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Purpose To describe the presentation, microbiology, management, and prognosis of eyes with endophthalmitis following Boston keratoprosthesis (KPro) implantation. Methods Retrospective case series with history, diagnostics, management, and outcomes data in endophthalmitis following KPro implantation presenting to a tertiary center between 2009 and 2020. Results Of 137 KPro-implanted eyes, 7 eyes of 7 patients (5%) developed endophthalmitis. On presentation, 6 (86%) reported decreased visual acuity (VA), and only 1 (14%) reported pain. Peripheral corneal ulcers were present in 2 eyes (29%). Seidel testing was negative in all cases. Six eyes (86%) had retroprosthetic membranes. One (14%) underwent initial pars plana vitrectomy (PPV) with mechanical vitreous biopsy, whereas 6 (86%) received a needle vitreous tap-half of which were dry. Organisms were isolated following vitreous tap in 2 eyes: Streptococcus intermedius and Mycobacterium abscessus. Mean VA pre-endophthalmitis, at presentation, and at 6 months were 20/267, 20/5944, and 20/734, respectively. VA improved 9.08 ± 11.78 ETDRS lines from presentation to 6 months. Six-month VA was correlated with pre-endophthalmitis VA (r=0.92, p=0.003) but not presenting VA (p=0.838). Conclusion Visual acuity at 6 months is correlated with pre-endophthalmitis VA, not presenting VA. Endophthalmitis should be considered in the differential diagnosis of painless intraocular inflammation any time after KPro implantation, even if Seidel negative.

Purpose The purpose of this study was to describe a novel bandage contact lens (BCL) interface technique for marking the Descemet membrane endothelial keratoplasty (DMEK) graft so that a single donor cornea can be used effectively for 2 recipients during acute shortage. Methods This was a retrospective comparative case series. In group A, 37 eyes underwent DMEK using a graft marked by the [DOUBLE HIGH-REVERSED-9 QUOTATION MARK]BCL interface technique" that was compared with 49 conventional DMEK grafts marked through the stromal window (group B). In group A, a resized BCL with a central 3-mm hole with the concavity up was placed between the stroma and peeled-off DM. This BCL with DM was flipped for S-stamping on the DM side. Final trephination was performed on a second Teflon block. The remaining anterior lamellar tissues of group A were used on the same day for other keratoplasty procedures. Endothelial cell density (ECD) and endothelial cell loss between the 2 groups were compared after 3 and 6 months. Results The ECD at 3 months in group A (n = 35) versus group B (n = 45) was 2228 ± 270/mm2 versus 2302 ± 254/mm2 (P = 0.48), and the ECD at 6 months (n = 23 and 22) was 2058 ± 324/mm2 versus 2118 ± 260/mm2 (P = 0.72). The corresponding endothelial cell loss was 23.3% ± 6.8% versus 20.3% ± 6.1% (P = 0.18) at 3 months and 29.1% ± 8.4% versus 26.7% ± 8.0% (P = 0.34) at 6 months. Among anterior tissues of group A, 17 (45.9%) were used for deep anterior lamellar keratoplasty, 18 (48.6%) were used for larger therapeutic and tectonic grafts, and 2 were used as keratoprosthesis carriers. Donor detachment rate (8.6% vs. 8.9%) was similar in both groups without primary graft failures. Conclusions The BCL interface technique is a simple and safe technique for stamping DMEK grafts. Anterior corneal tissues can be used for additional keratoplasties during donor shortage.

PURPOSE The purpose of this study was to report the indications, ocular and systemic comorbidities, and surgical outcomes of corneal transplantation in patients older than 90 years. METHODS A retrospective review was conducted to identify individuals 90 years and older who underwent corneal transplantation surgery at the Bascom Palmer Eye Institute between January 2013 and October 2020. Outcomes included best-corrected visual acuity and graft survival over time. Paired t tests were used to compare visual acuity preoperatively versus postoperatively. Graft survival was evaluated with Kaplan-Meier curves. RESULTS Fifty-eight eyes of 52 consecutive individuals were included. The mean age of individuals was 92 ± 2 years; 26.9% were male; and 48.1% self-identified as non-Hispanic White and 38.5% as Hispanic. Postoperative follow-up was 14.7 ± 12.1 months. Of the 58 eyes, 44.8% (26/58) underwent penetrating keratoplasty, 46.6% (27/58) Descemet stripping automated endothelial keratoplasty, and 6.9% (4/58) keratoprosthesis. All surgeries were performed under monitored local anesthesia, without major complications. Surgical indications included pseudophakic bullous keratopathy (36.2%), glaucoma-associated corneal decompensation (27.6%), Fuchs endothelial dystrophy (25.9%), and perforated corneal ulceration (19.0%). The best-corrected visual acuity improved by 0.32 (95% confidence interval 0.14-0.50; P < 0.01) as early as 1 month postoperatively, and vision gains were sustained for at least 12 months. Graft survival probability at 12 months was 88%. CONCLUSIONS Corneal transplantation is a safe and successful procedure in restoring the visual acuity for patients older than 90 years after careful preoperative evaluation. Further research is needed to evaluate the impact of corneal transplantation on quality of life in patients in the 10th decade of life.

AIM: To investigate the safety of vitreoretinal surgery when using a soft contact lens as a temporary keratoprosthesis (TKP) in patients with severe corneal opacifications. METHODS: Three patients with simultaneous corneal and vitreoretinal pathology were treated with a soft contact lens that was used as a TKP to facilitate vitreoretinal surgery. The soft contact lens was fixated with sutures onto the globe so that no leakage was possible. RESULTS: Vitreoretinal surgery with excellent fundus view was possible in all cases. The soft contact lens allowed safe central and peripheral vitrectomy. Surgery was successful in all cases. CONCLUSION: A soft contact lens properly fixated on the globe can successfully replace a TKP. This surgical procedure has several advantages like one size fits all, low costs, and easy access to the material.

Face is the mirror of the mind and the eyes serves as a window to the soul. The sensory system is accountable for providing information to the brain regarding where the body appears in reference to the horizon. Poor vision may lead to loss of balance. Corneal disease is the second most common cause of blindness in the world and occurs in association with a severely damaged corneal and ocular surface. Osteo-Odonto Keratoprosthesis (OOKP) is a surgical procedure to restore vision where the diseased cornea is replaced with an artificial cornea. OOKP consists of autologous tissue derived from tooth and bone that surrounds a central PMMA Optic (Poly Methyl Methacrylate). This review discusses the types, parts, indications, contraindications, surgical techniques and complications of Osteo-Odonto Keratoprosthesis.

Purpose: Suprachoroidal hemorrhage (SCH) is a rare but vision-threatening complication in patients with keratoprosthesis devices (KPro), particularly in the setting of concurrent glaucoma tube shunts. Although there are many approaches to draining an SCH, surgery can be especially challenging in these patients because a crowded anterior chamber, and frequent anterior extension of the SCH. Methods: A case report is discussed. Results: We describe a novel approach to surgical drainage of SCH in a 64-year-old monocular patient with a Type I Boston KPro, an Ahmed valve, and aphakia. Conclusion: Successful repair of appositional SCH in the context of KPro can be safely and effectively achieved by injecting viscoelastic through the backplate holes of the KPro, thereby providing internal tamponade within the vitreous compartment while liquefied hemorrhage is drained by sclerotomy.

