The sclera, the prion, and the ophthalmologist

Necrotizing Scleritis: A Review

Necrotizing scleritis is the most destructive and vision-threatening form of scleritis. Necrotizing scleritis can occur in systemic autoimmune disorders and systemic vasculitis, as well as following microbial infection. Rheumatoid arthritis and granulomatosis with polyangiitis remain the commonest identifiable systemic diseases associated with necrotising scleritis. Pseudomonas species is the most common organism causing infectious necrotizing scleritis, with surgery the most common risk factor. Necrotizing scleritis has the highest rates of complications and is more prone to secondary glaucoma and cataract than other phenotypes of scleritis. The differentiation between non-infectious and infectious necrotizing scleritis is not always easy but is critical in the management of necrotizing scleritis. Non-infectious necrotizing scleritis requires aggressive treatment with combination immunosuppressive therapy. Infectious scleritis is often recalcitrant and difficult to control, requiring long-term antimicrobial therapy and surgical debridement with drainage and patch grafting due to deep-seated infection and the avascularity of the sclera.

Novel use of an autologous scleral button graft to close the anterior defect in evisceration surgery

PURPOSE

To present an alternative evisceration technique with long-term follow-up data. This technique involves the insertion of an acrylic implant into a modified scleral shell which is closed using an autologous scleral graft.

METHODS

This was a retrospective analysis of eviscerations performed in a district-general hospital in the UK. All patients underwent conventional ocular evisceration after total keratectomy. A full thickness scleral graft is harvested from the posterior sclera, using an internal approach, with an 8 mm dermatological punch. An 18-20 mm acrylic implant is placed into the shell, and the scleral graft is used to close the anterior defect. Demographic characteristics, implant size and type, and cosmetic results from pictures of all patients were recorded. All patients were invited for a review to measure motility, eyelid height, patient recorded satisfaction and complications.

RESULTS

Of the five patients identified, one had since died. The remaining four attended a review in person. The mean time between surgery and review was 48 months. The mean implant size was 19 mm. There were no cases of implant extrusion or infection. All four had a <1 mm asymmetry in measured eyelid height and ≥5 mm horizontal gaze motility. All patients self-reported "good" cosmesis. An independent assessment identified "mild asymmetry" in two cases and "moderate" in the other two.

CONCLUSION

Evisceration with this novel autologous scleral graft technique restores volume in the anterior orbit with good cosmetic results, and with no cases of implant exposure reported in this small case series. This technique should be compared prospectively to established techniques.

Alzheimer PHF-tau aggregates do not spread tau pathology to the brain via the Retino-tectal projection after intraocular injection in mouse models

Neurofibrillary tangles (NFT), a neuronal lesion found in Alzheimer's disease (AD), are composed of fibrillary aggregates of modified forms of tau proteins. The propagation of NFT follows neuroanatomical pathways suggesting that synaptically connected neurons could transmit tau pathology by the recruitment of normal tau in a prion-like manner. Moreover, the intracerebral injection of pathological tau from AD brains induces the seeding of normal tau in mouse brain. Creutzfeldt-Jacob disease has been transmitted after ocular transplants of cornea or sclera and the scrapie agent can spread across the retino-tectal pathway after intraocular injection of scrapie mouse brain homogenates. In AD, a tau pathology has been detected in the retina. To investigate the potential risk of tau pathology transmission during eye surgery using AD tissue material, we have analysed the development of tau pathology in the visual pathway of mice models expressing murine tau, wild-type or mutant human tau after intraocular injection of pathological tau proteins from AD brains. Although these pathological tau proteins were internalized in retinal ganglion cells, they did not induce aggregation of endogenous tau nor propagation of a tau pathology in the retino-tectal pathway after a 6-month incubation period. These results suggest that retinal ganglion cells exhibit a resistance to develop a tau pathology, and that eye surgery is not a major iatrogenic risk of transmission of tau pathology, contrary to what has been observed for transmission of infectious prions in prion diseases.

The carbon footprint of cataract surgery in a French University Hospital

PURPOSE

To assess the carbon footprint of cataract surgery in a French university hospital.

