Corneal Plaques Research Articles

Postkeratoplasty Corneal Plaques: A Case Series.

To assess the risk factors and management of corneal plaques formed after keratoplasty. In this retrospective study, medical records of all eyes with plaques formed on top of corneal grafts performed in the period between January 2014 and January 2022 were reviewed. The retrieved data included prekeratoplasty corneal pathology, ocular risk factors, operative data and complications, plaque management, and chemical composition of the plaques using infrared spectrometer. Thirteen eyes were included in this study. Predisposing ocular comorbidities included ocular surface disorders with variable degrees of dry eye in nine patients, rheumatoid arthritis in three patients, history of herpetic keratitis in two eyes, and cicatrizing conjunctivitis in two patients. Surgical excision and amniotic membrane transplantation (AMT) were performed in 12 eyes. Postoperatively, five eyes showed recurrence after excision, two eyes developed graft vascularization and scarring, and one eye showed persistent epithelial defect and graft scarring, whereas four eyes showed complete epithelialization with mild haze. Rekeratoplasty and AMT were performed in two eyes with no plaque recurrence. Chemical analysis using infrared spectrometry showed that the plaques consisted of ammonium magnesium phosphate and calcium phosphate carbonate in 9 (75%) cases and pure mucus in 3 (25%) cases. Postkeratoplasty corneal plaque formation is an underestimated complication of keratoplasty that may occur after persistent epithelial defects. Ocular surface disorders are the primary predisposing risk factors. In our experience, the prognosis after medical treatment or surgical scraping is guarded, and regrafting can be the only solution to restore graft clarity.

IN VIVO CONFOCAL MICROSCOPY FOR CHARACTERIZATION OF MYCOTIC KERATITIS IN OWLS (BUBO SCANDIACUS, STRIX VARIA) AND A WOODCOCK (SCOLOPAX MINOR): THREE CASES.

This case series describes the use of in vivo confocal microscopy in the diagnosis and treatment of mycotic keratitis in two owls (one Bubo scandiacus, one Strix varia) and one woodcock (Scolopax minor). Each bird was at increased risk of fungal infection due to recent injury or stress. Ophthalmic findings in all birds included blepharospasm, ocular discharge, ulcerative keratitis, white or yellow corneal plaques, and anterior uveitis. Fungal hyphae were identified in corneal samples from all three eyes examined cytologically and in all three eyes by using in vivo confocal microscopy. Aspergillus fumigatus was isolated from a corneal culture in one bird. Despite medical treatment, progressive ocular disease prompted enucleation in two birds. Fungal hyphae were detected by histopathology in one of the two enucleated eyes. In vivo confocal microscopy aided the diagnosis of fungal keratitis in all birds and was the only diagnostic method that allowed immediate, real-time quantification of the extent (area and depth) and severity of mycotic keratitis.

Targeting Type I IFN/STAT1 signaling inhibited and reversed corneal squamous metaplasia in Aire-deficient mouse

Corneal transparency and integrity are essential for obtaining good vision; nevertheless, squamous metaplasia (SQM) of ocular epithelium is a kind of serious blinding corneal diseases, without therapeutic medication in clinic. Here, we found that deficiency of the autoimmune regulator (AIRE) in corneas spontaneously developed corneal plaques. Using corneal abrasion model, we revealed that deletion of Aire not only resulted in delayed corneal re-epithelialization, but also promoted a cell-fate transition from transparent corneal epithelium to keratinized epithelium, histopathologically characterized with SQM based on the transcriptomic analysis. Mechanistically, Aire-deficient corneas led to the heightened Type I interferon (IFN-I)/STAT1 signaling after abrasion. Pharmacological blockade of IFN-I/JAK/STAT1 signaling in Aire-knockout (KO) corneas not only accelerated epithelial wound healing, but also alleviated corneal plaques and SQM. Collectively, our findings revealed critical roles of AIRE in governing corneal epithelial homeostasis and pathologic keratinization, and further identified IFN-I/STAT1 signaling as a potential target for treating ocular surface diseases with SQM, and even for treating pathological scenarios related to SQM in other tissues.

