Ocular surface sealants and adhesives

Comparative Outcomes of Single Versus Multiple Cyanoacrylate Tissue Adhesive Applications in the Management of Corneal Thinning and Perforation

PURPOSE

To compare outcomes between patients treated with a single cyanoacrylate tissue adhesive (CTA) patch for corneal thinning or perforation and those requiring multiple CTA applications.

METHODS

We conducted a single-center, comparative cohort study of patients with corneal thinning or perforation treated with either a single or multiple CTA applications in Toronto, Canada, between 2006 and 2024. Primary outcomes were the need for penetrating keratoplasty (PKP) and the best-corrected visual acuity (BCVA) at final follow-up. Associations between the number of CTA applications with baseline characteristics, perforation characteristics, and final outcomes were analyzed using univariable and multivariable logistic regression models.

RESULTS

Overall, 189 patients (median age 69.0 years; 42% female) were included, with 116 (61%) in the single CTA group and 73 (39%) in the multiple-application group (mean 2.3 ± 0.6), over a median follow-up of 4.4 months. Baseline characteristics were similar between groups. Central and paracentral corneal defects were more likely to require multiple glue applications than peripheral defects (OR = 2.92, 95% CI, 1.31-6.51, P = 0.009). No difference was observed in final BCVA between groups (median: 2.0 logarithm of the minimum angle of resolution [single] vs. 2.0 logarithm of the minimum angle of resolution [multiple]; P = 0.838). Patients receiving multiple CTA applications (48%, n = 35/73) were more likely to require PKP (OR = 2.70, 95% CI, 1.42-5.15, P = 0.003) than those treated with a single glue patch (26%, n = 30/116).

CONCLUSIONS

Multiple CTA applications were more frequently needed for central/paracentral defects and were associated with a greater likelihood of PKP. Given no significant difference in final BCVA, a conservative, stepwise management approach can be pursued without compromising long-term visual outcomes, allowing flexibility in surgical planning.

Factors Influencing Cyanoacrylate Tissue Adhesive Outcomes for Corneal Thinning and Perforation

Background and Objectives: To report the outcomes of cyanoacrylate tissue adhesive (CTA) in patients with corneal perforations and thinning. Materials and Methods: A retrospective interventional study of 83 eyes treated with CTA for corneal thinning or perforation at a single institution between 2010 and 2020. Primary endpoints leading to CTA failure, visual acuity, and surgical outcomes were evaluated. Results: At presentation, 55 (66%) had frank perforations and 28 (34%) had thinning or desmetocele. Univariate analysis showed that only multiple CTA applications were associated with CTA failure (p = 0.047). Multivariate analysis did not show any statistically significant variables associated with CTA failure. No variables were associated with the need for future surgery at 30 days or any further point. Older patients (p = 0.005), use of topical steroids before gluing (p = 0.03), corneal thinning (vs. perforation) (p = 0.02), location of pathology (p = 0.048), and multiple CTA applications (p = 0.046) were associated with worse visual outcomes in univariate analysis. Multivariate logistic regression analysis showed that older age (OR 1.05) and use of topical steroids before gluing (OR 3.84) showed higher odds, and systemic immunosuppression (OR 0.08) and single (versus multiple) CTA application (OR 0.11) showed lower odds of worse visual acuity (BCVA ≥ 20/200). The presence of an anterior chamber prior to gluing was associated with spontaneous dislocation of CTA (p = 0.015). Spontaneous dislocation versus manual removal of glue was not associated with final visual acuity (p = 0.7), nor was duration of glue on the cornea (p = 0.2). Conclusions: CTA remains a mainstay of management in patients with corneal thinning or perforation. Only multiple CTA applications were associated with CTA failure, and duration of glue on the cornea was not associated with final visual acuity.

Evaluation of Cyanoacrylate Tissue Adhesive Glue Application Outcomes in Corneal Thinning and Perforation

OBJECTIVES

Corneal thinning and perforation are ocular emergencies necessitating urgent intervention to prevent visual impairment or enucleation. Cyanoacrylate tissue adhesive is frequently used to maintain globe integrity in these cases. However, gaps remain in understanding the outcomes of corneal gluing and the factors influencing its efficacy. This case series evaluates the clinical characteristics and outcomes of glue application in corneal thinning and perforation.

METHODS

A retrospective chart review was conducted on patients treated for corneal thinning and perforation at the University of Florida between January 2012 and May 2023. Demographic data, clinical history, glue application details, and posttreatment outcomes were collected and analyzed.