SETTING

Operating room of Cochin University Hospital, Paris, France.

DESIGN

Single-center component analysis.

METHODS

One day of surgery was used as a reference. Greenhouse gases (GHG) related to patient and staff transportation were calculated based on the distance travelled and the means of transportation used. The annual consumption of energy (heating and electricity) of our building was converted in kg equivalent of carbon dioxide (CO₂eq), and the principle of proportionality was used to calculate what was used for a single cataract procedure. GHG emissions related to the life cycle assessment (LCA) of the equipment used and the sterilization process were calculated.

RESULTS

The LCA of disposable items accounted for 59.49kg (73.32%) of CO₂eq for each procedure. A single procedure generated 2.83±0.10kg of waste. The average CO₂eq produced by the transportation of the patients to and from our center, adjusted for one procedure, was 7.26±6.90kg (8.95%) of CO₂eq. The CO₂eq produced by the sterilization of the phacoemulsifier handpiece was 2.12kg (2.61%). The energy consumption of the building and staff transportation accounted for the remaining CO₂eq emissions, 0.76kg (0.93%) and 0.08kg (0.10%) respectively. Altogether, the carbon footprint of one cataract procedure in our center was 81.13kg CO₂eq - the equivalent of an average car driving 800km.

CONCLUSION

Our data provide a basis to quantify cataract surgery as a source of GHG and suggests that reductions in emissions can be achieved.

Human Prion Disorders: Review of the Current Literature and a Twenty-Year Experience of the National Surveillance Center in the Czech Republic

Human prion disorders (transmissible spongiform encephalopathies, TSEs) are unique, progressive, and fatal neurodegenerative diseases caused by aggregation of misfolded prion protein in neuronal tissue. Due to the potential transmission, human TSEs are under active surveillance in a majority of countries; in the Czech Republic data are centralized at the National surveillance center (NRL) which has a clinical and a neuropathological subdivision. The aim of our article is to review current knowledge about human TSEs and summarize the experience of active surveillance of human prion diseases in the Czech Republic during the last 20 years. Possible or probable TSEs undergo a mandatory autopsy using a standardized protocol. From 2001 to 2020, 305 cases of sporadic and genetic TSEs including 8 rare cases of Gerstmann-Sträussler-Scheinker syndrome (GSS) were confirmed. Additionally, in the Czech Republic, brain samples from all corneal donors have been tested by the NRL immunology laboratory to increase the safety of corneal transplants since January 2007. All tested 6590 corneal donor brain tissue samples were negative for prion protein deposits. Moreover, the routine use of diagnostic criteria including biomarkers are robust enough, and not even the COVID-19 pandemic has negatively impacted TSEs surveillance in the Czech Republic.

Translational and Regulatory Challenges of Corneal Endothelial Cell Therapy: A Global Perspective

Cell therapies are emerging as a unique class of clinical therapeutics in medicine. In 2015, Holoclar (ex vivo expanded autologous human corneal epithelial cells containing stem cells) gained the regulatory approval for treating limbal stem cell deficiency after chemical eye burn. This has set a precedent in ophthalmology and in medicine, reinforcing the therapeutic promise of cell therapy. However, to generalize and commercialize cell therapies on a global scale, stringent translational and regulatory requirements need to be fulfilled at both local and international levels. Over the past decade, the Singapore group has taken significant steps in developing human corneal endothelial cell (HCEnC) therapy for treating corneal endothelial diseases, which are currently the leading indication for corneal transplantation in many countries. Successful development of HCEnC therapy may serve as a novel solution to the current global shortage of donor corneas. Based on the experience in Singapore, this review aims to provide a global perspective on the translational and regulatory challenges for bench-to-bedside translation of cell therapy. Specifically, we discussed about the characterization of the critical quality attributes (CQA), the challenges that can affect the CQA, and the variations in the regulatory framework embedded within different regions, including Singapore, Europe, and the United States. Impact statement Functional corneal endothelium is critical to normal vision. Corneal endothelial disease-secondary to trauma, surgery, or pathology-represents an important cause of visual impairment and blindness in both developed and developing countries. Currently, corneal transplantation serves as the current gold standard for treating visually significant corneal endothelial diseases, although limited by the shortage of donor corneas. Over the past decade, human corneal endothelial cell therapy has emerged as a promising treatment option for treating corneal endothelial diseases. To allow widespread application of this therapy, significant regulatory challenges will need to be systematically overcome.

