Endoscopic endonasal decompression of the optic nerve in the setting of compressive lesions: how I do it.

BACKGROUND: Many lesions in the anterior skull base may compress the optic nerve (ON), leading to vision loss, and even irreversible blindness. Although decompression of the optic nerve has traditionally been achieved transcranially, the endoscopic endonasal approach (EEA) is gaining traction as a minimally invasive approach recently. METHOD: We describe the key steps of an EEA ON decompression. The relevant surgical anatomy with illustration is described. Additionally, a video detailing our technique and instruments on an illustrative case is provided. CONCLUSION: Endoscopic endonasal approach ON decompression with a straight feather blade is a feasible, minimally invasive procedure to decompress the ON in the setting of anterior skull base mass lesions.

Minimally Invasive Bleb Surgery for Glaucoma: A Health Technology Assessment.

Background: Glaucoma is the term for a group of eye disorders that causes progressive damage to the optic nerve, which can lead to visual impairment and, potentially, irreversible blindness. Minimally invasive bleb surgery (MIBS) reduces eye pressure through the implantation of a device that creates a new subconjunctival outflow pathway for eye fluid drainage. MIBS is a less invasive alternative to conventional/incisional glaucoma surgery (e.g., trabeculectomy). We conducted a health technology assessment of MIBS for people with glaucoma, which included an evaluation of effectiveness, safety, the budget impact of publicly funding MIBS, and patient preferences and values. Methods: We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using the Cochrane Risk of Bias 1.0 tool for randomized controlled trials (RCTs) and the Risk of Bias Assessment tool for Nonrandomized Studies (RoBANS) for comparative observational studies, and the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We conducted an economic literature search and we estimated the budget impact of publicly funding MIBS in Ontario. We did not conduct a primary economic evaluation due to the limited long-term effectiveness data. We summarized the preferences and values evidence from previous health technology assessments to understand the perspectives and experiences of patients with glaucoma. Results: We included 41 studies (2 RCTs and 39 comparative observational studies) in the clinical evidence review. MIBS may reduce intraocular pressure and the number of medications used, but we are uncertain if MIBS results in outcomes similar to trabeculectomy (GRADE: Moderate to Very low). Compared with trabeculectomy, MIBS may result in fewer follow-up visits and interventions, and adverse events (GRADE: Moderate to Very Low). MIBS may also reduce intraocular pressure and the number of antiglaucoma medications used, compared with other glaucoma treatments, but the evidence is uncertain (GRADE: Very low). Our economic evidence review identified two directly applicable studies. The results of these studies indicate that the cost-effectiveness of MIBS is highly uncertain, and the cost of glaucoma interventions are likely to vary across provinces. The annual budget impact of publicly funding MIBS in Ontario ranged from $0.11 million in year 1 to $0.67 million in year 5, for a total 5-year budget impact estimate of $1.93 million. Preferences and values evidence suggests that fear of ultimate blindness and difficulty managing medication for glaucoma led patients to explore other treatment options such as MIBS. Glaucoma patients found minimally invasive glaucoma surgery (MIGS) procedure beneficial, with minimal side effects and recovery time. Conclusions: Minimally invasive bleb surgery reduces intraocular eye pressure and the number of antiglaucoma medications needed, but we are uncertain if the outcomes are similar to trabeculectomy (GRADE: Moderate to Very low). However, MIBS may be safer than trabeculectomy (GRADE: Moderate to Very low) and result in fewer follow-ups (GRADE: Moderate to Very low). MIBS may also improve glaucoma symptoms compared with other glaucoma treatments, but the evidence is very uncertain (GRADE: Very low).We estimate that publicly funding MIBS would result in an additional cost of $1.93 million over 5 years. Patients who underwent MIGS procedures found them to be generally successful and beneficial, with minimal side effects and recovery time. We could not draw conclusions about specific MIBS procedures or long-term outcomes.

