Corneal Lesions Research Articles

Replace or Regenerate? Diverse Approaches to Biomaterials for Treating Corneal Lesions.

The inner structures of the eye are protected by the cornea, which is a transparent membrane exposed to the external environment and subjected to the risk of lesions and diseases, sometimes resulting in impaired vision and blindness. Several eye pathologies can be treated with a keratoplasty, a surgical procedure aimed at replacing the cornea with tissues from human donors. Even though the success rate is high (up to 90% for the first graft in low-risk patients at 5-year follow-up), this approach is limited by the insufficient number of donors and several clinically relevant drawbacks. Alternatively, keratoprosthesis can be applied in an attempt to restore minimal functions of the cornea: For this reason, it is used only for high-risk patients. Recently, many biomaterials of both natural and synthetic origin have been developed as corneal substitutes to restore and replace diseased or injured corneas in low-risk patients. After illustrating the traditional clinical approaches, the present paper aims to review the most innovative solutions that have been recently proposed to regenerate the cornea, avoiding the use of donor tissues. Finally, innovative approaches to biological tissue 3D printing and xenotransplantation will be mentioned.

Increasing incidence of contact-lens-related Acanthamoeba keratitis in a tertiary ophthalmology department in an Italian population.

The purpose of this paper is to report the increasing incidence of contact-lens related Acanthamoeba keratitis (AK) in a tertiary ophthalmology department in Umbria, central Italy. Observational and retrospective case series were carried out. A total of nine eyes with a diagnosis of AK were examined. All patients underwent a full slit lamp examination, in vivo confocal microscopy (IVCM) and corneal scraping. The IVCM was repeated at one and two-week and at one, three and six-month intervals. Samples of domestic tap water were also examined for PCR analysis. Patients were treated with levofloxacin0,5%, Polyhexamethylene biguanide 0.02%, and Propamidine Isetionate0,1%. All patients were contact lens wearers. The average patient age was 27.75 (range 18-45), with three men and five women. The main clinical features were ciliary congestion, diffuse epitheliopathy with punctuated keratitis, multiple, small sub-epithelial, greyish, corneal infiltrates with epithelial defect, pseudodendritic corneal lesions, perineural infiltrates, corneal stromal cellularity, and stromal infiltrates. IVCM was indicative of Acanthamoeba in seven out of the nine eyes. All the positive IVCM images were section images showing double walled, bright-spot cysts with a clear chain-like arrangement of five or more cysts identified in three of the patients. PCR analysis of the water was negative in all cases. Although PCR is the most common method used, the increased incidence of AK could mainly be related to a proper IVCM interpretation. A broad-spectrum antibiotic, such as levofloxacin might play a role in the early treatment of AK reducing the virulence of the amoeba.

Clinical Outcomes and Indications of In-Office Sutureless Dried Gamma Ray-Sterilized Human Amniotic Membrane Transplantation With Bandage Contact Lenses in Various Ocular Surface Disorders.

The purpose of this study was to investigate the efficacy and indications of using dried gamma ray-sterilized amniotic membrane (AM) transplantation with bandage contact lenses for the in-office sutureless treatment of various ocular surface diseases. This study retrospectively included 56 eyes of 52 patients with various ocular surface diseases treated with sutureless dehydrated AM-assisted therapeutic contact lenses. The patients were followed up and assessed 1, 2, and 4 weeks after the treatment, and the therapeutic contact lenses were removed after 1 or 2 weeks. The size of the corneal lesion and the degree of pain experienced by each patient before and after the procedure were measured. Corneal re-epithelization rate and clinical aspects related to re-epithelialization were evaluated. Complete corneal re-epithelialization of the epithelial defect was observed in 40 eyes. The complete re-epithelialization rates of persistent epithelial defect caused by infectious ulcers, neurotrophic ulcers, ulcers due to burn, toxic keratopathy, previous penetrating keratoplasty or other corneal surgeries, and severe dry eye disease were 69.2%, 80.0%, 77.8%, 100%, 75.0%, and 100%, respectively. Five patients with uncontrolled infectious ulcers, neurotrophic ulcer, bullous keratopathy, and ulcers associated with rheumatic disease did not show significant improvement. Patient pain scores significantly decreased after the procedure. Dehydrated AM transplantation with a bandage contact lens is minimally invasive and easily applicable through in-office procedures. This approach is expected to be more actively applied in various ocular surface disorders, not only in severe corneal diseases but also in relatively mild corneal surface diseases.

A method for teaching depth of corneal lesions using a portable slit lamp (biomicroscope).