Purpose To evaluate long-term anatomical and functional outcomes of the MICOF keratoprosthesis to treat end-stage corneal blindness. Design Retrospective review of consecutive clinical case series. Participants Between October 2000 and October 2015, at the Department of Ophthalmology of Chinese PLA General Hospital (PLAGH), a total of 132 eyes of 131 patients had undergone a MICOF keratoprosthesis implantation. Of those, 91 eyes of 90 patients were included in this study. Methods Preoperative information, surgical procedures, and postoperative data were collected for each included eye. Main outcome measures Best-corrected visual acuity (BCVA), keratoprosthesis retention, and significant postoperative complications were reported. Results The most common indications for surgery were chemical or thermal burns (68.1%, 62 of 91 eyes) and explosive injury (12.1%, 11 of 91 eyes), followed by Stevens-Johnson Syndrome (10.0%, 9 of 91 eyes), Sjogren's syndrome (4.4%, 4 of 91 eyes), mucous membrane pemphigoid (3.3%, 3 of 91 eyes) and multi-penetrating keratoplasty failure (2.2%, 2 of 91 eyes). The mean follow-up duration was 8.38 ± 3.22 years (range: 5–17.25 years, median: 7.67 years). All patbients had a preoperative visual acuity of hand motions or worse. A MICOF keratoprosthesis significantly improved patients' visual function with bilateral end-stage corneal blindness. Postoperative visual acuity improved to 20/200 or better in 41 eyes (45.1%, of 91 eyes) and to 20/100 or better in 32 eyes (35.2% of 91 eyes) at the last follow-up visit. Preexisting glaucoma was present in 17 (18.7% of 91 eyes). The most common postoperative complications were overgrowth of the surface mucosa (31.9%, 29 of 91 eyes), glaucoma (25.3%, 23 of 91 eyes), retro-prosthetic membrane (15.4%, 14 of 91 eyes), keratoprosthesis device extrusion (15.4%, 14 of 91 eyes), superficial tissue thinning (14.3%, 13 of 91 eyes), endophthalmitis (13.2%, 12 of 91 eyes), titanium frame exposure (13.2%, 12 of 91 eyes), optical cylinder ante-displacement (13.2%, 12 of 91 eyes), cornea melting (7.7%, 7 of 91 eyes), retinal detachment (6.6%, 6 of 91 eyes) and aqueous humour leakage (2.2%, 2 of 91 eyes). 84.6% (77 of 91 eyes) of the eyes retained their initial keratoprosthesis at the latest follow-up. Conclusions A MICOF keratoprosthesis is a reliable approach to rescue vision in end-stage corneal blinded patients and has better retention than a Boston Kpro TypeⅡ.

Purpose: to evaluate the results of spontaneous non-penetrating keratoprosthesis with a Fedorov — Zuev prosthesis in a patient with severe chemical burns in both eyes. Material and methods.Patient K., 38, who had sustained a severe burn injury in the past and numerous reconstructive plastic operations on both eyes (amniotic tissue implantation, allolymbal transplantation, layer-by-layer and penetrative keratoplasty, cataract extraction with IOL implantation, total auto-conjunctival corneal plastic surgery) with no functional effect, was subjected to a multi-stage keratoprosthesis of the left eye according to the method practiced by the Helmholtz National Medical Research Center of Eye Diseases. Results.After one of the stages (implantation of the haptic part of the keratoprosthesis with a temporary cylindrical plug), an aseptic necrosis of the tissue above the cylinder occurred. As a result, an unexpected functional effect was revealed: visual acuity of the operated eye 0.02 sph -20.0 D = 0.2. During a dynamic follow-up that lasts 2.5 years, visual acuity remains stable, and the corneallayers behind the cylinder retain transparency. During this time, all stages of keratoprosthesis were performed on the fellow eye with a functional result of 1.0. Conclusion. The long-term result of spontaneous non-penetrating keratoprosthesis indicates the need to study the prospects and develop a method of non-penetrating keratoprosthesis with a Fedorov — Zuyev prosthesis.

Purpose The Boston keratoprosthesis (KPro) has been used for certain indications in pediatric patients with congenital corneal opacities. Here, we describe the use of a near-complete conjunctival flap at the time of Boston type 1 KPro surgery in pediatric patients, with the goal of improving pediatric KPro outcomes. Methods We performed a retrospective chart review of 21 eyes from 16 patients who received their first KPro before the age of 18 years at a tertiary care center in Rochester, NY. Surgeries were performed between 2011 and 2017 (3 years before and after the incorporation of a conjunctival flap, which began in 2014 as part of the pediatric KPro procedure). Patients who had a minimum 1-year postoperative follow-up, or had corneal melts within 1 year of KPro implantation, were included in our study. The main outcome measure in this study was a comparison of the number of complications that required surgical intervention, including retroprosthetic membrane, corneal melt, retinal detachment, and endophthalmitis, in eyes that received KPro implantation without a conjunctival flap compared with eyes that received KPro implantation with a conjunctival flap. Change in the visual acuity up to 1 year postoperatively was also measured. Results Ten eyes received KPro with no conjunctival flap, and 11 eyes received KPro with a near-complete conjunctival flap. After 1-year postoperative follow-up, eyes receiving a KPro with a conjunctival flap had fewer KPro-related complications requiring surgical intervention (5 vs. 16, P = 0.0002). Corneal melt was seen in 2 of 11 (18%) eyes in the conjunctival flap group and 5 of 10 (50%) eyes in the nonflap group (P = 0.12). No eyes developed endophthalmitis in the flap group, whereas 1 of 10 (10%) eyes developed endophthalmitis in the nonflap group. Visual acuity at 1-year follow-up improved in 9 of 11 (82%) eyes in the flap group compared with 5 of 10 (50%) eyes in the nonflap group (P = 0.3). Conclusions Implementation of a conjunctival flap in pediatric KPro may help decrease the short-term postoperative complications requiring surgical procedures and may lead to improved visual acuity after 1 year. Further investigation, including longer-term follow-up, is needed to better understand how the described technique affects surgical outcomes in children.

Background/aimsTo evaluate the time needed for patients with Boston type 1 keratoprosthesis (KPro) to reach their best-corrected visual acuity (BCVA) and all contributing factors.MethodsWe retrospectively reviewed 137 consecutive eyes from 118 patients, measured how long they needed to reach their BCVA and looked at factors that might affect this time duration including patient demographics, ocular comorbidities and postoperative complications.ResultsThe mean follow-up was 5.49 years. The median time to BCVA postoperatively was 6 months, with 47% of patients achieving their BCVA by 3 months. The mean best achieved logMAR visual acuity was 0.71, representing a gain of 6 lines on the Snellen visual acuity chart. Postoperative glaucoma, retroprosthetic membrane (RPM) and endophthalmitis prolonged this duration. We found no correlation between the following factors and time to BCVA: gender, age, indication for KPro surgery, primary versus secondary KPro, number of previous penetrating keratoplasties, previous retinal surgery, intraoperative anterior vitrectomy and preoperative glaucoma.ConclusionIn our retrospective cohort, the majority of subjects reached their BCVA between 3 and 6 months after KPro implantation. This duration was significantly prolonged by the development of postoperative glaucoma, RPM and endophthalmitis.

Endophthalmitis following keratoprosthesis could lead to permanent loss of vision and the eye. It needs systematic management and close follow-ups as the outcome is unpredictable. We present two cases of endophthalmitis following type I Boston keratoprosthesis (KPro). Both of our patients had lost one eye while the other eye developed endophthalmitis after they underwent prosthokeratoplasty. They were aggressively treated with topical and oral antibiotics with close follow-ups. Vitreous cultures were obtained, and intravitreal antibiotics were given. The endophthalmitis resolved with a dramatically improved vision.

Objective To report three consecutive cases with noninfectious corneal melting, whose disease progression could only be halted with tumor necrosis-α (TNF-α) inhibitor infusion, with a review of the relevant literature. Materials and methods Patients with toxic epidermal necrolysis, severe alkaline burn, and Sjogren syndrome had experienced severe corneal melting following penetrating keratoplasty, Boston type 1 keratoprosthesis implantation or spontaneously, respectively. Topical autologous serum eye-drops, medroxyprogesterone, and acetylcysteine formulations; frequent nonpreserved lubrication; systemic tetracyclines and vitamin-C supplements; topical and systemic steroids and steroid-sparing agents; surgical approaches including amniotic membrane transplantation, tectonic graft surgery; and tarsorraphy failed to alter the disease courses. Results Upon consultation with the rheumatology clinic, TNF-α inhibitor infliximab (Remicade; Centocor Ortho Biotech Inc, Horsham, PA) 5 mg/kg infusion was planned for each patient. After 0-, 2-, and 6-week doses, monthly infusion at the same dose was maintained for 12 months because of severe and intractable course of their diseases. Each case showed dramatic improvements in corneal melts; and sterile vitritis in the eye with Boston keratoprosthesis responded, as well. Conclusions Inhibiting TNF-α-mediated expression of matrix metalloproteinases responsible for collagen breakdown should be considered in refractory cases, as a means of globe salvage.