Pediatric Corneal Transplantation in Uyo, Nigeria: Early Experiences.

ABSTRACT: The burden of avoidable blindness from corneal disease is significantly higher where access to specialist eye care, the cost of treatment and the treatment infrastructure including eye banking, are beyond the reach of the impoverished masses. Corneal transplantation in children is challenging: it is more technically complex; patients often require multiple examinations under general anaesthesia to optimize treatment outcomes. There is also the increased risk of several complications including graft dehiscence, infection, rejection, and inappropriate patient or caregiver care. However, when successful, it restores vision. We present a report of our initial experience with penetrating keratoplasty in 2 children with blinding corneal disease in Uyo, Nigeria. Corneal transplantation history was retrieved and data (including data on age, sex, aetiology of corneal disease, indications for corneal transplantation, pre-operative and post-operative visual acuity and intraocular pressure measurements) was extracted for this report. Both patients had standard penetrating keratoplasty performed by one surgeon, under general anaesthesia. Case one was a 10-year-old male presenting with profound visual impairment from congenital hereditary endothelial dystrophy. His best corrected post-operative visual acuity was 6/24. Case two was a 3-year-old male with vision loss due to a corneal leucoma following treated herpes simplex keratitis. Post-operatively, his best corrected visual acuity improved to 6/12. Corneal graft tissue remained clear at more than 3 years of follow-up. Although amblyopia was a notable co-morbidity, corneal transplantation significantly improved their vision. Corneal banking services are advocated for in resource-limited settings where the magnitude of corneal blindness is greatest.

Indications and types of keratoplasties: Trends in the past 10 years (2011-2020) in Eastern India.

Purpose: To observe the trends of various types of keratoplasties in different etiologies over a period of 10 years (2011-2020) in a tertiary eye care center of eastern India. Methods: A retrospective review of patients undergoing keratoplasties from 2011 to 2020 was performed in a tertiary eye care hospital situated in eastern part of India. Apart from demographic data, primary indication for each surgery and type of procedure carried out was recorded. For comparison, data were divided into two time periods: Group I: Jan 2011 to Dec 2015 and Group II: Jan 2016 to Dec 2020. Results: Over a period of 10 years, a total of 2365 (Group I: 902, Group II: 1463) keratoplasties were performed. The average age of patients was 45.8 ± 19.9 and 46.9 ± 20.9 years in Group I and Group II, respectively. Among all the corneal grafts, 1747 (74%) surgeries were full-thickness. Although optical penetrating keratoplasty (OPK) was most the common indication for full-thickness keratoplasties, Descemet's stripping endothelial keratoplasty (DSEK) remained most performed lamellar keratoplasty. Keratitis, corneal scars, and bullous keratopathies remain to be most common indications in both groups. Number of lamellar keratoplasties increased significantly from Group I to Group II for corneal scars (P = 0.02), bullous keratopathies (P = 0.01), and endothelial dystrophies (P = 0.00). Conclusion: With change in time, the indication and technique of keratoplasty has witnessed a changing trend from full-thickness keratoplasty to lamellar keratoplasty. There is rise in trend of lamellar keratoplasties over the period.

Keratoprosthesis in dry eye disease.

Bilateral corneal blindness with severe dry eye disease (DED), total limbal stem cell deficiency with underlying corneal stromal scarring and vascularization, combined with adnexal complications secondary to chronic cicatrizing conjunctivitis is a highly complex situation to treat. In such eyes, procedures such as penetrating keratoplasty alone or combined with limbal stem cell transplantation are doomed to fail. In these eyes, keratoprosthesis (Kpro) or an artificial cornea is the most viable option, eliminating corneal blindness even in eyes with autoimmune disorders such as Stevens-Johnson syndrome, ocular mucous membrane pemphigoid, Sjogren's syndrome, and nonautoimmune disorders such as chemical/thermal ocular burns, all of which are complex pathologies. Performing a Kpro in these eyes also eliminates the need for systemic immunosuppression and may provide relatively early visual recovery. In such eyes, the donor cornea around the central cylinder of the Kpro needs to be covered with a second layer of protection to avoid desiccation and progressive stromal melt of the underlying cornea, which is a common complication in eyes with severe DED. In this review, we will focus on Kpro designs that have been developed to survive in eyes with the hostile environment of severe DED. Their outcomes in such eyes will be discussed.