Aurolab Aqueous Drainage Implant With and Without Scleral Patch Graft in Refractory Adult and Pediatric Glaucomas: A Comparative Study

PURPOSE

To compare the 2-year outcomes of eyes that received the Aurolab aqueous drainage implant (AADI) with and without a scleral patch graft.

DESIGN

Retrospective comparative interventional case series.

METHODS

Eyes with AADI and a minimum of a 2-year follow-up were included. Eyes that underwent implantation before January 2016 had surgery with a scleral patch graft covering the distal end of the tube, whereas those that were implanted after this period underwent surgery using a needle-generated scleral tunnel without the patch graft. The cumulative failure of the AADI was defined as intraocular pressure (IOP) >18 mm Hg or not reduced by 30% below baseline on 2 consecutive follow-up visits after 3 months.

RESULTS

We included 215 adult eyes (n = 147 with patch graft, n = 68 without patch graft) and 111 pediatric eyes (n = 73 with patch graft, n = 38 without a patch graft). The mean IOP in eyes without the patch graft was higher at 1 month in adult eyes (before, 27.5 ± 14.1 vs after, 22.3 ± 11.1; P = .01) but not in pediatric eyes (14.3 ± before, 5.8 vs after, 17.8 ± 11.0; P = .39); there were no differences in IOP, vision, number of antiglaucoma medications, and complications between groups at all other time points. None of the eyes without the patch graft experienced tube exposure. Cumulative success rates at 2 years in adults (66.2% vs 63.9%, respectively; P = .85) were similar to those in children (77.2% vs 71.9%, respectively; P = .83) with both techniques.

CONCLUSIONS

AADI placed without a scleral patch graft is as safe and effective as AADI placed with a patch graft in pediatric and adult refractory glaucomas.

Current clinical application of sclera and amniotic membrane for ocular tissue bio-replacement

To report the current clinical applications and trends of scleral and amniotic membrane use in ophthalmology. Review of annual reports from the Catalan Transplant Organization (OCATT), on scleral patch and amniotic membrane eye indications in Catalonia region (Spain) over a 6-year period from 2013 to 2018. A total of 874 scleral and 1665 amniotic membranes patches were implanted, from January 2013 to December 2018. The most frequent indication over the 6-year period for scleral patch was glaucoma surgery (77.5%), eyelid reconstruction (5.2%) and corneal or scleral ulcer (5%). Regarding amniotic membrane, corneal ulcer (26.9%), conjunctival reconstruction (23.8%) and corneal epithelial defect (22.7%) were the most common indications. During the study period, an increasing trend was found on sclera patches for eyelid reconstruction (p = 0.0032) and amniotic membrane for inflammation management (p = 0.0198). Glaucoma surgery and corneal ulcers have represented the top indications for scleral patch and amniotic membrane use, over the period, respectively. A significant trend has also been found towards eyelid reconstruction using scleral patches and amniotic membrane for anterior segment inflammation management. This evolving scenario in tissue use for ocular surgery has to be taken into consideration, especially regarding eye banks facing current and futures changes in tissue preservation, storage and indications.

Treatment of Exposed Hydroxyapatite Orbital Implants Wrapped with a Synthetic Dura Substitute

Purpose

To describe cases of exposed hydroxyapatite (HA) implants wrapped with the synthetic dura substitute Neuro-Patch treated via simple Neuro-Patch removal.

Methods

The medical records of seven patients who experienced exposure of their HA implant were reviewed. All patients had been enucleated and implanted with HA wrapped with Neuro-Patch. For treatment, Neuro-Patch was removed to the greatest extent possible. After applying local anesthesia with lidocaine, blunt dissection was performed to separate the conjunctiva and Neuro-Patch via the site of exposure. Pressure was applied to the remaining Neuro-Patch with forceps and removed with scissors.

