Management of corneal lacerations and perforations

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.

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.

Intra-stromal injection of honey-treated keratocytes as a cell-based therapy for experimental corneal laceration

OBJECTIVES

This study aimed to investigate the potential of honey-supplemented medium (HSM) for expanding corneal keratocytes and its transplantation in a model of corneal laceration.

METHODS

Keratocytes were cultured in 1 % HSM- or 10 % fetal bovine serum (FBS)-supplemented medium for 24 h. The effect of HSM on keratocyte proliferation was evaluated using the MTT assay. The relative expression of Lum, Kera, and ALDH3A1, known markers of native keratocytes, was quantified by real-time PCR. The safety and efficacy of HSM-treated keratocyte intrastromal injection in a rabbit model of corneal laceration were also evaluated.

RESULTS

The MTT assay showed that HSM treatment did not significantly affect cell viability compared to FBS-supplemented medium (84.71 ± 2.38 vs. 100.08 ± 10.92, respectively; p=0.076). Moreover, HSM-treated keratocytes had significantly increased expression of Lum, Kera, and ALDH3A1 compared to cells treated with FBS, while the expression of the proliferation biomarker Thy-1 did not significantly differ between the two treatments. Intrastromal injection of HSM-treated keratocytes in the laceration animal model was safe and uneventful, resulting in less stromal inflammation and neovascularization, and consequently, better final architecture with less residual haze compared to the group injected with FBS-treated keratocytes.

CONCLUSIONS

These findings suggest that honey is a suitable supplement for keratocyte treatment and corneal cell therapy. The use of HSM may have potential applications in the treatment of corneal injuries and diseases.

Treatment of Mechanical Corneal Wounds Emergencies during the COVID-19 Pandemic: Absorbable 10-0 Vicryl (Polyglactin 910) Sutures as a Suitable Strategy

Background—The COVID-19 pandemic has changed our standard practices: operating rooms were only available for functional emergencies and outpatient visits were drastically reduced in favor of telemedicine. Aim: To report the personalized “one-shot” surgery using absorbable 10-0 Vicryl (V10-0) or polyglactin 910 monofilament in mechanical corneal injuries from February 2020 to December 2021. Methods—Prospective case series with at least 12-months’ follow-up, in a French university hospital. Among the overall population of open or closed-globe emergencies (n = 40), non-penetrating corneal lamellar lacerations (long axis > 2 mm) in zone 1 (OTC group) were treated with V10-0 suture(s) (n = 10), replacing traditional non-absorbable 10-0 nylon suture(s) or medical options in first line. The outpatient visits were performed on day (D)10, month (M)2, M6 then every six months. One interim visit by phone teleconsultation was scheduled between D10 and M2, and other(s) as needed. The main outcome was best-corrected visual acuity (BCVA) at M6. Secondary outcomes included mainly corneal astigmatism (CA) at M6 complications. Results—Among the ten corneal wounds, there were three children (30%), eight domestic accidents (80%), three eyes with metallic foreign bodies (30%), four open-globe injuries (40%), and nine eyes that received high-speed projectiles or sharp objects (90%). The complete V10-0 suture(s) absorption occurred in all eyes between D10 and M2. At M6, mean far and near BCVA decreased from 0.680 ± 0.753 and 0.490 ± 0.338 preoperatively to 0.050 ± 0.071 and 0.220 ± 0.063 logMAR (p = 0.019 and p = 0.025 respectively), mean CA decreased from 4.82 ± 3.86 preoperatively to 1.15 ± 0.66 diopters (p = 0.008). BCVA and CA were unchanged thereafter. No serious adverse event nor repeated surgery occurred. The mean number of teleconsultations was 1.20 ± 0.63 without an additional nonscheduled outpatient visit. Conclusions—The absorbable V10-0 sutures might be a safe and effective alternative for eligible corneal wounds, while reducing the number of outpatient visits, especially for children (no suture removal). The COVID-19 pandemic highlighted that they are ideally suited to logistical challenges.

