Repair of scleromalacia using preserved scleral graft with amniotic membrane transplantation

Revisiting the Use of Deep Temporalis Fascia Grafts in Ophthalmology

PURPOSE

To report new indications for deep temporalis fascia (DTF) grafts in the ophthalmic field.

METHODS

Monocentric retrospective interventional case series study. All the patients who underwent a DTF graft in an unpublished new indication over the study period (May 2020-October 2023) were included. For each patient, gender, age, graft indication, outcomes, complications, and follow-up duration were collected. In most cases, the DTF graft was covered by a vascularized flap.

RESULTS

Eight patients underwent a DTF graft over the study period. The indications were: radiotherapy-induced scleral necrosis in three cases, tendinoplasty to replace the inferior rectus muscle tendon invaded by a locally advanced conjunctival carcinoma in one case, Ahmed glaucoma valve tube exposure in one case, intraocular lens with scleral fixation exposure in one case, orbital cerebrospinal fluid fistula (orbitorrhea) in one case, and post-traumatic complete corneal graft loss in one case. The DTF graft was successful in 87.5% of cases after a mean follow-up of 11.4 months. No complications were observed.

CONCLUSIONS

DTF graft is a highly versatile graft that can be easily harvested. New indications for DTF grafts may include the repair of radiotherapy-induced scleral necrosis, the creation of oculomotor tendon and the temporary packing of large ocular tissue loss in an emergency context. Further studies with a longer follow-up are needed to confirm our preliminary results.

The Evolving Surgical Paradigm of Scleral Allograft Bio-Tissue Use in Ophthalmic Surgery: Techniques and Clinical Indications for Ab-Externo and Ab-Interno Scleral Reinforcement

To review the latest surgical advances and evolving clinical use of scleral bio-tissue for reinforcement in the eye and review the published literature on novel surgical applications of scleral allograft bio-tissue. Conventional surgical procedures for scleral reinforcement using homologous scleral allograft have been traditionally ab-externo interventions comprising of anterior or posterior reinforcement of the sclera for clinical indications such as trauma, scleromalacia, glaucoma drainage device coverage, scleral perforation, buckle repair as well as posterior reinforcement for pathologic myopia and staphyloma. There have been a few novel ab-interno uses of scleral bio-tissue for reinforcement in both retina and glaucoma. Over the last decade, there has been an increase in peer-reviewed publications on scleral reinforcement, reflecting more interest in its clinical applications. With favorable biological and biomechanical properties, scleral allograft may be an ideal substrate for an array of new applications and surgical uses.

Scleral Grafts in Ophthalmic Surgery. A Review

AIM

To summarize the history and current trends in the use of scleral grafts in ophthalmology.

MATERIALS AND METHODS

We conducted a review of the literature through the MEDLINE and Cochrane Library databases. The search terms were "sclera", "graft", and "surgery". The search resulted in 1596 articles, of which we evaluated 192 as relevant. The relevant articles were sorted chronologically and according to the method of using scleral grafts, which enabled the development of a review article.

RESULTS

The sclera has been routinely used in ophthalmology since the 1950s in many different indications. Some of these indications have become practically obsolete over time (for example, use in the surgical management of retinal detachment), but a large number still find application today (especially use in glaucoma or oculoplastic surgery, or as a patch for a defect in the sclera or cornea).

CONCLUSION

Even though allogeneic sclera is currently used less frequently in ophthalmology compared to other tissue banking products and the range of its indications has partially narrowed, it remains a useful material due to its availability and properties.

Giant anterior scleral staphyloma caused by blunt ocular trauma: a case report

BACKGROUND

Anterior scleral staphyloma is a relatively rare disease characterized by thinning and expansion of sclera. We described the clinical presentation, diagnosis and treatment of a case with giant anterior scleral staphyloma caused by blunt ocular trauma.

CASE PRESENTATION

A 24-years-old male, presented with a black cyst-like mass protruding from the right eyeball for 9 years after a history of glass crush contusion. The ultrasound biomicroscopy examination showed two cysts in the right eyeball. The larger one was about 5.92 mm*4.69 mm in size and the scleral lacerations were connected to the posterior chamber below the cyst. For treatment, resection of the anterior scleral staphyloma and the scleral patch graft transplantation was performed. The vision of the patient was improved compared with that before surgery. There were no obvious complications.

