Scleral Contact Lens to Preserve a Corneal Graft in Chronic Lagophthalmos.

Facial burns involving the periorbital region may lead to cicatricial ectropion and lagophthalmos, causing severe exposure keratopathy and eventually blindness if uncorrected. In these patients, it is critical to provide aesthetic and functional surgical correction to protect the ocular surface from chronic desiccation in addition to visual rehabilitation. Conventional methods may not be sufficient to provide visual rehabilitation in complex cases. Scleral lenses can be a multipurpose alternative for these patients. Herein, we present the challenging case of a patient who developed cicatricial lagophthalmos and exposure keratopathy after facial transplantation due to gasoline burns and received a scleral contact lens for visual rehabilitation.

Ocular Complications of Facial Burns in the Pediatric Population.

Pediatric ocular burns carry a risk of permanent vision impairment. This study identifies risk factors that place these patients at high risk of permanent visual complications. A retrospective review was conducted in our academic urban pediatric burn center. All 300 patients under 18 years of age admitted from January 2010 to December 2020 with periorbital or ocular thermal injuries were included. Variables analyzed included patient demographics, burn characteristics, ophthalmology consultation, ocular exam findings, follow up time period, and early and late ocular complications. Etiologies of burn injuries were as follows: 112 (37.5%) scald, 80 (26.8%) flame, 35 (11.7%) contact, 31 (10.4%) chemical, 28 (9.4%) grease, and 13 (4.3%) friction. Overall, 207 (70.9%) patients with ocular burns received an ophthalmology consult. Of these patients, 61.5% had periorbital cutaneous burns and 39.8% had corneal injuries, and only 61 (29.5%) presented for a follow-up visit. Ultimately, six had serious ocular sequelae, including ectropion, entropion, symblepharon, and corneal decompensation. While thermal burns involving the ocular surface and eyelid margins are relatively infrequent overall, they carry a small risk of serious to long-term sequelae. Recognizing those at greatest risk, and initiating appropriate early intervention is critical.

Use of Ethylenediaminetetraacetic Acid in Chronic Calcium-Based Chemical Injury.

PURPOSE: This study presents the successful management of a patient with chronic chemical-based injury using ethylenediaminetetraacetic acid (EDTA) chelation. METHODS: This is a case report of a 59-year-old man who presented to us 2 months after a bilateral, accidental, ocular injury with lime particles at his workplace. RESULTS: The patient was initially managed with extensive debridement and amniotic membrane grafting for both eyes. At 4-month follow-up, the left eye appeared to have extensive calcium-based plaques. 0.02N EDTA chelation was performed for his left eye. Postchelation, the visual acuity improved to 20/800. At 1-week follow-up, a repeat EDTA chelation was performed. The corneal clarity improved further, and the patient recovered a visual acuity of 20/200. CONCLUSIONS: EDTA chelation in the setting of calcium deposition in the chronic phase of chemical injuries can be reasonably effective.

Role of tenon advancement in treating limbal ischemia in acute chemical injury.

Background: In acute chemical injury, damage can range from ocular surface epithelial defects to limbal and scleral ischemia. This may subsequently progress to corneal or scleral melting and perforation and finally result in phthisis bulbi. Thus, acute chemical injury is a potentially blinding condition and warrants attention. The accurate technique to assess the damage incurred should be practiced to avoid undertreatment and subsequent complications. Surgical intervention wherever needed should be appropriately timed and should be performed. The primary aim of medical or surgical intervention in acute chemical injury is to attain a stable and epithelized ocular surface. Even a conjunctival phenotype over the cornea is a desirable outcome. Purpose: This video discusses the nuances involved in the assessment and planning of Tenon advancement with amniotic membrane grafting for treating limbal ischemia in acute chemical injury. Synopsis: The video demonstrates the technique of restoration of limbal vascularization by performing Tenon advancement with amniotic membrane grafting and its outcome. Highlights: Ocular surface painting with fluorescein dye is essential to assess the areas of surface involvement. Merely instilling the fluorescein dye in the cul-de-sac will underestimate the extent of the damage. Tenon advancement should ideally be planned between 7 and 10 days following an injury when actual limbal blanching is obvious. A stable and epithelized ocular surface is the desirable outcome irrespective of the epithelial phenotype. Video Link: https://youtu.be/06XhwLKnsIA.

Orbital Compartment Syndrome in Severe Burns: Predictive Factors, Timing, and Complications of Intervention.