Fungal microbiota in carapace of red-eared slider (Trachemys scripta elegans) through microculture: Case report

Trachemys scripta elegans is a species of semi-aquatic freshwater turtle native to North America. It is popularly known as the “red-eared turtle”, as it has two red spots, one on each side of the head. In captivity, aquatic species are more prone to the appearance of fungal and bacterial diseases, especially if food and sanitation management is not adequate. High humidity in the environment can cause softening of the keratin and corneal plaques, facilitating the process of invasion by fungi, which in extreme cases can lead to the animal's death. Fungal infections can affect any part of the body, including the skin, respiratory tract, stomach, intestines, liver, kidneys and spleen. Therefore, the objective of this article is to carry out the microculture of the carapace of this species and verify the fungal findings, where it was possible to demonstrate the importance of an adequate management to avoid new infections and fungal resistance.

Subcutaneous administration of triamcinolone as part of the management of feline eosinophilic keratoconjunctivitis.

The aim of this retrospective case-control study was to report the efficacy of subcutaneous triamcinolone as part of a regimen for feline eosinophilic keratoconjunctivitis (FEK). Records and clinical photographs were reviewed and lesions semiquantitatively graded for cats with cytologically confirmed FEK. Clinical data were compared between a study population of nine cats (11 eyes) treated with, and a reference population of seven cats (eight eyes) treated without, a median of 0.11 mg/kg (range 0.10-0.20 mg/kg) of triamcinolone acetonide subcutaneously. Breed, sex, age and prevalence of corneal ulceration at presentation; corneal disease severity before and at the initiation of immunomodulation; and duration of antiviral treatment before immunomodulation did not differ significantly between populations (P ⩾0.059). Corneal plaques resolved in five cats each from the study and reference populations (P = 0.366). Median (range) time from immunomodulation to corneal plaque resolution did not significantly differ (P = 0.246) between the study (median 14 days; range 8-38 days) and reference (median 28 days, range 14-46 days) populations. No adverse reactions were attributed to triamcinolone administration, and all corneal ulcers in the study population re-epithelialized within 14 days (range 8-38 days) following triamcinolone injection. Time to corneal ulcer re-epithelialization following triamcinolone injection varied minimally in those receiving antivirals prior to (8 or 30 days until re-epithelialization), simultaneously with (38 days) or after (14 or 24 days) triamcinolone. In otherwise healthy cats with FEK, subcutaneous administration of triamcinolone appears to be well tolerated and as efficacious as conventional topical immunomodulatory therapies. It may be especially useful in ulcerated eyes where topical immunomodulation is contraindicated.

Transepithelial phototherapeutic keratectomy for the treatment of severe band keratopathy.

The goal of this study was to investigate the clinical outcomes of transepithelial phototherapeutic keratectomy (transepithelial PTK) for the treatment of severe band keratopathy. A consecutive series of severe band keratopathy cases treated with transepithelial PTK were retrospectively analysed between January 2018 and December 2019. Severe band keratopathy was defined as corneal plaques apparent in the obscuration of iris details. Patients' medical histories, preoperative and postoperative symptomatic relief, cosmesis, best-corrected visual acuity (BCVA), complications, and recurrences were analysed. Seventeen eyes of 16 patients were included in the study, with a mean follow-up of 9.8 ± 5.2months (3 to 19months). The mean age of the patients was 15.8 ± 10.2years (8 to 46years). Symptoms were significantly or completely relieved in all patients (100%). The results of cosmesis were good in 14 eyes (82.4%). Among those eyes that had BCVA of hand motion or better preoperatively, seven eyes (100%) showed an improvement in BCVA postoperatively. There were no complications or recurrences associated with transepithelial PTK treatment during the follow-up period. Transepithelial PTK is an effective treatment to eliminate corneal opacity and alleviate symptoms in patients with severe band keratopathy. This technique could be an alternative approach to managing severe band keratopathy.

Equine eosinophilic keratitis: An emergent ocular condition?