Intraoperative intraorbital bleeding: considerations from a collaborative and retrospective Italian study with a management algorithm proposal.

BACKGROUND: Intraoperative intraorbital bleeding is a rare but potentially catastrophic event that can lead even to blindness, if not treated promptly. The goal of surgery is to quickly reduce intraorbital pressure thus restoring normal visual function. Aim of our work is to propose a practical algorithm helping the surgeon in the setting of this critical event. METHODOLOGY: An Italian multi-institutional retrospective study was conducted. All the cases of intraoperative intra-orbital bleeding requiring at least some form of surgical management were analyzed. Cases simply managed conservatively were excluded from this analysis. RESULTS: Sixteen cases were collected. Of these, 12 were initially treated with a medial wall orbital decompression, while 4 were treated via a lateral canthotomy and inferior cantholysis (LCC). Ten patients recovered completely. Four patients presented post-op sequelae (diplopia, enophthalmous and/or eyelid malpositioning). Two major negative outcomes (blindness) were observed. CONCLUSIONS: Timely surgical intervention is critical. According to the setting in which the bleeding occurs, different options are available. LCC is probably the most rapid maneuver that can be done to reduce intraorbital pressure. Anyway, if the patient is still in the OR and a complete ethmoidectomy yet done we advise, as first step, to perform a medial orbital wall decompression.

[Keratoprostheses: Last Hope for the Most Severe Corneal Diseases]. / Keratoprothesen: letzte Hoffnung bei schwersten Hornhauterkrankungen.

Corneal blindness affects over 8 million adults and 1.5 million children worldwide, making it one of the top 5 causes of blindness. Depending on the recipient's corneal condition corneal transplantation may not be a viable treatment option. In such seemingly no-alternative situations, keratoprosthesis implantation can be an option in some patients. In terms of numbers, two types of keratoprostheses are currently used: 1. Keratoprostheses with biological haptics made of tooth or tibia bone. 2. The Boston type I-keratoprosthesis. Both types have optics made of PMMA. The most common complication is the formation of an optically disturbing retroprosthetic membrane behind the optic, which can usually be removed with YAG laser. Causes of blindness after keratoprosthesis implantation are glaucoma, endophthalmitis and retinal detachment. The extrusion rate of the Boston type I-keratoprosthesis seems to be higher than after keratoprosthesis implantation with biological haptic. Autoimmunological corneal diseases have increased extrusion rates and higher rates of endophthalmitis when compared to non-autoimmunological diseases. Visual outcomes after keratoprosthesis implantation are potentially very good and usually limited by extracorneal concomitant diseases. Advances in glaucoma diagnostic (OCT, implantation of intraocular pressure sensors), standard glaucoma prophylaxis by medication or surgery, modern retinal surgery and better treatment options in case of extrusion improve the prognosis of keratoprosthesis surgery. Still, the ideal technique for permanent anchoring of artifical optics in biological tissue has yet to be developed.

Postoperative Complications in the Primary Tube Versus Trabeculectomy Study During 5 Years of Follow-up.