PURPOSE: Severe burn patients require high-volume fluid resuscitation, which increases risk for orbital compartment syndrome (OCS). We aimed to understand surgeons' practice patterns and to examine risk factors for OCS, timing of lateral canthotomy and cantholysis (LCC), and complications of intervention. METHODS: A survey of American Society of Ophthalmic Plastic and Reconstructive Surgery and North American Society of Academic Orbital Surgeons' practice patterns in burn patients was undertaken. In addition, a retrospective analysis was conducted of 107 patients with burns greater than 20% total body surface area at 1 institution from January 1, 2009, to June 1, 2018. Patients with Stevens-Johnson Syndrome or Toxic Epidermal Necrolysis, frostbite, or no ophthalmologic consultation were excluded. Risk factors for OCS, timing of LCC, and complications of the intervention were examined. RESULTS: In the survey, 37 of 54 respondents had treated burn patients, of which 29 followed no protocol. Threshold intraocular pressure for intervention varied widely, and nearly all reported having seen complications from LCC in burn patients. For the retrospective analysis, 107 patients met criteria, of which 22 (20.6%) required LCC. Renal failure, inhalation injury, eyelid burns, higher total body surface area, elevated lactate, increased number of escharotomies, and greater total fluid required were significantly associated with the clinical decision that the patient was at risk for OCS requiring LCC. Fluid resuscitation in excess of the Ivy Index (250 ml/kg) increased odds of LCC 8.6 times. Average time of LCC was 15.8 hours after burn. LCC patients experienced higher rates of complications including eyelid retraction, exposure keratopathy, and corneal ulceration. CONCLUSIONS: Severe burn patients should be monitored closely by an ophthalmologist during the first 48 hours for signs of OCS. Further studies should aim to recommend protocols guiding evaluation and intervention.

AIP1 suppresses neovascularization by inhibiting the NOX4-induced NLRP3/NLRP6 imbalance in a murine corneal alkali burn model.

BACKGROUND: Apoptosis signal-regulating kinase 1-interacting protein 1 (AIP1) participates in inflammatory neovascularization induction. NADPH oxidase 4 (NOX4) produces reactive oxygen species (ROS), leading to an imbalance in nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) and NLR family pyrin domain containing 6 (NLRP6) expression. The mechanisms of AIP1, NOX4, ROS and inflammasomes in corneal neovascularization were studied herein. METHODS: C57BL/6 and AIP1-knockout mice were used in this study. The alkali burn procedure was performed on the right eye. Adenovirus encoding AIP1 plus green fluorescence protein (GFP) (Ad-AIP1-GFP) or GFP alone was injected into the right anterior chamber, GLX351322 was applied as a NOX4 inhibitor, and then corneal neovascularization was scored. The expression of related genes was measured by quantitative real-time polymerase chain reaction, western blotting and immunofluorescence staining. 2',7'-Dichlorofluorescin diacetate staining was used to determine the ROS levels. RESULTS: The expression of AIP1 was decreased, while that of cleaved interleukin-1ß (clv-IL-1ß) and vascular endothelial growth factor A (VEGFa) was increased after alkali burn injury. NOX4 expression was increased, the imbalance in NLRP3/NLRP6 was exacerbated, and corneal neovascularization was increased significantly in AIP1-knockout mice compared with those in C57BL/6 mice after alkali burns. These effects were reversed by AIP1 overexpression. NLRP3/NLRP6 expression was imbalanced after alkali burns. GLX351322 reversed the imbalance in NLRP3/NLRP6 by reducing the ROS levels. This treatment also reduced the expression of clv-IL-1ß and VEGFa, suppressing neovascularization. CONCLUSIONS: AIP1 and NOX4 can regulate corneal inflammation and neovascularization after alkali burn injury. Based on the pathogenesis of corneal neovascularization, these findings are expected to provide new therapeutic strategies for patients. Corneal alkali burn injury is a common type of ocular injury that is difficult to treat in the clinic. The cornea is a clear and avascular tissue. Corneal neovascularization after alkali burn injury is a serious complication; it not only seriously affects the patient's vision but also is the main reason for failed corneal transplantation. Corneal neovascularization affects approximately 1.4 million patients a year. We show for the first time that AIP1 and NOX4 can regulate corneal inflammation and neovascularization after alkali burns. The expression of AIP1 was decreased, while that of clv-IL-1ß and VEGFa was increased after alkali burns. We tried to elucidate the specific molecular mechanisms by which AIP1 regulates corneal neovascularization. NOX4 activation was due to decreased AIP1 expression in murine corneas with alkali burns. NOX4 expression was increased, the imbalance in NLRP3/NLRP6 was exacerbated, and corneal neovascularization was increased significantly in AIP1-knockout mice compared with those in C57BL/6 mice after alkali burns. These effects were reversed by AIP1 overexpression. Additionally, NLRP3/NLRP6 expression was unbalanced, with NLRP3 activation and NLRP6 suppression in the corneal alkali burn murine model. Eye drops containing GLX351322, a NOX4 inhibitor, reversed the imbalance in NLRP3/NLRP6 by reducing ROS expression. This treatment also reduced the expression of clv-IL-1ß and VEGFa, reducing neovascularization. Therefore, we provide new gene therapeutic strategies for patients. With the development of neovascularization therapy, we believe that in addition to corneal transplantation, new drug or gene therapies can achieve better results. Video Abstract.

