Retroprosthetic Membrane Formation Research Articles

BOSTON TYPE II KERATOPROSTHESIS, 7 YEARS OF EXPERIENCE AND OUTCOMES FROM A SPANISH TERTIARY EYE CARE HOSPITAL.

To report mid-term outcomes of Boston Keratoprosthesis type II at a reference center in Spain. Retrospective case series. This observational study included medical records of 9 patients who underwent Boston Keratoprosthesis type II surgery at Cruces University Hospital from May 2016 through May 2023. A total of 9 eyes received this device during the study period. One patient who had undergone a modification of the standard procedure was excluded. Preoperative and postoperative parameters were studied. Main outcomes analyzed were visual acuity, device retention, complications and their management. The most common indication for implantation was severe Sjögren's syndrome (33.3%) followed by graft vs. host disease (22.2%). The mean follow-up was 3.89 years (± 2.08). Visual acuity improved to better than or equal to 20/40 in 8 eyes (88.8%) and 20/25 in 6 eyes (66.6%), while best corrected visual acuity of 20/20 was achieved in 4 eyes (44.4%). At the last visit, maximum visual acuity was maintained in four patients. The most common postoperative complication was retroprosthetic membrane formation (77.7%). New-onset glaucoma was detected in four patients (44.4%). Device extrusion occurred in one eye and two more patients required a replacement surgery. All except one of the patients are on postoperative treatment with systemic immunosuppressants. The Boston type II Keratoprosthesis is a useful option for visual rehabilitation in end-stage ocular surface diseases. Multidisciplinary management of complications is of vital importance for the maintenance of vision and the device. Immunosuppressive treatment helps control the inflammation that leads to most associated complications.

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

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). 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. Of the 87 eyes identified, 37 (43%) developed an RPM within an average of 1.5years (range, 31days-7.5years) following Kpro implantation. Mean follow-up duration was 4.3years. 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. 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.

RETRACTED: Résultats à long terme de la kératoprothèse de Boston de type I au Canada

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

Long-term results of Boston keratoprosthesis surgery in Polish patients

Abstract Introduction To evaluate the long-term (10 year) outcomes of Boston type 1 keratoprosthesis (BKPro; Massachusetts Eye and Ear Infirmary, Boston, MA) surgery performed in 6 Polish patients. Materials and Methods 6 eyes of 6 patients (1 female and 5 males; mean age 49,5±6,34 years) were qualified for the surgery. Indications for BKPro surgery in the study group included: corneal graft failure (3 patients), chemical ocular burns (2 patients), and post-herpetic keratitis vascularized leucoma (1 patient). Visual acuity, slit-lamp examination with ocular surface assessment, anterior segment optical coherence tomography (AS OCT), fundoscopy, and intraocular digital pressure measurement were performed at each visit. Results Retention of keratoprosthesis was achieved in all patients during the follow-up period. At last recorded visits VA≥0,2 was observed in 3 patients, LP in one patient and NLP in 2 patients. The complications which occurred in our case series were: glaucoma (4 patients preoperatively, 6 patients postoperatively), retroprosthetic membrane formation (1 patient), epimacular membrane formation (2 patients) and severe Meibomian Gland Dysfunction (3 patients). OCT analysis allowed imaging of anterior iris synechiae, AGV tube, protrusion of the BKPro and retroprosthetic membrane not visible on the slit lamp examination. Conclusions BKPro surgery should be considered as a surgery of choice in patients who have high risk of PK failure. OCT plays a role in anterior eye segment monitoring and detection of complications not visible on the slit lamp examination in the follow up period. Implementing the dry eye disease treatment should be recommended in all patients undergoing BKPro surgery.

Retroprosthetic Membrane Formation in Boston Keratoprosthesis Type 1: Incidence, Predisposing Factors, Complications, and Treatment.

