Management of Corneal Perforation

Kinetic Model of Fluorescein Release through Bioprinted Polylactic Acid Membrane

Polylactic acid (PLA)-based cylindrical membranes for the controlled release of fluorescein sodium salt (FS) were prepared by bioprinting on systems with an initial FS concentration of 0.003763 gdm-3 and 37.63 gdm-3, and the drug release process was monitored in a bath at 37 °C. Photographs, acquired at regular intervals during the process, revealed marked osmotic swelling of the polymer. Osmotic swelling consists in the enlargement of the polymer structure and due to the influx of water molecules across the membrane. The cylindrical PLA membrane starts to significantly swell once a certain threshold range is crossed. Important amounts of FS can dissolve under these radically changed circumstances, and the dissolved FS molecules are mobile enough to diffuse out of the cylinder, thus allowing drug release. As a matter of fact, in this investigation, we ascertained that polymer swelling promotes the mass transport phenomenon by altering the conditions for drug dissolution and diffusion, hence facilitating FS release after a specific lag time. Furthermore, in order to compare the release kinetics, the half-release time, t0.5, was taken into consideration. The data of this study evidence that, while increasing the initial concentration of FS by three orders of magnitude, the time parameter, t0.5, is only reduced by 5/6. In addition, the yield of the release process is drastically reduced due to the strong aggregation ability of the dye. Finally, it is demonstrated that a compressed exponential kinetic model fits the experimental data well despite the varying physical conditions.

Efficacy of Emergency Penetrating Keratoplasty with Cryopreserved Human Donor Corneas

INTRODUCTION

To investigate the long-term outcomes of emergency penetrating keratoplasty using cryopreserved human donor corneas in the management of actual or imminent corneal perforation.

METHODS

A retrospective analysis was performed of the treatment efficacy of emergency penetrating keratoplasty using a cryopreserved human donor cornea, in 14 eyes of 14 patients with corneal ulcers of different etiology. For comparison, the medical histories of 14 patients who had undergone penetrating keratoplasty with the same indication, but received a regularly processed human corneal graft, were retrospectively analyzed. In both groups, the primary endpoint for graft failure was repeat surgery, defined as the necessity for amniotic membrane transplantation, conjunctival flap, or repeat penetrating keratoplasty, during a follow-up time of maximally 12 months.

RESULTS

The difference in the need for repeated surgeries between the cryopreserved human donor cornea group and cultivated tissue graft group was not statistically significant (p = 0.835). Specifically, repeat complex surgery of any kind within 6 months was necessary in 50% of the cryopreserved cornea group and in 57.1% of the control group, with no further surgical interventions during the remainder of the follow-up period. However, repeat penetrating keratoplasty occurred more frequently in the cryopreserved cornea group (n = 5) than in the control group (n = 1) during the first 12 months after treatment (p = 0.048).

CONCLUSION

Cryopreserved corneas appear to be a viable option for promptly addressing emergencies and stabilizing the corneal situation, providing a faster solution compared to waiting for fresh tissue availability. However, repeat penetrating keratoplasty is more frequent when cryopreserved human donor corneas are used. Cryopreserved human donor corneas may be useful if surgical treatment is urgent and alternative options, such as tissue use, a conjunctival flap, or multilayer amniotic membrane transplantation, are not available.

Management of corneal melting after collagen cross-linking for keratoconus: a case report and a review of the literature

PURPOSE

We describe the management of a case of severe corneal melting after corneal cross-linking (CXL) treated with a staged approach using a conjunctival flap followed by deep anterior lamellar keratoplasty (DALK).

METHODS

A 12-year-old male developed severe corneal melting with pending perforation after an accelerated epithelium-off CXL protocol. We initially treated the patient with a conjunctival flap to prevent perforation. Three months later, we performed DALK to restore vision.

RESULTS

Conjunctival flap surgery allowed us to avoid corneal perforation and penetrating keratoplasty (PK) à chaud. Once the inflammation had resolved, we recessed the conjunctiva and performed DALK for optical purposes. Twelve months later, the graft was clear and the corrected visual acuity was 20/25 (Snellen). No complications occurred after surgery.

CONCLUSIONS

Although CXL is considered a safe procedure, in rare cases it can lead to serious complications, such as corneal haze, infectious and non-infectious keratitis, stromal melting and perforation. Corneal melting and perforation are usually managed by emergency PK. Herein we suggest a staged approach involving an emergency conjunctival flap followed by DALK at a later time that allowed us to avoid PK à chaud.

Corneal stromal lenticule transplantation for the treatment of corneal ulcers

PURPOSE

To evaluate the safety and efficacy of using corneal stromal lenticules (CSLs) obtained during refractive surgery Refractive Lenticule Extraction (ReLEx) with the Small Incision Lenticule Extraction (SMILE) procedure for the treatment of corneal ulcers.

METHODS

This retrospective study included 12 eyes of 12 patients, 7 men and 5 women with varying degrees of corneal ulcer. The mean age was 64 ± 18 (range 34 to 95 years). The monitoring included corrected distance visual acuity (CDVA), slit-lamp biomicroscopy examination, a Seidel test, stability of the graft and anterior segment optical coherence tomography (AS-OCT) inspection. Patients were closely monitored for possible postoperative complications for at least 6 months.

RESULTS

In 7/12 (58%) eyes, the corneal ulcer was successfully sealed with CSL and amniotic membrane (AM) without the need for any additional surgical intervention. In 3 eyes, penetrating keratoplasty (PK) was needed in addition to CSL transplantation and in 2 eyes the scleral patch was used to fully seal after CSL transplantation. During the follow-up period no signs of rejection or infection were detected in any patient.

CONCLUSION

The use of CSLs from ReLEx SMILE may be considered as an alternative method for the treatment of corneal ulcers before a more extensive and definitive solution - PK - is used. Our preliminary findings suggest that properly performed CSL transplantation using cryopreserved lenticules is a safe and effective method to temporarily cover the corneal partial-thickness defect or even perforation.

Outcomes of N-butyl-2-Cyanoacrylate Tissue Adhesive Application in Corneal Perforation Disorders: Consecutive Case Series

INTRODUCTION

The purpose of this study was to report the success and long-term outcomes of cyanoacrylate tissue adhesive (CTA) application in the management of corneal perforation disorders.

METHODS

This retrospective case series describes the profile and outcomes of eyes that underwent CTA for corneal perforation over an 11-year period from January 2009 until January 2020 at a tertiary eye centre in the United Kingdom.

RESULTS

In total, 25 eyes underwent CTA application during the study period. Non-traumatic sterile corneal melt was responsible in more than half of the cases (56.0%; n = 14) followed by infection (32.0%; n = 8) and trauma (12.0%; n = 3). Median size of perforation was 2.0 mm (interquartile range, IQR 1.0-3.0). The most common anatomical location of corneal perforation was central (56.0%; n = 14). Ocular surface disease was seen in almost all eyes except two (92.0%; n = 23) with dry eye disease being the most common (48.0%; n = 12). Amongst 23 eyes that completed follow-up (median 27 months; IQR 9.5-46.5), single CTA application was successful in achieving intact globe in 13 (56.5%) eyes and repeat gluing sealed total of 20 (86.9%) eyes. Survival analysis showed cumulative success of 71.0% and 51.2% at 90 and 250 days, respectively. The CTA was retained in the eyes for median of 94.0 days (IQR 30.0-140.5). A total of five patients developed adverse events, including endophthalmitis (n = 2), following CTA application.