Results

Neuro-Patch was visible at the area of exposure in all patients. No surgery beyond initial Neuro-Patch removal was necessary in six of the seven patients. In five cases, the exposed area began to heal rapidly after Neuro-patch removal without primary closure of the defect. In one case, the Neuro-Patch material and all necrotic tissue was removed aggressively due to inflammation around the orbital implant. Lastly, an infection was noted in one case, prompting complete removal of the Neuro-Patch–wrapped HA implant.

Conclusions

Wrapping material may hinder implant vascularization. Exposure of HA in wrapped implants can be successfully treated by a simple removal procedure if detected and managed early.

A biomimetic tarso-conjunctival biphasic scaffold for eyelid reconstruction in vivo

Conventional 3D porous scaffolds used as tarsal plate substitute may cause corneal irritation and conjunctival mucoid discharge, and even lead to blindness and cicatricial blepharon deformities. In this study, collagen/chitosan (Col/CS) sponges with thickness of 240 μm, 466 μm, and 724 μm were composited onto poly(propylene fumarate)-co-2-hydroxyethyl methacrylate (PPF-HEMA) polymer networks to obtain the corresponding biphasic scaffolds, which simulate the natural anatomy of posterior lamella of eyelid. These three scaffolds exhibited a porous structure with porosity of ∼90%, simulated elastic modulus, appropriate degradation rate and good biocompatibility. Composited with Col/CS sponge of difference thickness, the scaffolds induced different cellular behaviors such as proliferation, distribution and stratification, by regulating the mechanical properties cells sensed as effective modulus. In a rabbit tarso-conjunctival defect model, the grafted biphasic scaffolds promoted re-epithelization with functional regenerated conjunctiva. Hence, the biphasic composite scaffolds may be a promising substitute for tarso-conjunctival repair.

Transplantation of autologous perichondrium with amniotic membrane for progressive scleral necrosis

PURPOSE

Scleral necrosis with severe ischemia is refractory to conventional treatment because of avascular progressive necrosis. We assessed the therapeutic efficacy and safety of autologous perichondrium transplantation in patients with progressive scleral necrosis (PSN) and analyzed the clinical effects.

METHODS

This study was a prospective, interventional, and noncomparative case series. Reconstructive surgery using autologous perichondrium and amniotic membrane (AM) was performed in patients with PSN who showed progressive ischemic scleral melting with impending perforation state and/or broad avascular area larger than 10 mm in diameter. The primary outcome was restoration of scleral integrity with healthy vascularized epithelium over the graft at six months after surgery. The secondary outcome was complication rate associated with autologous perichondrium graft use.

RESULTS

Eighteen eyes of 14 patients underwent reconstructive surgery using autologous perichondrium patch and AM grafts. Observations indicated the graft provided the eyeball with successful structural integrity in 17 out of the 18 cases (94.4%) at six months after surgery. One eye showed a small scleral defect due to wound dehiscence at four month after the surgery. Additional surgery using perichondrium and AM stabilized the eye. The scleral necrosis healed completely after perichondrium and AM transplantation, even in cases with full-thickness scleral defect. The scleral integrity was maintained until the last follow-up session. There were no serious complications of endophthalmitis or graft infection.

CONCLUSIONS

Reconstructive surgery using autologous perichondrium and AM is an effective method for restoration of scleral integrity and vascularization of the episclera and conjunctiva in eyes with PSN. Therefore, autologous perichondrium can be considered as an appropriate new biologic tissue for PSN.