The purpose of this study was to evaluate the incidence, rate of formation, and risk factors of retroprosthetic membrane (RPM) after Boston type 1 keratoprosthesis (BKPro) as well as identify secondary complications linked to its formation and describe its treatment. This was a retrospective cohort study. One hundred thirty-three eyes of 115 patients who underwent BKPro implantation at the Centre Hospitalier de l'Université de Montréal from 2008 to 2017 were included with at least 1-year follow-up. Charts were reviewed, and data were collected, including incidence of RPM formation, preoperative and intraoperative risk factors, postoperative complications, and treatment modalities. The mean follow-up was 5.5 years, and 39% (n = 52) of eyes developed RPM. No etiologies were found to be significantly associated with RPM development. Simultaneous lensectomy and simultaneous intraocular lens extraction were respectively positively and negatively correlated with RPM development [odds ratio (OR): 0.3590, 95% CI: 0.1629-0.7570, P = 0.0097; OR = 2.646, 95% CI: 1.273-5.585, P = 0.0086, respectively]. As for postoperative complications, the strongest correlation was between RPM and retinal detachment (OR = 6.16, 95% CI: 2.14-16.14; P = 0.0004). RPM development was also positively associated with the development of hypotony and corneal melt. Nd:YAG membranectomy was the most common treatment, performed in 83% of eyes with RPM (n = 24), with 58% resolution. More than one third of patients who undergo BKPro will develop RPM, requiring close monitoring for retinal detachment. Simultaneous intraocular lens extraction seems protective, whereas simultaneous lens extraction increases the rate of RPM formation significantly. Nd:YAG membranectomy can be used as an initial noninvasive approach.

Long-Term Anatomical and Functional Survival of Boston Type 1 Keratoprosthesis in Congenital Aniridia.

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.

CorNeat KPro: Ocular Implantation Study in Rabbits.

Purpose:The purpose of this study was to evaluate surgical feasibility and long-term integration of the CorNeat Keratoprosthesis (KPro), a novel synthetic cornea, in rabbits.Methods:The CorNeat KPro is a synthetic corneal implant designed to treat corneal blindness by using a polymeric scaffold for biointegration, consequently assimilating synthetic optics within ocular tissues. Eight New Zealand White rabbits were implanted unilaterally with the CorNeat KPro and observed for 6 months. Animals were regularly monitored by a certified ophthalmologist using slit-lamp biomicroscopy. One animal developed postoperative endophthalmitis and was removed from the study 7 weeks postsurgery. At termination, eyes were enucleated and evaluated histologically to assess local tissue integration and inflammatory response.Results:The surgical procedure was found feasible. The CorNeat KPro integrated into all operated eyes, resulting in a retention rate of 87.5% at the conclusion of the 6-month follow-up period. We observed minimal-to-mild conjunctival and iridial congestion and did not find additional inflammatory indicators, such as anterior chamber fibrin, flare, or cells. The optical element of the device remained clear with zero incidence of retroprosthetic membrane formation. Histopathological evaluation revealed comparable tissue and cellular reaction in all eyes, consisting of the presence of fibroblasts and associated collagen fibrils within the device's skirt component. Some eyes showed a mild foreign body reaction surrounding the skirt.Conclusions:Clinical and histological findings indicate the integration of the implanted device into the surrounding tissue, evident by the retention rate and the diffuse infiltration of fibroblasts with collagen deposition among the device's fibrils. These data hold promise for clinical application in humans.

Long-term Outcomes of Boston Type I Keratoprosthesis, and Efficacy of Amphotericin B and Povidone-Iodine in Infection Prophylaxis

To evaluate the long-term outcomes, anatomic retention, and complications of Boston type I keratoprosthesis (KPro). Retrospective, interventional case series METHODS: A retrospective chart review of implantations performed January 2008-December 2017 was conducted. Risk factors for anatomical retention and functional success were analyzed. The incidences of infections with and without antimicrobial medications were compared. Twenty-seven eyes of 26 patients were recruited. The most common indication for KPro surgery was failed penetrating keratoplasties (22 eyes, 81.5%). All patients had preoperative best-corrected visual acuity (BCVA) worse than 3/60. Over the mean follow-up of 83.4 ± 28.4 months, 15 eyes (55.6%) demonstrated improved BCVA. The anatomical retention rate was 88.9%, and the functional success rate was 44.4% (retained KPro with BCVA ≥ 3/60). Eyes with ocular surface disease (OSD) had significantly more complications than those without OSD. The most common complications were retroprosthetic membrane formation (15 eyes, 55.6%) and infection (13 eyes, 48.1%). Infectious keratitis was primarily caused by gram-positive bacteria, whereas endophthalmitis was chiefly caused by fungal infection. The infection incidence was significantly lower in eyes using topical 0.1% amphotericin B and 5% povidone iodine (P=.008 and .021, respectively). With its good retention rate and visual outcomes, Boston type I KPro could be an alternative treatment for patients with conventional penetrating keratoplasty failure, especially with appropriate patient selection and complication prevention. Standard prophylactic antibiotics with the addition of topical 0.1% amphotericin B and 5% povidone iodine might be optional effective regimens for infection prevention, especially in tropical countries.