CONCLUSION

The clinical presentation, diagnosis, and treatment of the case with giant anterior scleral staphyloma can provide a reference for the management of anterior scleral staphyloma. Surgical resection and scleral patch graft should be a good option for the treatment of giant anterior scleral staphyloma.

Scleral thinning causes, diagnosis, and management: A narrative review

INTRODUCTION

Sclera forms the outer fibrous coat of the eye and provides structural integrity for the housing of intraocular contents. Scleral thinning is a serious progressive condition which can lead to perforation and worsening visual functioning. This review aims to summarize the anatomical consideration and causes of scleral thinning, diagnosis, and the various surgical approaches available to treat scleral thinning.

MATERIALS AND METHODS

The narrative literature review was conducted by senior Ophthalmologists and researchers. PubMed, EMBASE, Web of Science, Scopus, and Google Scholar databases were searched for relevant literature from infinity till March 2022. Terms of the search referred to 'sclera' or 'scleral thinning' or 'scleral melting', and were combined with 'treatment', or 'management' or 'causes'. Publications were included in this manuscript if they offered information about the nature of these topics. Reference lists of relevant literature was searched. There were no limits on type of article to be included for this review.

RESULTS

Scleral thinning arises from diverse congenital, degenerative, immunological, infectious, post-surgical, and traumatic etiologies. It is diagnosed upon slit-lamp examination, indirect ophthalmoscopy, and optical coherence tomography. Conservative pharmacological treatment of scleral thinning may include anti-inflammatory drugs, steroid drops, immunosuppressors, monoclonal antibodies, and surgical treatments including tarsorrhaphy, scleral transplantation, amniotic membrane transplantation, donor corneal graft, conjunctival flaps, tenon's membrane flap, pericardial graft, dermis graft, cadaveric dura mater graft, and other autologous and biological grafts.

CONCLUSION

Scleral thinning treatments have developed dramatically in recent decades and the rise of alternative grafts for scleral transplantation procedures or use of conjunctival flaps have taken center stage in surgical management. This review adds a comprehensive summary of the scleral thinning with attention to the positive and negative features of new treatments alongside previous mainstay management strategies.

The role of Tenonplasty in the management of limbal and scleral ischemia due to acute ocular chemical burns

Of the various manifestations of ocular chemical burns (OCBs), ischemia of the limbus and the peri-limbal sclera indicates poor prognosis and in severe cases threaten the integrity of the globe. Tenonplasty is a surgical procedure which involves advancing the Tenon’s capsule over the ischemic areas to provide a vascular supply and to enable migration of the conjunctival epithelium. This review aims to provide an overview of the diagnosis of limbal ischemia and its management with Tenonplasty. A literature review was conducted using the keywords “Tenonplasty,” “Tenon’s capsule,” “ocular chemical injury,” “ocular thermal injury,” “Tenon advancement,” “scleral ischemia,” and “limbal ischemia,” and outcomes were studied from seven selected articles. In addition to clinical evaluation, in vivo imaging techniques such as anterior segment optical coherence tomography angiography can provide an objective method of measuring and monitoring the ischemia and re-perfusion of the peri-limbal vasculature. Tenonplasty can be performed in eyes with acute OCBs with scleral or limbal ischemia by dissecting the Tenon’s layer from the orbit and securing it to the limbus. The indications, mechanism of action, peri-operative considerations, surgical technique, and post-operative care of Tenonplasty are discussed in detail. The average time for post-operative re-epithelization ranges from 1 to 6 months with the formation of a symblepharon being the most common complication. In conclusion, Tenonplasty is a globe-salvaging procedure in cases with severe limbal and scleral ischemia because of OCBs and has good anatomical outcomes priming the globe for subsequent re-constructive and vision-restoring surgeries.

Long-term Outcome of Surgical Treatment with Various Reinforcement Material Grafts on Scleromalacia