Combined use of bulbar conjunctival pedicle flap and labial mucous membrane graft for porous orbital implant exposure: Long-term outcome

Implant exposure is the most common serious complication of porous orbital implants, and often requires surgical repair. This study aims to describe a new repair technique using a bulbar conjunctival pedicle flap and a labial mucous membrane patch graft, as well as to report its long-term results. A retrospective chart review was performed on all patients whose porous orbital implant exposures were repaired using this technique from 1995 to 2014. Twenty-three patients were included. The maximal defect dimension ranged from 2 to 18 mm. Sixteen patients (70%) also received a banked human scleral patch graft during their repair. The mean follow-up was 130 months (range 29-267 months). Eighteen patients (78%) were successfully treated with one repair surgery. At the final follow-up, 21 patients (91%) could comfortably wear a prosthetic eye, and 18 patients (78%) reported satisfactory cosmesis. Two patients (9%) developed small conjunctival cysts that were successfully excised. The combination of a bulbar conjunctival pedicle flap and a labial mucous membrane patch graft is a simple but effective technique in salvaging exposed porous orbital implants. Its long-term results are promising.

Orbital implants in retinoblastoma patients: 23 years of experience and a review of the literature

PURPOSE

To evaluate complications of different types of orbital implants following enucleation for retinoblastoma.

METHODS

We performed a retrospective chart study of all patients that underwent enucleation as treatment of retinoblastoma between April 1991 and June 2013. Events of implant exposure, extrusion (defined as a complete loss of the implant, or a major exposure that could not be closed) and socket abnormalities were analysed for association with implant type and influence of additional external beam radiation therapy (EBRT) and/or chemotherapy.

RESULTS

A total of 224 enucleations in 216 patients (eight bilateral) were identified. Mean age at surgery was 1.9 (median 1.5) years. Of the 219 included enucleated eyes, 20 were not replaced by a primary implant and 18 were replaced by an Allen implant. Scleral wrapped hydroxyapatite (HA) and acrylic implants (polymethylmethacrylate) were inserted in, respectively, 79 and 102 cases. In the total population, 29 treatment or implant-specific events (13.2%) were registered. Main complications were implant exposure n = 10 (4.6%) and extrusion n = 6 (2.7%). The acrylic/sclera group had less exposures or extrusions (5 of 102, 4.9%) compared to the HA/sclera group (10 of 79, 12.7%), although this difference did not quite reach statistical significance (p = 0.06). Additional treatment (chemotherapy and/or EBRT for the fellow eye) was administered in 78 cases (35.8%). The overall complication rate in the entire study population was significantly higher (16.7% versus 5.7%) in the group exposed to additional therapy (OR 3.3; 95% CI 1.30-8.36 p = 0.008). This negative effect of additional therapy was also significant in the combined acrylic/HA group (OR 2.9; 95% CI 0.97-8.46 p = 0.048).

CONCLUSION

Our results suggest a favourable outcome for acrylic implants compared to the HA implant. Additional treatment with chemotherapy and/or EBRT is associated with an increased risk of complications.

[Reconstruction of anophthalmic socket]

PURPOSE

Evaluate different surgical techniques in the management of the contracted anophthalmic socket.

PATIENTS AND METHODS

A retrospective study including 12 patients with acquired anophthalmic socket presenting inadequate fornices and/or orbital volume loss. The surgeries performed were conjunctival suture to the periosteum (mild fornix contraction), buccal mucosa graft (moderate fornix retraction), auricular cartilage graft (severe fornix retraction), and dermis-fat graft (loss of orbital volume).

RESULTS

Fornix retraction was mild in two patients, moderate in three patients, and severe in two patients. We observed five patients with loss of orbital volume. Successful correction was achieved in all patients with fornix retraction who were able to wear an external prosthesis. One patient with orbital volume loss developed graft atrophy.

CONCLUSION

Autologous grafts are useful in the rehabilitation of the contracted socket.

Myopexy of the vertical rectus muscles using expanded polytetrafluoroethylene for management of a lost medial rectus muscle

Strabismus due to a lost rectus muscle is uncommon. Surgical treatment of the condition by means of scleral augmented myopexy of the vertical rectus muscles can reduce the potential for anterior segment ischemia by leaving the vascular supply intact. We report a successful use of expanded polytetrafluoroethylene in this procedure to correct long-term exotropia caused by a lost medial rectus muscle.

