Incidence, risk factors, and treatment of retroprosthetic membranes following Boston keratoprosthesis eyes and the impact of glaucoma surgery.

PURPOSE: To assess incidence, risk factors, and treatment of retroprosthetic membrane (RPM) formation in eyes following Boston keratoprosthesis (Kpro) implantation and their correlation with glaucoma drainage device placement (GDD). METHODS: A retrospective review was performed on eyes that underwent Kpro type I or II implantation between 2005 and 2020 at a tertiary academic center. Multiple variables were collected including preoperative characteristics, presence of RPM, management of RPM, and outcomes including corrected visual acuity (VA). A Fischer's exact test was used to evaluate the significance of risk factors of RPM formation and an odds ratio was calculated for each possible risk factor. A Mann-Whitney U test was used to evaluate comparisons between outcomes and qualitative analyses. RESULTS: Of the 87 eyes identified, 37 (43%) developed an RPM within an average of 1.5 years (range, 31 days-7.5 years) following Kpro implantation. Mean follow-up duration was 4.3 years. Eyes that developed RPM had significantly worse preoperative VA compared to those that did not (logMAR 2.55 vs. 2.28, p = 0.022). The mean number of prior penetrating keratoplasty procedures trended higher in eyes that developed RPM (2.46 vs. 2.18, p = 0.44) but was not significant. GDD placement after Kpro implantation was associated with an increased risk of RPM formation (RR = 1.69 p = 0.026). Of the 37 eyes that developed an RPM following Kpro, 17 (47%) were treated with Nd:YAG laser, and four of those 17 (21%) also underwent pars plana vitrectomy (PPV). Seven of 37 eyes (19%) underwent PPV without Nd:YAG. Comparisons between RPM occurrence and final VA were not significant. CONCLUSIONS: The incidence of RPM formation following Kpro implantation was 43%. Eyes that developed RPM had significantly worse preoperative VA. GDD placement after Kpro implantation increased the risk of developing RPM. Final VA and occurrence of RPM were not significantly different between the Nd:YAG and PPV treatment groups.

Impact of keratoprosthesis implantation on retinal and visual pathway function assessed by electrophysiological testing.

PURPOSE: To investigate the impact of Boston Type I Keratoprosthesis (BI-Kpro) implantation on retinal and visual pathway function, respectively, assessed by full-field electroretinography (ERG) and visually evoked potentials (VEPs). METHODS: This is a prospective interventional longitudinal study, and patients with BI-Kpro implantation were assessed preoperatively and at 3 and 12 months after surgery. ERG, flash, and pattern-reversal VEPs (15' and 60' checks) along with visual acuity (VA) were performed. RESULTS: A total of 13 patients (24 to 88 years of age) were included. Mean baseline VA (logMAR) improved from 2.30 to 1.04 at 3 months and to 1.00 at 12 months. Flash VEPs were normal in 6 (46%) patients and in 10 (77%) patients at the 12-month follow-up. PVEP was non-detectable in all patients preoperatively for both check sizes. For 15' check size, 6 (46%) patients showed responses after 3 and 12 months except for 1 patient with normal responses at 12 months with the remaining non-detectable. For 60' checks, 11 (85%) patients had responses 3 months after surgery with only 9 (70%) showing responses at 12 months. Abnormal full-field ERGs were found in all patients preoperatively. Amplitude improvement was found in 10 (77%) patients from baseline to 3 months and in 8 (62%) patients from the 3- to the 12-month follow-up. CONCLUSIONS: In this small cohort of patients with BI-Kpro implantation, a remarkable improvement on visual function quantitatively assessed by electrophysiological testing was found in the majority of cases. Visual electrophysiological testing can contribute to objectively assess functional outcomes in this population.

Anatomical and functional outcomes of Boston type I keratoprosthesis as primary penetrating corneal procedure in high-risk and non-high-risk cases.