Hydrogels derived from acellular porcine corneal stroma enhance corneal wound healing

Acellular cornea derived hydrogels provide significant advantages in preserving native corneal stromal keratocyte cells and endothelial cells. However, for clinical application, hydrogel physical properties need to be improved, and their role in corneal epithelial wound healing requires further investigation. In this study, an acellular porcine corneal stroma (APCS) hydrogel (APCS-gel) was successfully prepared from 20 mg/ml APCS, demonstrated optimal light transmittance and gelation kinetic properties and retained critical corneal ECM of collagens and growth factors. Compared with fibrin gel, the APCS-gel had a higher porosity ratio and faster nutrition diffusion with an accompanying improvement in the proliferation of primary rabbit corneal epithelial cells (RCECs) and stromal cells (RCSCs). These corneal cell types also displayed improved viability and cellular infiltration. Furthermore, the APCS-gel provides significant advantages in the preservation of RCECs stemness and enhancement of corneal wound healing in vitro and in vivo. After 7 days of culture, 3-4 layers of RCECs were formed on the APCS-gel in vitro, while only 1-2 layers were found on the fibrin gel. More corneal stem/progenitor cell phenotypes (K12-, p63+, ABCG2+) and proliferation phenotypes (Ki67+) were detected on the APCS-gel than fibrin gel. Using a corneal epithelial wound healing model, we also found faster reepithelization in corneas that received APCS-gel compared to fibrin gel. Additionally, our APCS-gel demonstrated better physical and biological properties when compared to Tisseel, a clinically used type of fibrin gel. In conclusion, our APCS-gel provided better corneal epithelial and stromal cell biocompatibility to fibrin gels and due to its transparency and faster gelation time could potentially be superior for clinical purposes. STATEMENT OF SIGNIFICANCE: Extracellular matrix (ECM) can be used to provide tissue specific physical microstructure and biochemical cues for tissue regeneration. Here, we produced an ECM hydrogel derived from acellular porcine cornea stroma (APCS-gel) that retained critical biological characteristics of the native tissue and provided significant transparency and fast gelation time. Our data demonstrated that the APCS-gel was superior to clinically used fibrin gel, as the APCS-gel showed high porosity and permeability, better corneal stromal keratocytes infiltration, increased cellular proliferation and retention of corneal epithelial cells stemness. The APCS-gel improved corneal wound healing in vitro and in vivo. This APCS-gel may have clinical utility for corneal diseases, and the more general approach used to make this hydrogel might be used in other tissues.

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.

Full- versus partial-thickness sutures: experimental models of corneal injury repair

PURPOSE

To evaluate the performance of full-thickness (FT) versus partial-thickness (PT) sutures in a full-thickness corneal wound in an animal model.

METHODS

This is a prospective, experimental, comparative, longitudinal study. A 6-mm linear, full-thickness corneal incision was performed on the right eye of eight domestic pigs. Eyes were randomly assigned for repair with interrupted PT (80-90% depth) sutures or FT 10-0 nylon sutures. Anterior segment OCT, corneal pachymetry and clinical photographs were obtained 1, 4 and 8 weeks postoperatively. Corneal thickness, depth of suture placement, perilesional edema, coaptation of wound edges and complications were noted. Histopathologic examination was performed at 8 weeks.

RESULTS

100% of the eyes with FT sutures developed a linear, less opaque scar. 100% of the eyes with PT developed a dense, opaque stromal scar (p = 0.02). Vascularization of the cornea was present in 75% of PT group and 25% in the FT group (p = 0.50). As the corneas healed, there was a marked trend toward thicker corneas in the PT group versus FT group with a median difference of - 63 µm at week 1 [median 788 µm vs. 725 µm, (p = 0.11)], - 38 µm at week 4, (724 µm vs. 686 µm, (p = 0.63)) and - 47 µm median difference at week 8 with (670 µm vs. 623 µm, (p = 0.06)). Histopathology showed disorganization of the collagen fibers and the formation of a retrocorneal fibrous membrane in the PT group.

CONCLUSIONS

The FT group presented less corneal edema at week 8 with a more linear and less opaque scar. Histopathology showed a better-organized scar and endothelialization without the formation of a fibrous membrane.

Emergency corneal grafting in the UK: a 6-year analysis of the UK Transplant Registry

BACKGROUND

Corneal graft (CG) surgery is the most common and successful tissue transplant worldwide. A small and important group of patients are operated in emergency situations, typically to save a perforated eye. Our knowledge of the indications and outcomes of emergency corneal graft (eCG) is limited.

METHODS

Retrospective, multifactorial analysis of all CGs registered by the UK Transplant Service from April 1999 to March 2005.

RESULTS

A total of 12 976 CGs were performed. 1330 (11.4%) were eCGs including 433 regrafts. Actual perforation occurred in 876 (65.9%) patients. 420 (31.5%) grafts were for tectonic purposes alone and 217 (16.3%) were also grafted for visual rehabilitation. The main diagnostic categories were infection (39.4%), non-infectious ulcerative keratitis (32.2%) and other causes (ectasias, previous ocular surgery, injury, dystrophies and opacification). Graft survival of first eCG at 1, 2 and 5 years was 78%, 66% and 47%, respectively. Best-corrected visual acuity of surviving grafts at 1 year was: 6/12 or better in 29.9%, 6/18 to 6/60 in 38.4%, counting finger to LP in 30.6% and NPL in 1%, with worsening of vision in only 8.7% of the patients.