Purpose: To investigate the long-term efficacy and stability of the use of various reinforcement material grafts on scleromalacia.Methods: This retrospective study was conducted on scleromalacia patients who underwent surgical treatment with reinforcement material grafts from January 2012 to March 2019. The choice of amniotic membrane, Tenon’s capsule, acellular sclera, or collagen matrix implanted in the area of scleromalacia was made based on disease severity. Amniotic membrane transplantation with a pedicular rotatory inferior conjunctival flap was performed to prevent having a bare sclera. The patient demographics, cause of scleromalacia, best-corrected visual acuity (BCVA), recurrence rate, postoperative complications, and restoration appearance were evaluated.Results: A total of 58 patients (58 eyes) were enrolled in this study. The mean age of patients was 65.7 ± 9.6 years, and 32 patients (55.2%) were women. The mean follow-up period was 28.1 ± 17.3 months. The most common cause of scleromalacia was pterygium operation (53 patients, 91.4%). The reinforcement materials were mainly amniotic membrane (31 patients, 53.4%) and acellular sclera (15 patients, 25.7%). There was no recurrence of scleromalacia or structural instability during the follow-up period. The preoperative and postoperative mean BCVA values were 0.24 ± 0.24 and 0.21 ± 0.23 logMAR, respectively. Wound dehiscence (three patients, 5.2%) and conjunctival cyst (three patients, 5.2%) occurred with the highest frequency.Conclusions: The use of the appropriate reinforcement material graft according to the severity of scleromalacia and amniotic membrane transplantation using a pedicular rotatory inferior conjunctival flap to prevent a bare sclera can be effective for treating scleromalacia, without long-term recurrence.

Preserved corneal lamellar transplantation for infectious and noninfectious scleral defects: Three case reports and literature review

RATIONALE

: Reinforcement of thinned or necrotizing sclera has been conducted using various materials, including allogeneic sclera, allogenic cornea, amniotic membrane, fascia lata, pericardium, periosteum, and perichondrium. Among them, good outcomes have traditionally been obtained using preserved scleral grafts. However, scleral patch grafts have complications such as graft retraction, thinning, dehiscence, and necrosis. Furthermore, to promote epithelial healing, scleral patch grafting must be accompanied by procedures such as amniotic membrane transplantation (AMT) or grafting using conjunctival flaps or autografts. Recently, acellular preserved human corneas have been used in various ophthalmic surgeries, with emerging evidence supporting its use for treating scleral defects as an option that does not require AMT or conjunctival autografting. We investigated whether corneal patch grafting would show wound healing and tectonic success rate outcomes comparable to those of existing techniques.

PATIENT PRESENTATION

: Three patients presented with intractable ocular pain. Slit-lamp examination showed marked scleral thinning at the nasal side.

DIAGNOSIS

: Scleral thinning progressed with conservative treatment; microbial staining and culturing were performed. Infectious or non-infectious scleritis was diagnosed according to slit-lamp examination and microbial culture results.

INTERVENTIONS

: A preserved corneal lamellar patch was grafted at the scleral thinning area.

OUTCOMES

All patients achieved tectonic success with reduction of inflammation following corneal patch grafting. Two patients achieved complete re-epithelialization within 7 days, while 25 days were required for the third patient. No patients experienced graft thinning, rejection, or infection.

LESSONS

: Our report suggests the feasibility of using acellular preserved human cornea patch grafts to reinforce inflammatory scleral defects and obtain successful outcomes in terms of wound healing. This technique shows a comparable tectonic success rate and superior effect on scleral defect healing without the need for adjunctive AMT or conjunctival autografting.

Preserved Corneal Lamellar Grafting Reduces Inflammation and Promotes Wound Healing in a Scleral Defect Rabbit Model

Purpose

To investigate the effect of preserved corneal lamellar grafting on inflammation and wound healing and to compare its effect with that of preserved scleral grafting in a scleral defect rabbit model.

Methods

New Zealand White rabbits were assigned to a corneal lamellar grafting group (n = 5) or a scleral grafting group (n = 5). After lamellar dissection of superotemporal sclera using 6.0-mm trephine, the same sizes of preserved human corneal or scleral grafts were transplanted with 10-0 nylon interrupted sutures. The grafted areas were photodocumented at 3 to 21 days after surgery to evaluate epithelial wound healing index (%), neovascularization and presence of filaments. The existence of CD3⁺ T cells and CD34⁺ cells at the grafted areas was analyzed at 21 days.

Results

Epithelial wound healing index was significantly higher in the corneal grafting group at 9 days (P < 0.05). Scleral grafts showed copious formation of filaments adherent to the engrafted area from 9 to 14 days, whereas the corneal grafts were free of filaments. The numbers of inflammatory cells were significantly higher in the scleral grafts (P < 0.05), and CD3⁺ T cells and CD34⁺ cells were populated within inflammatory cells at graft-recipient junctions in both groups. The mean areas of the estimated perigraft and intragraft neovascularization tended to be higher in scleral grafts.