PURPOSE: To analyze the anatomical and functional results of Boston type I keratoprosthesis (B1-KPro) as a primary corneal procedure in high-risk (HR) cases and non-high-risk (NHR) cases. METHODS: In this retrospective interventional case series, all patients who underwent B1-KPro at a single center between January 2006 and March 2021 were reviewed and identified. Cases were classified according to the primary diagnosis. Anatomical failure was considered in the case of prosthesis extrusion or phthisis bulbi. Functional failure was a postoperative corrected distance visual acuity (CDVA) ≥ 1.3 LogMAR (≤ 0.05 decimal) at the end of the follow-up period. RESULTS: Twenty-three eyes were included for analysis. Thirteen eyes were classified as HR and 10 as NHR. The mean age was 46.5 ± 26.5 years (5-84 years) in the HR group and 49.5 ± 26.9 years (2-78 years) in the NHR group. The mean follow-up was 42.0 ± 35.9 months (1.5-118 months) in HR and 44.8 ± 38.8 months (1-107 months) in NHR. Three eyes in the HR and none in the NHR group showed anatomical failure. Functional failure was reported in 5/13 eyes in the HR and 8/10 in the NHR group. Functional cumulative survival probability was 92% and 82% for the HR group at 1 and 2 years, respectively. In the NHR group, it was 27% at both times. No significant differences were found between groups, except for functional survival in the HR group due to better visual potential of the eyes. CONCLUSIONS: B1-KPro as a primary corneal procedure is a valid option for visual rehabilitation in high-risk cases.

The treatment of end-stage corneal disease: penetrating keratoplasty compared with Boston type 1 keratoprosthesis.

Penetrating keratoplasty (PKP) yields excellent results for restoring vision in end-stage corneal diseases. However, its success is limited to high-risk diseases such as aniridia, chemical burns, autoimmune corneal diseases, and herpetic eye disease. Boston type 1 keratoprosthesis (BKPro) offers another option to these patients. Since 1992, improvements in perioperative management and device construction have significantly increased the use of BKPro worldwide and challenged the therapeutic role of PKP in these patients. This review aims to evaluate BKPro's place in the treatment algorithm of these high-risk patients to assist surgeons' decision-making. PKP and BKPro are compared in three outcome categories: visual acuity, graft retention and failure, and complications profile. Special attention is given to comparing secondary BKPro versus repeated PKP as well as primary BKPro versus primary PKP. We conclude that secondary BKPro bears a better prognosis than repeated PKP in most high-risk patients. Similarly, primary BKPro likely confers improved outcomes over primary PKP in most high-risk recipients. However, current evidence is based on retrospective designs, and controlled prospective randomized trials are required to validate these conclusions.

Wide-field vitreoretinal surgery in eyes with Boston type 1 keratoprosthesis.

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®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.

Perspectives for preclinical mouse models of glaucoma after Boston keratoprosthesis type 1.

Animal models of the Boston keratoprosthesis type 1 (KPro) are needed to study glaucoma damage after KPro implantation to control for confounding comorbidities common in human KPro recipients. The purpose of this study was to determine the feasibility of establishing a reproducible mouse model of glaucoma after KPro surgery, specifically that of a miniaturized mouse model of KPro (mKPro). In the present study, a total of 20 corneas of donor C57BL/6 mice (n = 10) were implanted in one eye of each recipient BALB/C mouse (n = 20), assembled as part of the mKPro, either with or without intraoperative lensectomy. Main feasibility outcomes consisted in incidence rates of loss of tone, capsule nicking, and lens extrusion, as well as acquisition of posterior segment optical coherence tomography (OCT) images. With lensectomy (n = 10), loss of ocular tone and retinal detachment occurred in 100% of mice. Without lensectomy (n = 10), capsule nicking and opening, as well as lens extrusion, occurred in 80% of mice. Causes of these complications included the large proportion of intraocular volume occupied by the lens, the shallow anterior chamber, and thus the lack of available intraocular volume to implant the KPro if the lens remains present. Successful mouse KPro surgery may require a great deal of practice to be useful as a reproducible model. Animal KPro models ought to be pursued further by research teams in future studies.

Corneal power values for use with keratoprostheses and intraocular lenses.