RESULTS

The study included 128 eyes from 125 subjects. Corneal perforation was found in 71 eyes (55.5%), mostly centrally (49.2%). The leading cause of perforation/thinning was microbial infection (45.3%). The average number of glue applications per eye was 1.66. Within 1 month, 23 patients (18.0%) required only glue reapplication, 37 (28.9%) required surgical intervention (regardless of glue reapplication), and 68 (53.1%) required no further treatment. Factors significantly linked to gluing failure (requiring surgery within 1 month) in univariate analysis included large perforation size, microbial infection, ocular surface disorder, single glue application, and indirect application via sterile drape. Multivariate analysis showed that only large perforation size was significantly associated with gluing failure.

CONCLUSION

Corneal glue application is an effective temporizing measure for corneal thinning and perforation, with multiple applications potentially providing added stability to the globe. However, the need for surgical intervention is high.

Intraocular Bioadhesives in Vitreoretinal Surgeries: A Systematic Review

BACKGROUND

Bioadhesion is the ability of materials to adhere to biological surfaces. Bioadhesives are substances which induce or promote bioadhesion. The internal application of bioadhesives is gaining popularity in recent years and is being increasingly utilized in vitreoretinal surgeries. The aim of this review is to discuss the various bioadhesives and their applications in vitreoretinal surgeries.

METHODS

PubMed, Google Scholar, ePub and Cochrane library database were used for literature selection. Keywords such as vitreoretinal surgery, bioadhesives, intraocular bioadhesives, glue, fibrin glue, cyanoacrylate glue and transforming growth factor were used individually and in differing combinations to perform a comprehensive systematic literature search.

RESULTS

A total of 47 papers were retrieved and included in this review. Cyanoacrylate glue was the first bioadhesive to be utilized for vitreoretinal surgery in human eyes in 1976. The most common indications for the use of bioadhesives were in optic disc pit maculopathy, macular holes and rhegmatogenous retinal detachments.

CONCLUSION

The use of intraocular bioadhesives in vitreoretinal surgery represents a significant and evolving area of interest within ophthalmic research. While the pioneering use of cyanoacrylate glue, fibrin glue and transforming growth factor beta demonstrated the possible use of intraocular adhesives, fibrin glue is the most widely used intraocular bioadhesive in vitreoretinal surgery.

Photocurable and Temperature-Sensitive Bioadhesive Hydrogels for Sutureless Sealing of Full-Thickness Corneal Wounds

Penetrating corneal wounds can cause severe vision impairment and require prompt intervention to restore globe integrity and minimize the risk of infection. Tissue adhesives have emerged as a promising alternative to suturing for mitigating postoperative complications. However, conventional water-soluble adhesives suffer formidable challenges in sealing penetrating corneal wounds due to dilution or loss in a moist environment. Inspired by the robust adhesion of mussels in aquatic conditions, an injectable photocurable bioadhesive hydrogel (referred to as F20HD5) composed of polyether F127 diacrylate and dopamine-modified hyaluronic acid methacrylate is developed for sutureless closure of corneal full-thickness wounds. F20HD5 exhibits high transparency, wound-sealing ability, proper viscosity, biodegradability, and excellent biocompatibility. It allows in situ cross-linking via visible light, thereby providing sufficient mechanical strength and adhesiveness. In vivo, the adhesive hydrogel effectively closed penetrating linear corneal incisions and corneal injuries with minimal tissue loss in rabbits. During the 56-day follow-up, the hydrogel facilitates the repair of the injured corneas, resulting in more symmetrical curvatures and less scarring in distinction to the untreated control. Thus, bioinspired hydrogel holds promise as an effective adhesive for sealing full-thickness corneal wounds.

Application of Convergent Science and Technology toward Ocular Disease Treatment

Eyes are one of the main critical organs of the body that provide our brain with the most information about the surrounding environment. Disturbance in the activity of this informational organ, resulting from different ocular diseases, could affect the quality of life, so finding appropriate methods for treating ocular disease has attracted lots of attention. This is especially due to the ineffectiveness of the conventional therapeutic method to deliver drugs into the interior parts of the eye, and the also presence of barriers such as tear film, blood-ocular, and blood-retina barriers. Recently, some novel techniques, such as different types of contact lenses, micro and nanoneedles and in situ gels, have been introduced which can overcome the previously mentioned barriers. These novel techniques could enhance the bioavailability of therapeutic components inside the eyes, deliver them to the posterior side of the eyes, release them in a controlled manner, and reduce the side effects of previous methods (such as eye drops). Accordingly, this review paper aims to summarize some of the evidence on the effectiveness of these new techniques for treating ocular disease, their preclinical and clinical progression, current limitations, and future perspectives.

