Clinical Spectrum and Treatment Approaches in Corneal Burns

Imatinib@glycymicelles entrapped in hydrogel: preparation, characterization, and therapeutic effect on corneal alkali burn in mice

Imatinib (IMB) is a type of tyrosine kinase inhibitor with great application potential for inhibiting corneal neovascularization (CNV), but its poor water solubility limits its application in eye disease treatment. In this study, novel IMB@glycymicelles entrapped in hydrogel (called IMB@glycymicelle-hydrogel) were prepared, characterized, and evaluated for their therapeutic effects on corneal alkali burn in mice. Imatinib could be successfully loaded in glycymicelles using glycyrrhizin as a nanocarrier with an optimized weight ratio of IMB:nanocarrier. The apparent solubility of IMB was significantly improved from 61.69 ± 5.55 μg/mL to bare IMB to 359,967.62 ± 20,059.42 μg/mL to IMB@glycymicelles. Then, the IMB@glycymicelles were entrapped in hydrogel fabricated with hydroxypropyl methylcellulose and sodium hyaluronate (HA) to prolong retention time on the ocular surface. Rabbit eye tolerance tests showed that IMB@glycymicelle-hydrogel possessed good ocular safety profiles. In a mouse model of corneal alkali burns, the topical administration of IMB@glycymicelle-hydrogel showed strong efficacy by prompting corneal wound healing, recovering corneal sensitivity, relieving corneal opacities, and inhibiting CNV, and these efficacy evaluation parameters were better than those of the positive drug HA. Overall, these results demonstrated that IMB@glycymicelle-hydrogel may be a promising candidate for the effective treatment of alkali ocular damage.

Epidemiology and etiology of chemical ocular injury: A brief review

Chemical ocular injury is one of the common ophthalmologic emergencies that can cause vision loss and serious complications. Despite all protective measures, it continues to be a serious public health problem, especially in young male patients. Although it is known that injuries occur most frequently in the workplace and in young male patients, there is a variable frequency and distribution in different regions around the world. In addition, with the coronavirus disease 2019 pandemic, there are changing trends in ocular chemical injuries. This review aims to specify an update on the epidemiological and etiological features of ocular chemical injuries.

Ocular-periocular burns in a tertiary hospital: Epidemiologic characteristics

PURPOSE

Ocular burns are ophthalmic emergencies that can cause devastating injuries. This study aimed to analyze the epidemiology, complications, and management of ocular-periocular burns.

METHODS

A total of 193 patients with ocular-periocular burns were admitted to our tertiary hospital from January 2018 to December 2020. The demographic characteristics of the patients, injury variables, complications, and treatments were evaluated.

RESULTS

There were 142 male (73.6%) and 51 female (26.4%) patients with a mean age of 32.53±17.75 years. The average total body surface area was 12% (range, 1-80%). Injuries were most common at work (52.3%) and home (36.3%). Thermal burns were the most common injuries (74.6%), followed by chemical (14.5%) and electrical burns (10.9%). Alkaline agents (75.0%), mainly sodium hydroxide and lime, were common in chemical burns. Superficial lid burns were significantly higher in the thermal group (p < 0.001), and grade III-IV corneal burns were significantly higher in the chemical group (p < 0.001). Various complications were developed in 50 (13%) eyes. Medical treatment only was performed in 318 (82.4%) eyes, and additional surgical treatment was performed in 64 (17.6%) eyes; however, 54 (14.0%) underwent more than one surgery. The most common complications were corneal scars (7.3%), limbal deficiency (4.1%), and ectropion (3.9%). The most frequent procedures performed were amniotic membrane transplantation (AMT) (11.9%) and tarsorrhaphy (6.7%).

CONCLUSION

Chemical burns, limbal and conjunctival ischemia, and full-thickness eyelid defects had a poor prognosis. The degree of limbal deficiency and ınjury of intraocular structures were found to have a great influence on the outcome of their visual acuity.

Clinical Characteristics and Severity Distribution of Tertiary Eye Center Attendance by Ocular Chemical Injury Patients

OBJECTIVES

To report demographic characteristics, types and grades of injury, regional distribution of injury severity, clinical findings, and long-term results of acute ocular chemical burns.

METHODS

Medical records of patients with chemical burns between 2010 and 2020 who were admitted to Ege University less than 72 hr after the injury were reviewed. Age, gender, cause of the burn, injury severity, initial and final best-corrected visual acuity, surgical intervention, and complications were recorded. The injury severity was graded according to Dua classification.