CONCLUSIONS

CTA was highly effective in sealing corneal perforations in acute setting and showed moderate long-term success. However, multiple applications are often required.

Bovine pericardium membrane (TutoPatch) for emergency repair of total corneal melting over an infected corneal graft

Purpose

Corneal perforation due to severe melting is a very dangerous, sight-threatening condition requiring immediate management due to the high risk of endophthalmitis and critical hypotony. In the case of perforated corneal grafts, retransplantation is usually postponed to avoid the detrimental effects of inflammation on the new graft. We describe the first case of the use of a TutoPatch graft for emergency replacement of a lamellar graft perforation over acute infectious total melting.

Observations

A 42-year-old male patient presented to the Emergency Department with pain in the left eye, which was red photophobic. He had been treated with bilateral deep anterior lamellar keratoplasty (DALK) for advanced keratoconus 5 years previously and had been experiencing recurrent corneal ulcers in the left eye within the last 8 months. Clinical examination documented corneal perforation over acute infectious melting involving the total graft surface in the left eye. The infected graft was removed along with the perforated infected residual Descemet membrane, and a double-layer TutoPatch covering was sutured to the host's margin with 10.0 nylon. The covering was left in place for three weeks, allowing the patient to undergo retransplant three weeks later without complications.

Conclusions and importance

TutoPatch covering can be safely used as an easy-to-preserve emergency material for a temporary bridge to retransplantation in large acute infectious corneal melting.

DALK combined intralamellar tectonic patch graft: an alternative approach to treat frank corneal perforation

BACKGROUND

Deep anterior lamellar keratoplasty (DALK) has gained popularity in cases of corneal thinning and leaking descemetocele. In this study, we introduced an intralamellar tectonic patch graft in addition to conventional DALK procedures to treat frank cornea perforation.

METHODS

This retrospective case series included 13 patients (13 eyes) with frank corneal perforations who underwent DALK combined with intralamellar tectonic patch graft between December 2015 and December 2021. In addition to the standard DALK procedure, the perforation site was repaired with an extra intralamellar tectonic patch graft. The collected data included patient demographics, aetiology, size and location of the corneal perforation, visual acuity, surgical details, and postoperative complications.

RESULTS

Seven patients underwent autologous intralamellar patch grafts, whereas six received allogeneic ones. Anatomical success was achieved in all patients. The mean postoperative follow-up was 33.31 ± 25.96 months (6-73 months). The postoperative visual acuity (0.90 ± 0.65 logMAR) was significantly improved (P = 0.003) compared to the preoperative score (1.74 ± 0.83 logMAR). Best corrected visual acuity (BCVA) improved in 12 eyes (92.3%). The mean endothelial cell density was 2028 ± 463 cells/mm2, 6-12 months postoperatively. There was no recurrence of perforation, and the anterior lamellar graft remained transparent in 12 patients (92.3%). Postoperative complications included epithelial defects (23.1%), ocular hypertension (15.4%), and cataract (7.7%).

CONCLUSIONS

DALK combined with intralamellar tectonic patch graft may serve as a secure and effective alternative in treating frank corneal perforation, with reduced complications compared to conventional penetrating keratoplasty.

Whole Corneal Descemetocele

Background and Objectives: To report a case of microbial keratitis complicated by severe corneal melting and whole corneal descemetocele. Methods: A 72-year-old male farmer presented with a right corneal ulcer involving nearly the entire cornea, which was almost completely melted down with the remaining Descemet's membrane (DM). The pupil area was filled with melted necrotic material, with the intraocular lens partially protruding from the pupil and indenting the DM. Corneal optical coherence tomography (OCT) examination revealed a corneal thickness of 37 µm that was attached to its back surface, with the iris and a part of the intraocular lens (IOL) protruding through the pupil. The patient was hospitalized and treated with local and systemic antibiotics until control of the inflammation was achieved. Corneoscleral transplantation plus excision/transplantation of the corneal limbus were performed, and the entire corneal limbus was lamellarly incised. After completely suturing all around the transplanted corneoscleral graft, the anterior chamber was formed. Postoperative treatment included local antibiotics, anti-inflammatory drugs, and cycloplegic drops. Results: There was no recurrence of infection, and the corneal epithelium gradually regenerated and covered the whole graft. Visual acuity was light perception at 6 months after the surgery. The patient was satisfied that the globe was preserved and did not wish to undergo any further treatment. Conclusions: Corneoscleral transplantation is preferred for the treatment of large-sized descemetoceles with active microbial keratitis and extensive infiltrates, especially in cases where the whole cornea has transformed into a large cyst.

Arrested Phase Separation Enables High-Performance Keratoprostheses

Corneal transplantation is impeded by donor shortages, immune rejection, and ethical reservations. Pre-made cornea prostheses (keratoprostheses) offer a proven option to alleviate these issues. Ideal keratoprostheses must possess optical clarity and mechanical robustness, but also high permeability, processability, and recyclability. Here, it is shown that rationally controlling the extent of arrested phase separation can lead to optimized multiscale structure that reconciles permeability and transparency, a previously conflicting goal by common pore-forming strategies. The process is simply accomplished by hydrothermally treating a dense and transparent hydrophobic association hydrogel. The examination of multiscale structure evolution during hydrothermal treatment reveals that the phase separation with upper miscibility gap evolves to confer time-dependent pore growth due to slow dynamics of polymer-rich phase which is close to vitrification. Such a process can render a combination of multiple desired properties that equal or surpass those of the state-of-the-art keratoprostheses. In vivo tests confirm that the keratoprosthesis can effectively repair corneal perforation and restore a transparent cornea with treatment outcomes akin to that of allo-keratoplasty. The keratoprosthesis is easy to access and convenient to carry, and thus would be an effective temporary substitute for a corneal allograft in emergency conditions.

Urgent unmet needs in the care of bacterial keratitis: An evidence-based synthesis

Bacterial corneal infections, or bacterial keratitis (BK), are ophthalmic emergencies that frequently lead to irreversible visual impairment. Though increasingly recognized as a major cause of global blindness, modern paradigms of evidence-based care in BK have remained at a diagnostic and therapeutic impasse for over half a century. Current standards of management - based on the collection of corneal cultures and the application of broad-spectrum topical antibiotics - are beset by important yet widely underrecognized limitations, including approximately 30% of all patients who will develop moderate to severe vision loss in the affected eye. Though recent advances have involved a more clearly defined role for adjunctive topical corticosteroids, and novel therapies such as corneal crosslinking, overall progress to improve patient and population-based outcomes remains incommensurate to the chronic morbidity caused by this disease. Recognizing that the care of BK is guided by the clinical axiom, "time equals vision", this chapter offers an evidence-based synthesis for the clinical management of these infections, underscoring critical unmet needs in disease prevention, diagnosis, and treatment.

Safety and Efficacy of Double Lamellar Keratoplasty for Corneal Perforation

INTRODUCTION

To assess the outcomes of double lamellar keratoplasty in the treatment of corneal perforation secondary to various keratopathies.

METHODS

In this prospective non-comparative interventional case series, 15 eyes from 15 consecutive patients with corneal perforation were chosen to undergo double lamellar keratoplasty, which is characterized by two layers of lamellar grafting in the perforated area. The posterior graft was separated from a relatively healthy and thin lamellar graft of the recipient, and the anterior graft was transplanted from the donor lamellar cornea. Preoperative characteristics and postoperative examination and relevant complications throughout the study were recorded.