Evaluation of Ahmed glaucoma valve implantation through a needle-generated scleral tunnel in Mexican children with glaucoma

Purpose:

To evaluate the results and extrusion rates of the Ahmed glaucoma valve (AGV) implantation through a needle-generated scleral tunnel, without a tube-covering patch, in children.

Materials and Methods:

A retrospective review of the charts of 106 Mexican children implanted with 128 AGVs operated between 1994 and 2002, with the needle track technique, at our institution, with at least six months follow up was done. Main outcome measures were intraocular pressure (IOP) control, tube extrusions or exposure and other complications.

Results:

Kaplan-Meier analysis demonstrated a 96.9% survival rate at six months, 82.4% at one year, 78.7% at two years, 70% at three years and 41.6% at four years. Total success at the last follow-up (IOP between 6 and 21 mm Hg without medications) was achieved in 30 eyes (23.5%), 58 eyes (45.3%) had qualified success (only topical hypotensive drugs) and 40 eyes (31.3%) were failures. The mean pre- and post-operative IOP at the last follow up was 28.4 mmHg (SD 9.3) and 14.5 mmHg (SD 6.3), respectively. No tube extrusions or exposures were observed. Tube-related complications included five retractions, a lens touch and a transitory endothelial touch. The risk of failure increased if the eye had any complication or previous glaucoma surgeries.

Conclusion:

Medium-term IOP control in Mexican children with glaucoma can be achieved with AGV implantation using a needle-generated tunnel, without constructing a scleral flap or using a patch to cover the tube. There were no tube extrusions, nor any tube exposures with this technique.

Graft-free Ahmed tube insertion: a modified method at 5 mm from limbus

Objective

To determine the medium-term outcome of Ahmed implants inserted through a needle tract at 5 mm from limbus that eliminates the need for a donor scleral graft.

Methods

A retrospective case series of 19 patients undergoing Ahmed implant surgery for refractory glaucoma with a mean follow-up of 12 months. Primary outcome measures included control of intraocular pressure after surgery. Secondary outcome measure included the frequency of intraoperative and postoperative complications.

Results

Intraocular pressure was maintained between 6 and 21 mmHg throughout the study. There was no postoperative hypotony. There were no complications related to this modified technique.

Conclusion

Needle tract at 5 mm from limbus maintains implant’s ability to control intraocular pressure and eliminates the need for a donor scleral graft or heterologous material.

Effect of excision of avascular bleb and advancement of adjacent conjunctiva for treatment of hypotony

PURPOSE

To evaluate the efficacy of excision of avascular bleb and advancement of adjacent conjunctiva (EBAC) for treatment of hypotony after trabeculectomy with mitomycin C (MMC).

METHODS

Fifteen patients (17 eyes) who received EBAC for correction of hypotony between September 1996 and October 2008 were reviewed retrospectively. The main outcomes were intraocular pressure (IOP) and postoperative complications.

RESULTS

Hypotony (IOP <6 mmHg) of eight eyes (47.1%, seven patients) was caused by bleb perforation. Of these, two eyes (two patients) had a history of trauma. Hypotony appeared at 33.9+/-30.8 months, and EBAC was performed at 48.2+/-35.3 months after trabeculectomy with MMC. The mean follow-up period was 38.3+/-29.8 months. The qualified success rate of EBAC was 100% at 51 months after EBAC, and the complete success rate of EBAC was 76.5% at six months and 70.6% at 51 months, as determined by Kaplan-Meier analysis. Post-EBAC complications included blepharoptosis in four eyes (23.5%) and bleb perforation in one (5.9%). The blepharoptosis resolved within one month after EBAC in two patients. However, in the other patients, mild blepharoptosis remained at 17 and 22 months postoperatively.

CONCLUSIONS

EBAC was found to be an effective method for treatment of hypotony after trabeculectomy with MMC, and postoperative blepharoptosis was a major complication.

Bovine pericardium in treating large corneal perforation secondary to alkali injury: a case report

To describe use of a locally processed bovine pericardium (BP) to cover a large central corneal perforation following alkali injury and discuss postoperative outcome.