Conclusions

Preserved corneal lamellar grafting enhances epithelial wound healing and alleviates inflammation in a scleral defect rabbit model.

Translational Relevance

This work suggests that the preserved corneal graft may be considered as a favorable alternative option for repairing scleral defects.

Microfluidic-based non-enzymatic glycation enhances cross-linking of human scleral tissue compared to conventional soaking

We evaluated nano-structural and chemical changes in human scleral collagen caused by non-enzymatic glycation using AFM, Raman spectroscopy, and microfluidics. Twenty 8 × 2 mm² scleral strips (n = 5, each) were divided into four groups of pure sclera tissues (control group) and sclera tissues with incubation (1 hr in BSS and ribose) and preservation (23 hr in 90% ethanol) for 7 days (BSS + DR₇ group) and 30 days (BSS + DR₃₀ group) at room temperature, and 7 days in a microfluidic chip (BSS + DR + µF₇ group). The BSS + DR₇ and BSS + DR₃₀ groups were incubated in a mixture of balanced salt solution (BSS) and 0.2 M D-ribose in PBS, pH 7.4 containing 0.1% sodium azide, while the BSS + DR + µF₇ group was incubated in the same solutions supplied by two inlet reservoirs from a microfluidic chip. The scleral tissues incubated in the microfluidic environment showed a clear irregular parallel arrangement of collagen fibrils with tangled fibrils. A Raman shift was observed at 919 cm^-1 in the glycation groups. Non-enzymatic glycation led to an increased in the density of scleral stromal collagen. Our method using non-enzymatic glycation in a microfluidic environment successfully induced collagen cross-linking. These in vitro results suggested that glycation can be used to strengthen connective tissues. SCANNING 38:421-426, 2016. © 2016 Wiley Periodicals, Inc.

Biodegradable collagen matrix (Ologen™) implant and conjunctival autograft for scleral necrosis after pterygium excision: two case reports

BACKGROUND

Scleromalacia, in the form of scleral thinning, melting, and necrosis, is a potentially serious complication of pterygium excision. This study introduces a new biodegradable material, Ologen™ collagen matrix (OCM), to repair scleral thinning as an alternative to preserved scleral tissue, and evaluates the long-term outcomes of OCM for ocular surface reconstruction surgery.

CASE PRESENTATION

Two cases of possibly mitomycin C (MMC)-associated marked scleral thinning after pterygium excision with 0.02 % topical MMC for 2-weeks were included in this study. An OCM graft at the scleral thinning area and conjunctival autograft (CAU) were performed on both patients. The scleral defect size was measured and its margin was marked with a biopsy punch. The margin of the scleral thinning area was trimmed by Vannas scissors and the OCM was cut using a circular-shape biopsy punch of the same size. The OCM was sutured with a recipient scleral wall using 10-0 nylon interrupted sutures. Free CAU was harvested from the superonasal bulbar conjunctiva with a punch biopsy 1-mm larger in diameter than that of the OCM. The previously sutured OCM bed was covered with CAU and the graft was secured with 10-0 nylon interrupted sutures. Both patients were examined periodically for over two years by assessing graft thickness and surface vascularization using a slit lamp biomicroscope. Reepithelialization of the ocular surface was observed within three to six days after surgery. Ocular discomfort and inflammation ceased in both patients as the ocular surface quickly stabilized. The entire graft site remained intact and provided a good healthy ocular surface with fluorescein stain negative intact epithelium and good vascularization of grafted conjunctiva. Epithelial defects and scleral thinning did not recur in either patient over the two year follow-up period.

CONCLUSION

For treatment of a possibly MMC-associated scleral necrosis following the surgical excision of the pterygium, an OCM graft with CAU is highly recommended for good clinical outcomes and low recurrence rates. With the clinical results of this study, the new biodegradable Ologen™ collagen matrix qualifies as an alternative treatment to scleral tissue for ocular surface reconstruction.

Randomized trial comparing multilayer amniotic membrane transplantation with scleral and corneal grafts for the treatment of scleral thinning after pterygium surgery associated with beta therapy

PURPOSE

The aim of this study was to compare the use of multilayer amniotic membrane transplantation (AMT) with lamellar corneal transplantation (LCT) and lamellar scleral transplantation (LST) for the treatment of scleral thinning after pterygium surgery associated with beta therapy.