RESULTS

Nine men and six women with an average age of 50.73 ± 19.89 (range, 9-84) years were enrolled. The median follow-up period was 18 (range, 12-30) months. In all postoperative patients, the integrity of the eyeball was successfully rebuilt, and the anterior chambers were formed without aqueous leakage. At the last visit, best-corrected visual acuity improved in 14/15 patients (93.3%). Slit-lamp microscopy showed that all treated eyes remained fully transparent. Anterior segment optical coherence tomography revealed that the double-layer structure of the treated cornea was clear in the early postoperative stage. In vivo confocal microscopy revealed intact epithelial cells, sub-basal nerves, and clear keratocytes in the transplanted cornea. No immune rejection or recurrence was detected during the follow-up period.

CONCLUSIONS

Double lamellar keratoplasty presents a new therapeutic option for patients undergoing corneal perforation, and it provides improvement in visual acuity and reduces the risk of postoperative adverse events.

Applications of hydrogel materials in different types of corneal wounds

Severe corneal injury can lead to a decrease in light transmission and even blindness. Currently, corneal transplantation has been applied as the primary treatment for corneal blindness; however, the worldwide shortage of suitable corneal donor tissue means that a large proportion of patients have no access to corneal transplants. This situation has contributed to the rapid development of various corneal substitutes. The development and optimization of novel hydrogels that aim to replace partial or full-thickness pathological corneas have advanced in the last decade. Meanwhile, with the help of 3D bioprinting technology, hydrogel materials can be molded to a refined and controllable shape, attracting many scientists to the field of corneal reconstruction research. Although hydrogels are not yet available as a substitute for traditional clinical methods of corneal diseases, their rapid development makes us confident that they will be in the near future. We summarize the application of hydrogel materials for various types of corneal injuries frequently encountered in clinical practice, especially focusing on animal experiments and preclinical studies. Finally, we discuss the development and achievements of 3D bioprinting in the treatment of corneal injury.

Development and optimization of an ocular hydrogel adhesive patch using definitive screening design (DSD)

Adhesive hydrogels based on chemically modified photocrosslinkable polymers with specific physicochemical properties are frequently utilized for sealing wounds or incisions. These adhesive hydrogels offer tunable characteristics such as tailorable tissue adhesion, mechanical properties, swelling ratios, and enzymatic degradability. In this study, we developed and optimized a photocrosslinkable adhesive patch, GelPatch, with high burst pressure, minimal swelling, and specific mechanical properties for application as an ocular (sclera and subconjunctival) tissue adhesive. To achieve this, we formulated a series of hydrogel patches composed of different polymers with various levels of methacrylation, molecular weights, and hydrophobic/hydrophilic properties. A computerized multifactorial definitive screening design (DSD) analysis was performed to identify the most prominent components impacting critical response parameters such as adhesion, swelling ratio, elastic modulus, and second order interactions between applied components. These parameters were mathematically processed to generate a predictive model that identifies the linear and non-linear correlations between these factors. In conclusion, an optimized formulation of GelPatch was selected based on two modified polymers: gelatin methacryloyl (GelMA) and glycidyl methacrylated hyaluronic acid (HAGM). The ex vivo results confirmed adhesion and retention of the optimized hydrogel subconjunctivally and on the sclera for up to 4 days. The developed formulation has potential to be used as an ocular sealant for quick repair of laceration type ocular injuries.

SMILE lenticule versus amniotic membrane graft (AMG) augmented with platelet-rich plasma (PRP) for the treatment of perforated corneal ulcer

PURPOSE

To evaluate the safety and efficacy of stromal lenticule obtained from small-incision lenticule extraction (SMILE) surgery versus amniotic membrane graft (AMG) augmented with platelet-rich plasma (PRP) for the treatment of perforated corneal ulcers and compare the results between the two groups.

PATIENTS AND METHODS

This is a comparative retrospective study that included 40 eyes with medium-sized corneal perforations, which were classified into two equal groups of 20 eyes each; group (A) was treated with SMILE lenticule graft and group (B) was treated with AMG augmented with PRP. Pre- and postoperative evaluations were carried out using both slit-lamp (SL) examination and anterior segment optical coherence tomography (AS-OCT), including closure of perforation, complete healing, and best corrected visual acuity (BCVA).

RESULTS

Complete closure of the perforation was achieved in both groups. However, healing was faster in the SMILE lenticule group than in the AMG with PRP group (P < 0.05). Complete healing was achieved in both groups: 100% in SMILE lenticule group and 95% in AMG with PRP group (P > 0.05). Both groups had few insignificant complications (30% in each), which were managed.

CONCLUSION

Both methods achieved adequate healing of corneal perforations within few weeks without significant complications. However, the stromal lenticule obtained from small-incision lenticule extraction (SMILE) surgery tended to be safer with faster healing than AMG with PRP.

Recurrence of perforation and overall patient survival after penetrating keratoplasty versus amniotic membrane transplantation in corneal perforation

PURPOSE

The following is a comparative analysis on the treatment outcomes of corneal perforations using amniotic membrane transplantation (AMT) or penetrating keratoplasty (PK).

METHODS

This monocentric retrospective study was performed at the Department of Ophthalmology, University Hospital Ulm, Germany. A total of 78 eyes of 78 patients were included. Thirty-nine eyes received an AMT, and 39 patients were treated with a PK. Primary outcome was recurrence of perforation. Secondary outcomes were patient mortality and visual acuity.

RESULTS

No statistically significant difference was observed with regard to a recurrence of perforation between the two groups (26% in AMT vs 23% in PK, p > 0.99). The time of recurrences was within the first two years and did not differ statistically (p = 0.97). In addition, a proportional hazards model with cox regression regarding recurrent perforation showed no significant differences (p = 0.5). After AMT, 41% and after KP, 28% of the patients died during follow-up (p = 0.2), respectively. The Charlson Comorbidity Index (p < 0.0001) and the age at the time of surgery (p = 0.0002) were statistically significantly higher in those who were deceased. A mean follow-up of 485 ± 517 days was recorded.

CONCLUSION

Both surgical methods show good results and no statistically significant difference regarding recurrent perforation rate. About a third of the patients died during the follow-up period. The decision regarding the appropriate method should therefore be based on a combination of all factors.

Tissue Adhesives for the Management of Corneal Perforations and Challenging Corneal Conditions

Corneal perforations are ophthalmological emergencies which can have serious and detrimental consequences, if not managed timely and appropriately. These are a significant cause of ocular morbidity and can result in decreased vision, blindness, and even loss of the eye. Corneal perforations can be managed using a range of treatment approaches, including temporary solutions such as the application of corneal glue and bandage contact lens, as well as definitive treatment such as corneal transplantation. Tissue glues/adhesives were developed as substitutes for sutures in ophthalmic surgery. Unlike sutures, these glues are associated with shorter overall surgical times and reduced inflammation, thus improving postoperative comfort without compromising wound strength. The available tissue adhesives can be broadly classified into two types: synthetic (eg, cyanoacrylate derivatives) and biological (eg, fibrin glue). Cyanoacrylate glue is chiefly used as a corneal patch to manage acute corneal perforations and improve visual outcomes. Fibrin glue can be used instead of cyanoacrylate glue in many conditions with the benefits of reduced conjunctival and corneal inflammation and reaction. Apart from this, each type of adhesive is distinct in terms of its benefits as well as limitations and is accordingly used for different indications. The present review focuses on the two main types of tissue adhesives, their applications in the management of corneal perforations, the associated complications, safety and efficacy data related to their use available in the literature and the need for newer adhesives in this field.

