure (IOP) was measured via an intracameral pressure sensor; tissues were harvested and analyzed 8 weeks after surgery. Expression of TNFα and IL-1β in the retina was analyzed using real-time quantitative (q)PCR. Optic nerve degeneration (axon count, circularity, and area) was assessed quantitatively using ImageJ software. After m-KPro implantation, mice were treated with saline, anti-TNFα, or anti-IL-1β antibody, and axonal loss was assessed after 10 weeks.ResultsMean IOP was within normal limits in the operated and fellow eyes in all groups. The mRNA expression of TNFα and IL-1β was highest in m-KPro groups with either syngeneic or an allogeneic carrier. We observed optic nerve degeneration in both allogeneic PK and m-KPro implanted eyes with an allogeneic carrier. However, TNFα blockade significantly reduced axonal loss by 35%.ConclusionsAllogeneic PK and m-KPro implants with an allogeneic carrier lead to chronic inflammation in the posterior segment of the eye, resulting in optic nerve degeneration. In addition, blockade of TNFα prevents axonal degeneration in this preclinical model of allogeneic m-KPro (alloKPro) implantation.

Keratoprosthesis in pediatric keratitis-icthyosiform-deafness syndrome

We report the first case of Boston Keratoprosthesis (KPro) implantation in a 7-year-old girl with keratitis-ichthyosiform-deafness syndrome and persistent, highly vascular corneal surface disease. An adult aphakic KPro with 8.5 mm backplate was implanted successfully and without operative or postoperative complications following 3 failed penetrating keratoplasties. Visual acuity improved from hand motions to 20/70 in the left eye 22 months after KPro surgery and from hand motion to hand motion with direction in the right eye. Glaucoma developed in the left eye, but intraocular pressure was successfully controlled with Ahmed valve placement and topical dorzolamide-timolol.

High MMP-9 Expression May Contribute to Retroprosthetic Membrane Formation after KPro Implantation in Rabbit Corneal Alkali Burn Model.

Purpose. To evaluate aqueous humor MMP-9 levels in alkali-burned rabbit cornea following KPr implantation and their roles in RPMs formation. Methods. Left eyes of 36 rabbits received a deep corneal alkali wound. 12 corneas were implanted with KPro and the other 24 control corneas were either penetrating keratoplasty or left without keratoplasty. Aqueous humor MMP-9 and TIMP-1 levels were determined and RPMs were obtained for histopathological and ultrastructural examination. Results. Alkali exposure induced significant increase in aqueous humor MMP-9 level and the data were further enhanced by KPro implantation. By contrast, TMIP-1 levels in aqueous humor showed a decreased trend following corneal alkali burn and KPro surgery. RPMs were developed in 5 out of 10 cases of KPro successfully implanted eyes. Histopathology showed the presence of a large number of fibroblasts and collagen fibers arranged irregularly with inflammatory cells infiltration, and an ingrowth of new blood vessels in this retrokeratoprosthesis fibrous tissue. Immunohistochemical analysis showed positive stain of RPMs for both MMP-9 and TIMP-1. Aqueous humor MMP-9 levels were significantly higher in RPM group postoperatively, while TIMP-1 levels were comparatively lower than that of No-RPM group. Conclusions. Our study evidenced the potential pathophysiological role of MMP-9 expression in RPM formation following KPro implantation.

Retinal detachments after Boston Keratoprosthesis: incidence, predisposing factors, and visual outcomes.

To determine the rates, predisposing factors, and visual outcomes of retinal detachment (RD) after Boston Keratoprosthesis (KPro) implantation. In this noncomparative, interventional case series, the medical records of 170 patients (205 eyes) who underwent Boston type 1 and type 2 KPro implantation at the Massachusetts Eye and Ear Infirmary between April 1993 and June 2009 were retrospectively reviewed. Incidence and annual rates of RD were calculated, and the roles of possible predictive factors for RD after KPro were investigated. Main outcome measures were rates of and risk factors for RD, visual acuity after RD, and surgical outcomes after repair. Sterile vitritis and autoimmune systemic disease significantly predisposed patients to RD after KPro placement. Of patients who developed RD after implantation, 50% progressed to visual acuity of no light perception despite surgical repair. Inflammation plays a major role in RD development after KPro implantation. Patients with predisposing factors should be advised of the high rates of RD and comanaged with a vitreoretinal specialist.

Fungal Infections After Boston Type 1 Keratoprosthesis Implantation: Literature Review and In Vitro Antifungal Activity of Hypochlorous Acid.

To review the current literature describing cases of fungal keratitis and endophthalmitis after Boston keratoprosthesis (KPro) implantation and to characterize the antifungal activity of 0.01% hypochlorous acid against medically relevant fungi. A literature review of fungal keratitis or endophthalmitis in KPro patients from January 2001 to April 2015, and an in vitro time kill assay characterizing the fungicidal activity of 0.01% hypochlorous acid against fungi causing ocular infections. Fifteen publications, predominantly retrospective case series, were identified. Infection rates after KPro implantation ranged from 0.009 to 0.02 fungal infections per patient-year of follow-up. The largest single-surgeon series reported an incidence of 2.4% for fungal endophthalmitis during a 10-year period. Causative organisms included both yeasts and molds. Outcomes were favorable if infections were caught early and treated appropriately; less favorable outcomes were reported in developing countries where fungal species are endemic and resources are limited. 0.01% hypochlorous acid is rapidly fungicidal, reducing the number of viable yeast cells or mold conidia by at least 99.99% within 60 seconds. The antifungal activity extended to all molds (Acremonium kiliense, Aspergillus flavus, Aspergillus fumigatus, Fusarium solani, and Mucor indicus) and yeast species (Candida albicans and Candida parapsilosis) tested. Fungal infections remain a lifelong concern in patients after KPro implantation. There is a growing need for a standard antifungal prophylaxis regimen, especially in the developing world. The rapid broad-spectrum in vitro fungicidal activity of 0.01% hypochlorous acid against all fungi tested makes it an attractive candidate as an antifungal prophylaxis in KPro patients.