METHODS

Twenty-six eyes from 26 different patients with scleral thinning as a consequence of beta therapy after pterygium surgery were evaluated at the Federal University of São Paulo, Brazil. Ophthalmologic examination and ultrasound biomicroscopy were performed to assess scleral thinning before the transplant surgery and then repeated at 30, 90, and 180 days after surgery. An increase in scleral thickness, epithelialization of the ocular surface, and preservation of the ocular globe were the main outcome measures.

RESULTS

Irrespective of the surgical technique used (AMT, LCT, or LST), no clinical or statistical changes in corrected distance visual acuity were found in any of the patients during this study. The median preoperative scleral thickness was similar in all 3 groups: AMT = 0.45 mm, LST = 0.48 mm, and LCT = 0.52 mm (P = 0.257); however, 6 months after surgery, the median thickness in the AMT group (0.19) was significantly less than that of the LCT group (0.57) (P = 0.27) or the LST group (0.76) (P = 0.19). Epithelialization occurred in all the patients.

CONCLUSIONS

LCT was the best option for the structural treatment of scleral thinning, followed by LST with a conjunctival flap. A high rate of reabsorption was found with AMT, which was the least effective of the 3 therapeutic options and should not be used for this condition.

Clinical applications of anterior segment optical coherence tomography

Anterior segment optical coherence tomography (AS-OCT) was recently developed and has become a crucial tool in clinical practice. AS-OCT is a noncontact imaging device that provides the detailed structure of the anterior part of the eyes. In this review, the author will discuss the various clinical applications of AS-OCT, such as the normal findings, tear meniscus measurement, ocular surface disease (e.g., pterygium, pinguecula, and scleromalacia), architectural analysis after cataract surgery, post-LASIK keratectasia, Descemet's membrane detachment, evaluation of corneal graft after keratoplasty, corneal deposits (corneal dystrophies and corneal verticillata), keratitis, anterior segment tumors, and glaucoma evaluation (angle assessment, morphological analysis of the filtering bleb after trabeculectomy, or glaucoma drainage device implantation surgery). The author also presents some interesting cases demonstrated via AS-OCT.

Use of an Autologous Lamellar Scleral Graft to Repair a Scleral Melt After Mitomycin Application

Mitomycin (MMC) has been associated with a variety of complications, including corneoscleral melt. We report the successful repair of a scleral melt with a partial thickness autologous scleral graft of the scleral melting. A 55-year-old male patient underwent pterygium resection surgery and intraoperative MMC application. The patient developed a deep melting area that almost reached the choroid layer at the nasal sclera. We repaired scleral defect with a partial thickness autologous scleral graft. Closure of an MMC-associated scleral melting area with an autologous partial thickness scleral graft is an effective and easy-to-use method.

Human amniotic membrane transplantation: Different modalities of its use in ophthalmology

The amniotic membrane (AM) is the inner layer of the fetal membranes and consist of 3 different layers: the epithelium, basement membrane and stroma which further consists of three contiguous but distinct layers: the inner compact layer, middle fibroblast layer and the outermost spongy layer. The AM has been shown to have anti-inflammatory, anti-fibrotic, anti-angiogenic as well as anti-microbial properties. Also because of its transparent structure, lack of immunogenicity and the ability to provide an excellent substrate for growth, migration and adhesion of epithelial corneal and conjunctival cells, it is being used increasingly for ocular surface reconstruction in a variety of ocular pathologies including corneal disorders associated with limbal stem cell deficiency, surgeries for conjunctival reconstruction, as a carrier for ex vivo expansion of limbal epithelial cells, glaucoma surgeries and sceral melts and perforations. However indiscriminate use of human AM needs to be discouraged as complications though infrequent can occur. These include risk of transmission of bacterial, viral or fungal infections to the recipient if the donors are not adequately screened for communicable diseases, if the membrane is not processed under sterile conditions or if storage is improper. Optimal outcomes can be achieved only with meticulous case selection. This review explores the ever expanding ophthalmological indications for the use of human AM.

Preserved scleral patch graft for unexpected extreme scleral thinning found at the scleral buckling procedure: a case report

Pre-existing scleral pathology is an important risk factor for globe rupture during scleral buckling procedures. We report here, the surgical management of an unexpected scleral pathology found at the scleral buckling procedure in a retinal detachment patient. A 77-year-old white female with retinal detachment underwent a scleral buckling procedure. The surgery was converted into a scleral graft procedure, as extreme scleral thinning was found intraoperatively. An alcohol-preserved donor sclera graft was used. The second surgery for definitive retinal alignment was performed two weeks later. The presented case of an unexpected scleral pathology in a retinal detachment patient was managed with a combination of scleral grafting and pars plana vitrectomy, without any major complications. The anatomical outcome was excellent and the scleral rupture was prevented; the visual outcome was satisfactory. A conversion of the scleral buckling procedure into a scleral graft procedure has proved to be safe and effective for unexpected scleral pathology.