PURPOSE: To specify a keratoprosthesis (KPro) power value for use with an intraocular lens (IOL). METHODS: Raytracing software was used to determine the imaging properties of both the natural cornea and conceptual KPro designs, and IOL power calculation methods were reviewed. Traditional calculations use 'thick lens' models for the overall eye, while also using 'thin lens' approximations for the cornea and IOL. The power of the natural cornea acts approximately at the apex, although this is unlikely to be the case for a KPro. The IOL location is determined using an empirical adjustment that is calculated from clinical results for natural eyes. RESULTS: The use of a KPro has a similar optical effect to corneal refractive surgery, where the cornea no longer matches the original eye. A modification of the 'double-K' calculation method can be used by specifying the KPro effective power at the original corneal apex, but still estimating the postoperative IOL location using the original corneal power. The KPro power is measured by assembling the KPro with fluid and a window to simulate the way it is used, recording the best focus power at room temperature with a 3 mm diameter aperture, rescaling to the in situ power at 35°C using refractive index changes, and then rescaling again to the power expected relative to the original corneal apex. When expressed as a K value, a keratometer refractive index of 1.332 is proposed. If necessary, clinical results may be used later to make empirical adjustments to the calculation method. CONCLUSIONS: A KPro power can be specified relative to the expected location of the original corneal apex using a keratometer index of 1.332. A double-K calculation can then be used to determine the correct KPro and IOL power values for a pseudophakic eye.

[Morphological changes in rabbit cornea after implantation of a new keratoprosthesis supporting plate]. / Morfologicheskie izmeneniya rogovitsy krolika pri implantatsii novoi modeli opornoi plastinki keratoproteza.

PURPOSE: To evaluate biocompatibility of the new keratoprosthesis supporting plates (KSP) in rabbits in vivo. MATERIAL AND METHODS: The study included 15 chinchilla rabbits. In the first group (5 rabbit eyes) KSP made of hydrophobic acryl with square penetrating holes of 220×220 micron (model 1) were inserted into rabbits' corneas. In the second group (5 eyes), KSP made of hydrophobic acryl were used that had trapezoidal fenestrations with size (from 170×130 micron to 180×70 microns) gradually changing from periphery to the center of KSP (model 2). The control group rabbits (5 eyes) had 1/2 of Fyodorov-Zuev KSP made of titanium implanted. All animals were observed for up to 3 months with biomicroscopy and optical coherence tomography of the anterior segment. The animals were then euthanized and had their corneo-scleral discs excised and then examined with optical microscopy and scanning electron microscopy (SEM). RESULTS: After 3 months, there was only one case of KSP protrusion in the first group. In the second group, thinning of the corneal layers above the central part of KSP occurred in one case. The presence of polymer KSP (of both models) in the corneal stroma was found not to cause formation of rough fibrotic tissue. At the same time, adhered cellular and fibrous elements were discovered on the surface and inside the holes of the polymer KSP, while on the surface of the titanium plate cellular elements were absent. CONCLUSION: Supporting plates made of hydrophobic acrylic material can potentially serve as a foundation for the new keratoprosthesis design.

Comparative study of penetrating keratoplasty and vitreoretinal surgery with Eckardt temporary keratoprosthesis in ocular trauma versus non-trauma patients.

PURPOSE: To evaluate the effectiveness of temporary keratoprosthesis combined with vitreoretinal surgery and penetrating keratoplasty in patients with or without trauma. METHODS: 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. RESULTS: 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%). CONCLUSION: 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.

Comparison of an Er: YAG laser osteotome versus a conventional drill for the use in osteo- odonto-keratoprosthesis (OOKP).