CONCLUSION

This study which is the largest of its kind shows that despite the seriousness of the critical corneal pathology and the surgical challenges that it poses, the outcomes of eCG are favourable with most patients keeping their eyesight and avoiding immediate rejection. These clinical outcomes show the value of eye banking facilities that are developed to support corneal tissue supply for eCG.

Change of Optical Intensity during Healing Process of Corneal Wound on Anterior Segment Optical Coherence Tomography

The purpose of this study is to investigate the process of corneal wound healing after penetrating injury with the change in optical intensity on anterior segment optical coherence tomography (AS-OCT) and to investigate factors associated with severity of corneal scar. Forty-seven eyes from 47 patients with repaired corneal laceration were included. AS-OCT was performed on 1day, 1week, 1, 3 and 6 months after primary repair. Internal aberrations of wound edges were observed on AS-OCT images. Parameters including height of steps, width of gaps, maximal corneal thickness, area and optical intensity of corneal wound/scar were measured. The relationship between the parameters at day 1 and the optical intensity at 6 months were analyzed. The results showed that optical intensity of corneal wound/scar increased from 124.1 ± 18.8 on day 1 postoperatively to 129.3 ± 18.7, 134.2 ± 23.4, 139.7 ± 26.5, 148.2 ± 26.4 at 1 week, 1 month, 3 months and 6 months postoperatively. Height of steps at 1 day after surgery was the only factor identified as correlated with optical intensity of corneal scar at 6 months (beta = 0.34, p = 0.024). The increase of optical intensity represents the process of fibrosis of corneal wound healing. Higher step after suturing is associated with more severity of corneal scar at last.

Use of Fish Scale-Derived BioCornea to Seal Full-Thickness Corneal Perforations in Pig Models

The aim of this study was to test the use of BioCornea, a fish scale-derived collagen matrix for sealing full-thickness corneal perforations in mini-pigs. Two series of experiments were carried out in 8 Lan-Yu and 3 Göttingen mini-pigs, respectively. A 2mm central full thickness corneal perforation was made with surgical scissors and 2mm trephines. The perforations were sealed immediately by suturing BioCornea to the wounded cornea. The conditions of each patched cornea were followed-up daily for 3 or 4 days. Status of operated eyes was assessed with slit lamp examination or optical coherence tomography (OCT). Animals were sacrificed after the study period and the corneas operated were fixated for histological examination. Both OCT imaging and handheld slit lamp observations indicated that a stable ocular integrity of the perforated corneas was maintained, showing no leakage of aqueous humor, normal depth of anterior chamber and only mild swelling of the wounded cornea. Hematoxylin and eosin staining of the patched cornea showed no epithelial ingrowths to the perforated wounds and no severe leucocyte infiltration of the stroma. The fish scale-derived BioCornea is capable to seal full-thickness corneal perforation and stabilize the integrity of ocular anterior chamber in pre-clinic mini-pig models. BioCornea seems to be a safe and effective alternative for emergency treatment of corneal perforations.

Corneal laceration caused by river crab

A 5-year-old boy presented with right eye pain associated with tearing and photophobia of 1-day duration. He gave a history of playing with a river crab when suddenly the crab clamped his fingers. He attempted to fling the crab off, but the crab flew and hit his right eye. Ocular examination revealed a right eye corneal ulcer with clumps of fibrin located beneath the corneal ulcer and 1.6 mm level of hypopyon. At presentation, the Seidel test was negative, with a deep anterior chamber. Culture from the corneal scrapping specimen grew Citrobacter diversus and Proteus vulgaris, and the boy was treated with topical gentamicin and ceftazidime eyedrops. Fibrin clumps beneath the corneal ulcer subsequently dislodged, and revealed a full-thickness corneal laceration wound with a positive Seidel test and shallow anterior chamber. The patient underwent emergency corneal toileting and suturing. Postoperatively, he was treated with oral ciprofloxacin 250 mg 12-hourly for 1 week, topical gentamicin, ceftazidime, and dexamethasone eyedrops for 4 weeks. Right eye vision improved to 6/9 and 6/6 with pinhole at the 2-week follow-up following corneal suture removal.