Long-Standing Corneal Edema and Endothelial Decompensation due to Ecballium elaterium.

PURPOSE: The purpose of this study was to report the most severe documented ocular injury caused by Ecballium elaterium , an invasive and toxic herb characterized by an explosive seed dispersal. METHODS: A 55-year-old man presented to the emergency department several hours after direct exposure to the contents of E. elaterium to his left eye. Clinical examinations, investigations, and imaging findings are reported. RESULTS: Medical and ocular histories were unremarkable. On presentation, the patient exhibited markedly decreased visual acuity, severe periorbital edema, conjunctival chemosis, and corneal edema. Although other signs gradually improved, corneal edema worsened despite rapid initiation of systemic and topical steroids and normal intraocular pressure. After 4 months of follow-up, the cornea cleared and visual acuity returned to normal; however, a significant decrease in endothelial cell count was observed. CONCLUSIONS: Ecballium elaterium may cause a severe corneal chemical burn, with subsequent long-standing corneal edema and endothelial decompensation. Specular microscopy is a modality of great importance in these cases.

Topical Effects of N-Acetyl Cysteine and Doxycycline on Inflammatory and Angiogenic Factors in the Rat Model of Alkali-Burned Cornea.

The aim of this study was to analyze the single and combined effects of N-acetyl cysteine (NAC) and doxycycline (Dox) on the inflammatory and angiogenic factors in the rat model of alkali-burned cornea. Rats were treated with a single and combined 0.5% NAC and 12.5 µg/mL Dox eye drops and evaluated on days 3, 7, and 28. In the corneas of various groups, the activity of Catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) enzymes was assessed. The expression of inflammatory factors (TNF-α, Rel-a, and CXCL-1) and angiogenic factors (VEGF-a, MMP2, and MMP9) was measured using real-time polymerase chain reaction. The antioxidant enzyme activities decreased substantially 3 days after injury with sodium hydroxide (NaOH). NAC and combined NAC+ Dox topical treatments increased the SOD enzyme activity on day 28 (P < 0.05). The expression of TNF-α and Rel-a genes following single and combined treatment of NAC and Dox decreased significantly on days 7 and 28 (P < 0.05). The mRNA level of angiogenic factors and corneal neovascularization (CNV) level declined in NaOH-injured rats treated with Dox (P < 0.05). The topical treatment of Dox could attenuate inflammation and CNV complications. However, NAC treatment may not reduce the expression of angiogenic genes.

Ocular Surface Characteristics and Colonization in a Burn Center: A Prospective Cohort Study.

We aimed to evaluate the characteristics and colonization by pathogenic microorganisms of the ocular surface in patients in a burn center and to determine their association with sedation, mechanical ventilation, and periocular burn. We prospectively evaluated 40 patients during an 8-mo period. Five evaluations where performed, at baseline and weekly on four more occasions or until hospital discharge or death. On each visit, we assessed periocular burn, lid position, Bell's phenomenon, Schirmer's test, presence of chemosis, conjunctival hyperemia, and exposure keratopathy; conjunctival fornix swabs were taken for microbiology culture. Also, we documented the level of sedation, mechanical ventilation status, and systemic and ocular treatment. Absent Bell's phenomenon and chemosis were significantly different at baseline in patients under mechanical ventilation, sedation, and in those with a periocular burn. The cumulative incidence of exposure keratopathy was 22.5% and the cumulative incidence of ocular surface colonization by pathogenic microorganisms was 32.5%. Both outcomes were associated with mechanical ventilation and periocular burn. The most frequent pathogenic microorganisms on the ocular surface were Candida parapsilosis, Acinetobacter baumanii, and Pseudomonas aeuroginosa. We did not observe any case of a persistent epithelial defect, infectious keratitis, corneal perforation or corneal opacity in this cohort. Results from our study may benefit future patients by allowing better risk stratification and treatment strategies for the ocular surface care in burn units.