The review presents an analysis of clinical trials results for autologous cultured oral mucosal epithelium transplantation (COMET) in patients with bilateral corneal limbal stem cell deficiency (LSCD) over the past 15 years. Detailed characteristics and evaluation are given for anatomical outcomes, visual acuity changes, and complication rates. The results obtained during the analysis confirm the consistency of the concept of corneal re-epithelization by means of COMET. COMET promoted persistent corneal re-epithelization in 81.5% of cases, and visual acuity improvement in 78.8% of patients with LSCD. COMET does not require systemic immunosuppression, and it is accompanied by much smaller numbers and significantly lower grades of complications compared with keratoprosthesis. About 15% of patients experienced developing superficial peripheral corneal neovascularization regressed spontaneously by 12 months of observation. Based on the COMET clinical trials results, the management of patients with bilateral LSCD is under optimization by reference to the pathogenesis of the underlying disease. Thus, autologous cultured oral mucosal epithelium transplantation seems promising for further studies and introduction into routine clinical practice. Key words: limbal stem cell deficiency, ocular surface reconstruction, corneal epithelium, oral mucosal epithelium, transplantation.

We report three cases of bilateral microsporidial keratitis, which is an unusual presentation. All three patients presented with bilateral, simultaneous, asymmetrical, deep stromal corneal infiltrates with symptoms ranging from 5 to 12 months. Predisposing factors were noted in two of three patients. Corneal scrapings for microbiology and histopathology of corneal tissue revealed microsporidial spores from both eyes of all patients. There was no response to medical therapy and all underwent bilateral corneal transplantation. Case one additionally had recurrences in the graft and underwent repeat keratoplasties and eventually keratoprosthesis. Microsporidial stromal keratitis is a possible cause of keratitis in cases of very long-standing, indolent, culture-negative, deep stromal corneal infiltrates. So far, this infection has been reported as unilateral; however, we report these cases of bilateral infection, which is rare. Corneal transplantation is the preferred line of management due to lack of response to medical therapy.

Purpose Vitreoretinal surgery in eyes with Boston type 1 keratoprosthesis (KPro) is challenging due to narrow optic of the KPro. This study analyzed the results of pars plana vitrectomy (PPV) using a wide-field imaging accessory, Resight (R) 700 Fundus Viewing System (Carl Zeiss Meditec, Inc., Germany), for better intraoperative peripheral retinal imaging. Methods In this retrospective case series, KPro patients who underwent simultaneous or sequential PPV at Dokuz Eylul University Hospital between June 2010 and January 2020 were evaluated in terms of anatomic and visual prognoses, as well as KPro- and PPV-associated complications. Results Among 9 KPro eyes that necessitated vitreoretinal surgery, 3 (33.3%) underwent simultaneous KPro and PPV due to proliferative vitreoretinopaties; 6 (66.7%) underwent PPV for retinal detachment or suprachoroidal hemorrhage that appeared after KPro surgery. Retina could be attached in 7 eyes (77.8%), and vision improved in 3 eyes (33.3%). In 1 eye, injected silicone oil moved to subconjunctival area through glaucoma drainage device. Conclusion In eyes with a Boston KPro, wide-angle viewing systems helped handling peripheral retinal problems successfully during PPV, with no observed inadequacy of imaging. Despite anatomical success in most cases, visual prognosis depends on vitality of the macula and the optic disc.

Background/AimsWe analysed the ability of B-scan ultrasound, ocular electrophysiology testing and videoendoscopic examination for predicting visual prognosis in Boston Type 1 keratoprosthesis (KPro-1) candidates. Indirect anatomical and electrophysiological findings and results from direct endoscopic evaluations were correlated with postoperative functional data.MethodsIn this prospective and interventional study, we included 13 individuals who had previously been indicated for Kpro-1 surgery. All subjects underwent preoperative screening, including ophthalmic evaluation, B-scan ultrasound, electrophysiological testing, and perioperative intraocular videoendoscopic evaluation (VE). B-scan ultrasound, electrophysiological testing, and VE evaluation results were categorised as favourable or unfavourable predictors of postoperative functional results according to predefined criteria. The predictability values of B-scan ultrasound, electrophysiological testing, and VE prognostication were calculated based on the visual acuity level achieved.ResultsAll surgeries and perioperative VEs were uneventful. Preoperative best-corrected visual acuity (BCVA) ranged from light perception to counting fingers. The 1-year postoperative BCVA was better than 20/200 (satisfactory visual acuity result) in 10 eyes (76.9%) and 20/40 or better in 5 eyes (38.5%). B-scan ultrasound presented a positive predictive value (PPV) of 85.7% for satisfactory postoperative visual acuity, electroretinography showed a PPV of 66.7%, and visual evoked potential presented a PPV of 66.7%. The perioperative VE PPV of a negative finding for satisfactory visual acuity was 100%.ConclusionsFundoscopic visualisation by intraocular VE is a minimally invasive procedure that can be used to predict functional outcomes in keratoprosthesis candidates. This technique demonstrated better prognostication in keratoprosthesis candidates than B-scan ultrasound and electrophysiological testing.

Aim: To analyze the incidence, microbiological profile, risk factors, and outcomes in eyes with osteo-odonto keratoprosthesis (OOKP) developing endophthalmitis. Methods & material: Retrospective re...

To study the long-term visual- and device retention-related outcomes and complications of the Boston Type I Keratoprosthesis (KPro).Single-center, retrospective cohort study of all patients undergoing KPro implantation from February 2007 to April 2014 with at least 5 years of follow-up.68 eyes from 65 patients underwent KPro implantation during the study period. At 5 and 10 years, the probability of maintaining or improving visual acuity (VA) was 75.0% and 66.7%, respectively, and the probability of KPro retention was 89.2% and 89.2%, respectively. Initial device retention rate at 10 years was significantly lower in those with underlying ocular surface disease (46.8% [30.6-63.2] vs 75.8% [61.0-90.7], P = 0.03), while other baseline characteristics showed no significant association. Final VA was more likely to be stable or improved in patients with fewer failed grafts (2 [1-6] vs 3 [1-6], P 0.01), and a final VA of 20/200 or better was more likely in primary KPro eyes (44.8% [26.7-62.9] vs 19.4% [6.5-32.3], P = 0.03). Combined KPro-vitrectomy eyes were more likely to have stable or improved final VA than non-vitrectomy eyes (88.5% [76.2-100.0] vs 64.1% [49.1-79.1], P = 0.04). All complications had increasing incidence beyond 5 years; in particular, corneal melt, surgical glaucoma interventions, and endophthalmitis tended to have late presentations, with 79.0%, 78.6%, and 88.9% of these complications occurring beyond one year, respectively.KPro devices show favorable long-term visual and retention outcomes in select patients. Careful long-term, multidisciplinary follow-up is warranted to address potential complications.

Purpose To evaluate outcomes of Boston keratoprosthesis (KPro) repair versus repeat KPro as treatment for corneal melt in KPro patients. Methods Retrospective study of adult KPro patients with melt managed by KPro repair or repeat KPro by one surgeon (MH-D). Incidence of sight- or globe-threatening complications, risk of recurrence of melt and change in BCVA before and 3 months after the procedure were compared between both treatment groups. Change from pre-melt BCVA to final BCVA was compared between primary versus secondary repeat KPro after repair attempt. Results This study included 19 eyes of 19 patients with melt and mean follow-up of 8.7 years. Primary repeat KPro was performed in 6 eyes (32%) and KPro repair in 13 eyes (68%). There were no significant differences in gender, age, or incidence of complications after KPro repair versus after repeat KPro (92% and 83% complication rate respectively, p > 0.05). The odds ratio for melt recurrence after KPro repair versus repeat KPro was 24 (95% CI 1.68–340). Change in BCVA was not significantly different in KPro repair versus repeat KPro nor in primary versus secondary repeat KPro (p > 0.05). Conclusions Repeat KPro offers a lower risk of recurrence of melt compared to KPro repair. However, repair may be considered when timely access to a new KPro and corneal graft is not possible. Delaying repeat KPro does not significantly affect final BCVA. Finally, repeat KPro is the only effective treatment when melt has led to extrusion or uncontrollable infection.