SummaryEosinophilic keratitis (EK) is considered an immune mediated disorder associated with an underlying type I orIVhypersensitivity reaction to parasitic or environment allergens. It is believed that the persistency of inflammatory mediators and recruitment of eosinophils into the conjunctival tissue have detrimental effects on the corneal surface. Epithelial cells are consequently damaged, particularly by eosinophilic toxic proteins, which determine the lack of epithelial healing and plaque formation. Although some clinical signs are common to other corneal diseases, the location of the lesion, presence of corneal plaques and time of the year, may help practitioners to identifyEK. Topical therapy with steroids or immune‐modulators seems to be the most effective treatment in small, localised lesions while large epithelial defects will benefit from a thorough debridement and/or early keratectomy, before secondary microbial infection may occur.

Ocular involvement in atopic dermatitis : Clinical aspects and therapy

Patients with atopic dermatitis frequently complain of ocular symptoms. The general dermatitis can directly affect the periocular skin and patients often present with chronic atopic blepharokeratoconjunctivitis. Early diagnosis of the characteristic ophthalmological alterations, such as blepharitis, allergic conjunctivitis, keratoconjunctivitis sicca, conjunctival scarring with formation of symblepharon and lid malpositioning, filiform keratitis, corneal plaques, (persistent) epithelial defects, corneal ulcers and keratoconus as well as appropriate stage-adapted treatment, including lid hygiene with preservative-free lubricants, topical and sometimes systemic anti-inflammatory therapy and surgical treatment are important for patients to prevent long-term damage of the ocular surface leading to severe visual impairment.

Steroid-Sparing Effect of 0.1% Tacrolimus Eye Drop for Treatment of Shield Ulcer and Corneal Epitheliopathy in Refractory Allergic Ocular Diseases

To evaluate the effects of 0.1% topical tacrolimus alone or in combination with steroids for the treatment of shield ulcers and corneal epitheliopathy in patients with refractory allergic ocular diseases. Open cohort study. Patients with refractory allergic conjunctivitis epitheliopathy, shield ulcers, or corneal plaques (N= 791). The 791 patients were treated with topical tacrolimus alone or in combination with topical or oral steroids. The effectiveness of the treatments was determined by a corneal epitheliopathy score during the 3-month follow-up period. The clinical signs were rated on a 4-grade scale. Corneal epitheliopathy with no corneal staining was graded as 0, and shield ulcers or plaques were graded as 3, the highest grade. The effects of tacrolimus with and without topical steroids on the epitheliopathy scores were assessed after adjustments for the severity of the clinical signs and characteristics. Changes in the corneal epitheliopathy score. Adjusted mean epitheliopathy score at the baseline was 1.73 (95% confidence interval [CI], 1.65-1.81) for patients treated with tacrolimus alone, and this was significantly reduced by-0.93 at 1 month. The reduction of the score by topical and oral steroids was-0.02 for fluorometholone, 0.02 for betamethasone, and-0.02 for oral steroids, and these reductions were not significant compared with the reduction effect of topical tacrolimus alone at-0.93. The 238 patients with shield ulcer (score 3) were analyzed with adjustments, and the mean epitheliopathy score at 1 month was reduced to 1.38 with tacrolimus alone (95% CI, 1.24-1.51), 1.41 (95% CI, 1.26-1.56) with adjuvant fluorometholone, and 1.46 (95% CI, 1.32-1.61) with adjuvant betamethasone. No significant difference was observed in the adjunctive topical steroids. The presence of severe palpebral conjunctival symptoms, including giant papillae, was a significant resisting factor for topical tacrolimus. The significant effects of topical tacrolimus alone on shield ulcers and corneal epitheliopathy suggest that it may be used without the need for steroids.