Surgical treatment of necrotic scleral calcification using combined conjunctival autografting and an amniotic membrane inlay filling technique

PURPOSE

To introduce a novel technique to treat necrotic scleral calcification caused by previous regional conjunctivectomy using conjunctival autografting and amniotic membrane inlay filling, and to evaluate the clinical outcome.

METHODS

Ten patients (11 eyes, 12 regions) who had undergone regional conjunctivectomy with postoperative mitomycin C (MMC) for pterygia or pingueculae were included. Scleral calcification was removed using a bevel-down crescent knife. After the conjunctival donor tissue was harvested from the upper bulbar conjunctiva, the tissue was grafted to the scleral defect and secured with sutures. Amniotic membrane was inserted randomly into spaces between the conjunctival graft and the scleral bed. Protective amniotic membrane was transplanted over the graft, with stromal side up.

RESULTS

Scleral calcification developed in ischaemic areas in 11 of the 12 regions; 50% of cases had a surface defect seen with a fluorescent dye. The grafted conjunctiva epithelialized successfully in all cases. In 10 regions, the epithelialization occurred in 1 or 2 weeks. In the remaining two regions, one region required another surgery because of graft failure, and epithelialization occurred in the last region in 9 weeks. Vascular growth into the graft from the surrounding tissue occurred in all cases in 1 to 10 weeks. The surgical wound stabilized 3 weeks postoperatively.

CONCLUSION

The combined technique had high success rates of graft survival and good revitalization of the necrotic area of scleral calcification, eliminated the need for invasive and time-consuming scleral autografting or allografting, and provided good cosmesis. Scleral ischaemia, which was caused by MMC, may induce scleral calcification.

Cosmetic improvement of nevus of Ota by scleral allograft overlay

OBJECTIVE

To report surgical outcome of a new therapeutic technique for nevus of Ota by scleral allograft overlay.

DESIGN

Noncomparative clinical interventional study.

PARTICIPANTS

Eight eyes of 7 patients with scleral nevus of Ota.

METHODS

Patients underwent subconjunctival scleral allograft overlay between September 2005 and June 2007 at Seoul National University Hospital. Preoperative neval extent, postoperative cosmesis, complications, and visual acuity change were evaluated.

RESULTS

Most of the patients showed satisfying cosmetic improvement. There were no significant complications in a follow-up period of more than 3 years.

CONCLUSIONS

Scleral allograft overlay is a safe and effective procedure for cosmetic improvement of nevus of Ota.

Repair of limbal dermoid with excision and placement of a circumlimbal pericardial graft

OBJECTIVES

To report the treatment of a limbal dermoid tumor with excision of the lesion combined with the placement of a processed pericardial graft.

METHODS

A case report of a new approach to treat large limbal dermoids after excision of the lesion from the cornea and limbus.

RESULTS

The surgical result was very reasonable from a cosmetic result, and the patient recovered quite well.

CONCLUSIONS

The use of processed pericardium on the scleral side of the lesion has not been reported previously with limbal dermoid excision. Intraoperatively, the abnormal tissue blended with the sclera and excision of perilimbal tissue was necessary to obtain a clear margin. One might want to consider the method described here for the treatment of large limbal dermoid lesions when the pathology seems indistinct at the conjunctival-corneal border during surgery.

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.

Surgical approach for scleral ischemia and melt

PURPOSE

To describe the combined use of tenonplasty, lamellar corneal patch graft, and amniotic membrane transplantation in managing scleral ischemia and/or melt by using sutures or fibrin glue.

METHODS

We subjected five eyes of 4 patients with scleral ischemia and/or melt of diverse etiologies to debridement of all necrotic tissue, followed by a lamellar corneal graft (cases with melt, n = 3) or a cryopreserved amniotic membrane (cases without melt, n = 2), and a Tenon pedicle graft was used to cover the ischemic zone; surgery was completed by using a second layer of cryopreserved amniotic membrane. These procedures were performed by using either sutures or fibrin glue. Reduction of photophobia, facilitation of epithelialization, and correction of scleral ischemia and/or melt with preservation of the globe integrity were considered the main outcome measurements.