UV-Photokeratitis Associated with Germicidal Lamps Purchased during the COVID-19 Pandemic.

PURPOSE: To report photokeratitis caused by the improper use of germicidal lamps purchased during the COVID-19 pandemic. METHODS: Case series. RESULTS: Seven patients presented with acute ocular surface pain after exposure to UV-emitting germicidal lamps. Visual acuity was 20/30 or better in 13 of 14 eyes (93%). Anterior segment examination revealed varying degrees of conjunctival injection and diffusely distributed punctate epithelial erosions (PEEs) in every patient. No intraocular inflammation was identified across the cohort and all fundus examinations were normal. Treatment varied by provider and included artificial tears alone or in combination with antibiotic ointments and/or topical steroids. Five patients were followed via telehealth, one patient returned for an in-office visit, and one patient was lost to follow-up. Five of six patients endorsed complete resolution of symptoms within 2-3 days. CONCLUSIONS: Patients should follow manufacturer recommendations when using UV-emitting germicidal lamps and avoid direct exposure to the ocular surface.

Corneal burn injury in picosecond laser treatment: A potential hazard in cosmetic therapy.

Key PointsWithout appropriate protection, cosmetic laser treatments can cause severe ocular side effects and permanent visual impairment. We present this case to emphasize the importance of ocular protection during the entire treatment period, especially treatments of lesions over the eyelids. According to our knowledge and database search, this is the first reported ocular injury caused by picolaser.

AMPK Activation by 5-Amino-4-Imidazole Carboxamide Riboside-1-ß-D-Ribofuranoside Attenuates Alkali Injury-Induced Corneal Fibrosis.

Purpose: Increased TGF-ß1 synthesis after corneal alkali injury is implicated in corneal fibrosis, as it promotes transdifferentiation of keratocytes into myofibroblasts. The activation of 5'-adenosine monophosphate-activated protein kinase (AMPK) by 5-amino-4-imidazole carboxamide riboside-1-ß-d-ribofuranoside (AICAR) inhibits TGF-ß1-induced fibrosis in other cell types. We investigated the antifibrotic effect of AICAR in corneal fibroblasts after alkali injury. Methods: Mouse models of corneal alkali burn, produced by placing 2-mm-diameter filter paper soaked in 0.1-N NaOH on the right cornea for 30 seconds, were treated with the test drugs 4× daily for 21 days. The central cornea was scanned by optical coherence tomography (OCT). Corneal tissues were obtained and processed for western blotting and immunohistochemistry. For in vitro analysis, primary human corneal fibroblasts were treated directly with TGF-ß1 to induce fibrosis, with or without AICAR pretreatment. Myofibroblast activation and extracellular matrix (ECM) protein synthesis were detected by western blotting, real-time PCR, and collagen gel contraction assay. Signaling proteins were analyzed by western blotting. Results: Alkali injury induced the upregulation of TGF-ß1 expression, which led to increased α-smooth muscle actin (α-SMA) and fibronectin synthesis and myofibroblast differentiation. AMPK activation by AICAR significantly suppressed TGF-ß1 and ECM protein expression. The antifibrotic effect of AICAR was AMPK dependent, as treatment with the AMPK inhibitor Compound C attenuated the antifibrotic response. Conclusions: AMPK activation by AICAR suppresses the myofibroblast differentiation and ECM synthesis that occur after alkali injury in corneal fibroblasts.

Glaucoma after ocular chemical burns: Incidence, risk factors, and outcome.

Effects of chemical injuries on the cornea and limbus have been widely studied; however, little is known about glaucoma after ocular chemical injuries. We herein investigated the incidence, risk factors, and outcome of glaucoma in patients with ocular chemical burns. Medical records were reviewed of patients who visited our clinic for chemical injuries to the ocular surface. Patients were divided into glaucoma and non-glaucoma groups based on high intraocular pressure (IOP) readings. Clinical characteristics, treatment method, and therapeutic and visual outcomes were compared between the two groups. Of 29 patients (40 eyes), 9 patients (15 eyes, 37.5%) were diagnosed with glaucoma at 2.64 ± 2.92 months after injury. Factors associated with glaucoma included male gender (p = 0.0114), bilateral ocular involvement (p = 0.0478), severe ocular surface involvement (Dua grades IV-VI, p = 0.0180), poor initial visual acuity (p = 0.0136), high initial IOP (p < 0.0001), pupil involvement at initial examination (p = 0.0051), and the need for amniotic membrane transplantation in the acute stage (p = 0.0079). At final follow-up, IOP was uncontrolled in 3 eyes (20.0%), and visual acuity was worse in the glaucoma group than in the non-glaucoma group (logMAR 2.94 ± 1.86 vs 0.34 ± 0.69, p < 0.0001). These findings suggest that careful evaluation and intensive treatment for glaucoma are essential in patients with severe ocular burns.