Clinical outcome and course of Tenon's patch graft in corneal perforation and descemetocele

Purpose

To assess the efficacy and clinical outcome of Tenon's patch graft (TPG) in corneal perforation and descemetocele.

Methods

In this retrospective study, medical records of 83 patients (85 eyes) who underwent TPG for corneal perforation (58, 68%) or descemetocele (27, 32%) between July 2018 and October 2021 were reviewed. Clinical examination and anterior segment optical coherence tomography (AS-OCT) were performed on every follow-up visit. Anatomical success was considered as the restoration of the structural integrity with the formation of scar and anterior chamber (AC).

Results

The mean size of the corneal lesions (corneal perforation or descemetocele) was 4.20 ± 1.01 mm. The mean follow-up period was 9.2 ± 5.48 months. The common underlying etiologies were infectious keratitis in 48% and autoimmune disorders in 35% of cases. TPG successfully restored the globe integrity in 74 (87%) eyes (83% in perforation and 96% in descemetocele). Anatomical failure occurred in 11 eyes (13%). The failures were due to graft dehiscence (8 eyes), graft ectasia (1 eye), and scarring with flat AC (2 eyes). The median time to epithelialization and scar formation were 3 and 15 weeks, respectively. Logistic regression analysis showed few predictors for a successful outcome: descemetoceles, noninfective causes, viral keratitis in infectious etiology, and paracentral or peripheral lesions.

Conclusion

TPG can be considered an effective and inexpensive treatment for restoring the structural integrity in the eyes with perforations and descemetoceles, particularly when the donor tissue is unavailable. AS-OCT is a valuable noninvasive tool for monitoring the graft status.

Neurotization of the human cornea - A comprehensive review and an interim report

We present a comprehensive review of existing literature on surgical corneal neurotization (SCN) as a treatment modality for neurotrophic keratopathy (NK) with an interim report of seven cases where SCN was performed using the indirect approach and followed up till 18 months postoperatively to look for improvement in ocular surface, corneal sensations, and nerve regeneration by using in vivo confocal microscopy (IVCM). A literature search was performed for publications with keywords “corneal nerves,” “neurotization,” “esthesiometry,” “corneal anesthesia,” and “neurotrophic keratopathy.” All literature available till December 31, 2020 was reviewed and included to describe NK and its management options, particularly SCN. NK is associated with absent or reduced corneal sensations and is managed using a step-ladder algorithm ranging from medical management for symptomatic relief to surgical corneal neurotization. Both direct and indirect approaches of SCN have a favorable outcome with reduced surgical morbidity in the indirect approach using sural nerve graft. Post neurotization, corneal sensation recovery may take up to 3–6 months, while nerve regeneration on confocal microscopy can take as long as 6 months–1 year.

Early Endothelialization of Ab Interno Stromal Tectonic Patch in the Management of Corneal Perforation Secondary to Bacterial Keratitis

PURPOSE

The purpose of this study was to describe a novel surgical technique using an ab interno stromal patch to treat corneal perforation and to present the histological findings of the patch after its removal during definitive mushroom keratoplasty.

METHODS

The endothelium had already been removed with the submerged cornea using backgrounds away (SCUBA) technique.

RESULTS

The patient was managed successfully with a sutureless ab interno stromal tectonic patch. Two months later, definitive mushroom keratoplasty was performed and the patch was sent for histological examination. Immunohistochemistry revealed a reactive endothelium covering the posterior surface of the graft. Nine months later, her best-corrected visual acuity was 6/9.

CONCLUSIONS

This is the first case to our knowledge demonstrating that stromal tectonic grafts without the endothelium can successfully attach to the host tissue and seal a perforation. The stroma may undergo reendothelialization and begin to restore vision, even before penetrating keratoplasty.

Crosslinker-free collagen gelation for corneal regeneration

Development of an artificial cornea can potentially fulfil the demand of donor corneas for transplantation as the number of donors is far less than needed to treat corneal blindness. Collagen-based artificial corneas stand out as a regenerative option, having promising clinical outcomes. Collagen crosslinked with chemical crosslinkers which modify the parent functional groups of collagen. However, crosslinkers are usually cytotoxic, so crosslinkers need to be removed from implants completely before application in humans. In addition, crosslinked products are mechanically weak and susceptible to enzymatic degradation. We developed a crosslinker free supramolecular gelation strategy using pyrene conjugated dipeptide amphiphile (PyKC) consisting of lysine and cysteine; in which collagen molecules are intertwined inside the PyKC network without any functional group modification of the collagen. The newly developed collagen implants (Coll-PyKC) are optically transparent and can effectively block UV light, are mechanically and enzymatically stable, and can be sutured. The Coll-PyKC implants support the growth and function of all corneal cells, trigger anti-inflammatory differentiation while suppressing the pro-inflammatory differentiation of human monocytes. Coll-PyKC implants can restrict human adenovirus propagation. Therefore, this crosslinker-free strategy can be used for the repair, healing, and regeneration of the cornea, and potentially other damaged organs of the body.

Management of a central corneal perforation in the emergency room: Tenon patch technique

Purpose

Corneal perforations are defined as a solution of continuity in the cornea. Usually, these cases evolve to the formation of a corneal-iridial scar or require surgical intervention. The tenon patch graft represents a good alternative to other methods and has many advantages.

Observation

A 63-year-old patient who had been followed for severe dry eyes due to rheumatoid arthritis for 10 years presented to the emergency room with a central corneal perforation, partially sealed by the iris, accompanied by significant corneal edema in the right eye. Given the clinical picture that had been developing for 5 days, we decided to perform a tenon patch graft on the perforation. At 4 weeks of follow-up, globe integrity was maintained with a well-placed tenon patch. No evidence of leakage in the Seidel test was noted.

Conclusion

The tenon patch graft represents a good alternative in the management of corneal perforations and has many advantages, among which the feasibility in an emergency, allowing a corneal graft afterwards.

•

Open corneal fistulas require immediate treatment with tissue adhesives, amniotic membrane grafting, or keratoplasty.

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Due to a lack of availability or financial constraints, these processes may not be possible in all cases.

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In these situations, a tenon patch graft is a useful method.

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Tenon patch grafts have the advantages of being autologous, having low tissue reactivity, being cost-effective, and having a simple learning curve.

Hitch suture assisted tuck in Tenon's Patch Graft for management of Corneal Perforations

PURPOSE

To describe a novel modification of tuck-in Tenon's patch graft (TPG) using temporary horizontal mattress sutures and fibrin glue to hitch the graft in the management of corneal perforations.

DESIGN

Ambispective interventional case series.

METHODS

Modified technique of autologous TPG was used to seal corneal perforations measuring 3-5 mm, using horizontal mattress sutures to hitch the graft in a lamellar pocket, followed by application of fibrin glue. The horizontal mattress sutures were removed after the reformation of the anterior chamber. The primary outcome measure was a well formed anterior chamber in the post-operative period and the secondary outcome was epithelization time.

RESULTS

The surgery was performed in 22 eyes. The mean age was 43.86 ± 16.02 (26-66) years, with 14 males and eight females. The etiologies of corneal perforation included dry eye (n = 10), neurotrophic keratitis (n = 6), trauma (n = 2), chemical injury (n = 2) and exposure (n = 2). The mean size of the perforation with the thinned-out area was 4.3 mm (range 3-5 mm). The mean duration of epithelialization was 14.31 ± 2.63 days (7-21 days). No intraoperative complications were observed. All eyes had a well-formed anterior chamber in the immediate postoperative period. Postoperatively, two eyes had graft pseudoectasia due to a thick graft and supra tenon haemorrhage each; one eye each had graft thinning with the formation of pseudopterygium and graft melting.