Keratoprosthesis (KPro) devices have the remarkable ability to restore vision in patients suffering from corneal blindness who are poor candidates for traditional penetrating keratoplasty. However, eyes with KPro can experience various complications, including the development of retroprosthetic membrane (RPM). RPMs reduce visual acuity in patients due to physical obstruction of the visual axis, but studies have shown that RPM can also lead to a variety of other consequences, from melting of the corneal carrier graft to precipitating retinal detachments. Histopathologic studies have shown that RPMs are composed of elements from both the recipient and donor. The presence of myofibroblasts in RPMs imparts them with contractile properties, which can contribute to their downstream complications, including angle closure, hypotony, and retinal detachment. At present, there are limited treatments to combat the growth of RPM. Future therapies could include anti-metabolites and targeted anti-inflammatory treatments, as well as device coatings or textured device surfaces that can hinder RPM proliferation. The long-term success of KPro depends on devising an effective solution for preventing RPM growth.

Keratoprosthesis is used for corneal transplantation in high-risk patients who require penetrating keratoplasty (PKP). Boston keratoprosthesis (BKpro) is a representative type of keratoprosthesis used worldwide. In Japan, the first BKpro was implanted in an eye after multiple corneal graft failures in 2008, but its use remains limited. A recent patient survey revealed that among the Japanese patients who had previously undergone multiple PKPs, the retention rate of BKpro was significantly higher than that of PKP at 5 years postoperatively (100% vs. 26%; P < 0.01). Patients with implanted BKpro also had better best corrected visual acuity of 20/200 or higher than those with PKP at 5 years postoperatively (80.0% vs. 17.6%; P = 0.03). Regarding the postoperative complications, retroprosthetic membrane formation was observed in 88.9%, infectious keratitis in 33.3%, and glaucoma progression in 11.1% of cases. Another retrospective analysis showed that fungal keratitis occurred in 0.09 patients per year and severely affected visual acuity. Furthermore, because it is difficult to accurately examine intraocular pressure after BKpro implantation, the intraocular pressure of patients with implanted BKpro was prospectively estimated using a transpalpebral tonometer (Diaton). In conclusion, BKpro implantation is effective and safe for Japanese patients, given the reported improvements in visual acuity and low rates of complications.

Currently, many corneal diseases are treated by corneal transplantation, artificial corneal implantation or, in severe cases, keratoprosthesis. Owing to the shortage of cornea donors and the risks involved with artificial corneal implants, such as infection transmission, researchers continually seek new approaches for corneal regeneration. Corneal tissue engineering is a promising approach that has attracted much attention from researchers and is focused on regenerative strategies using various biomaterials in combination with different cell types. These constructs should have the ability to mimic the native tissue microenvironment and present suitable optical, mechanical and biological properties. In this article, we review studies that have focused on the current clinical techniques for corneal replacement. We also describe tissue-engineering and cell-based approaches for corneal regeneration.

Purpose In recent decades, the medical and surgical treatment of limbal stem cell deficiency (LSCD) has evolved significantly through the incorporation of innovative pharmacological strategies, surgical techniques, bioengineering, and cell therapy. With such a wide variety of options, there is a need to establish a global consensus on the preferred approaches for the medical and surgical treatment of LSCD. Methods An international LSCD Working Group was established by the Cornea Society in 2012 and divided into subcommittees. Four face-to-face meetings, frequent email discussions, and teleconferences were conducted since then to reach agreement on a strategic plan and methods after a comprehensive literature search. A writing group drafted the current study. Results A consensus in the medical and surgical management of LSCD was reached by the Working Group. Optimization of the ocular surface by eyelid and conjunctival reconstruction, antiinflammatory therapy, dry eye and meibomian gland dysfunction treatment, minimization of ocular surface toxicity from medications, topical medications that promote epithelialization, and use of a scleral lens is considered essential before surgical treatment of LSCD. Depending on the laterality, cause, and stage of LSCD, surgical strategies including conjunctival epitheliectomy, amniotic membrane transplantation, transplantation of limbal stem cells using different techniques and sources (allogeneic vs. autologous vs. ex vivo-cultivated), transplantation of oral mucosal epithelium, and keratoprosthesis can be performed as treatment. A stepwise flowchart for use in treatment decision-making was established. Conclusions This global consensus provides an up-to-date and comprehensive framework for the management of LSCD.

Gamma-irradiated sterile cornea (GISC) is a relatively new graft tissue that follows the 30-year success of irradiation to other tissues (bone and sclera) to lessen antigenic load and infection transmission. It can serve as a graft to cover glaucoma drainage devices, as graft tissue for frank or impending corneal perforations in tectonic keratoplasty, as graft tissue in lamellar keratoplasty, and as carrier tissue for keratoprosthesis. With the limited availability of fresh corneal tissue in less developed countries, GISC may fill a need for corneal tissue worldwide. It can be used in situations where corneal endothelium is not needed and with a greatly reduced risk of rejection and infection because of the effect of irradiation on corneal tissue.

This short report includes 5 eyes of 5 patients (mean age 63.2 ± 12 years) who underwent a tectonic keratoplasty [deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PK)] in order to rehabilitate the eye after the extrusion of the non-perforating keratoprosthesis (Kpro) KeraKlear (KeraMed, USA). The non-perforating Kpro was extruded after a mean period of 21.4 ± 21.8 months due to melting. In two cases, the keratoplasty was performed the same day of the non-perforating Kpro removal due to a severe melting, while in the other three cases it was performed one to 3 months later. Two eyes received a DALK, but in 3 eyes a macroscopic Descemet membrane perforation forced the conversion into a PK. The mean follow-up period after the keratoplasty was 16.8 ± 6.6 months. No cases of rejection were recorded. All the 5 eyes achieved “anatomical success” (transparent graft, with no signs of infection or inflammation). Two eyes showed limited “functional success” because the achievement of the best visual potential was prevented by the development of glaucomatous optic atrophy during the follow-up period. In conclusion, this short report presents an unexpected success of a keratoplasty performed with a tectonic purpose after the extrusion of the non-perforating Kpro because the corneal graft remained transparent, without neovascularization or scarring during the follow-up period. This initial evidence shows some encouraging results regarding graft survival rate and the achievement of a useful visual rehabilitation with keratoplasty after a non-perforating Kpro failure instead of repeating the Kpro implantation.

Purpose To study the mucosal complications of osteo-odonto-keratoprosthesis (OOKP) surgery from the UK national keratoprosthesis cohort. Methods A retrospective study was conducted at the Sussex Eye Hospital, Brighton, UK. The case records of patients who underwent OOKP surgery were reviewed and analysed. Results The cohort contained 64 patients, among which 25 were females and 39 were males. Eyelid and adnexal abnormalities were treated in 69% of the cases prior to OOKP surgery. Mucosal graft complications after OOKP affected 46% of the cases after stage 1 and 22% after stage 2. Most of the complications were observed in cases with autoimmune conditions like Stevens-Johnson syndrome (43% post-stage 1, 59% post-stage 2) and cicatrising conjunctivitis (31% post-stage 1, 20% post-stage 2). On the contrary, mucosal overgrowth covering the anterior surface of the optic, which was noted in 28% of the cases, was a common complication after stage 2. Thinning and ulceration of the mucosa was noted in 22% of cases after stage 2. Laminar exposure due to mucosal ulcers was identified in 11 cases. The central part of the mucosa was frequently affected by thinning and ulceration after stage 1. The mucosa overlying the supero-nasal corner of the lamina was eroded commonly after stage 2 leading to exposure of the lamina. Mucosal thinning after stage 1 was treated with conservative measures such as observation and increased lubrication in 15 cases, and with surgical procedures in 7 cases. Post-stage 1 mucosal ulcers were mostly treated by surgery (7 out of 8 cases). Following stage 2, minor cases of mucosal ulcers and thinning and three cases of overgrowth were conservatively treated with lubrication and observation. However, 18 cases of overgrowth required surgical excision. All cases of lamina exposing ulcers were surgically treated. Surgical treatment of mucosal defects included mucosal grafts, flaps and eyelid corrections. Fusion of the eyelids and conversion to a trans-palpebral OOKP were performed in two cases to treat resistant mucosal ulcers. Two eyes lost lamina as a consequence of lamina exposing ulcers. One lamina was explanted due to severe resorption and one due to infection. Conclusion The majority of surgical revisions following OOKP surgery are due to mucosal problems, such as mucosal thinning and ulcerations. These may be treated with increased lubrication of the mucosa or surgical closure of the defects. Mucosal defects resulting in laminar exposure can be a serious threat to laminal viability, and must be treated promptly and aggressively.