A 27-year-old Malay male patient presented two weeks after alkali splashed in his left eye while working. A clinical diagnosis of left central corneal ulcer with limbal ischemia following alkali injury with secondary infection was made. After failed medical therapy, we performed a Gunderson conjunctival flap under local anesthesia that retracted after one week and resulted in a large central corneal perforation with surrounding stromal thinning. The perforation was covered with a locally processed BP xenograft (Lyolemb) supplied by the National Tissue Bank, University Sains Malaysia. Nine months follow-up showed a well-taken graft without any exposure/dehiscence and minimal inflammation.

Amniotic membrane transplantation when used as a patch graft needs an urgent tectonic graft to promote corneal stability in patients with severe corneal thinning. The use of processed BP can be a viable option in treating such cases.

Optical microscopy study of human sclera stored in different media

PURPOSE

To describe microscopic changes in the structure of human sclera immediately after enucleation (negative control group) and to compare them after being stored for three months in four different media: pure glycerin, absolute alcohol, benzalkonium chloride diluted in absolute alcohol (1:5000), and benzalkonium chloride diluted in balanced salt solution (1:5000). The comparison took into consideration their final state of conservation.

DESIGN

Experimental study, laboratory investigation.

METHODS

Optical microscopy was used to study the specimens after they had been in storage for one, two, and three months. The scleral fragments were prepared in thin plates, dyed, and then submitted to histologic analysis by two masked specialists. Unpreserved scleral fragments obtained right after enucleation were assessed and served as negative controls.

RESULTS

The collagen fibers of scleras stored in glycerin presented with a more regular pattern, closer in appearance to the negative control group. Scleras stored in the other three media presented contorted collagen fibers.

CONCLUSIONS

Our findings suggest that glycerin is close to being the ideal storage medium for sclera, because it maintains the structural characteristics of the collagen fibers. Research is ongoing to determine how to increase the bactericidal and antiviral properties of glycerin storage.

Transplantation of ocular tissue from a donor with sporadic Creutzfeldt-Jakob disease

BACKGROUND

One definite, one probable and several possible transmissions of sporadic Creutzfeldt-Jakob disease (sCJD) have followed corneal transplantation. We report an incident in the UK in 1997 in which both corneas and scleras from a donor, subsequently confirmed to have had sCJD, were transplanted. The final clinical outcome for two surviving recipients is still not yet known.

CASE REPORT

In 1997, a 56-year-old woman died from biopsy-proven carcinoma of the bronchus. Both eyes were donated for transplantation. Shortly before she died, she had developed neurological symptoms thought to be due to brain metastases. However, the final result of a neurological post-mortem examination revealed evidence of sCJD. By this time the corneas had been transplanted, one 3 months previously into a 40-year-old man for keratoconus and the other 4 months previously into an 85-year-old woman for Fuchs' dystrophy. In addition, both scleras had been transplanted into a 36-year-old man undergoing oculoplastic reconstructive surgery. The surgeons and patients were informed and removal of tissue was advised but undertaken in only two of the patients. Immunohistochemistry failed to demonstrate the presence of the abnormal form of the prion protein in explanted tissue.

CONCLUSIONS

Eight years after the event, two patients remain free of symptoms suggestive of iatrogenic CJD (http://www.cjd.ed.ac.uk/criteria.htm). The third having died aged 92 years, some 7 years after surgery, showing signs of dementia not considered indicative of iatrogenic CJD. Nevertheless this adverse incident attracted substantial publicity. Coupled with continuing concerns in the UK about person-to-person transmission of variant CJD, this has lead to a number of important consequences in donor eye retrieval, ocular tissue banking and transplantation.

Outcome of graft free Molteno tube insertion

AIMS

To determine the long term outcome of Molteno implants inserted using a modified surgical technique that eliminates the need for a donor scleral graft.

METHODS

Retrospective case series involving a medical record analysis of 35 consecutive patients undergoing first Molteno implant surgery for refractory glaucoma. The main outcomes included life table analysis of intraocular pressure control following surgery and frequency of intraoperative and postoperative complications.

RESULTS

There were no complications related specifically to the modified method of tube placement. Medium term intraocular pressure control was similar to other series.