CONCLUSION

Tenon's patch graft, along with the use of temporary horizontal mattress sutures and fibrin glue, is an effective modification of the technique for managing corneal perforations measuring 3-5 mm.

Gore-Tex- as an adjuvant to Tenon's patch graft for large perforated corneal ulcers during Covid times

Purpose

Observations

Conclusions and Importance

Photocurable GelMA Adhesives for Corneal Perforations

The current treatments for the management of corneal and scleral perforations include sutures and adhesives. While sutures are invasive, induce astigmatism and carry a risk of infection, cyanoacrylate glues are toxic, proinflammatory and form an opaque and rough surface that precludes vision. Consequently, the clinical need for a fast curing and strong tissue adhesive with minimised cytotoxicity and host inflammation remains unmet. In this paper, we engineer a gelatine methacryloyl (GelMA) adhesive that can be crosslinked in situ within 2 min using UV or visible light and a riboflavin (RF)/sodium persulfate (SPS) system. Optical coherence tomography (OCT) images demonstrated that the flowable GelMA adhesive could completely fill corneal wounds and restore the ocular curvature by forming a smooth contour on the ocular surface. Further, ex vivo studies in porcine eyes showed that GelMA bioadhesives exhibited burst pressures that were comparable to cyanoacrylates (49 ± 9 kPa), with the hydrogels exhibiting a transmittance (90%), water content (85%) and storage modulus (5 kPa) similar to the human cornea. Finally, using human dermal fibroblasts, we showed that our GelMA adhesive was non-toxic and could effectively support cell adhesion and proliferation. Taken together, the adhesive’s performance, injectability and ease of administration, together with gelatin’s availability and cost-effectiveness, make it a potential stromal filler or sealant for corneal and conjunctival applications.

Development and characterization of a hydrogel-based adhesive patch for sealing open-globe injuries

Full-thickness wounds to the eye can lead to serious vision impairment. Current standards of care (from suturing to tissue transplantation) usually require highly skilled surgeons and use of an operating theater. In this study, we report the synthesis, optimization, and in vitro and ex vivo testing of photocrosslinkable hydrogel-based adhesive patches that can easily be applied to globe injuries or corneal incisions. According to the type and concentration of polymers used in the adhesive formulations, we were able to finely tune the physical properties of the bioadhesive including viscosity, elastic modulus, extensibility, ultimate tensile strength, adhesion, transparency, water content, degradation time, and swellability. Our in vitro studies showed no sign of cytotoxicity of the hydrogels. Moreover, the hydrogel patches showed higher adhesion on freshly explanted pig eyeballs compared to a marketed ocular sealant. Finally, ex vivo feasibility studies showed that the hydrogel patches could seal complex open-globe injuries such as large incision, cruciform injury, and injury associated with tissue loss. These results suggest that our photocrosslinkable hydrogel patch could represent a promising solution for the sealing of open-globe injuries or surgical incisions. STATEMENT OF SIGNIFICANCE: Current management of severe ocular injuries require advanced surgical skills and access to an operating theater. To address the need for emergent management of wounds that cannot be handled in the operating room, surgical adhesives have gained popularity, but none of the currently available adhesives have optimal bioavailability, adhesive or mechanical properties. This study describes the development, optimization and testing of a light-sensitive adhesive patch that can easily be applied to the eye. After solidification using visible light, the patch shows no toxicity and is more adherent to the tissue than a marketed sealant. Thus this technology could represent a promising solution to stabilize ocular injuries in emergency settings before definitive surgical repair.

Tenons Patch Graft: A Review of Indications, Surgical Technique, Outcomes and Complications

PURPOSE

Corneal perforations are common corneal emergencies faced by ophthalmologists across the globe. There are multiple modalities of management, most of which require an eye bank support or availability of tissue adhesives. Tenons patch graft (TPG) is a technique that does not depend on these factors as the graft is harvested from the same eye of the patient. The aim of this review is to provide an overview of the indications, technique, normal postoperative course, and management of complications.

METHODS

After carrying out a literature search on "tenons capsule", "corneal patch graft", "tenons patch graft", "multilayered amniotic membrane" and "corneal perforations", 28 articles were included for this review.

RESULTS

TPG graft can be performed in cases of small to moderate perforations without active suppuration. The procedure can also be combined with amniotic membrane grafting or tissue adhesives to provide additional tectonic support. Postoperatively, the epithelium heals over a course 2-3 weeks and restoration of a stable ocular surface with a corneal scar is completed by the third postoperative month. Complications following the surgical procedure are rare but can include graft displacement, melt and pseudoectasia. Subsequent visual rehabilitation with contact lenses or keratoplasties can be planned in these eyes that yields good visual outcomes.

CONCLUSIONS

Tenons patch graft is a simple yet viable option in management of small to moderate corneal perforations. The procedure does not necessitate the prior availability of specialized products and can be performed with routine equipment of an ophthalmic theatre, making it an attractive option in low resource settings.

Effects of Gelatin Methacrylate Hydrogel on Corneal Repair and Regeneration in Rats

Purpose

This study investigates the repairing process of rat cornea after surgery of lamellar keratoplasty (LKP) and evaluates the effects of gelatin methacrylate (GelMA) hydrogel.

Methods

In the LKP group, the lamellar stroma matrixes of Sprague-Dawley rats were transplanted to enhanced green fluorescent protein rats, whereas those in the GelMA group were also embedded with a GelMA hydrogel during the corneal transplantation. Grafted eyes were harvested on days seven, 30, and 90. Hematoxylin and eosin staining, immunofluorescence staining, scanning electron microscopy, optical coherence tomography, and a slit-lamp microscope were used to study the process of corneal restoration and regeneration.

Results

A total of 42 rats were analyzed, including 18 rats in each of the experimental group and six rats in the control group. After three months, the infiltration degree of inflammatory cells differed between the LKP group and the GelMA group (P < 0.001). Moreover, in multiple comparisons in corneal thickness, significant difference was observed between the LKP group and the GelMA group. There was also divergence in the results between the LKP group and the control group (P < 0.001, P < 0.001). At the same time, the expression of α-smooth muscle actin (α-SMA) and transforming growth factor (TGF)-β1 varied distinctly between the LKP group and the GelMA group (P < 0.05, P < 0.001).

Conclusions

Significant differences were demonstrated between the LKP group and the GelMA group in inflammatory cell infiltration, corneal thickness, as well as the expression of α-SMA and TGF-β1. Those differences indicate the ability of GelMA hydrogel to support alleviation in corneal stroma fibrosis and show the influences of fibrosis in the dysfunction of corneal refractive power.

Translational Relevance

Our research provides new ideas for the future development of LKP and tissue-engineered corneas.

Sutureless Tectonic Mini-Descemet's Stripping Automated Endothelial Keratoplasty ("mini-DSAEK") for the management of corneal perforations

PURPOSE

To report the outcomes of a new technique, pull-through sutureless 'mini-DSAEK', to manage corneal perforations secondary to different aetiologies including trauma, neurotrophic ulcer following penetrating keratoplasty (PK), herpes simplex keratitis and microbial keratitis.