PURPOSE: To describe postoperative complications encountered in the Primary Tube Versus Trabeculectomy (PTVT) Study during 5 years of follow-up. DESIGN: Multicenter randomized clinical trial. PARTICIPANTS: A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group. METHODS: Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes). MAIN OUTCOME MEASURES: Surgical complications, reoperations for complications, visual acuity, and cataract progression. RESULTS: Early postoperative complications occurred in 24 patients (19%) in the tube group and 40 patients (34%) in the trabeculectomy group (P = 0.013). Late postoperative complications developed in 27 patients (22%) in the tube group and 32 patients (27%) in the trabeculectomy group (P = 0.37). Serious complications producing vision loss and/or requiring a reoperation were observed in 3 patients (2%) in the tube group and 9 patients (8%) in the trabeculectomy group (P = 0.11). Cataract progression was seen in 65 patients (52%) in the tube group and 52 patients (44%) in the trabeculectomy group (P = 0.30). Surgical complications were not associated with a higher rate of treatment failure (P = 0.61), vision loss (P = 1.00), or cataract progression (P = 0.77) CONCLUSIONS: A large number of surgical complications were observed in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was higher following trabeculectomy with MMC than with tube shunt surgery. The rates of late postoperative complications, serious complications, and cataract progression were similar with both surgical procedures after 5 years of follow-up. Surgical complications did not increase the risk of treatment failure, vision loss, or cataract progression.

[The research progress of mesenchymal stem cell induction and differentiation into corneal tissue].

Keratopathy is one of the most important blinding eye diseases in the world. Corneal opacity caused by keratopathy can seriously damage visual function. For example, corneal ulcer can lead to perforation and even loss of the eyeball. Although corneal transplantation is a routine treatment in clinical practice, there are not only a serious shortage of corneal donors in our country, but also various complications after keratoplasty that can not be avoided. In recent years, with the rapid development of regenerative medicine, it has been found that mesenchymal stem cells can differentiate into a variety of functional cells including corneal tissue under suitable induction conditions, which has a broad prospect of clinical application. This finding provides new ideas and methods for the treatment of keratopathy and corneal blindness in many aspects. This article reviews the research status of induction methods of mesenchymal stem cells in various specialties, particularly in the corneal subspecialty.

A case study in phenomenology of visual experience with retinal prosthesis versus visual-to-auditory sensory substitution.

The phenomenology of the blind has provided an age-old, unparalleled means of exploring the enigmatic link between the brain and mind. This paper delves into the unique phenomenological experience of a man who became blind in adulthood. He subsequently underwent both an Argus II retinal prosthesis implant and training, and extensive training on the EyeMusic visual to auditory sensory substitution device (SSD), thereby becoming the first reported case to date of dual proficiency with both devices. He offers a firsthand account into what he considers the great potential of combining sensory substitution devices with visual prostheses as part of a complete visual restoration protocol. While the Argus II retinal prosthesis alone provided him with immediate visual percepts by way of electrically stimulated phosphenes elicited by the device, the EyeMusic SSD requires extensive training from the onset. Yet following the extensive training program with the EyeMusic sensory substitution device, our subject reports that the sensory substitution device allowed him to experience a richer, more complex perceptual experience, that felt more "second nature" to him, while the Argus II prosthesis (which also requires training) did not allow him to achieve the same levels of automaticity and transparency. Following long-term use of the EyeMusic SSD, our subject reported that visual percepts representing mainly, but not limited to, colors portrayed by the EyeMusic SSD are elicited in association with auditory stimuli, indicating the acquisition of a high level of automaticity. Finally, the case study indicates an additive benefit to the combination of both devices on the user's subjective phenomenological visual experience.

Endoilluminator-aided cataract surgery in eyes with corneal opacity - A modified surgical approach.