OBJECTIVES: The osteo-odonto-kerato-prosthesis (OOKP) procedure is a complex, multi-stage, multidisciplinary surgical intervention for the treatment of severe corneal blindness. One step of the OOKP consists of creating a precise hole into a tooth in which an optic cylinder is subsequently inserted; its shape must ensure a perfect watertight fit. The Er: YAG laser (L) used in this study is part of CARLO®, the first laser osteotome that enables surgical planning based on computed tomography data, robot guidance, and a precise execution of laser cuts in teeth and bone tissue, using laser photoablation rather than conventional mechanical methods. The purpose of this study was to assess whether the Er: YAG laser is non-inferior compared to a conventional drill. METHODS: Thirty-two bovine incisors were grounded to a thickness of 1.5 mm. In 16 teeth, a 3.5 mm hole was drilled progressively into each tooth, using dental burs (B) of increasing diameter that were attached to a fixed drill machine. In the other 16 teeth, a hole was created using an Er: YAG laser at a wavelength of 2.94 µm (Part of CARLO®). In seven teeth of each group, the cylinder was inserted and fixated with polymethylmethacrylate (PMMA) bone cement. In the remaining seven teeth of each group, the cylinder was inserted without fixation material (press-fit). After bonding and drying, all specimens were stored in water until force measurements were recorded using a uniaxial traction machine. The force required to move the optical cylinder out of the hole in the tooth was measured using an Instron 3344 testing system. Scanning electron microscope (SEM) and light microscope (LM) visualization of the holes created with the laser and the drill were performed in two teeth (SEM)/four teeth (LM) per method. RESULTS: Significant differences (P < 0.001) were found for the following parameters: B PMMA versus B press-fit; B PMMA versus L press-fit; L PMMA versus B press-fit; L PMMA-L press-fit. This shows that PMMA bone cement fixation is superior to press-fit. No significant differences were found between B PMMA-L PMMA (P = 0.93) and B press-fit-L press-fit (P = 0.83). The SEM pictures showed a smoother surface using L. CONCLUSIONS: The laser cut holes were as strong as bur-drilled holes, although SEM pictures showed a smoother surface of the laser cut holes. Hence, laser osteotomes open the possibility to custom fit the hole exactly to the width of the cylinder, which represents a potential advantage of the laser over the conventional bur. Lasers Surg. Med. 51:531-537, 2019. © 2019 Wiley Periodicals, Inc.

Design and evaluation of artificial cornea with core-skirt design using polyhydroxyethyl methacrylate and graphite.

PURPOSE: Artificial cornea is the effective treatment option for corneal blindness. One of the challenges with the artificial cornea is limited, or no tissue integration necessitates reimplantation due to necrosis or corneal melting. We propose here a new formulation approach for core-skirt incorporating graphite in the outer skirt region to improve cell adhesion. METHODS: Hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate were procured from Sigma-Aldrich. Polyhydroxyethyl methacrylate (PHEMA) was synthesized by free radical polymerization of HEMA. PHEMA hydrogel core with graphite incorporated skirt was developed with the help of mould and spacer. Pores were introduced into the skirt by salt leaching technique using sodium chloride as porogen. The porous skirt was improved for its aesthetic appeal of black colour and mechanical strength to sustain intraocular pressure by incorporating graphite. The material properties of the newly developed design were evaluated in terms of wetting behaviour, mechanical strength, water vapour permeability, degradation profile and cell adhesion. RESULTS: The polymerization of HEMA was confirmed by thin layer chromatography and FTIR. Water content of the polymeric film was optimized at 50% where maximum transparency with required refractive index of 1.4 was obtained. The concentration of salt vital for the essential porosity was also optimized using optical microscopy and scanning electron microscopy. Other properties, namely mechanical strength, water vapour transmission rate and degradation behaviour, showed that the developed design is suitable for ocular applications. Furthermore, cell adhesion study confirmed tissue adhesion in the skirt region but absent in the core. CONCLUSION: The core-skirt design may offer an efficient cornea replacement alternative with enhanced tissue integration in addition to desired mechanical behaviour with a clear and aesthetic vision.

[Fixed and temporary keratoprosthesis]. / Keratoprotezy stale i czasowe.

Keratoprosthesis is a chance for all patients who have bilateral visual loss due to corneal pathology so serious and extensive that it cannot be removed by graft transplantation. This problem mainly affects less developed countries. The eyesight of these patients could return to normal if corneal transplants were practiced and keratoprosthesis were widely available. Keratoplasty makes great progress and gets better and better results. The future will show whether there will be more reliable and biologically integrated keratoprosthesis, with low risk of complications.

Osteo-odonto keratoprosthesis: Innovative dental and ophthalmic blending.

Corneal diseases are among the major causes of global blindness, secondary to cataract. osteo-odonto keratoprosthesis (OOKP) is the ideal treatment for patients with end-stage inflammatory corneal diseases where a portion of tooth along with bone is used to support an optical cylinder to restore vision in such patients. OOKP surgery requires multidisciplinary approach involving dentists, ophthalmologists, and radiologists. Very less is known in dentistry about the role of the periodontium in the field of ophthalmology. This paper highlights OOKP indications, contraindications, surgical procedure, role of oral structures, advantages, and limitations.

Corneal graft dellen in a patient implanted with a Boston keratoprosthesis type 1.