METHODS

In this retrospective case series, we report the clinical outcomes of five cases of sutureless tectonic mini-DSAEK performed in patients presenting with large corneal perforations to Southend University Hospital between November 2019 and October 2020. One corneal perforation was sufficiently peripheral for the tectonic mini-DSAEK graft to be successfully positioned outside of the central visual axis. Four corneal perforations were central or paracentral for which the tectonic grafts involved the visual axis.

RESULTS

Anterior chambers remained deep and formed with no evidence of leak in all subsequent follow ups in all patients representing 100% tectonic success. All tectonic grafts remained attached except one partially detached graft. One patient underwent uneventful phacoemulsification with intraocular lens implant 8 months after the primary intervention with excellent visual outcome. Two patients underwent two-piece mushroom PK and one patient underwent triple procedure (cataract extraction   +   intraocular lens   +   PK) for visual rehabilitation 2-6 months after the primary intervention with good visual outcome.

CONCLUSION

Sutureless tectonic pull-through mini-DSAEK is a useful technique in the management of corneal perforations, with a number of advantages compared with conventional techniques.

Tectonic Deep Anterior Lamellar Keratoplasty to Treat Corneal Perforation and Descemetocele from Microbial Keratitis

Purpose

To evaluate the result of tectonic deep anterior lamellar keratoplasty (DALK) for keratitis with perforation and descemetocele.

Patients and Methods

A prospective clinical study of 36 patients (36 eyes) treated with tectonic DALK for corneal perforation or descemetocele from microbial keratitis managed at the Vietnam National Eye Hospital over a two-year period. The surgical technique was manual lamellar dissection. The grafts were harvested from the anterior corneal cap of pre-cut donor tissues used for DSAEK or donor corneas with a low endothelial cell count.

Results

A mean age was 55.36 ± 13.98 years (ranged from 25 to 75 years). Female gender represented 52%. causative agents were herpes simplex virus (58.3%), bacteria (22.2%), fungi (13.9%) and microsporidia (5.6%). There were 24 eyes with descemetocele (66.7%) and 12 with perforation (33.3%). There were 33 successful cases (91.7%) and 3 failed cases (8.3%). Best corrected visual acuity (BCVA) improved in 28 eyes (84.8%). The range of post-operative BCVA was from hand motions to 20/70. Eleven eyes (33.3%) attained vision 20/200 and higher. Clear graft was obtained in 15 eyes (45.5%), while mild or severe graft opacity was observed in 14 eyes (42.4%), and 4 eyes (12.1%), respectively. Surgical complications included descemet rupture (20.8%), pseudo anterior chamber (41.6%), persistent corneal epithelial defects (8.3%), reinfection (11.1%), glaucoma or ocular hypertension (5.6%) and cataract (8.3%).

Conclusion

The study demonstrates that DALK is an effective procedure to treat corneal descemetocele, especially when an urgent penetrating keratoplasty (PKP) cannot be performed.

Prognosis and etiology of traumatic and non-traumatic corneal perforations in a tertiary referral hospital: a 30-year retrospective study

PURPOSE

To clarify the prognosis of corneal perforation, we compared the etiology and characteristics of patients with traumatic and non-traumatic corneal perforations.

METHODS

This retrospective observational study included patients treated for traumatic or non-traumatic corneal perforations at a single tertiary hospital from 1989 to 2019. The variables collected included the primary cause of corneal perforation, final best-corrected visual acuity (BCVA), and treatment administered. The initial treatment administered and treatment success rates were compared between the traumatic and non-traumatic groups. Multivariate linear regression analysis was performed to determine the predictors of final visual acuity.

RESULTS

Ninety eyes of 90 patients (mean age, 61.1 ± 19.7 years) were included. Traumatic and non-traumatic corneal perforations occurred in 40 (44.4%) and 50 eyes (55.6%), respectively. Among non-traumatic causes, infection and autoimmune disease were the causes for corneal perforation in 18 (20.0%) and 12 eyes (13.3%), respectively. The success rate for the closure of the perforated site with the initial procedure was significantly higher in traumatic corneal perforations than in non-traumatic corneal perforations (90.0% and 72.2%, respectively; p = 0.038). Patients with traumatic corneal perforation had significantly better final BCVA than those with non-traumatic corneal perforation (0.71 ± 1.18 and 1.52 ± 1.12, respectively; p = 0.0016). On multivariate analysis, older age and non-traumatic corneal perforation were significantly related to the final lower BCVA (p < 0.001 and p = 0.029, respectively).

CONCLUSION

Traumatic corneal perforation demonstrated a significantly better prognosis than non-traumatic corneal perforation. It is critical to consider the primary cause of corneal perforation to anticipate prognosis.

Cyanoacrylate Tissue Adhesive for the Treatment of Corneal Thinning and Perforations: A Multicenter Study

PURPOSE

To examine the outcomes of cyanoacrylate tissue adhesive (CTA) application for impending or frank corneal perforations and assess for predictors of treatment response.

METHODS

A multicenter cohort study was conducted to assess the clinical outcomes of adult patients who underwent CTA gluing for impending or frank corneal perforations between 2013 and 2018. The primary outcome was the proportion of successful CTA applications, defined as tectonic stability of the globe without subsequent keratoplasty (KP). Secondary outcomes included visual acuity and success of subsequent surgical interventions, if performed.

RESULTS

Fifty-three eyes of 52 patients were included in this study [56% women; mean age at presentation 70 ± 13 years; median length of follow-up of 387 days (interquartile range: 191-704)]. Medical comorbidities were present in 62% of patients. The most common etiologies for perforations included infections (43%) and Sjogren disease (9%). Of the CTA-treated eyes, 22% had a complete resolution of the corneal lesion. Fifty-four percent of patients underwent KP. Longer duration of CTA treatment was associated with CTA success (P = 0.04). For patients requiring KP, 71% were successful and 29% failed. There is no significant difference in the median time delay between patients with successful and failed KPs (P = 0.4).

CONCLUSIONS

CTA may be considered a stand-alone treatment for corneal perforations. It yielded a success rate of 22%. Failed CTA treatment occurred quickly, largely because of the severity of presentation. In cases requiring KP, the delay between glue application and surgery did not influence the PK success.

Efficacy of conjunctival flap surgery for deep corneal ulcers

Aim: To evaluate the clinical efficacy of a selective, partial, pedicle conjunctival flap in the treatment of deep corneal ulcers with or without perforation, resistant to medical treatment.

Method: This interventional self-controlled retrospective study included 31 eyes of 31 patients with deep corneal ulcers who underwent conjunctival flap surgery in a tertiary eye care unit between 2017 and 2019. Of these, 9 eyes exhibited corneal perforation. The follow-up period was 12 months. The primary outcome measures were restoring ocular surface integrity and secondary outcome measures were improvement in visual acuity and postoperative complications encountered.

Results: Out of the total of 31 patients, 17 patients (55%) were males and 14 patients (45%) were females. The mean age was 56.03 ± 15.46 years. The mean disease duration was 64.10 ± 35.01 days, the mean diameter of the ulcer was 3.61 ± 1.02 mm and the mean depth of the ulcer was 70.65 ± 20.28% of the thickness of the cornea. The etiology was extensive and the corneal ulcers were categorized as infectious (12), noninfectious (16), and unknown (3). An anatomic cure was obtained in 29 (94%) of 31 eyes. Conjunctival flap surgery was unsuccessful in 2 eyes that required evisceration. The postoperative visual acuity (BCVA) improved in 13 (42%) of the 31 eyes, decreased in 9 eyes (29%) and remained unchanged in 9 eyes (29%). The most frequent complications after conjunctival flap surgery were pseudopterygium, cataract and corneal opacity and less frequent complications were glaucoma, astigmatism, flap retraction, corneal perforation and endophthalmitis.