Background: Cataract and corneal blindness continue to be leading causes of reversible blindness in India. These can co-exist in a multitude of pathologies such as trauma, healed keratitis (old herpetic scar), chronic degenerative changes such as labrador keratopathy, bullous keratopathy, corneal dystrophies etc. Phacoemulsification in such eyes is rewarding to the patient in terms of minimal intervention, less risk of complications owing to reduced open sky time (as in case of combined keratoplasty), and better predictable visual outcomes. Approach to such eyes with poor visualisation is highly challenging. Purpose: We illustrate a modified surgical technique of chandelier illumination through pars plana for cataract surgery in eyes with corneal opacity of varying grades. Synopsis: Five patients with dense cataract and small pupils, associated with corneal opacity (leucomatous and macular grade) are described. Closed chamber phacoemulsification with intraocular lens with or without pupil expanders was performed assisted by 23 or 25 gauge pars plana chandelier illumination introduced in the vitreous cavity through a sclerotomy wound made prior to phacoemulsification in the inferotemporal quadrant. Highlights: Chandelier illumination aids in reducing the light scatter that occurs due to corneal opacity. Ease of visualisation of lens structures and of performing cataract surgery was noticed. One case was combined with penetrating keratoplasty with reduced open sky time. This assisted technique has advantages such as enhancing visualisation intraoperatively and allowing working in closed chamber. Its self-retaining nature aids bimanual manipulation. No complications were encountered. The video highlights the utility, advantages and practicality of chandelier retroillumination in patients with corneal opacities of varying degree undergoing phacoemulsification. Video Link: https://youtu.be/I3z6QG-_wD8.

Development of Visual Memory Capacity Following Early-Onset and Extended Blindness.

It is unknown whether visual memory capacity can develop if onset of pattern vision is delayed for several years following birth. We had an opportunity to address this question through our work with an unusual population of 12 congenitally blind individuals ranging in age from 8 to 22 years. After providing them with sight surgery, we longitudinally evaluated their visual memory capacity using an image-memorization task. Our findings revealed poor visual memory capacity soon after surgery but significant improvement in subsequent months. Although there may be limits to this improvement, performance 1 year after surgery was found to be comparable with that of control participants with matched visual acuity. These findings provide evidence for plasticity of visual memory mechanisms into late childhood but do not rule out vulnerability to early deprivation. Our computational simulations suggest that a potential mechanism to account for changes in memory performance may be progressive representational elaboration in image encoding.

Osteo-odonto-keratoprosthesis According to Strampelli Original Technique: A Retrospective Study With Up to 30 Years of Follow-up.

PURPOSE: To describe clinical, anatomical, and visual outcomes obtained from a long-term follow-up of 59 patients who underwent osteo-odonto-keratoprosthesis (OOKP) using the Strampelli original technique. DESIGN: Retrospective clinical cohort study. METHODS: The study included 82 eyes of 59 patients who underwent OOKP surgery between 1969 and 2011. Patients' clinical characteristics before surgery as well as complications and further surgeries until the end of follow-up were recorded. Best-corrected visual acuity (BCVA) was revised before surgery and at 1 month, 1 year, and every 5 years until the 30th year of follow-up. RESULTS: Mean follow-up post-OOKP was 27.4 ± 11.2 years (range, 2.4-52). The most frequent cause of blindness was chemical injuries (71%). OOKP integrity was maintained in 77 of 82 eyes (94%) until the end of follow-up. Excluding cataract, acquired glaucoma was the most frequent complication, with a prevalence at 10 years of 36%. Mean BCVA improved from 2.60 ± 0.32 at presentation to 0.40 ± 0.65 at 1 year and 1.21 ± 1.19 logMAR at 30 years. Overall, 51% of the included eyes attained a BCVA better than 0.05 logMAR, and stabilization of BCVA was observed for the first 10 years of follow-up post-OOKP. Better BCVA outcomes were observed in the Stevens-Johnson syndrome or toxic epidermal necrolysis (SJS/TEN) group, whereas glaucoma was found not to significantly affect visual acuity. CONCLUSIONS: The original OOKP still represents a valid surgical choice, which is durable over time, for restoring vision in end-stage corneal blindness patients who are not eligible for a corneal transplant.

The evolution of the modified osteo-odonto-keratoprosthesis, its reliability, and long-term visual rehabilitation prognosis: An analytical review.