The purpose of this study was to report a case of corneal dellen in a patient implanted with a Boston type 1 keratoprosthesis (KPro), which rapidly appeared after the loss of the large-diameter soft contact lens. This study is an observational case report of a 56-year-old man who underwent KPro implantation in his right eye in November 2010. In March 2014 during a follow-up visit, two areas of corneal dellen were observed. The patient had lost his bandage contact lens. With the application of a new soft contact lens, the thinned areas recovered completely within 5 days. After keratoprosthesis implantation, it is necessary to maintain uninterrupted wear of a bandage contact lens as it allows for adequate ocular surface hydration and prevents consequent complications. This case report highlights the need to provide proper instructions to such patients, in order to minimize the risk.

Publication trends in corneal transplantation: a bibliometric analysis.

BACKGROUND: Our aim was to demonstrate the publication trends of corneal transplantation in the last decade. METHODS: All of the keratoplasty research articles, letters, case reports, reviews and meeting abstracts published between January 2006 and December 2015 indexed on the Thomson Reuters Web of Knowledge were evaluated. A bibliometric filter was used to capture keratoplasty related publications by using the key words 'keratoplasty', 'corneal transplantation' or 'keratoprosthesis' in the 'title' selection mode. RESULTS: A total of 2726 publications were evaluated in the present study. Documents related to penetrating keratoplasty only have been decreased, whereas the documents related to endothelial keratoplasty were increased in the last decade. The total keratoplasty publication counts had been increased from the year 2006 to 2015. The average citation count per keratoplasty documents was 9.34. CONCLUSIONS: There is a growing interest to the lamellar keratoplasty techniques especially the endothelial keratoplasty in the last decade.

Boston type 1 keratoprosthesis for failed keratoplasty.

The purpose of this study was to evaluate the outcomes of the Boston type 1 keratoprosthesis (Kpro-1) in eyes with failed keratoplasty. A retrospective review was performed of every patient treated with a Kpro-1 at a tertiary eye care center between January 1, 2008 and July 1, 2013. Eyes with a failed keratoplasty originally performed for corneal edema, trauma, or keratoconus were included in the statistical analysis. The main outcome measures were visual outcome, prosthesis retention, and postoperative complications. Twenty-four eyes met the inclusion criteria, including 13 eyes with corneal edema, 8 eyes with trauma, and 3 eyes with keratoconus. After a mean follow-up period of 28.9 months (range 7-63 months), the median best corrected visual acuity (BCVA) was 20/125. The BCVA was ≥ 20/40 in 4 (16.7 %) eyes, ≥ 20/70 in 9 (37.5 %) eyes, and ≥ 20/200 in 14 (58.3 %) eyes. Overall, the postoperative BCVA improved in 17 (70.9 %) eyes, was unchanged in 3 (12.5 %) eyes, and was worse in 4 (16.7 %) eyes. The initial Kpro-1 was retained in 22 (91.7 %) eyes, and was successfully repeated in the other 2 eyes. One or more serious prosthesis- or sight-threatening complications occurred in 8 (33.3 %) eyes. These included 1 case of wound dehiscence leading to prosthesis extrusion, 1 case of fungal keratitis leading to prosthesis extrusion, 4 cases of endophthalmitis, and 5 retinal detachments. The Boston Kpro-1 is associated with an excellent prognosis for prosthesis retention and satisfactory visual improvement in eyes with previous failed keratoplasty.

The Boston keratoprosthesis provides a wide depth of focus.

PURPOSE: To measure the through-focus curve for eyes implanted with a type 1 Boston keratoprosthesis (KPro) and compare it to that of pseudophakic controls with fixed pupil sizes. The results should assist in evaluating postoperative visual quality after surgery. They should also help to determine the necessary KPro inventories in terms of refractive power steps. METHODS: Autorefraction and manifest refraction were performed on all eyes. The monocular through-focus acuity curve was plotted in reference to the best-corrected visual acuity by spectacle plane defocus ranging from +5.00 to -5.00 dioptres in 0.50 dioptre increments. These measurements were obtained on KPro-implanted eyes, pseudophakic eyes as controls, and on the same control eyes after fixing the pupil diameter to 3 and 2 mm using black painted iris contact lenses. RESULTS: Ten KPro eyes and five control eyes were included. Good agreement was noted between the subjective refractions and autorefraction in KPro eyes. The average through-focus curve for the control eyes was significantly steeper than that of the KPro curve, but became comparable after fixing the control pupil to 2 and 3 mm. CONCLUSION: The KPro's wide depth-of-focus makes the visual acuity less dependent on an exact refractive correction at distance and explains the 'pseudoaccomodation' experienced by these patients. This is primarily due to the small pupil diameter of the KPro. The current manufacturing steps in 0.50 dioptre increments appears to be sufficient.