RESULTS

Surgical measures were effective to reduce or eliminate photophobia, facilitate epithelialization, halt scleral ischemia and/or melt, and preserve the globe integrity in all eyes except for 1 eye, in which a second attempt was needed to completely correct scleral ischemia. Complications included granuloma formation in 1 case and dellen formation and extreme gaze horizontal diplopia caused by a small symblepharon formation in another case.

CONCLUSIONS

The combination of tenonplasty and amniotic membrane transplantation with or without lamellar corneal patch grafting, by using sutures or fibrin glue, is a feasible alternative for treating scleral ischemia and/or melt.

Structural and functional outcome of scleral patch graft

PURPOSE

To evaluate the visual and structural outcomes of scleral patch grafting in cases of scleral defect.

METHODS

The study was a retrospective interventional case series. Medical records of all patients who underwent scleral patch grafting at a tertiary care centre between 1997 and 2003 for scleral defects were reviewed. After removal of all the devitalized tissue, alcohol-preserved full-thickness sclera was tailored to fit the defect and sutured in place. The graft was covered with a conjunctival flap or amniotic membrane. Structural integrity and visual outcome were assessed as the main outcome measures.

RESULTS

A total of 13 eyes of 13 patients required scleral patch grafting for scleral defects of varying aetiologies, the most common being necrotizing scleritis following pterygium surgery (40%). The patients were followed up for 6-60 months, an average period of 24.3 months. Tectonic success was achieved in 10 eyes (76.9%). Three complications were noted: endophthalmitis, graft necrosis, and graft dehiscence with uveal prolapse. However, no regrafts were needed. Epithelialization and vascularization were seen in the remaining eyes after an average duration of 3-4 weeks. Visual acuity remained stable in the majority (9/13, 60%), improved in one and deteriorated in three eyes.

CONCLUSIONS

Scleral grafting with overlying conjunctival or amniotic membrane graft is an effective and simple measure for preserving globe integrity both structurally and functionally.

Expression of Tumor Necrosis Factor Alpha and Matrix Metalloproteinase-9 in Surgically Induced Necrotizing Scleritis

BACKGROUND

Surgically induced necrotizing scleritis is primarily managed with immunosuppressive regimens. Such treatments can alter inflammatory cytokines and products such as tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase-9 (MMP-9), which are an important proinflammatory cytokine and a tissue-degrading protease involved in necrosis of some ocular tissues.

OBJECT

To evaluate TNF-alpha and MMP-9 in the tear or sclera of surgically induced necrotizing scleritis.

METHODS

After tear collection from healthy and diseased eyes of 2 patients, immunoblot analysis using monoclonal antibody specific for human TNF-alpha and MMP-9 was performed. In another patient, scleral tissues were obtained during scleral allograft surgery, and the same immunoblot analysis was done.

RESULTS

The level of TNF-alpha and MMP-9 was increased in tear fluid from patients compared to that of control volunteers and returned to the control level after treatment. The diseased sclera showed an increased expression of MMP-9 compared to that of the normal donor sclera.

CONCLUSIONS

TNF-alpha and MMP-9 may suggest disease activity of surgically induced necrotizing scleritis and can be altered by proper immunosuppressive treatment.

Scleral Melting in a Patient With Carotid Artery Obstruction

PURPOSE

To report a case of severe scleral melting in a patient with carotid artery obstruction.

METHODS

This is an observational case report. We reviewed the patient's chart and the available literature on ocular melting and ocular ischemia.

RESULTS

A 71-year-old man with a history of carotid vascular disease and a blind left eye due to a previous vascular accident developed scleral melting of the right eye. Despite frequent lubricants, systemic immunosuppressives, and repeated conjunctiva transplants, the thinning progressed and his visual acuity deteriorated. Intensive screening for possible underlying diseases revealed no infectious or collagen vascular disease. Magnetic resonance angiography, however, showed a subtotal obstruction of the right internal carotid artery. Further investigations revealed coronary artery obstruction. Carotid surgery combined with coronary artery bypass grafting was performed, and a stable ocular situation was achieved.

CONCLUSIONS

Although a causal factor cannot always be determined, corneoscleral melting should be regarded as a manifestation of underlying systemic or ocular disorders. In the absence of more common causes of corneoscleral melting, a thorough workup is warranted and might reveal life-threatening disorders.