Early Application of Bevacizumab After Sclerocorneal Grafting for Patients With Severe Late-Stage Ocular Chemical Burns.

PURPOSE: To investigate whether subconjunctival bevacizumab help prevent corneal graft neovascularization and prolong the graft survival of patients with chemical burns. METHODS: We performed a prospective nonrandomized comparative case series study. Twenty-six eyes received subconjunctival bevacizumab (10 mg/0.4 mL) once and topical immunosuppressive agents after sclerocorneal lamellar keratoplasty as the treatment, and 13 eyes received a topical immunosuppressant alone and served as the control group. The main outcomes were a cumulative probability of graft survival, development of corneal neovascularization, and complications. RESULTS: The postoperative follow-up time was 14.3 months (range, 2-62 mo). The cumulative graft survival time was significantly longer in the treatment group than that in the control group (42.9 ± 5.9 vs. 4.8 ± 0.7 mo; log rank < 0.001). In the treatment group, 19 of the 26 grafts (73.1%) survived as transparent with a mean follow-up of 18.7 ± 3.0 months. At the end of the follow-up, 4 grafts remained free of neovascularization, 2 developed edema without neovascularization, and 15 remained transparent with a stable ocular surface and some neovascular vessels in the peripheral transplant interface. The other 5 grafts became opaque and neovascularized. In the control group, all grafts became opaque and neovascularized within the follow-up period (5.5 ± 0.7 mo). During the follow-up, a corneal epithelial defect developed in 9 eyes in the treatment group and 7 in the control group. CONCLUSIONS: Early application of subconjunctival bevacizumab after sclerocorneal lamellar keratoplasty can significantly prevent corneal neovascularization and promote graft survival for severe late-stage ocular chemical burns.

Multidisciplinary Treatment to Restore Vision in Ocular Burns.

Periorbital burns generate contraction and distortion of periorbital soft tissue, causing eyelid malfunction, further contributing to loss of vision from corneal scarring or perforation. We present our multidisciplinary algorithm to restore vision in patients with burn-related bilateral corneal blindness with light perception. Chart review was performed for four consecutive burn patients requiring periocular reconstruction and keratoprosthesis. Initial treatment included globe coverage with eyelid releases and grafts. Strategy of corneal replacement was determined by eyelid position and function and sufficiency of tear production. All patients were corneal blind with light perception only and cicatricial ectropion. The eye with better visual prognosis was reconstructed. Eyelid reconstruction procedures consisted of lid releases with full-thickness skin graft (FTSG) or split-thickness skin graft (STSG). Two patients regained adequate lid function and underwent standard keratoprosthesis placement. Two underwent mucous membrane grafts followed by keratoprosthesis. All patients experienced improved postoperative vision in their reconstructed eye. Corneal injury due to periocular burns can lead to blindness. Early involvement of ophthalmology, protective measures, and early ectropion release are critical. For severe burns, a multidisciplinary approach, where adequate globe protection is followed by keratoprosthesis placement, can effectively restore vision in patients with burn-related corneal blindness.

Comparative Analysis of KGF-2 and bFGF in Prevention of Excessive Wound Healing and Scar Formation in a Corneal Alkali Burn Model.