Penetrating Ocular Trauma with Retained Intraocular Foreign Body: Management, Follow-up and Medico-legal Evaluation.

Ocular trauma is the leading cause of acquired monocular blindness, accounting for 1.97-6% of such cases. Particularly, penetrating ocular injuries are among the most common eye injuries with this kind of outcome. Early diagnosis and prompt management are crucial to avoid complications, and the especially dreaded enucleation. In this article, the authors describe the clinical management, and evaluate the visual and anatomical results obtained in a case of ocular injury with retained intraocular foreign body (IOFB) in a 20-year old female patient. The course of treatment involved a combination of penetrating keratoplasty with a temporary keratoprosthesis, phacoemulsification with intraocular lens implantation and pars plana vitrectomy. At three years from the initial injury, the patient was able to count fingers at 30 centimetres and anatomical restitutio ad integrum of the globe had been achieved.

Erratum to: Endophthalmitis in Boston keratoprosthesis: case series and review of literature.

To report the clinical and microbiological characteristics of infectious endophthalmitis after Boston type I keratoprosthesis (B-K-Pro) implantation. Retrospective analysis of 45 eyes that received a B-K-Pro type 1 between 2009 and 2012 was performed. Five eyes with a diagnosis of exogenous endophthalmitis after B-K-pro type 1 were identified and information about demographic data, indication for K-Pro, post-operative bandage contact lens use, post-operative prophylactic antibiotic use, timing and clinical presentation of endophthalmitis, gram stain and culture results of intraocular fluid and preoperative and post-operative visual acuity were collected. The incidence of endophthalmitis was 11.1 % (5 of 45 eyes) and average time to develop endophthalmitis was 5.62 months (range 2 days to 8 months). Mean patient age was 31.4 years (5 to 65 years). The surgical indications included corneal injury due to chemical burns (n = 2), multiple failed grafts secondary to microbial keratitis (n = 2) and congenital glaucoma with congenital herpetic keratitis (n = 1). Post-Boston K-Pro, the visual acuity ranged from light perception (LP) to 20/50. K-pro was explanted in 4 patients. There was bacterial and fungal growth in two patients each and one vitreous did not grow anything. All the eyes were phthisical at last visit. Infectious endophthalmitis after K-Pro implantation in our study had a higher incidence, early onset and extremely poor visual outcome compared with post-cataract surgery endophthalmitis, as reported in literature. Not only bacterial but also fungal infections are an important etiology for infectious endophthalmitis in these cases.

A new approach of aspheric intralamellar keratoprostheses optic design made with poly(2-hydroxy ethylmethacrylate) hydrogel.

Keratoprosthesis (KPro) is a surgical procedure largely confined to end-stage corneal blindness correction, where artificial cornea substitutes the native tissue. Though the problem of bio integration was addressed partially by strategic utilization of synthetic polymers and native tissue, major challenges like optical performance and design-associated post-operative complications of KPro were overlooked. Herein, a novel intralamellar KPro design is conceptualized to address these challenges using a light-transparent poly(2-hydroxy ethylmethacrylate) (pHEMA) hydrogel with good shape memory. pHEMA-based optics' theoretically modelled refractive surfaces for both phakic and aphakic conditions were investigated against the standard Navarro model and optimized to new aspheric geometries having high optical functionality utilizing the Zemax OpticStudio software. The optical clear aperture size standardized achieved a 15% improvement in the illumination field. The introduction of asphericity on the two refractive surfaces of the optic on both models resulted in substantial improvements in the spot spread confinement on the retina, spatial resolution, and Seidel aberration. The design simulation study shows that the developed materials' optical characteristics coupled with newly optimized refractive surface geometries can indeed deliver very high visual performance. Furthermore, the procedure can be adapted to analyze and optimize the optical performance of a KPro, intraocular lens, or contact lens.