Unusual case of dislocation of cyanoacrylate glue into the anterior chamber

A patient with history of previous right eye penetrating keratoplasty for viral keratitis presented with an inferonasal graft melt, loose sutures and a flat anterior chamber (AC) in the same eye. B-scan ultrasound revealed 360° choroidal detachment. Cyanoacrylate adhesive and bandage contact lens were placed to restore ocular integrity. About 5 weeks after the procedure, the glue was found inside the AC with healed corneal melt. An emergency procedure was planned to remove the intraocular glue to prevent long-term toxicity. During the procedure, glue was found adherent to the intraocular lens (IOL), which necessitated an IOL exchange. Following the procedure, the eye settled well with residual scarring and an uncorrected visual acuity of 6/60, which improved to 6/18 with a pinhole. We discuss this case of late dislocation of the glue into the AC, which was managed with an IOL exchange highlighting a rare complication of corneal glueing.

Novel Application of Photo-Crosslinked Urocanic-Acid-Modified Chitosan in Corneal Wounds

In the last few years, the use of tissue adhesives in corneal perforation has gained immense popularity in clinical practices. The present study aimed to devise a new application of urocanic-acid-modified chitosan (CS) with methylene blue (MB) as a photosensitizer for the development of a photo-crosslinked tissue adhesive. In particular, the curing time was controlled with the aid of a 650 nm red diode. Under the same irradiation condition, the mechanical properties were tuned using the photosensitizer at different concentrations. In vitro tests revealed that the gel was ductile and biocompatible. The application of the gel to a perforated cornea model stopped the leakage of aqueous humor, immediately after the gel was photo-crosslinked. The blue appearance of the gel provided high precision when applied to corneal wounds. Importantly, the crosslinked gel became transparent within 24 h, owing to the dissipation of MB from tears, and the gel spontaneously sloughed off without artificial removal. Altogether, the study reported the development of a novel photo-crosslinkable urocanic-acid-modified CS gel that exhibited significant potential to be utilized in the healing of corneal perforation.

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.

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.

Treatment of Non-Infectious Corneal Injury: Review of Diagnostic Agents, Therapeutic Medications, and Future Targets

Corneal injuries can occur secondary to traumatic, chemical, inflammatory, metabolic, autoimmune, and iatrogenic causes. Ocular infection may frequently occur concurrent to corneal injury; however, antimicrobial agents are excluded from this present review. While practitioners may primarily rely on clinical examination techniques to assess these injuries, several pharmacological agents, such as fluorescein, lissamine green, and rose bengal, can be used to formulate a diagnosis and develop effective treatment strategies. Practitioners may choose from several analgesic medications to help with patient comfort without risking further injury or delaying ocular healing. Atropine, cyclopentolate, scopolamine, and homatropine are among the most frequently used medications for this purpose. Additional topical analgesic agents may be used judiciously to augment patient comfort to facilitate diagnosis. Steroidal anti-inflammatory agents are frequently used as part of the therapeutic regimen. A variety of commonly used agents, including prednisolone acetate, loteprednol, difluprednate, dexamethasone, fluorometholone, and methylprednisolone are discussed. While these medications are effective for controlling ocular inflammation, side effects, such as elevated intraocular pressure and cataract formation, must be monitored by clinicians. Non-steroidal medications, such as ketorolac, bromfenac, nepafenac, and diclofenac, are additionally used for their efficacy in controlling ocular inflammation without incurring side effects seen with steroids. However, these agents have their own respective side effects, warranting close monitoring by clinicians. Additionally, ophthalmologists routinely employ several agents in an off-label manner for supplementary control of inflammation and treatment of corneal injuries. Patients with corneal injuries not infrequently have significant ocular surface disease, either as a concurrent pathology or as an exacerbation of previously existing disease. Several agents used in the management of ocular surface disease have also been found to be useful as part of the therapeutic armamentarium for treatment of corneal injuries. For example, several antibiotics, such as doxycycline and macrolides, have been used for their anti-inflammatory effects on specific cytokines that are upregulated during acute injuries. There has been a recent wave of interest in amniotic membrane therapies (AMTs), including topical, cryopreserved and dehydrated variants. AMT is particularly effective in ocular injuries with violation of corneal surface integrity due to its ability to promote re-epithelialization of the corneal epithelium. Blood-based therapies, including autologous serum tears, plasma-enriched growth factor eyedrops and autologous blood drops, have additionally been explored in small case series for effectiveness in challenging and recalcitrant cases. Protection of the ocular surface is also a vital component in the treatment of corneal injuries. Temporary protective methods, such as bandage contact lenses and mechanical closure of the eyelids (tarsorrhaphy) can be particularly helpful in selective cases. Glue therapies, including biologic and non-biologic variants, can also be used in cases of severe injury and risk of corneal perforation. Finally, there are a variety of recently introduced and in-development agents that may be used as adjuvant therapies in challenging patient populations. Neurotrophic corneal disease may occur as a result of severe or chronic injury. In such cases, recombinant human nerve growth factor (cenegermin), topical insulin, and several other novel agents may be an alternate and effective option for clinicians to consider.

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.