An exhaustive search of the world's literature was performed to analyze all case reports and series on the modified osteo-odonto-keratoprosthesis (MOOKP) published up to January 2022. The demographic profile, the primary indication for surgery, surgical technique variations, postoperative medical management, long-term functional and anatomical outcomes, and intra- and postoperative complications were analyzed and compared. Additionally, some of the authors' (GI, VP, and GA) unpublished MOOKP cases were studied. An extensive literature search yielded 37 case series and case reports. Overall, 958 patients were analyzed. The most common indication for surgery was autoimmune disease (39.1%), closely followed by chemical injury (38.8%). The most common intraoperative complications (21.67%) included maxillofacial, vitreous hemorrhage/vitritis, and mucosal. The most common postoperative complications (78.4%) were lamina and oral mucosa-associated, secondary glaucoma, and choroid/retinal detachment. Follow-up periods ranged from one to 364 months (median: 36.7 months). Altogether, 78% of patients achieved a visual acuity of 20/400 or better at the end of the follow-up period, and 91.2% improved at least temporarily after MOOKP surgery. Mean anatomic success at the end-of-follow-up for all patients was 88.25% (range, 50-100%). The long-term anatomic and functional success of the MOOKP makes it a reliable option for visual rehabilitation in patients with bilateral corneal blindness and end-stage ocular surface disease. This review aims to describe the evolution of the MOOKP procedure, analyzing all published case series for its long-term reliability, visual and anatomical outcomes, complications, and future directions.

The historical development and an overview of contemporary keratoprostheses.

Corneal blindness is a major cause of ocular morbidity that affects 4.5 million people worldwide. Though penetrating keratoplasty is an excellent option for most patients with corneal blindness, there are various conditions for which corneal transplantation carries a low likelihood of success. In cases of multiple failed transplants, the keratoprosthesis, an artificial cornea, is a well-documented surgical option, though few models are commercially available. Keratoprostheses also provide a solution to those in developing areas of the world who do not have access to penetrating keratoplasty owing to limitations in the supply of corneal donor tissue. We summarize the history of keratoprostheses, examine the various keratoprosthesis models used across the globe, and highlight efforts to improve the accessibility and biointegration of keratoprosthesis through novel technological developments.

Acellular Porcine Cornea Produced by Supercritical Carbon Dioxide Extraction: A Potential Substitute for Human Corneal Regeneration.

PURPOSE: The aim of this study was to develop a non-cytotoxic, biocompatible innovative acellular porcine cornea (APC) for corneal wound healing and corneal blindness treatment. METHODS: APC was produced by using supercritical carbon dioxide (SCCO2) to decellularize the porcine cornea. Decellularization of the porcine cornea was examined by hematoxylin and eosin staining and 4,6-diamidino-2-phenylindole, dihydrochloride staining. The residual DNA content of APC was analyzed in comparison with the native porcine cornea. Virus inactivation up to at least 6 log10 was confirmed for the stepwise process of APC for 4 different model viruses. In addition, a series of in vitro and in vivo tests in accordance with ISO-10993 biocompatibility assay and animal performance tests were performed. RESULTS: APC produced by the SCCO2 process revealed complete decellularization, without any residual non-collagenous proteins. The scanning electron microscopy structural features of the decellularized cornea were similar to those of human. APC was found to be nontoxic and exhibited excellent biocompatibility in both in vitro and in vivo studies. The animal performance test proved that APC exerted excellent adaptability on the cornea and no sign of irritation and good compatibility in lamellar corneal transplantation. CONCLUSIONS: APC manufactured by SCCO2 technology revealed complete cells and non-collagenous protein removal compared with the Triton-sodium dodecyl sulfate decellularization process. APC showed excellent biocompatibility in rabbit lamellar corneal transplantation with a follow-up to 1 year. APC can be a potential substitute for human-donated cornea for corneal transplantation in the near future.