The use of Boston type 1 keratoprosthesis (BKPro) has significantly increased worldwide. It is no longer considered a procedure of last resort but a reasonable option for patients with otherwise poor prognosis for a traditional penetrating keratoplasty. BKPro was approved by the Food and Drug Administration in 1992 for bilateral severe corneal blindness due to multiple corneal transplant failure. Over the years, indications have extended beyond recurrent immunologic rejection to include other conditions such as chemical injury and other causes of bilateral limbal stem cell deficiency, extensive corneal neovascularization, neurotrophic corneas and hypotony, among others. Numerous advances in the design of the BKPro, improvement of preoperative, intraoperative and postoperative management have resulted in favorable outcomes and a reduction in postoperative complications. Accordingly, many studies have shown that implantation of this device is highly effective in restoring vision with very good short-term outcomes. However, due to the lifetime risk of sight-threatening complications after BKPro implantation, a longer follow-up period should provide outcomes that are more realistic. In this review, the authors examined only the results of publications with an average of at least 2 years of follow-up. The overall intermediate to long-term visual outcomes and retention rate in BKPro seem to be favorable. However, autoimmune diseases and cicatrizing conditions continue to show a higher incidence of postoperative complications that require further management.

We evaluated the visual outcome of combined penetrating keratoplasty (PKP) and 25G pars plana vitrectomy (PPV) performed without a temporary keratoprosthesis or endoscopy in a patient with vitreoretinal disease complicated by severe corneal opacity. The patient was a 68-year-old woman who had severe corneal opacity and silicone oil in her left eye after several previous intraocular surgeries for rhegmatogenous retinal detachment and proliferative vitreoretinopathy. We successfully performed a combined surgery of conventional PKP followed by 25G PPV without the use of a keratoprosthesis.At 6 months after surgery, visual acuity had not improved, and the density of corneal endothelial cells of the donor cornea had declined from 3,205 to 1,969 cells/mm2. However, corneal transparency remained good, and additional surgery for vitreoretinal disease was not necessary. The combined surgical procedure designed to minimize the number of open-sky steps and to limit vitreoretinal complications thus proved to be safe and achieved stable corneal clarity in a patient with vitreoretinal disease and severe corneal opacity.

Introduction: Mooren’s ulcer is a painful, inflammatory chronic keratitis that affects corneal periphery, progressing centripetally, ultimately ending in perforation. The first line of treatment includes systemic immunomodulators, with surgery being the last option. We present a case of bilateral Boston keratoprosthesis implantation for severe Mooren’s ulcer that responded differently in each eye. Clinical case: A 32-year-old male with corneal opacification, anterior staphylomas, vision of hand movement, was started on systemic immunosuppression with cyclosporine. After two failed penetrating keratoplasties in each eye, high intraocular pressure despite diode cyclophotocoagulation, and cystic macular edema, we performed Boston keratoprosthesis type 1 in both eyes. The right eye responded initially well, with a best-corrected visual acuity of 20/80 and normal intraocular pressure. The left eye presented high intraocular pressure, which required cyclophotocoagulation, ultimately resulting in hypotony. Boston keratoprosthesis was performed but had peripheral corneal necrosis that progressed despite amniotic membrane transplantation and aggressive intensive treatment with medroxyprogesterone, autologous platelet-rich-in-growth-factors eye drops, and oral doxycycline. Thus, replacement of the semi-exposed Boston keratoprosthesis with tectonic penetrating keratoplasty was necessary. However, both eyes developed phthisis bulbi with final visual acuity of perception of light with poor localization. Conclusion: Mainstay treatment of Mooren’s ulcer is systemic immunomodulation. Surgical treatment must be considered only when risk of perforation, preferably with inflammation under control. Penetrating keratoplasty frequently fails, and Boston keratoprosthesis may be a viable option. However, postoperative complications, especially uncontrolled high intraocular pressure, corneal necrosis, and recurrence of Mooren’s ulcer may jeopardize the outcomes and need to be addressed promptly with intensive topical and systemic treatment.

This is a case report on the use of Eckardt keratoprosthesis for pars plana vitrectomy in a patient with endophthalmitis and suppurative keratitis that developed after cataract surgery. A 79-year-old woman developed acute-onset infectious endophthalmitis and suppurative keratitis after cataract surgery that failed to respond to treatment with antibiotic eyedrops and intravitreal antibiotic injection. Using a temporary keratoprosthesis that enabled sufficient visualization, vitrectomy was performed, followed by therapeutic keratoplasty using a cryopreserved donor cornea. The patient's vision was improved from light perception to counting fingers at 30 cm, 3 months postoperatively. There was no recurrence of infection or other significant complications.

Purpose To report the first histopathological examination of an explanted KeraKlear keratoprosthesis device and surrounding host corneal tissue 1 year after transplantation. Methods An explanted KeraKlear artificial cornea was evaluated by histopathology to assess for tissue integration and corneal remolding. Results Histopathological examination revealed collagenous ingrowth between the anterior and posterior corneal stromal lamellae through the holes in the device skirt. Hematoxylin and eosin stain (H&E), periodic acid Schiff (PAS), and Masson trichrome stains demonstrated no significant inflammation, vascularization, or edema. Conclusions The KeraKlear artificial corneal device seems to be a biocompatible alternative to donor corneal tissues for visual rehabilitation for suitable patients.

PURPOSE: Corneal opacity is a leading cause of reversible blindness worldwide. An electronic corneal prosthesis, or intraocular projector, could potentially restore high-quality vision without need for corneal clarity. MATERIALS AND METHODS: Four intraocular projection systems were constructed from commercially available electronic components and encased in biocompatible plastic housing. They were tested for optical properties, biocompatibility, heat dissipation, waterproofing and accelerated wear. A surgical implantation technique was developed. RESULTS: Intraocular projectors were produced of a size that can fit within the eye. Their optics produce better than 20/200 equivalent visual acuity. MTT assay demonstrated no cytotoxicity of devices in vitro. Temperature testing demonstrated less than 2° C increase in temperature after one hour. 3 devices lasted over 12 weeks under accelerated wear conditions. Implantation surgery was demonstrated via corneal trephination insertion in a cadaver eye. CONCLUSION: This is the first study to demonstrate and characterize fully functional intraocular projection systems. This technology has the potential to be an important new tool in the treatment of intractable corneal blindness.

Purpose The aim of this study was to evaluate the preliminary results of osteo-odonto keratoprosthesis (OOKP) performed in Alexandria Main University Hospital, Alexandria, Egypt in eyes with end-stage cicatrizing conjunctivitis. Patients and methods OOKP surgery was done in two stages. Stage 1 included preparation of the globe, buccal mucous membrane harvesting, and preparation of osteo-odonto alveolar lamina with the cemented optical cylinder. The prepared lamina was then placed in the submuscular space for 2–3 months. In stage 2, the lamina–optical cylinder complex was implanted under the buccal mucous membrane and the posterior part of the optical cylinder was placed in a central corneal opening to act as an artificial cornea, transmitting image to the retina. Results Six eyes with end-stage ocular surface disease were included in this study. Anatomical success, in the form of retention of the prosthesis, was achieved in five eyes. The procedure failed in one eye due to unhealthy canines with a small amount of bone in the lamina. Functional success, defined as restoration of vision, was achieved in four eyes. Visual improvement was not attained in one eye (in addition to the eye with anatomical failure) due to optic atrophy despite good retention of the device. Conclusion OOKP is a promising procedure to regain vision in severe cases of end-stage corneal blindness, unsuitable for cadaveric corneal grafts. Proper selection of cases is crucial to achieve the best anatomical and functional results.