CONCLUSIONS

This simplified method for the insertion of Molteno implants eliminates the need for a donor scleral graft while maintaining the implant's ability to control intraocular pressure.

Exposure of Orbital Implants Wrapped With Polyester-Urethane After Enucleation for Advanced Retinoblastoma

PURPOSE

Enucleation is the main form of treatment for advanced retinoblastoma. The major complication of this procedure is orbital implant exposure. Different implants and wrapping materials are currently in use. The aim of the current study was to analyze the complications associated with the use of polyester-urethane, an artificial dura substitute, as a wrapping material for enucleation in advanced retinoblastoma.

METHODS

A retrospective review of 32 cases (28 patients), who were treated with enucleation for advanced retinoblastoma, was performed. The age of the patients ranged between 3 months and 6.7 years (median, 19 months). Additional chemotherapy was administered in 12 cases. The removed eyeball was replaced either with a silicone implant and polyester-urethane wrapping (13 cases) or hydroxyapatite, silicone-hydroxyapatite, or polyethylene implants without additional wrappings (19 cases). The follow-up period ranged from 7 months to 5.9 years (median, 22.4 months). Statistical analysis was performed using the Kaplan-Meier method.

RESULTS

Single or multiple exposures occurred in 22% of cases (7/32). There were 6 exposures (46%, 6/13) in the group with polyester-urethane wrapping compared with only 1 exposure (5%, 1/19) in the implants without wrapping. This difference was statistically significant (p=0.0236). None of the other analyzed factors (additional chemotherapy, surgeon, age of the patient, or size of the implant) demonstrated a significant correlation to implant exposures.

CONCLUSIONS

Wrapping of orbital implants with polyester-urethane resulted in a high rate of implant exposures after enucleation for advanced retinoblastoma. In this series, the best results were achieved with integrated implants without additional wrapping.

Eyelid reconstruction: the state of the art

PURPOSE OF REVIEW

The goals of eyelid reconstruction are corneal protection, restoration of the integrity of the lid lamellae, and improvement of facial symmetry. Inadequate reconstruction may lead to corneal exposure and sight-threatening keratopathy; in the younger patient, visual deprivation and amblyopia may also follow. The purpose of this review is to describe new materials and approaches used in reconstructing the damaged eyelid.

RECENT FINDINGS

Although the surgical principles of lid reconstruction remain unchallenged, new materials and techniques have emerged. These include the use of both autogenous and cadaveric acellular dermis in the management of lower eyelid retraction, and amniotic membrane transplantation in the management of tarsal conjunctival disease. Recent work on upper facial nerve branch reinnervation in the animal model may also offer hope for eyelid reanimation after facial palsy.

SUMMARY

The lid surgeon requires a sound knowledge of the principles involved in reconstructing the respective lamellae of the lid. Anterior lamellar reconstruction carries a significant risk of ectropion, and large defects may require several interposition flaps for optimum skin texture and color reconstruction. New materials (autogenous and cadaveric) for posterior lid reconstruction may reduce donor site morbidity and surgical time, but they may contract significantly after surgery. Recent experience with amniotic membrane transplantation may improve the prognosis for patients with entropion and symblepharon caused by conjunctival cicatricial changes.

Intérêt d’un questionnaire de dépistage du risque de transmission de la maladie de Creutzfeldt-Jacob en consultation d’Ophtalmologie

INTRODUCTION

The risk of prion transmission during an ophthalmic examination concerns all ophthalmologists screening patients at risk, a procedure normally based on collecting past history and clinical data.

PATIENTS AND METHODS

The authors proposed a shortened version of a questionnaire where the patient provides only the past history by answering three questions, which are then validated by the ophthalmologist.

RESULTS

This procedure was proposed to 500 patients. Only five patients answered one of the questions positively, and the ophthalmologist did not use any contact device during their examination. Of these five patients, none was confirmed to be at risk for prion transmission.

CONCLUSION

This questionnaire seems to be a suitable way to compensate the lack of time and reduced staff in ophthalmology, whatever the ophthalmic practice may be.