LRIG1 inhibits STAT3-dependent inflammation to maintain corneal homeostasis

Corneal integrity and transparency are indispensable for good vision. Cornea homeostasis is entirely dependent upon corneal stem cells, which are required for complex wound-healing processes that restore corneal integrity following epithelial damage. Here, we found that leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) is highly expressed in the human holoclone-type corneal epithelial stem cell population and sporadically expressed in the basal cells of ocular-surface epithelium. In murine models, LRIG1 regulated corneal epithelial cell fate during wound repair. Deletion of Lrig1 resulted in impaired stem cell recruitment following injury and promoted a cell-fate switch from transparent epithelium to keratinized skin-like epidermis, which led to corneal blindness. In addition, we determined that LRIG1 is a negative regulator of the STAT3-dependent inflammatory pathway. Inhibition of STAT3 in corneas of Lrig1-/- mice rescued pathological phenotypes and prevented corneal opacity. Additionally, transgenic mice that expressed a constitutively active form of STAT3 in the corneal epithelium had abnormal features, including corneal plaques and neovascularization similar to that found in Lrig1-/- mice. Bone marrow chimera experiments indicated that LRIG1 also coordinates the function of bone marrow-derived inflammatory cells. Together, our data indicate that LRIG1 orchestrates corneal-tissue transparency and cell fate during repair, and identify LRIG1 as a key regulator of tissue homeostasis.

Surgical management and immunohistochemical study of corneal plaques in vernal keratoconjunctivitis

Two children with shield ulcer in vernal keratoconjunctivitis unresponsive to steroid therapy received plaque removal by superficial keratectomy, followed by amniotic membrane transplantation (AMT). Hematoxylin and eosin staining of the excised corneal specimen revealed a thick layer of eosinophilic material attached to the Bowman's layer. These deposits were positive for eosinophil granule major basic protein, as confirmed by an immunohistochemical study. The shield ulcer healed after the amniotic membrane was removed. No recurrent corneal plaque developed, although corneal opacity complicated in both cases. Lamellar keratectomy with AMT offers an effective management by removing the cytotoxic plaques and protecting the denuded stroma from deposition of inflammatory debris.

Eosinophilic keratoconjunctivitis in two rabbits

The purpose of this case report is to describe the clinical course and cytologic findings, treatment, and outcome of eosinophilic keratoconjunctivitis in two rabbits. Ophthalmic examination revealed ocular discharge, dacryocystitis, blepharitis, conjunctivitis, white conjunctival and corneal plaques, corneal vascularization, and stromal infiltration with different degrees of severity in each case. In case 2 there was also ulcerative disease of the cornea. Computerized tomography scan of the head, corneal biopsy for histopathologic examination with additional Luna and Giemsa stain were performed in case 2 and conjunctival as well as corneal specimens were obtained for bacteriologic culture and cytologic examination in case 1. Based on test results, a diagnosis of eosinophilic keratoconjunctivitis was made in case 2 and a tentative diagnosis of eosinophilic keratoconjunctivitis was made in case 1. Response to treatment with a topical steroid and topical cyclosporin was supportive of the diagnosis in both cases and shared many similarities with the response to treatment previously described in cats. Eosinophilic keratitis should be considered as part of a differential diagnosis list in rabbits with a history of keratitis.

Current therapy of allergic conjunctivitis

Allergic conjunctivitis is a common ocular disorder. The main clinical types of conjunctival allergic reactions are seasonal allergic conjunctivitis, perennial allergic conjunctivitis, atopic kerato-conjunctivitis, vernal keratoconjunctivitis (VKC), and giant papillary conjunctivitis. The pathophysiology of allergic conjunctivitis involves primarily a type I hypersensitivity mechanism, with release of histamine and other chemical mediators from mast cells; however, a type IV hypersensitivity with participation of secondary inflammatory cells, such as T-helper cells, eosinophils, and their chemical mediators, also plays a role. Current therapy of allergic conjunctivitis is based on general measures that aim at eliminating exposure to the allergen, and medical treatment. The main classes of drugs involved in medical therapy are antihistamines (used with or without vasoconstrictors), mast-cell stabilizers, nonsteroidal anti-inflammatory drugs, and corticosteroids. Topical immunosuppressive drugs, such as cyclosporine, have recently been used in severe VKC with good results. In addition, laser or surgical removal of the corneal plaques and shield ulcers of VKC has led to a better visual outcome. The future of allergic conjunctivitis treatment lies in a better understanding of the complex intercellular relationships that occur during the immune response to the offending allergen.