Periorbital burns generate contraction and distortion of periorbital soft tissue, causing eyelid malfunction, further contributing to loss of vision from corneal scarring or perforation. We present our multidisciplinary algorithm to restore vision in patients with burn-related bilateral corneal blindness with light perception. Chart review was performed for four consecutive burn patients requiring periocular reconstruction and keratoprosthesis. Initial treatment included globe coverage with eyelid releases and grafts. Strategy of corneal replacement was determined by eyelid position and function and sufficiency of tear production. All patients were corneal blind with light perception only and cicatricial ectropion. The eye with better visual prognosis was reconstructed. Eyelid reconstruction procedures consisted of lid releases with full-thickness skin graft (FTSG) or split-thickness skin graft (STSG). Two patients regained adequate lid function and underwent standard keratoprosthesis placement. Two underwent mucous membrane grafts followed by keratoprosthesis. All patients experienced improved postoperative vision in their reconstructed eye. Corneal injury due to periocular burns can lead to blindness. Early involvement of ophthalmology, protective measures, and early ectropion release are critical. For severe burns, a multidisciplinary approach, where adequate globe protection is followed by keratoprosthesis placement, can effectively restore vision in patients with burn-related corneal blindness.

PURPOSE To quantitatively analyze the angle anatomy in eyes with a Boston type 1 keratoprosthesis (KPro) using anterior segment optical coherence tomography (AS-OCT) and to assess the diagnostic ability of AS-OCT in KPro-associated glaucoma. METHODS AS-OCT (RTVue) images from KPro eyes with and without glaucoma were reviewed. The angle opening distance at 500 μm from the scleral spur (AOD500), trabecular-iris angle at 500 μm from the scleral spur (TIA500), and trabecular-iris surface area at 500 μm from the scleral spur (TISA500) were measured by 2 observers masked to the diagnosis. The measurements for each visible quadrant were compared between KPro eyes with and without glaucoma. RESULTS Twenty-two eyes with glaucoma and 17 eyes without glaucoma from 39 patients with KPro were included. Of the 4 quadrants imaged, the temporal angle was the most visible (79.5%) and angle measurements of the temporal quadrant were the only ones that differentiated the 2 groups: the mean AOD500, TIA500, and TISA500 were significantly lower in KPro eyes with glaucoma than without glaucoma (388.2 ± 234.4 μm vs. 624.5 ± 310.5 μm, P = 0.02; 26.1 ± 14.0 degrees vs. 39.1 ± 17.1 degrees, P = 0.03; and 0.15 ± 0.09 mm vs. 0.23 ± 0.12 mm, P = 0.03; respectively). The highest area under the receiver operating characteristic curve for detecting glaucoma was 0.75 for temporal TIA500 (95% confidence interval 0.57-0.94, P = 0.02) with 50% specificity at 80% of sensitivity and a cutoff value of 37 degrees. CONCLUSIONS The temporal angle was the most visible on AS-OCT in eyes with a KPro. Significant narrowing of the temporal angle detected on AS-OCT was associated with glaucoma in these eyes.

Eye trauma is a relevant cause of blindness and visual impairment worldwide. The cornea and the corneoscleral region are the most common places of injury. The main etiologies of corneal injuries are corneal abrasion, corneal foreign bodies, corneal perforation, and eye burns. Damage to the cornea leads to swelling, increased thickness, and development of opacification due to the healing process. Therefore, a normal cornea allows visualization of intraocular surgical maneuvers in the anterior and posterior segment of the eye during eye surgery. In situations requiring immediate action by the ocular surgeon, numerous abnormalities in the anterior segment (blood in the anterior chamber, iris deformities, pupil membranes, and traumatic cataracts) can be managed if the cornea is transparent. However, the presence of important corneal opacities (such as intense or rapidly progressing corneal edema, large and thick scars, hematic impregnation, and neovascularization of the cornea) impairs a safe and effective vitrectomy, limiting the possibility of reconstruction of the anterior and posterior segments. The posterior segment surgeon is faced with the following choices when dealing with eyes with corneal opacities: postponing posterior segment surgery while waiting for corneal clearing; performing immediate surgery with temporary keratoprosthesis (TKP) combined with pars plana vitrectomy (PPV) or performing endoscopy-guided vitrectomy. The decision will be guided by the urgency to approach the posterior segment and the availability of materials. TKP or endoscopic vitrectomy is ideal in urgent cases that require immediate surgical approach. Furthermore, two cases of trauma with opacities, one with blood in the anterior chamber (hyphema) and the other with corneal opacity.

Corneal diseases are a leading cause of blindness with an estimated 10 million patients diagnosed with bilateral corneal blindness worldwide. Corneal transplantation is highly successful in low-risk patients with corneal blindness but often fails those with high-risk indications such as recurrent or chronic inflammatory disorders, history of glaucoma and herpetic infections, and those with neovascularisation of the host bed. Moreover, the need for donor corneas greatly exceeds the supply, especially in disadvantaged countries. Therefore, artificial and bio-mimetic corneas have been investigated for patients with indications that result in keratoplasty failure. Two long-lasting keratoprostheses with different indications, the Boston type-1 keratoprostheses and osteo-odonto-keratoprostheses have been adapted to minimise complications that have arisen over time. However, both utilise either autologous tissue or an allograft cornea to increase biointegration. To step away from the need for donor material, synthetic keratoprostheses with soft skirts have been introduced to increase biointegration between the device and native tissue. The AlphaCor¿, a synthetic polymer (PHEMA) hydrogel, addressed certain complications of the previous versions of keratoprostheses but resulted in stromal melting and optic deposition. Efforts are being made towards creating synthetic keratoprostheses that emulate native corneas by the inclusion of biomolecules that support enhanced biointegration of the implant while reducing stromal melting and optic deposition. The field continues to shift towards more advanced bioengineering approaches to form replacement corneas. Certain biomolecules such as collagen are being investigated to create corneal substitutes, which can be used as the basis for bio-inks in 3D corneal bioprinting. Alternatively, decellularised corneas from mammalian sources have shown potential in replicating both the corneal composition and fibril architecture. This review will discuss the limitations of keratoplasty, milestones in the history of artificial corneal development, advancements in current artificial corneas, and future possibilities in this field. This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 814439. The authors also wish to acknowledge the support of the European Union COST Programme under COST Action CA-18116, ANIRIDIA-NET. In addition, the authors acknowledge the support of Grant Number 13/RC/2073_P2, a research grant from Science Foundation Ireland (SFI) cofunded under the European Regional Development Fund. peer-reviewed

Purpose: To analyze the long-term anatomical survival, functional survival, and complications of Boston type 1 keratoprosthesis (KPro) in the eyes with congenital aniridia-associated keratopathy (AAK).Methods: A retrospective review of 12 eyes with congenital aniridia that underwent a Boston type 1 KPro surgery was conducted. A Kaplan–Meier analysis was performed. Anatomical and functional success criteria were KPro retention and a best corrected visual acuity (BCVA) ≤1.3 LogMAR (≥0.05 decimal) at the end of a follow-up period. Postoperative complications were recorded.Results: The mean preoperative BCVA was 2.1 ± 0.9 (range: 3.8–1) LogMAR, and glaucoma was a comorbidity in all the cases. Five years after the surgery, the overall retention rate was 10/12 (83.3%), and 50% had functional success. Only three (25%) of the 12 cases did not achieve a BCVA ≤1.3 LogMAR. The cumulative probability of anatomical success was 92, 79, and 79% after 1, 5, and 10 years, respectively. The cumulative probability of functional success was 57 and 46% after 1 and 5 years, respectively. The mean anatomical and functional survival time was 10 ± 1.3 (95% IC = 7.5–12.3 years) and 3.8 ± 0.9 years (95% IC = 1.8–5.8 years), respectively. The most common postoperative complication was retroprosthetic membrane (RPM) formation in 8/16 cases (66%). The mean number of complications per case was 2.4 ± 1.8 (0–6).Conclusions: The Boston type 1 KPro is a viable option for patients with AAK with good anatomical and functional long-term results. Glaucoma is an important preoperative condition that affects functional results. Retroprosthetic membrane formation seems to have a higher incidence in this condition.

Stevens Johnson syndrome and toxic epidermal necrolysis are on a spectrum of a severe, immune-mediated, mucocutaneous disease. Ocular involvement occurs in the vast majority of cases and severe involvement can lead to corneal blindness. Treatment in the acute phase is imperative in mitigating the severity of chronic disease. Advances in acute treatment such as amniotic membrane transplantation have shown to significantly reduce the severity of chronic disease. However, AMT is not a panacea and severe chronic ocular disease can and does still occur even with aggressive acute treatment. Management of chronic disease is equally critical as timely intervention can prevent worsening of disease and preserve vision. This mini-review describes the acute and chronic findings in SJS/TEN and discusses medical and surgical management strategies.