Challenges in management of the Boston Keratoprosthesis Type 1.

The Boston Keratoprosthesis Type 1 was pioneered by Claes Dohlman several decades ago. Since its inception, the device has undergone multiple revisions to address challenges associated with retroprosthetic membrane formation, retention, extrusion, stromal melt and endophthalmitis. Although visual outcomes and retention rates have improved, challenges, especially glaucoma, remain. The Boston Keratoprosthesis Type I device has seen an increase in popularity because of the improvement in rates of retention and visual rehabilitation. Recent outcome studies have allowed clinicians to identify diagnoses and indications that can lead to more favorable results with the Boston Keratoprosthesis Type I device. The Boston Keratoprosthesis Type I device continues to play a vital role in visual rehabilitation for eyes with very low chance of realistic allograft survival -- such as in eyes where corneal grafting is considered high-risk: eyes with corneal limbal stem cell failure, extensive deep corneal stromal neovascularization, and multiple allograft failures. This review article summarizes the perioperative and postoperative challenges, as well as other considerations associated with the device.

Long-term outcomes of Boston keratoprosthesis type I: the Chinese People’s Liberation Army General Hospital experience

PurposeTo report the long-term outcomes of Boston keratoprosthesis type I (B-KPro type I) implantation in the management of severe ocular surface disorders.MethodsRetrospective case series. Patients who underwent B-KPro type I...

Short-term Interim Results of Clinical Outcomes and Complications After Implantation of Boston Keratoprosthesis in Japanese Patients.

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.

Implantable self-aligning fiber-optic optomechanical devices for in vivo intraocular pressure-sensing in artificial cornea.

Artificial cornea is an effective treatment of corneal blindness. Yet, intraocular pressure (IOP) measurements for glaucoma monitoring remain an urgent unmet need. Here, we present the integration of a fiber-optic Fabry-Perot pressure sensor with an FDA-approved keratoprosthesis for real-time IOP measurements using a novel strategy based on optical-path self-alignment with micromagnets. Additionally, an alternative noncontact sensor-interrogation approach is demonstrated using a bench-top optical coherence tomography system. We show stable pressure readings with low baseline drift (<2.8 mm Hg) for >4.5 years in vitro and efficacy in IOP interrogation in vivo using fiber-optic self-alignment, with good initial agreement with the actual IOP. Subsequently, IOP drift in vivo was due to retroprosthetic membrane (RPM) formation on the sensor secondary to surgical inflammation (more severe in the current pro-fibrotic rabbit model). This study paves the way for clinical adaptation of optical pressure sensors with ocular implants, highlighting the importance of controlling RPM in clinical adaptation.

Long-term visual outcomes of the Boston type I keratoprosthesis in Canada

Background/aimsTo evaluate long-term visual outcomes of Boston type I keratoprosthesis (KPro) surgery and identify risk factors for visual failure.MethodsSingle surgeon retrospective cohort study including 85 eyes of 74 patients who...

The First Study Investigating the Clinical Outcomes of Boston Keratoprosthesis Type I Implantation in Indonesia

Introduction and Objective: Boston keratoprosthesis (Boston KPro) is an artificial cornea (collar button design) for a severely damaged cornea that is not suitable for penetrating keratoplasty (PKP). One main advantage of Boston KPro type I is there is no need to perform tarsoraphy. There were no previous studies investigating the clinical outcome of Boston KPro implantation in Indonesia, therefore we aimed to investigate the visual outcomes, device retention, and complications following Boston KPro type 1 keratoprosthesis.&#x0D; Case Presentation: This study was a case series of 11 patients conducted at Jakarta Eye Center with 18 months follow up period. The inclusion criteria were patients with severe corneal diseases that are not amenable for PKP. We found that VA baseline were LP (±72.72%) and HM (27.27%) (mean VA baseline=2.51±0.14 logMAR or equal to HM – LP VA) which significantly improved to 1.09 ± 0.69 logMAR (equal to 6/60 Snellen, ±36.3% were near normal vision based on WHO criteria), p=0.007. Two cases (±16.7%) were still HM because of implant explantation with corneal melting. There were 80.5% retention rates at final follow-up and other complications were retroprosthetic membrane formation (26.7%), elevated IOP (13.9%), and sterile corneal stromal necrosis (17.8%).There was no endophtalmitis found in this study.&#x0D; Conclusion: Boston K-Pro type 1 is a recommended option for patients with multiple corneal graft failure. It provides promising visual outcome with good retention rates. The number of Boston K-Pro type 1 implantations should be increased to counterbalance the corneal blindness burden in Indonesia.