Assessment of the Retinal Toxicity and Sealing Strength of Tissue Adhesives

PURPOSE

The purpose of this in vitro prospective nonrandomized study is to compare the toxicity and strength of cyanoacrylate and hydrogel adhesives on human retinal pigment epithelium (RPE) cells and porcine retina, respectively.

METHODS

The toxicity of cyanoacrylate (histoacryl, dermabond, superglue), ReSure PEG, and Tisseel fibrin glue on human RPE cells was determined by growing RPE cells in vitro, applying the different adhesives to the cells, and monitoring for disruption of growth over 3 days. The relative strength of these adhesives was tested by gluing a 3 mm piece of foam to a porcine retina and determining the amount of force needed to break the attachment.

RESULTS

0.085 N of force was required to break the porcine retinal tissue (p = .913). Histoacryl adhesive exhibited high strength (0.247 N) and high RPE toxicity (0.55 mm inhibition zone after 24 hrs). The strength of Tisseel fibrin glue was 0.078 N while that of ReSure was only 0.053 N. Both Tisseel and ReSure were nontoxic to the RPE cells.

CONCLUSIONS

Tisseel VH fibrin sealant may provide the best option for sealing retinal breaks because of its high strength and low retinal toxicity.

A paintable ophthalmic adhesive with customizable properties based on symmetrical/asymmetrical cross-linking

In situ and efficient incision sealing for ophthalmic surgery remains unresolved. Current commercially available gel adhesives often suffer from unsuitable gelation time, difficulty in micro-delivery, and mismatched degradation period, leading to difficulties for application in ocular tissue areas. Herein, a novel hydrogel adhesive was developed based on the simultaneous crosslinking of poly(lysine) (PLL) and lysine (Lys) with an end-modified active ester multi-arm polyethylene glycol (PEG) via the amidation reaction, where the residual terminal active ester of PEG can also bond to amino groups on tissue to provide strong adhesion. Due to the different molecular structures around their amino groups, PLL and Lys can crosslink with 4-arm-PEG-NHS (active ester) respectively, to form symmetrical and asymmetrical crosslinking networks, which exhibit various mechanical properties. Therefore, just by adjusting PLL/Lys ratios, the PEG-PLL-Lys hydrogel can easily possess a suitable gelation time, appropriate mechanical properties and matched degradation rate. As a result, a paintable, readily accessible and biocompatible ophthalmic tissue adhesive (sealant) is prepared for sealing ocular tissue incision. Considering the simple strategy and outstanding performance, the PEG-PLL-Lys hydrogel is promising for clinical transformation.

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.

Adhesive Tissue Engineered Scaffolds: Mechanisms and Applications

A variety of suture and bioglue techniques are conventionally used to secure engineered scaffold systems onto the target tissues. These techniques, however, confront several obstacles including secondary damages, cytotoxicity, insufficient adhesion strength, improper degradation rate, and possible allergic reactions. Adhesive tissue engineering scaffolds (ATESs) can circumvent these limitations by introducing their intrinsic tissue adhesion ability. This article highlights the significance of ATESs, reviews their key characteristics and requirements, and explores various mechanisms of action to secure the scaffold onto the tissue. We discuss the current applications of advanced ATES products in various fields of tissue engineering, together with some of the key challenges for each specific field. Strategies for qualitative and quantitative assessment of adhesive properties of scaffolds are presented. Furthermore, we highlight the future prospective in the development of advanced ATES systems for regenerative medicine therapies.

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.

Versatility of use of fibrin glue in wound closure and vitreo-retinal surgery

Background

Fibrin glue is an absorbable blood-derived product, a biological tissue adhesive which imitates the final stages of the coagulation cascade, it produces a firm clot, forming a seal along the whole length of the wound, the resultant fibrin clot degrades physiologically into granulation tissue 2 weeks after the application. Biological glue has been used extensively in many forms of surgical procedures. Its use in eye surgery has grown lately as we have evidence that showed it was effective in securing conjunctival grafts in pterygium surgery, in securing wounds after glaucoma surgery and more importantly in 20G and 23G vitrectomy.

Purpose

The aim of this study is to present our experience in the use of fibrin glue in vitreoretinal surgery.

Material and methods

We included 281 eyes of 221 patients who underwent vitreoretinal surgery during the period of May 2009 to July 2012, the preoperative diagnoses were as following: proliferative diabetic retinopathy, rhegmatogenous retinal detachment, macular hole, epiretinal membrane, luxation of cataratous nucleous and cortex, intraocular lens luxation, penetrating trauma, silicone extraction, phaco + IOL + vitrectomy + Ahmed valve implant, vitreous biopsy and optic nerve pit associated to macular detachment. The procedures were performed with Alcon Accurus Surgical System 20-gauge, 23-gauge or a combination of both. We used fibrin glue in all of the 20-gauge sclerotomies and leaking 23-gauge sclerotomies, scleral wound for IOL extraction, conjunctival peritomy for buckle implantation, conjunctiva in Ahmed valve implant, corneal graft in corneal perforation in trauma and leaking corneal wounds for phacoemulsification, in an optic pit, and in subretinal space in a giant retinal tear.