Thomas John,1,2,&ast; Sean Tighe,3,4,&ast; Hosam Sheha4,5,&ast; 1Thomas John Vision Institute, Tinley Park, IL, USA; 2Department of Ophthalmology, Loyola University at Chicago, Maywood, IL, USA; 3Department of Biochemistry and Molecular Biology, University of Miami, Miami, FL, USA; 4Department of Ophthalmology, Florida International University Herbert Wertheim College of Medicine & Glaucoma Research Organization, Miami, FL, USA; 5Department of Ophthalmology, Manhattan Eye, Ear, and Throat Hospital, Hofstra Northwell School of Medicine, New York, NY, USA&ast;These authors contributed equally to this workCorrespondence: Hosam ShehaManhattan Eye, Ear, and Throat Hospital, 210 East 64th Street, New York, NY, 10065, USATel +1 917-810-9555Email Hoss88@gmail.comSean TigheDepartment of Ophthalmology, Florida International University, 11200 SW 8th Street, Miami, FL, 33199, USATel +1 813-690-0099Email seanthomastighe@gmail.comAbstract: Corneal melt remains a challenging complication of Boston keratoprosthesis (KPro) and may lead to disastrous consequences such as endophthalmitis, KPro extrusion, and permanent loss of vision. Several procedures have been suggested to repair established melts; however, KPro removal or exchange is often required due to high recurrence. We herein describe a novel surgical technique to repair corneal melt: a lamellar corneal graft is centrally trephined, and a radial cut is extended from the central opening to create a keyhole graft. The graft is draped around the KPro and tightly secured around the central stem. The radial cut is closed with sutures, and the graft is secured into the underlying tissue with fibrin glue and sutures. The graft remains stable with the KPro in place, while the patients maintain a 20/200 vision or better at two years. This technique is a useful alternative for securing KPro and preventing corneal melt recurrence.Keywords: corneal melt, keratoprosthesis, lamellar keratoplasty

Purpose To assess outcomes and glaucoma management in eyes with aniridia following Boston type 1 Keratoprosthesis (KPro) implantation. Design Retrospective, interventional comparative case series. Methods The population included patients with aniridia and patients with other preoperative diagnoses (excluding Stevens-Johnson syndrome, mucous membrane pemphigoid, and congenital disorders) who underwent KPro implantation at Massachusetts Eye and Ear with at least 2 years of follow-up. One eye per patient was selected based on the longer follow-up time. The main outcome was intermediate and long-term outcomes related to glaucoma. Results The aniridia (n = 22) and comparison (n = 61) groups had similar preoperative visual acuity (VA, mean ± standard deviation, 1.86 ± 0.52 logMAR, P = .33) and follow-up time (65.6 ± 26.3 months, P = .25). Before KPro implantation, eyes with aniridia had more glaucoma (76.2%) and glaucoma surgery (57.1%) than comparison eyes (51.8%, P = .053; 23.2%, P = .005, respectively). More Ahmed valves were co-implanted with KPro in aniridia (47.6%) vs comparison eyes (17.9%, P = .008). At final follow-up, more aniridia eyes had glaucoma (90.5%) than comparison eyes (64.3%, P = .02), but the 2 groups had similar percentages of eyes with cup-to-disc ratio (CDR) >0.8 (23.8% vs. 30.4%, P = .57) or CDR progression of ≥0.2 (42.9% vs 44.6%, P = .89, respectively). None of the eyes with prophylactic tube implantation developed glaucoma. Eyes with and without aniridia did not differ in post-KPro VA improvement (72.7%, 72.1%, P = .96), and final VA (1.28 ± 0.79 logMAR, 1.23 ± 0.98 logMAR, P = .51). Conclusion Despite a higher glaucoma prevalence, eyes with aniridia achieved similar VA as comparison eyes with more than 5 years of mean follow-up time. Boston KPro offers satisfactory visual rehabilitation in aniridia when glaucoma is managed aggressively.

Objectives To evaluate the clinical results of combined pars plana vitrectomy (PPV) with Landers wide-field temporary keratoprosthesis and penetrating keratoplasty (PK). Materials and methods From January 2016, traumatic eyes with coexisting corneal and vitreoretinal diseases that underwent combined keratoprosthesis/PPV/PK surgery were retrospectively evaluated. Demographic characteristics, visual acuity (VA), intraocular pressure (IOP) and clinical findings of the cornea, lens, and retina were recorded during the follow-up. Cases with clear corneal graft, attached retina, normotonic IOP, and improved or stable VA were considered successful. Results Eight eyes were enrolled in the study. The mean follow-up time was 21.1±8.20 months. Surgery was performed a mean of 23 (10-40) days after trauma. Preoperative VA ranged from no light perception to counting fingers from 50 cm. Postoperatively, corneal graft was clear in 5 patients (62.5%) and retina was attached in 6 eyes (75%). Chronic hypotonia developed in 3 patients (37.5%). VA was unchanged in 3 patients and improved in 5 patients. A total of 5 cases (50%) were considered successful. Shorter interval between trauma and surgery was associated with higher likelihood of success (p=0.043). No significant difference was observed between the groups in terms of type or location of trauma (p=1; p=0.143). Conclusion Although the functional results are not very satisfactory, the combined procedure provides a final opportunity for preserving remaining vision and anatomic reconstruction in eyes that will otherwise result in phthisis due to severe anterior and posterior segment pathologies.

Purpose To compare the clinical outcomes of Boston Type I keratoprosthesis (Boston Kpro) with its low-cost version, the Aurolab Kpro (auroKPro). Design Retrospective comparative case series. Methods This study included 134 eyes of 130 patients with severe bilateral corneal blindness but with wet ocular surfaces. The patients underwent either Boston Kpro (n = 78) or auroKPro (n = 56) implantation based on the device availability and patient's affordability. The primary outcome measurements were anatomical retention (defined as absence of device extrusion, exchange, or explantation) and functional recovery of 20/200 or better visual acuity at yearly time points until 5-years of follow-up. Results Limbal stem cell deficiency was the most common indication (60.5%) for surgery, followed by multiple failed grafts (35%). Both groups were comparable at baseline with respect to indications for surgery and associated ocular co-morbidities (P > 0.05). The overall anatomical retention rates were similar in the Boston Kpro (55 of 78, 70.5%) and auroKPro (35 of 56, 62.5%) groups (P = 0.11). Kaplan-Meier survival rates at 5 years of follow-up were greater for the Boston Kpro with respect to both anatomical retention (63 ± 6% vs. 43.4 ± 10%, respectively; P = 0.057) and functional recovery (42.4 ± 6% vs. 32.2 ± 7%, respectively; P = 0.345), but these differences were not statistically significant. Complications such as intraoperative device breakage (7%) and postoperative extrusions (12.5%) were significantly more common with the auroKPro (P = 0.023). Conclusions Both the auroKPro and the Boston Kpro are effective treatment options for patients with severe bilateral corneal blindness. The auroKPro can be considered an alternative to the Boston Kpro when affordability or availability of the Boston Kpro is a limiting factor.

PURPOSE To determine patient-reported vision-related quality of life (VR-QoL) after Boston type I keratoprosthesis (BKPro) and its determinants. METHODS A cross-sectional study including consecutive consenting BKPro patients was conducted. The French National Eye Institute Visual Function Questionnaire-25 measured postoperative VR-QoL. Medical charts were retrospectively reviewed for demographics, ocular comorbidities, indication for surgery, postoperative visual acuity (VA), and complications. Univariate analyses were used to identify VR-QoL determinants. Multivariate linear regression was additionally performed for patients operated unilaterally, using VR-QoL as the dependent variable and age, sex, and postoperative VA as covariates. P < 0.05 indicated statistical significance. RESULTS Sixty-three patients, aged 63 ± 13 years, with a mean follow-up of 54 ± 19 months, were included. VR-QoL was measured 53 ± 18 months postoperatively. "Composite" VR-QoL scores in patients with unilateral (n = 51) and bilateral (n = 12) BKPro were 65 ± 23 and 63 ± 19, respectively, and did not significantly differ between the 2 groups (P = 0.71). In patients with unilateral BKPro, VR-QoL was determined by postoperative VA in the better eye, which was the contralateral nonoperated eye in most cases. Achieved vision in the operated eye contributed to VR-QoL when vision in the contralateral nonoperated eye was poorer. In the bilateral BKPro group, VR-QoL was determined by postoperative VA in the better eye and the number of ongoing complications. CONCLUSIONS Five-year VR-QoL scores were lower in BKPro patients compared with healthy cohorts reported in the literature and were similar after unilateral and bilateral BKPro surgery. The main determinant of postoperative VR-QoL was postoperative vision in the better eye.