Conclusions: Conjunctival flap surgery can successfully treat refractory deep corneal ulcers. It can restore ocular surface integrity and provide metabolic and mechanical support for corneal healing. Also, it can avoid emergency penetrating keratoplasty or create appropriate conditions for a future optic keratoplasty.

Intracorneal scleral patch supported cyanoacrylate application for corneal perforations secondary to rheumatoid arthritis

Purpose:

To describe a new technique of intracorneal scleral patch (ICSP) supported cyanoacrylate tissue adhesive (CTA) application in corneal perforations, greater than 3.0 mm secondary to rheumatoid arthritis (RA).

Methods:

This Prospective, non-randomized, non-comparative, interventional series included 14 eyes (14 patients). All patients had corneal perforations sized 3.5 to 4.5 mm due to RA, which were treated with ICSP supported CTA application. A partial thickness scleral patch 1.0 mm larger than diameter of corneal perforation was prepared. A lamellar corneal pocket 0.5 mm all around the corneal perforation was created. The partial thickness scleral patch was placed in the corneal perforation site and the edge was fitted into the lamellar intracorneal pocket. A minimum quantity of CTA was applied on the scleral patch to seal the perforation.

Results:

The corneal perforations healed in 14 eyes (100%) in a mean 7.71 ± 1.14 (range, 6–9) weeks. One eye (7.14%) had inadvertent extrusion of ICSP due to premature removal of CTA but, Seidel's test was negative, and the corneal epithelial defect healed with BCL alone. One eye each (7.14%) developed steroid induced cataract and glaucoma. None of eyes developed infective keratitis, re-opening of corneal perforation (necessitating repeat procedure) or enlargement of corneal perforation requiring penetrating keratoplasty (PKP).

Conclusion:

ICSP supported CTA application is a successful alternative option to emergency PKP in treating corneal perforations sized 3.5 to 4.5 mm with associated RA.

Mini-Descemet Stripping-Automated Endothelial Keratoplasty for Macro Corneal Perforations

PURPOSE

We present a technique that preserves good vision in paracentral macroperforations and avoids challenges of tectonic lamellar or penetrating keratoplasty in eyes with poor visual potential.

METHOD

A wet laboratory was implemented for mini-Descemet stripping endothelial keratoplasty to seal macroperforations ab interno. This included a suture support technique designed to prevent graft herniation. We also present 3 cases who were treated successfully with this technique.

RESULTS

The laboratory test confirmed that mini-Descemet stripping endothelial keratoplasty can successfully seal macroperforations without the need of large incisions. The minidisc is introduced through the perforation, and a double mattress suture prevents graft herniation. The technique allowed us to preserve 20/15 unaided vision in a case with paracentral macroperforation. It also restored eye globe integrity and achieved long-term stability in 2 cases with limbal stem-cell deficiency.

CONCLUSIONS

Mini-Descemet stripping-automated endothelial keratoplasty technique can be an alternative approach to avoid poor visual outcomes of tectonic keratoplasty in paracentral perforations. It also offers host tissue preservation in eyes with high risk of rejection for tectonic grafts.

Tuning gelatin-based hydrogel towards bioadhesive ocular tissue engineering applications

Gelatin based adhesives have been used in the last decades in different biomedical applications due to the excellent biocompatibility, easy processability, transparency, non-toxicity, and reasonable mechanical properties to mimic the extracellular matrix (ECM). Gelatin adhesives can be easily tuned to gain different viscoelastic and mechanical properties that facilitate its ocular application. We herein grafted glycidyl methacrylate on the gelatin backbone with a simple chemical modification of the precursor, utilizing epoxide ring-opening reactions and visible light-crosslinking. This chemical modification allows the obtaining of an elastic protein-based hydrogel (GELGYM) with excellent biomimetic properties, approaching those of the native tissue. GELGYM can be modulated to be stretched up to 4 times its initial length and withstand high tensile stresses up to 1.95 MPa with compressive strains as high as 80% compared to Gelatin-methacryloyl (GeIMA), the most studied derivative of gelatin used as a bioadhesive. GELGYM is also highly biocompatible and supports cellular adhesion, proliferation, and migration in both 2 and 3-dimensional cell-cultures. These characteristics along with its super adhesion to biological tissues such as cornea, aorta, heart, muscle, kidney, liver, and spleen suggest widespread applications of this hydrogel in many biomedical areas such as transplantation, tissue adhesive, wound dressing, bioprinting, and drug and cell delivery.

CLEAR - Medical use of contact lenses

The medical use of contact lenses is a solution for many complex ocular conditions, including high refractive error, irregular astigmatism, primary and secondary corneal ectasia, disfiguring disease, and ocular surface disease. The development of highly oxygen permeable soft and rigid materials has extended the suitability of contact lenses for such applications. There is consistent evidence that bandage soft contact lenses, particularly silicone hydrogel lenses, improve epithelial healing and reduce pain in persistent epithelial defects, after trauma or surgery, and in corneal dystrophies. Drug delivery applications of contact lens hold promise for improving topical therapy. Modern scleral lens practice has achieved great success for both visual rehabilitation and therapeutic applications, including those requiring retention of a tear reservoir or protection from an adverse environment. This report offers a practical and relevant summary of the current evidence for the medical use of contact lenses for all eye care professionals including optometrists, ophthalmologists, opticians, and orthoptists. Topics covered include indications for use in both acute and chronic conditions, lens selection, patient selection, wear and care regimens, and recommended aftercare schedules. Prevention, presentation, and management of complications of medical use are reviewed.

Corneal stromal mesenchymal stem cells: reconstructing a bioactive cornea and repairing the corneal limbus and stromal microenvironment

Corneal stroma-derived mesenchymal stem cells (CS-MSCs) are mainly distributed in the anterior part of the corneal stroma near the corneal limbal stem cells (LSCs). CS-MSCs are stem cells with self-renewal and multidirectional differentiation potential. A large amount of data confirmed that CS-MSCs can be induced to differentiate into functional keratocytes in vitro, which is the motive force for maintaining corneal transparency and producing a normal corneal stroma. CS-MSCs are also an important component of the limbal microenvironment. Furthermore, they are of great significance in the reconstruction of ocular surface tissue and tissue engineering for active biocornea construction. In this paper, the localization and biological characteristics of CS-MSCs, the use of CS-MSCs to reconstruct a tissue-engineered active biocornea, and the repair of the limbal and matrix microenvironment by CS-MSCs are reviewed, and their application prospects are discussed.

Tectonic Mini-DSAEK Facilitates Closure of Corneal Perforation in Eyes With Healthy Endothelium

PURPOSE

The purpose of this study was to report a surgical technique for closure of a traumatic corneal perforation in a patient with healthy endothelium.

METHODS

A 69-year-old male patient presented to Southend University Hospital with a 2.5 mm round temporal corneal perforation caused by a metallic foreign body from an industrial accident. Best-corrected visual acuity at presentation was 6/36. The patient received a tectonic small diameter Descemet stripping automated endothelial keratoplasty (mini-DSAEK) to close the perforation. The patient subsequently developed traumatic cataract and underwent cataract surgery 8 months later. Clinical outcomes at 1 week, 1 month, 3 months, 6 months, and 9 months were evaluated. The primary outcomes of interest were successful sustained closure of the perforation and surgical complications, with secondary outcomes of best-spectacle corrected visual acuity (BSCVA, Snellen) and keratometric astigmatism (KA, Pentacam).