Results

We did not use any suture in any of the patients throughout the different procedures, there was no leakage in any wounds in the postoperative period, we found no inflammatory reaction, infection, and whenever we had excess amount, it was trimmed. Two patients presented a small dehiscence of the wound that was corrected in-office with a small amount of fibrin glue in the post-operative period.

Conclusions

Fibrin glue reduces surgical time, it is a good sealant, safe, with minimal allergic or toxic reactions and inflammation, minimizes bleeding, easy to undo and that eventually degrades. This small series shows that fibrin glue is a viable alternative for tissue coaptation in vitreoretinal surgery. However, further studies are required before fibrin glue takes the place of sutures.

Fibrin glue for treatment of optic disc maculopathy

We describe clinical and anatomical outcomes of optic disc maculopathy using internal limiting membrane (ILM) peeling and fibrin glue application over the optic nerve in this retrospective, interventional case series of five eyes. Extent of neurosensory detachment and foveoschisis along with foveal thickness at baseline and follow-up were evaluated. The mean age was 29 ± 10.6 years. The most common location of disc pit was temporal (3 eyes). All eyes underwent peripapillary laser with 532 nm green laser before surgery with a mean interval of 4.9 ± 1.9 months. The mean baseline and final vision was 0.68 ± 0.23 and 0.61 ± 0.33 logMAR, respectively, with a mean follow-up of 7.2 ± 3.5 months. Three eyes showed complete resorption of serous detachment, while the remaining two had reduction in schisis and subretinal fluid. None of the eyes had any complications. Glue application in addition to ILM peeling improves the visual prognosis in optic disc pit maculopathy with restoration of macular anatomy.

Polymeric Materials for Eye Surface and Intraocular Applications

Ocular applications of polymeric materials have been widely investigated for medical diagnostics, treatment, and vision improvement. The human eye is a vital organ that connects us to the outside world so when the eye is injured, infected, or impaired, it needs immediate medical treatment to maintain clear vision and quality of life. Moreover, several essential parts of the eye lose their functions upon aging, causing diminished vision. Modern polymer science and polymeric materials offer various alternatives, such as corneal and scleral implants, artificial ocular lenses, and vitreous substitutes, to replace the damaged parts of the eye. In addition to the use of polymers for medical treatment, polymeric contact lenses can provide not only vision correction, but they can also be used as wearable electronics. In this Review, we highlight the evolution of polymeric materials for specific ocular applications such as intraocular lenses and current state-of-the-art polymeric systems with unique properties for contact lens, corneal, scleral, and vitreous body applications. We organize this Review paper by following the path of light as it travels through the eye. Starting from the outside of the eye (contact lenses), we move onto the eye's surface (cornea and sclera) and conclude with intraocular applications (intraocular lens and vitreous body) of mostly synthetic polymers and several biopolymers. Initially, we briefly describe the anatomy and physiology of the eye as a reminder of the eye parts and their functions. The rest of the Review provides an overview of recent advancements in next-generation contact lenses and contact lens sensors, corneal and scleral implants, solid and injectable intraocular lenses, and artificial vitreous body. Current limitations for future improvements are also briefly discussed.

Outcomes of Cyanoacrylate Tissue Adhesive Application in Corneal Thinning and Perforation

PURPOSE

To report the outcomes of cyanoacrylate tissue adhesive (CTA) application in corneal thinning and perforation.

METHODS

A retrospective interventional case series of 137 patients receiving CTA for corneal thinning and perforation in 140 eyes between 2001 and 2018 at a single center was reviewed. Success rate and factors associated with glue failure were analyzed.

RESULTS

Median age of the cohort was 63 years and 69 (50%) were women. One hundred fifteen patients (84%) had at least 1 systemic condition, 46 (34%) had autoimmune diseases. Eighty-nine eyes (64%) presented with perforation and 51 (36%) with thinning. The perforation/thinning was central/paracentral in 82 eyes (59%) and peripheral in 57 eyes (41%). Median size of perforation was 3.1 mm. Causes of perforation and thinning were microbial infection in 75 (55%), sterile melt in 49 (35%), laceration in 10, and keratoprosthesis melt in 8 eyes. Median glue retention was 58 days. Success rate of glue application (defined as intact globe without surgical intervention) was 72%, 61%, and 46% at 10, 30, and 90 days after glue application, respectively. Larger size of perforation/thinning, perforation (vs. thinning), and single glue application (vs. multiple) were correlated with higher failure rate. Systemic conditions, use of topical corticosteroid, etiologies, and location of perforation/thinning were not significantly correlated with glue failure.