PURPOSE: Basic fibroblast growth factor (bFGF) is an effective drug for corneal injury. However, the explicit role of bFGF in corneal scar formation still remains unclear. Keratinocyte growth factor-2 (KGF-2) is associated with the treatment of wound healing. We aimed to compare the efficacy of bFGF and KGF-2 in prevention of excessive wound healing and consequent scar formation in a rat alkali burn model, which provides important clues on the significance of KGF-2 to be developed as a new drug for such injuries. METHODS: The epithelial defect area was evaluated using fluorescein sodium at a concentration of 0.5%. The therapeutic effect of KGF-2 and bFGF on proliferation of rabbit corneal fibroblasts (RCFs) was evaluated by methylthiazoletetrazolium. RCF migration assays were performed with a modified scratch method. Activation of mitogen-activated protein kinase (MAPK) was evaluated by Western blot with specific antibodies. RESULTS: All corneal wounds treated with KGF-2 were found closed within 7 days; however, the wounds treated with bFGF or phosphate buffer saline (PBS) required 14 days to close. RCFs treated with KGF-2 or bFGF showed similar dose-dependent proliferation. The KGF-2 group significantly promoted cell migration compared with the bFGF group. The KGF-2 group showed less expression of α-smooth muscle actin (SMA) and numbers of myofibroblasts compared with the bFGF group. Our findings suggested identification of cascade reaction of extracellular regulated protein kinases (ERK)1/2 and p38 signals in KGF-2- and bFGF-induced proliferation and migration of RCFs. In addition, KGF-2 showed stronger effects during ERK1/2 and p38 phosphorylation in methylthiazoletetrazolium proliferation assay and scratch migration assay. CONCLUSIONS: KGF-2 exhibited better effects than bFGF in reepithelialization, acceleration of migration, and reduction of scar formation, which has potential to become a new drug to cure corneal injury.

Periorbital lesions in severely burned patients.

PURPOSE: This study aimed to characterize the injuries involving periorbital region in our severely burned patients. METHOD: A 2 years retrospective study was conducted with a total of 210 severe burns admissions. Periorbital burn injuries (all produced in association with facial injuries) were encountered in 126 patients, representing the study group that was further analyzed for multiple parameters: demographics, mechanism of injury, TBSA (total body surface area), burn depth, inhalation injury, need for intubation and mechanical ventilation. The presence and severity of ocular injuries were also evaluated. RESULTS: Analyzing our study group (n=126), we observed the presence of multiple negative prognosis factors: elderly patients, extensive burns, deep burns affecting functional areas, unfavorable mechanism (electric, chemical or explosions), inhalation injuries, need for intubation and mechanical ventilation, leading to severe morbidity and high mortality level. Ocular injuries were encountered in 37 patients (30 primary and 7 secondary lesions). The predominance of primary ocular lesions is explained trough high severity burns encountered in our patients with high mortality and lack of long-term clinical observations. CONCLUSION: The clinical outcome for periorbital burn injuries depends on patient characteristics, etiology, burn extension and depth, associated lesions, infectious risk and the quality of the treatment applied. Presence of ocular injuries in various severity degrees impose an adequate evaluation and specialized treatment, being associated with important morbidity. In severely burned patients, it is mandatory to apply preventive measures to avoid ocular complications. If exposure keratopathy is detected, prompt ophthalmologic treatment is essential to avoid functional impairment including loss of vision. Abbreviations: TBSA = total body surface area, MSOF = multisystem organ failure, OCS = orbital compartment syndrome, AION = anterior ischemic optic neuropathy.

Effect of metronidazole ophthalmic solution on corneal neovascularization in a rat model.

PURPOSE: To evaluate the effect of metronidazole ophthalmic solutions on corneal neovascularization (CNV) in a rat model. METHODS: A chemical burn was created in the right central cornea of 40 rats. Animals were randomized and distributed into four study groups (n = 10 rats per group) designated Met_0.1%, Met_0.5%, sham, and untreated groups. Chemical-burned corneas in the Met_0.1% and Met_0.5% groups received ophthalmic solutions of 0.1 and 0.5% metronidazole, respectively. Corneas in the sham group received phosphate-buffered saline (metronidazole diluent). All treated eyes received ophthalmic solution at intervals of 6 h, for up to 30 days. Untreated corneas received no treatment. CNV was evaluated postinjury using corneal photographs at different evaluation time points. The main CNV outcome measures were: burn intensity, index of CNV, and percentage of vascularized corneal area. Five rats from each group were euthanized, on days 15 and 30; the samples were collected for histological analyses. Differences with P < 0.05 were considered significant. RESULTS: CNV was observed in the eyes from day 7 postinjury. However, the indices of CNV for the Met_0.1% and Met_0.5% groups were smaller than those for the sham and untreated groups (P < 0.05). Furthermore, corneas treated with 0.1 or 0.5% metronidazole had smaller vascularized areas compared to control corneas. On histological study, the presence of blood vessels confirmed clinical outcomes. CONCLUSIONS: Regular instillation of 0.1 or 0.5% metronidazole had a significant inhibitory effect for CNV on chemical burns induced in a rat model.