Post-operative outcomes associated with Boston type 1 keratoprosthesis implantation in Northeast China.

The aim of the present study was to investigate the post-operative outcomes associated with Boston type 1 keratoprosthesis (Kpro-1) implantation in the treatment of patients with corneal blindness in Northeast China. Clinical data of patients who had undergone Kpro-1 implantation between July 2010 and November 2014 were retrospectively collected. The visual performance, implant retention and post-surgical complications were recorded for each patient. A total of 20 patients (20 eyes) with corneal blindness were included in the study. Prior to surgery, the patients exhibited poor vision and decreased levels of light perception. At 3 days, 1 month, 6 months, 1 year and 2 years post-surgery, logarithm of the minimum angle of resolution values were significantly decreased compared with the pre-operative values. The initial Kpro-1 implants were retained in 16 eyes. Regarding the post-operative complications, six patients exhibited retroprosthetic membrane formation, two patients presented with endophthalmitis, two patients developed secondary glaucoma, two patients experienced optical cylinder detachment, two patients presented with corneal melting, three patients had retinal detachment, three patients developed corneal ulcers and one patient had secondary optic neuropathy. Overall, the results of the present study suggested that implantation with Kpro-1 may represent an alternative therapeutic strategy for patients following previously failed keratoplasty in Northeast China. Serious complications associated with Kpro-1 implantation are common, and thus, suitable patient selection, continuous follow-up and early treatment interventions are recommended.

Clinical Outcomes Using Oversized Back Plates in Type I Boston Keratoprosthesis.

To examine clinical outcomes of oversized titanium back plates in type I Boston keratoprosthesis (KPro) implantation. Retrospective study of 22 sequential eyes (20 patients) undergoing type I KPro implantation with an oversized titanium back plate (larger than trephined wound diameter by 1.0 mm or more), performed by a single surgeon (K.A.C.) from June 2010 to November 2014. Data were collected regarding preoperative eye characteristics, surgical details, and postoperative clinical outcomes. Mean follow-up time per eye was 24.1±14.9 months. All eyes had improved vision after surgery; 13 eyes (59.1%) maintained visual acuity improvement at last follow-up. Initial KPro's were retained in 19 eyes (86.4%); one eye required KPro replacement. Primary retroprosthetic membrane (RPM) developed in three eyes (13.6%), with similar occurrence in aniridic (14.3%) and nonaniridic eyes (13.3%). Secondary RPM's developed in two eyes (9.1%) after vitritis (one eye) and retinal and choroidal detachment (one eye). Glaucoma was a common comorbidity: 2 of 14 eyes (14.3%) with preoperative glaucoma had glaucoma progression, and 4 of 8 eyes (50.0%) without preoperative glaucoma developed glaucoma postoperatively. Other postoperative complications included retinal detachment (5 eyes, 22.7%) and idiopathic vitritis (3 eyes, 13.6%). Oversized titanium KPro back plates are associated with a low rate of primary RPM formation and may have particular utility in reducing primary RPM formation in aniridic eyes. Glaucoma remains a challenge in postoperative KPro management. Complex eyes, at increased risk of postoperative complications, require careful management.

COMPARISON OF VISUAL AND ANATOMICAL OUTCOMES OF EYES UNDERGOING TYPE I BOSTON KERATOPROSTHESIS WITH COMBINATION PARS PLANA VITRECTOMY WITH EYES WITHOUT COMBINATION VITRECTOMY.