CONCLUSIONS

CTA application was moderately effective in stabilizing corneal perforation and thinning in the very short-term. Multiple applications are often required. Maintenance of globe integrity after glue application decreases with time and the need for surgical intervention remains high.

Ocular adhesives: Design, chemistry, crosslinking mechanisms, and applications

Closure of ocular wounds after an accident or surgery is typically performed by suturing, which is associated with numerous potential complications, including suture breakage, inflammation, secondary neovascularization, erosion to the surface and secondary infection, and astigmatism; for example, more than half of post-corneal transplant infections are due to suture related complications. Tissue adhesives provide promising substitutes for sutures in ophthalmic surgery. Ocular adhesives are not only intended to address the shortcomings of sutures, but also designed to be easy to use, and can potentially minimize post-operative complications. Herein, recent progress in the design, synthesis, and application of ocular adhesives, along with their advantages, limitations, and potential are discussed. This review covers two main classes of ocular adhesives: (1) synthetic adhesives based on cyanoacrylates, polyethylene glycol (PEG), and other synthetic polymers, and (2) adhesives based on naturally derived polymers, such as proteins and polysaccharides. In addition, different technologies to cover and protect ocular wounds such as contact bandage lenses, contact lenses coupled with novel technologies, and decellularized corneas are discussed. Continued advances in this area can help improve both patient satisfaction and clinical outcomes.

Fibrin Glue and Internal Limiting Membrane Abrasion for Optic Disc Pit Maculopathy

BACKGROUND AND OBJECTIVE

To describe a novel surgical technique using pars plana vitrectomy (PPV), internal limiting membrane (ILM) abrasion, and intravitreal fibrin glue for the treatment of optic disc pit maculopathy.

PATIENTS AND METHODS

Surgical case series technique with scanning electron microscopy (SEM) of human post-mortem eyes.

RESULTS

Using SEM, the authors demonstrate the persistent adherence of vitreous fragments to the optic disc following induction of posterior vitreous detachment in human postmortem eyes. The authors describe a surgical technique using PPV, Tano Diamond Dusted Membrane Scraper for an ILM abrasion, intravitreal fibrin glue (Tisseel), and gas-air exchange to seal optic disc pits. The authors report successful long-term visual and anatomical outcomes in three patients.

CONCLUSIONS

Intravitreal fibrin glue, when combined with ILM abrasion, may be a viable treatment option for optic disc pit maculopathy with good short- and long-term visual acuity outcomes. SEM shows that ILM abrasion removes vitreous fragments, which are persistently adherent and may lead to failure with other interventional techniques. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e271-e277.].

Surgical adhesives in ophthalmology: history and current trends

Tissue adhesives are gaining popularity in ophthalmology, as they could potentially reduce the complications associated with current surgical methods. An ideal tissue adhesive should have superior tensile strength, be non-toxic and anti-inflammatory, improve efficiency and be cost-effective. Both synthetic and biological glues are available. The primary synthetic glues include cyanoacrylate and the recently introduced polyethylene glycol (PEG) derivatives, while most biological glues are composed of fibrin. Cyanoacrylate has a high tensile strength, but rapidly polymerises upon contact with any fluid and has been associated with histotoxicity. Fibrin induces less toxic and inflammatory reactions, and its polymerisation time can be controlled. Tensile strength studies have shown that fibrin is not as strong as cyanoacrylate. While more research is needed, PEG variants currently appear to have the most promise. These glues are non-toxic, strong and time-effective. Through MEDLINE and internet searches, this paper presents a systematic review of the current applications of surgical adhesives to corneal, glaucoma, retinal, cataract and strabismus surgeries. Our review suggests that surgical adhesives have promise to reduce problems in current ophthalmic surgical procedures.

Wound closure and tissue adhesives in clear corneal incision cataract surgery

PURPOSE OF REVIEW

Achieving secure wound closure in clear corneal incision cataract surgery remains highly desired for its role in reducing infection risk and leak-related complications, including hypotony, corneal edema, and lens dislocation. Although classic techniques of stromal hydration or wound suturing represent traditional approaches, the introduction of newer and more effective ocular surface adhesives has increased the options that are available. This review aims to provide an update on the peer-reviewed literature regarding wound closure and the currently available and investigational tissue adhesives used to seal clear corneal incisions in cataract surgery.

RECENT FINDINGS

Stromal hydration and sutured closure of clear corneal incisions remain viable options for wound closure. Wound sealants, particularly polyethylene glycol (PEG)-based hydrogels, have been found to provide watertight wound seal with less foreign-body sensation and surgically induced astigmatism compared with sutures, and less adverse effects and greater ease of use compared with cyanoacrylate and fibrin glues.