RESULTS

The anterior chamber was reformed by the graft, restoring the globe's mechanical integrity. The bare stroma reepithelized by 1 week. Neither intraoperative nor postoperative surgical complications were reported. The anterior chamber remained deep and formed during subsequent follow-ups through 9 months. At the 9-month follow-up, final best spectacle-corrected visual acuity was 6/6-1 (Snellen fraction). Keratometric astigmatism was 1.1 diopters.

CONCLUSIONS

Tectonic mini-Descemet stripping automated endothelial keratoplasty is a safe technique in the management of corneal perforations too large for tissue adhesives, with a low astigmatic profile and rapid visual recovery.

Novel technique of tetra trephination for elliptical-shaped tectonic patch grafts in peripheral sterile keratolysis

PURPOSE

To describe a novel technique of tectonic patch grafts for elliptical-shaped peripheral sterile keratolysis with iris prolapse.

METHODS

We performed a full thickness corneo-scleral patch graft in five eyes of five patients with elliptical-shaped peripheral sterile keratolysis with perforation and iris tissue prolapse. In this technique, four disposable trephines with predetermined diameter were employed to fashion both the host and the donor without any free-hand dissection. An intact anatomical integrity of the globe without the need for any repeat tectonic measures was considered as a successful outcome.

RESULTS

The mean age was 34.2 ± 10.2 years (18-45). The mean total surgical time and donor preparation time was 94.4 ± 7.12 min and 7.6 ± 1.14 min, respectively. The intraoperative course was uneventful in all cases and all eyes had a well-maintained corneal integrity till 6 months follow up.

CONCLUSION

We describe a simple, reproducible, and time-saving technique of performing elliptical shaped corneoscleral patch grafts for peripheral corneal perforations with iris prolapse.

Nano-Scale Modifications of Amniotic Membrane Induced by UV and Antibiotic Treatment: Histological, AFM and FTIR Spectroscopy Evidence

The efficiency of amniotic membrane (AM) transplantation in different types of ocular surface disorders is due to its outstanding properties such as antifibrotic, antibacterial, anti-inflammatory and antiangiogenic, working as a versatile scaffold to promote corneal tissue epithelialization. A proper preparation, preservation and clinical application are crucial for the best outcomes in the treatment of different severe ocular disorders, taking into account its fragility. In this context, by combining high-sensitivity tools such as atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy with histological and immunohistochemical examination, we aimed to investigate the ultrastructural modifications of the amniotic membrane (AM) upon UV exposure and/or antibiotic treatment, with relevance for clinical applications in ocular surface surgery. From the morphological point of view, we noticed a loss of cuboidal cells in the basal membrane, accompanied by the splitting of collagen fibers upon UV and/or gentamicin treatment, while structural alteration of proteins was evidenced by the FTIR quantitative analysis of the secondary structure. A decrease in α-helix and β-sheet content, accompanied by increased content in less ordered structures (turns, random and side chains), was noticed after all the treatments. At the nano-scale, AFM details showed modifications of collagen fibrils in terms of their thickness and network compaction upon gentamicin and/or UV treatment. The enzymatic digestion assay demonstrated that UV exposure significantly reduces the degradation rate of the AM, while gentamicin treatment promotes an accelerated enzymatic digestion upon UV exposure. In order to highlight the clinical impact of the research, a clinical case is presented showing the relevance of amniotic membrane transplantation in pterygium surgery.

Tectonic Keratoplasty in Patients with Non-traumatic, Non-infectious Corneal Perforations

Introduction:

The study aims to report clinical results of tectonic keratoplasty for non-traumatic, non-infectious corneal perforations.

Materials and Methods:

The medical records of 12 patients who underwent tectonic penetrating keratoplasty between October 2014 and August 2018 at Ege University Ophthalmology Department were retrospectively reviewed.

Results:

The mean age of the patients was 52.92±30.34 (range, 2-82) years. The causes of corneal perforation were dry eye (neurotrophic keratopathy (n=4), limbal stem cell deficiency (n=2), exposure keratopathy (n=2) and graft versus host disease (n=1)) in 9 patients. In the remaining 3 patients, the etiology of perforation was not determined. The mean Visual Acuity (VA) was 2.98±0.39 (range, 1.8-3.1) LogMAR before the surgery. Despite conservative treatment, tectonic penetrating keratoplasty had to be performed in all patients in order to manage the perforation. Mean time in between initial examination and surgery was 10.75±12.04 (1-41) days. In 2 patients, allogenic limbal stem cell transplantation; in one patient, lateral tarsorrhaphy and in one patient symblepharon release with amniotic membrane transplantation were performed additional to tectonic keratoplasty. Mean follow-up time was 57.88±55.47 (4-141) weeks. Grafts were clear in 6 eyes and opaque in 5 eyes. The main causes of graft failure among opaque grafts were ocular surface disease (3), allograft rejection (1) and glaucoma-related endothelial failure (1). Phthisis bulbi was detected in one patient with congenital glaucoma due to vitreous loss at the time of perforation. The mean final VA in patients who had clear grafts was 1.83±1.03 (range, 0.8-3.1) LogMAR.

Conclusion:

To prevent serious complications in non-traumatic, non-infectious corneal perforations, providing anatomic integrity immediately is a must. If conservative treatment is inadequate or the perforation area is extensive, tectonic penetrating keratoplasty is indicated. Besides, it is important to manage the etiological risk factors in order to obtain successful clinical follow up.

Individualized Corneal Patching for Treatment of Corneal Trauma Combined with Tissue Defects

Aim

To evaluate the efficacy of individualized corneal patching using a minimal graft for corneal trauma combined with tissue defects.

Methods

Fifteen eyes (15 patients) were enrolled in this study, including 8 eyes with corneal perforation induced by removal of metal foreign bodies, 5 eyes with corneal laceration resulting from metal trauma, and 2 eyes with pencil injuries to the cornea. The size, shape, and depth of the tissue defects were assessed. For corneal perforation or irregular tissue defects, if the diameter or length was ≥3.0 mm, traditional penetrating keratoplasty (PK) or lamellar keratoplasty (LK) was adopted; if the diameter or length was ＜3.0 mm, a conical or irregular patch consistent with the defects was used. The visual acuity, corneal status, and postoperative complications were observed during the follow-up.

Results

The diameter of corneal perforations was 1.0 mm in 2 eyes, 1.5 mm in 1 eye, 2.0 mm in 4 eyes, and 3.5 mm in 1 eye. During their PK procedures, a conical corneal graft was used in 7 eyes, while a traditional cylindrical graft was used in 1 eye. The other 7 eyes had corneal trauma combined with irregular tissue defects, which were full-thickness corneal defects in 5 eyes and lamellar defects in 2 eyes, all less than 3.0 mm in length. Thus, five eyes received PK, and 2 eyes received LK using an irregular wedge-shaped patch. The visual acuity increased greatly postoperatively, with mild corneal astigmatism. None of the patients developed immune rejection.

Conclusion

Individualized corneal patching with a minimal graft can save corneal materials, relieve corneal scars, gain a good visual prognosis, and avoid immune rejection in the treatment of corneal trauma combined with tissue defects.