RESULTS

A total of 104 patients (137 eyes) were included. The mean age was 42.69±17.39 (7-90) years with a male-to-female ratio of 86:18. The most common causes were home (32.6%) and industrial accidents (45.1%). The causative agent percentages for alkaline, acid, and neutral were 49.0%, 35.5%, and 5.7%, respectively. The percentages of eyes in each grade (1-6) were 16.0%, 16.0%, 15.3%, 16.7%, 17.5%, and 18.2%, respectively. Complications mostly occurred in eyes with grade 2 or higher injuries (83.7%). The relationship between injury grade and limbal stem-cell deficiency was statistically significant (P<0.001). Surgery was mostly needed in grade 4 or higher injuries (44 eyes).

CONCLUSION

The severity of the burn is one of the most important prognostic factors in chemical burns. It is important to determine the spreading of the regional injury severity beside the global one to predict complication risk of the injuries. In the present study, the injury distribution was homogeneous in all grades. Limbal stem-cell deficiency development took place mostly in grade 5 and 6 burns as expected.

Corneal neovascularization

The optical clarity of the cornea is essential for maintaining good visual acuity. Corneal neovascularization, which is a major cause of vision loss worldwide, leads to corneal opacification and often contributes to a cycle of chronic inflammation. While numerous factors prevent angiogenesis within the cornea, infection, inflammation, hypoxia, trauma, corneal degeneration, and corneal transplantation can all disrupt these homeostatic safeguards to promote neovascularization. Here, we summarize its etiopathogenesis and discuss the molecular biology of angiogenesis within the cornea. We then review the clinical assessment and diagnostic evaluation of corneal neovascularization. Finally, we describe current and emerging therapies.

Biomechanical Modulation Therapy-A Stem Cell Therapy Without Stem Cells for the Treatment of Severe Ocular Burns

Ocular injuries caused by chemical and thermal burns are often unmanageable and frequently result in disfigurement, corneal haze/opacification, and vision loss. Currently, a considerable number of surgical and pharmacological approaches are available to treat such injuries at either an acute or a chronic stage. However, these existing interventions are mainly directed at (and limited to) suppressing corneal inflammation and neovascularization while promoting re-epithelialization. Reconstruction of the ocular surface represents a suitable but last-option recourse in cases where epithelial healing is severely impaired, such as due to limbal stem cell deficiency. In this concise review, we discuss how biomechanical modulation therapy (BMT) may represent a more effective approach to promoting the regeneration of ocular tissues affected by burn injuries via restoration of the limbal stem cell niche. Specifically, the scientific basis supporting this new therapeutic modality is described, along with our growing understanding of the role that tissue biomechanics plays in stem cell fate and function. The potential impact of BMT as a future treatment option for the management of injuries affecting tissue compliance is also further discussed.

Long-Term Outcomes of Allogeneic Ocular Surface Reconstruction: Keratolimbal Allograft (KLAL) Followed by Penetrating Keratoplasty (PK)

Purpose

Long-term results of the patients with total LSCD, who had undergone keratolimbal allograft (KLAL) for limbal reconstruction followed by penetrating keratoplasty (PK).

Methods

The study analyzes surgical treatment of 43 eyes with severe ocular surface disorders. All subjects underwent KLAL to achieve suitable conditions for consecutive PK. Due to failures of primary treatment in 17 eyes (39%), the KLAL was repeated. PK was performed in all the patients at 9-12 months after KLAL. As a retrospective study we analyzed data from the medical records including the preoperative and postoperative best corrected visual acuity, corneal clarity, surgical outcomes and complications, postoperative intraocular pressure, graft rejection, and other comorbidities and complications.

Results

The preoperative visual acuity ranged from light perception to 0.01. The final improvement of visual acuity within a gain of one or more lines with the Snellen chart, including the results of successive surgical treatments after PK, was achieved in 23 operated eyes (53%). Early graft rejection was observed in 4 eyes (9%). In 3 eyes, it was manifested as endothelial rejection, and in 1 eye, as combined endothelial and epithelial rejection. PK failure requiring repetitive PK was present in 14 eyes (32%). Phthisis bulbi developed in 6 eyes (14%). Glaucoma or ocular hypertension was reported in 25 eyes (58%). A majority were treated with up to 3 topical agents or referred for trabeculectomy in 3 cases, transscleral cyclophotocoagulation in 2 eyes, and EX-PRESS glaucoma shunt implantation in 3 cases.

Conclusions

Successful KLAL carries a high risk of subsequent PK failure. Visual function remains the second aim of treatment; the primary one is to stabilize the surface.