SUMMARY

Stromal hydration, sutured closure, and use of a corneal adhesive are all wound closure options for clear corneal incisions. Of the currently available tissue adhesives, PEG hydrogel sealants have become the most widely accepted, with an improved side-effect and biocompatibility profile.

Safety of Cultivated Limbal Epithelial Stem Cell Transplantation for Human Corneal Regeneration

Ex vivo cultivated limbal stem cell transplantation is a promising technique for the treatment of limbal stem cell deficiency. While the results of the clinical trials have been extensively reported since the introduction of the technique in 1997, little has been reported regarding the potential health risks associated with production processes and transplantation techniques. Culture procedures require the use of animal and/or human-derived products, which carry the potential of introducing toxic or infectious agents through contamination with known or unknown additives. Protocols vary widely, and the risks depend on the local institutional methods. Good manufacturing practice and xeno-free culture protocols could reduce potential health risks but are not yet a common practice worldwide. In this review, we focus on the safety of both autologous- and allogeneic-cultivated limbal stem cell transplantation, with respect to culture processes, surgical approaches, and postoperative strategies.

Cataract surgery and methods of wound closure: a review

Clear corneal incisions are routinely used in cataract surgery, but watertight wound closure may not always be achieved, which can increase the risk for anterior chamber fluid egress or ocular surface fluid ingress. A new US Food and Drug Administration-approved ocular sealant appears to have good efficacy in sealing clear corneal incisions; its use may be indicated when wound integrity is in question.

Ophthalmic use of blood-derived products

There is a wide spectrum of blood-derived products that have been used in many different medical and surgical specialties with success. Blood-derived products for clinical use can be extracted from autologous or allogeneic specimens of blood, but recombinant products are also commonly used. A number of blood derivatives have been used for a wide range of ocular conditions, from the ocular surface to the retina. With stringent preparation guidelines, the potential risk of transmission of blood-borne diseases is minimized. We review blood-derived products and how they are improving the management of ocular disease.

[Non-infectious corneal macroperforations treated with a combination of Tachosil(®) and Tutopach(®). A report of 2 cases]

CLINICAL CASE

We report 2 cases of patients affected by non-infectious corneal macroperforations treated with TachoSil(®) and Tutopach(®), which closed the defect.

DISCUSSION

This procedure is an excellent choice for the emergency treatment of corneal perforation, especially in those centres that have no other therapeutic options, preserving the eye and visual acuity.

Paste-pinch-cut conjunctivoplasty: subconjunctival fibrin sealant injection in the repair of conjunctivochalasis

PURPOSE

To describe a new surgical technique for the repair of conjunctivochalasis (CCh) using subconjunctival injection of fibrin sealant followed by conjunctival resection and to present a case series demonstrating our experience with the paste-pinch-cut technique.

METHODS

A total of 139 eyes of 70 patients (43 women, 27 men) with CCh unresponsive to medical therapy received the described surgical treatment. The procedure consists of 3 primary steps-paste: fibrin sealant is injected subconjunctivally in a line inferior to the limbus; pinch: the conjunctiva is grasped with curved ptosis forceps, gathering the excess conjunctiva into a ridge, which is held, allowing the sealant to polymerize; and cut: the ridge of excess conjunctiva and sealant is resected. Subjective symptoms were assessed after surgery.

RESULTS

Conjunctival redundancy was absent postoperatively in all eyes, resulting in a smooth conjunctival surface and restored tear meniscus. At the 3-month follow-up visit, 91.4% of patients reported improvement in symptoms. There were no recurrences or significant complications.

CONCLUSIONS

The present retrospective, noncomparative, consecutive, interventional case series study introduces paste-pinch-cut conjunctivoplasty as a simple and an effective surgical treatment for the repair of CCh in symptomatic patients.

Treatment of a large corneal perforation with a multilayer of amniotic membrane and TachoSil

OBJECTIVE

To describe a novel surgical technique for the sealing of large corneal perforations.

METHOD

Case report of a perforated, 3-mm, postherpetic, corneal ulcer. A single layer of amniotic membrane was sewn to the internal surface of the cornea. An absorbable fibrin sealant patch (TachoSil) was placed in the area of the perforation, and a folded double layer of amniotic membrane was finally sewn to the external face of the cornea.

RESULT

Surgery without complications, leading to restoration of the anterior chamber and good subjective tolerance.

CONCLUSION

The reported technique seems to represent a good alternative emergency procedure for the management of corneal perforations larger than 2 mm.

Sharps injuries in ophthalmic practice

PURPOSE

Accidental sharps injuries are a potential route for transmission of blood-borne infection to healthcare workers. Ophthalmic staff in particular are at risk of sustaining such injuries due to the microsurgical nature of the speciality. Forthcoming European Union legislation aimed at reducing sharps injuries requires the development of risk-based sharps policy. The authors believe that this is the first study to assess the risks of sharps injuries and their management specific to ophthalmic practice within the European Union.