Precis: Three-dimensional (3D) spectral domain optical coherence tomography (OCT) volume scans of the optic nerve head (ONH) and the peripapillary area are useful in the management of glaucoma in patients with a type I or II Boston Keratoprosthesis (KPro). Purpose: The purpose of this study was to report the use of spectral domain OCT in the management of glaucoma in patients with a type I or II Boston KPro. Materials and Methods: This study is an observational case series. Four consecutive patients with KPro implants were referred for glaucoma evaluation. A comprehensive eye examination was performed which included disc photography, visual field testing, and high-density spectral domain OCT volume scans of the ONH and the peripapillary area. 2D and 3D parameters were calculated using custom-designed segmentation algorithms developed for glaucoma management. Results: Spectral domain OCT parameters provided useful information in the diagnosis and management of 4 KPro patients. OCT parameters which can be used in KPro patients included 2D retinal nerve fiber layer (RNFL) thickness, 3D peripapillary RNFL volume, 3D peripapillary retinal thickness and volume, 3D cup volume, and 3D neuroretinal rim thickness and volume. In 3 of 4 cases where the traditional 2D RNFL thickness scan was limited by artifacts, 3D spectral domain OCT volume scans provided useful quantitative objective measurements of the ONH and peripapillary region. Therefore, 3D parameters derived from high-density volume scans as well as radial scans of the ONH can be used to overcome the limitations and artifacts associated with 2D RNFL thickness scans. Conclusions: Spectral domain OCT volume scans offer the possibility to enhance the evaluation of KPro patients with glaucoma by using both 2D and 3D diagnostic parameters that are easily obtained in a clinic setting.

To evaluate the effectiveness of temporary keratoprosthesis combined with vitreoretinal surgery and penetrating keratoplasty in patients with or without trauma. This retrospective study included 49 eyes in 49 non-trauma patients and 51 eyes in 48 ocular trauma patients who underwent penetrating keratoplasty and vitreoretinal surgery with Eckardt temporary keratoprosthesis between 2009 and 2016, with a follow-up of at least 12 months. Study variables included previous corneal, glaucoma, or retinal surgeries; various intraoperative surgical maneuvers; lens status; vitreoretinal and corneal pathology; functional outcomes; anatomical retinal reattachment; graft clarity; and need for glaucoma surgery or treatment. The mean age was 56 years in the non-trauma group and 42 years in the ocular trauma group. A total of 45% of the non-trauma cases and 24% of the ocular trauma cases had a single functional eye. Pseudophakic and aphakic keratopathy was diagnosed in 41% of the non-trauma group and corneal laceration in 65% of the ocular trauma group. In the ocular trauma group, injuries were open globe injury in 78%, closed globe injury in 12%, and intraocular foreign body in 10%. Retinal detachment with proliferative vitreoretinopathy was present in 39% of patients in the non-trauma group and in 35% of the ocular trauma group. Improvement or stability of visual acuity was higher among ocular trauma patients (86%) than in non-trauma patients (78%). The rate of clear corneal grafts was 49% in both groups. Retinal attachment was achieved in 90% and 78% of patients in the non-trauma and ocular trauma groups, respectively. The use of retinotomy had a positive influence on the final attached retina (p = 0.016). The placement of a scleral buckle significantly increased the risk of glaucoma (p = 0.004). Poor functional outcome was related to persistent retinal detachment (10% versus 16% in the non-trauma and ocular trauma groups, respectively), phthisis (25% versus 12%), hypotony (33% versus 18%), corneal graft end failure (51% in both groups), and secondary glaucoma (18% versus 24%). In patients with both vitreoretinal and corneal pathology, the use of Eckardt temporary keratoprosthesis combined with vitreoretinal surgery and penetrating keratoplasty resulted in improvement of visual acuity, particularly in the groups of ocular trauma and monocular patients. The high rate of retinal reattachment and the low rate of graft rejection was probably related to the use of new vitreoretinal techniques, including retinotomy in selected patients.

Purpose To compare anatomical and functional results between three types of keratoprosthesis (KPro) in chemical injury and autoimmune disease. Methods 70 clinically comparable cases were included as follows: Boston KPro Type 1 25 eyes, osteo-odonto-keratoprosthesis (OOKP) 23 eyes, Tibial bone KPro 22 eyes. Survival times for anatomical and functional success were evaluated with Kaplan-Meier estimations and Log-rank tests. KPro exchange was considered a complication, not as failure. Results Prosthesis retention in chemical injury group at 5 years was 86% for OOKP, 100% for Tibial bone KPro, and 65% for Boston KPro (p = 0.09), while in the autoimmune disease group it was 66% for Tibial bone KPro and 50% for Boston KPro (p = 0.19; OOKP only one case). Functional success in the chemical injury group at 5 years was 86% for OOKP, 84% for Tibial bone KPro and 71% for Boston KPro (p = 0.38), while in the autoimmune group, it was 44% for Tibial bone KPro and 15% for Boston KPro (p = 0.15; OOKP only one case). The post-operative complications in all groups were: retinal detachment, vitreous hemorrhage, endophthalmitis, retro-prosthetic membrane, uncontrolled glaucoma, the last two being more common in Boston KPro. Conclusions For both diagnoses, chemical injury and autoimmune diseases, there was a tendency for better long-term anatomical and functional results with Tibial bone KPro followed by OOKP and Boston KPro Type 1. However, these results were not statistically significant.

Purpose: To report histopathological findings for different types of polymers proposed as support for a Pintucci-type keratoprosthesis. Methods: Six polymers, including three types of polyesters ( # 1-3), one type of polytetrafluoroethylene (PTFE, # 4), polyethylene ( # 5), and expanded polytetrafluoroethylene (ePTFE, # 6) were evaluated. Four samples of each material were placed under the orbicularis oculi muscles of 12 rabbits. After five weeks, the samples were removed and evaluated histopathologically. Fibrovascular tissue ingrowths were investigated in terms of tissue penetration depth into the materials (graded as none, mild, moderate, and intense) and fibrovascular ingrowth area at the ultimate level of tissue penetrance. ImageJ software was used to calculate fibrovascular tissue area between the material fibers, and the mean area values were compared between the materials. Results: Polyester materials # 1 and # 3 demonstrated intense fibrovascular tissue penetration with a large fibrovascular ingrowth area; no overt tissue ingrowth was observed into material #6. The mean area of penetrated fibrovascular tissues was significantly different between materials ( P < 0.001). Materials # 2, # 4, and # 5 showed moderate fibrovascular tissue ingrowth and the area of presented fibrovascular tissue at the paracentral parts of material # 4 was significantly smaller than that of materials # 1 ( P = 0.02) and # 3 ( P = 0.01). Conclusion: Two polyester materials that had relatively large pore sizes demonstrated a deep and large area of fibrovascular ingrowth. Given that material #3 is thicker and more consistent than material # 1, the former can be used as the appropriate material for supporting the Pintucci-type keratoprosthesis.

Purpose: To present our experience in Osteo-odonto-keratoprosthesis (OOKP) as the only option to restore vision after severe ocular dog bite injuries. Methods: We describe our results in OOKP performed in two patients with previous severe dog bite facial injuries that required exenteration of one eye and facial reconstruction. Results: Both cases achieved initially successful anatomical and visual outcome; however, one case suffered retinal detachment after one year. Buccal mucosa (BM) ulcerations and tilted lamina were present as a result of extraocular muscles loss, and both were difficult to treat. Conclusion: OOKP has the capability to restore vision in the most challenging cases of ocular trauma; however, refractory BM ulcerations and tilted lamina could be expected as a result of an ischemic ocular surface and orbital pulleys loss. Keywords: Osteo-odonto-keratoprosthesis, Keratoprosthesis, Dog bite ocular injury