To determine whether 1-year visual and anatomical results after surgery combining pars plana vitrectomy, Boston keratoprosthesis, and a glaucoma drainage device as needed are similar, better, or worse than Boston keratoprosthesis initial implantation alone. We performed a retrospective review of adult patients undergoing Boston keratoprosthesis at our institution. Visual acuity outcomes, anatomical results, and complication rates of patients undergoing combination surgery (including pars plana vitrectomy and a posterior glaucoma drainage device) were compared with those undergoing keratoprosthesis placement alone. There were 70 eyes in the keratoprosthesis alone group and 55 eyes in the keratoprosthesis with pars plana vitrectomy group. Mean follow-up durations were 54.67 months in the keratoprosthesis alone group and 48.41 months in the combination group. Baseline mean Snellen equivalent visual acuities were worse for the combination group compared with the keratoprosthesis alone group (P = 0.027). Visual acuities improved postoperatively by 1 month after keratoprosthesis implantation for both groups and improved three or more lines of Snellen acuity in the majority of eyes for both groups (≥72% by 12 months). Eyes undergoing pars plana vitrectomy had lower rates of de novo (P = 0.015) and significantly lower rates of secondary procedures (P = 0.002) at 1 year. One year complications rates for retroprosthetic membrane formation, retinal detachment, hypotony, cystoid macular edema, epiretinal membrane formation, endophthalmitis, and corneal melting were similar for both groups. Compared with keratoprosthesis alone, combining keratoprosthesis with pars plana vitrectomy and a glaucoma drainage device as needed, resulted in lower rates of de novo glaucoma, lower rates of additional surgical procedures, similar visual acuity outcomes at 1 year, and did not result in higher complication rates.

LVP keratoprosthesis: anatomical and functional outcomes in bilateral end-stage corneal blindness

PurposeTo describe the anatomical and functional outcomes of the novel LVP keratoprosthesis (Kpro), developed as an alternative to the modified osteo-odonto keratoprosthesis (MOOKP), in eyes with end-stage corneal blindness where...

The modified polymethyl methacrylate-silicone keratoprosthesis in rabbit model.

To evaluate the safety and effectiveness of a modified polymethyl methacrylate-silicone keratoprosthesis and its operation method in alkali-burned rabbit model. The polymethyl methacrylate-silicone keratoprostheses were implanted into seven alkali-burned rabbit corneas by a special operation method using autologous graft as the keratoprosthesis (Kpro) carrier. The long-term postoperative outcomes were evaluated. During a postoperative study period of 16 months, except for one Kpro extruded at 3 months, all Kpros were in good position and were kept transparent without Kpro extrusion, keratolysis, infection, endophthalmitis, or retinal detachment. The postoperative complications included elevated intraocular pressure in two cases and temporary retroprosthetic membrane formation in two cases. The modified polymethyl methacrylate-silicone Kpro and its operation method is a relatively safe and effective choice for alkali-burned rabbit eyes. Elevated intraocular pressure is the main complication needing to be resolved.

Comparison of long-term results between osteo-odonto-keratoprosthesis and tibial bone keratoprosthesis

PurposeTo compare the anatomical and the functional results between osteo-odonto-keratoprosthesis (OOKP) and keratoprosthesis using tibial bone autograft (Tibial bone KPro). MethodsWe reviewed the charts of 258 patients; 145 had OOKP whereas 113 had Tibial bone KPro implanted. Functional success was defined as best corrected visual acuity ≥0.05 on decimal scale and anatomical success as retention of the keratoprosthesis lamina. Kaplan-Meier survival curves were calculated for anatomical and functional survival as well as to estimate the probability of post-op complications. ResultsThe anatomical survival for both KPro groups was not significantly different and was estimated as 67% for OOKP and 54% for Tibial bone KPro at 10 years after surgery. There was also no difference found after subdividing for primary diagnosis groups such as chemical injury, thermal burn, trachoma and all autoimmune cases combined. Estimated functional survival at 10 years post-surgery was 49% for OOKP and 25% for Tibial bone KPro, which was significantly different. The probability of patients with Tibial bone KPro developing one or more post-operative complications at 10 years after surgery (65%) was significantly higher than those with OOKP (40%). Mucous membrane necrosis and retroprosthetic membrane formation were more common in Tibial bone KPro than OOKP. ConclusionBoth types of autologous biological KPro, OOKP and Tibial bone KPro, had statistically similar rate of keratoprosthesis extrusion. Although functional success rate was significantly higher in OOKP, it may have been influenced by a better visual potential in the patients in this group.