METHODS

A retrospective review of all reported sharps injuries across three eye units in the UK over a period of 6 years was undertaken. Data were analysed to determine the circumstances surrounding the injury, occupation of the injured person, and whether appropriate actions were taken following incidents.

RESULTS

A total of 68 sharps injuries were reported over the 6-year period. Nurses sustained 54.4% (n=37) of needlestick injuries, doctors 39.7% (n=27), and allied healthcare staff 5.9% (n=4). In all 51.5% (n=35) of sharps injuries occurred in the operating theatre, 30.9% (n=21) in the outpatient clinic, 13.2% (n=9) on the ophthalmic ward, and 4.4% (n=3) in unspecified locations. There was a median rate of 1.3 sharps injuries per 1000 surgical procedures per year and a range of 0.4-3.5 per 1000.

CONCLUSIONS

This study demonstrates the need to raise awareness of the unique risks of sharps injuries in ophthalmic practice. This is necessary in order to develop speciality-specific policy that promotes strategies to reduce such injuries, enhances the accuracy of reporting of such events, and provides guidance for appropriate management.

Fibrin glue in ophthalmology

Suturing is a time consuming task in ophthalmology and suture induced irritation and redness are frequent problems. Postoperative wound infection and corneal graft rejection are examples of possible suture related complications. To prevent these complications, ophthalmic surgeons are switching to sutureless surgery. A number of recent developments have established tissue adhesives like cyanoacrylate glue and fibrin glue as attractive alternatives to sutures. A possible and promising new application for tissue adhesives is to provide a platform for tissue engineering. Currently, tissue glue is being used for conjunctival closure following pterygium and strabismus surgery, forniceal reconstruction surgery, amniotic membrane transplantation, lamellar corneal grafting, closure of corneal perforations and descematoceles, management of conjunctival wound leaks after trabeculectomy, lid surgery, adnexal surgery and as a hemostat to minimise bleeding. The purpose of this review is to discuss the currently available information on fibrin glue.

Sutureless amniotic membrane transplantation for partial limbal stem cell deficiency

PURPOSE

To evaluate the results of sutureless amniotic membrane (AM) transplantation using fibrin glue for reconstructing corneal surfaces with partial limbal stem cell deficiency (LSCD).

DESIGN

Retrospective noncomparative interventional case series.

METHODS

Eleven eyes of nine patients that had LSCD with 120 degrees to almost 360 degrees of limbal involvement underwent superficial keratectomy to remove the conjunctivalized pannus followed by AM transplantation using fibrin glue. Additional sutureless AM patch (ProKera; Bio-Tissue, Inc, Miami, Florida, USA) was used in seven patients, and mitomycin C was applied on the cornea in four eyes and during fornix reconstruction in seven eyes. The surgery was repeated in three eyes for residual pannus.

RESULTS

During a mean follow-up of 14.2 +/- 7.7 months (range, six to 26 months), all eyes maintained a smooth and stable corneal epithelial surface without recurrent erosion or persistent epithelial defect, and showed less stromal cloudiness and vascularization. Best-corrected visual acuity improved in nine eyes (81.8%). Corneal epithelialization proceeded by epithelial growth over AM (n = 4), accompanied by dissolution of AM (n = 4) or a combination of both (n = 3). No complication was noted regarding initial or repeated uses of fibrin glue.

CONCLUSION

AM transplantation using fibrin glue appears to be a safe and effective method of restoring a stable corneal epithelium for cases with partial LSCD. This approach avoids the need of transplanting limbal epithelial stem cells.

Sutureless amniotic membrane transplantation for ocular surface reconstruction with a chemically defined bioadhesive

The purpose of this study was to evaluate the efficiency and safety of a sutureless amniotic membrane transplantation (AMT) for ocular surface reconstruction with a chemically defined bioadhesive (CDB). The CDB was synthesized from aldehyded polysaccharides and epsilon-poly(L-lysine), two kinds of medical and food additives, as starting materials. Biocompatibility assay indicated that the CDB showed excellent biocompatibility with in vitro and in vivo ocular surface tissues and most of the CDB was histologically degraded within 4 weeks. Sutureless AMT using the CDB was safely and successfully performed onto a rabbit scleral surface. Transplanted amniotic membrane (AM) evaluated by histological, electron microscopic- and immunohistochemical examination indicated that the CDB did not affect normal differentiation of the cells or the integrity of the surrounding tissue. Thus, this newly developed CDB was found to be very useful for sutureless AMT for ocular surface reconstruction, without considering the risk of infection. It has the ability to fix AM to the ocular surface for a long time-period without additional inflammation, scarring, or damage to the surrounding tissues.