A novel, simple, and inexpensive model for teaching depth of lesions within the cornea using slit lamp biomicroscopy to veterinary students, ophthalmology residents, and general clinicians with access to a slit lamp biomicroscope is described. Using common laboratory items, this method can be created in any clinic and can be used to teach and quiz students through independent study with objective self-testing achieved.

THE EFFECT OF SUPER OXIDE DISMUTASE (SOD) ON THE HEALING OF WHITE RAT CORNEAL EPITHELIAL WOUNDS CORNEAL EPITHELIAL WOUNDS

Abstract
 Introduction & Objectives : Keratitis and corneal erosion are part of eye trauma. Injury to the cornea will cause cell damage, triggering an inflammatory reaction that can increase the production of ROS (Reactive Oxygen Species). SOD (Superoxide Dismutase), one of the endogenous enzymatic antioxidants works by limiting the level of inflammation of the corneal damage caused by oxidation. Objective: Determine the effect of superoxide dismutase concentrations of 2%, 3%, 5% and placebo on the healing of corneal epithelial wound lesions in white rats with corneal trauma models
 Methods : Experimental study pre and post-test only with control group design in vivo with 24 samples of white wistar rats that met the inclusion and exclusion criteria. The research was conducted at the Animal House Laboratory, the Biotechnology Laboratory of the UNSRI Medical Faculty and the Eureka Research Center laboratory within 6 months.
 Results : 5% SOD showed a smaller reduction in wound area with the largest reduction (mean 0.67cm ± 0.007) followed by SOD 3% (mean 0.67cm ± 0.005). SOD 3% and 5% significantly correlated with weak strength at 48 hours and 72 hours. A significant reduction in the area of corneal epithelial wound lesions was only seen at 48 hours.
 Conclusion : SOD 5% most affected the healing of corneal epithelial wound lesions, followed by SOD 3%. SOD concentrations of 3% and 5% had a significant correlation on corneal epithelial wound healing at 48 and 72 hours with weak correlation strength.

A Rare Case of Congenital Corneal Keloids

Introduction : A corneal keloid is a uncommon ophthalmic condition that manifest as proliferation of fibrous tissue in the cornea and presents as an enlarging, white, elevated, well circumscribed corneal lesion. It is a relatively uncommon lesion that typically appears after surgery, injury, or corneal perforation. Pathological examination of the resected specimen leading to a diagnosis of corneal keloid.
 Case Illustration : A 6-year-old girl came with chief complaint was blurry vision in both eyes accompanied with a white opacity in her left eye that was gradually growing. The patient has been diagnosed with congenital glaucoma ever since birth. Nobody of her parents acknowledged having a history of inflammatory, infection, or ocular damage. At first glance, her visual acuity appeared to be light reflex in both eyes. Slit lamp biomicroscopy revealed a pearly white, enhanced opacity with sharp edges and smooth surface in the left eye (figure 1). New vessels were present in the lesion adjacent to the limbus. The patient is undergoing keloids excision, multilayer amnion membrane transplant and fine needle diathermy (figure2).
 Discussion : Corneal keloid can present at any age, present as a glistening white enlarging mass on the cornea and well demarcated from the adjacent normal tissue. Histopathologic examination demonstrates a thickened corneal epithelium overlying stroma and hyalinized collagen (figure 3).
 Conclusion : A corneal keloid should be suspected in cases of enlarging white glistening avascular corneal scars. Biopsy and histopathology confirmed the diagnosis.

Risk factors of cytomegalovirus infection in patients with failed corneal grafts

Objective: To investigate the levels of cytomegalovirus (CMV) infection and associated risk factors in corneal transplant recipients who experienced transplant failure. Methods: This was a case-control study. Clinical data from 576 cases (576 eyes) of patients who underwent repeat corneal transplant surgery at the Department of Ophthalmology, Peking University Third Hospital, due to corneal transplant failure from January 2016 to May 2022 were collected. Of these, 305 were male and 271 were female, with a median age of 44.0 (0.7, 91.0) years. The CMV infection rate was analyzed based on the detection of CMV DNA in aqueous humor or corneal tissue during corneal transplant surgery. Patients were divided into the CMV group (CMV DNA positive) and the control group (herpes virus DNA negative). The main research indicators included the CMV infection rate, clinical characteristics, and risk factors in corneal transplant recipients. Chi-square tests and binary logistic analysis were used to compare differences between the two groups in general information, systemic diseases, ocular lesions, ocular surgical history, and local and systemic medications. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for each CMV infection risk factor. Results: The overall CMV infection rate was 21.9%(126/576), with annual rates ranging from 10.9% to 37.7% from 2016 to 2021. After applying inclusion and exclusion criteria, 378 patients were included in the control trial, with 126 in the CMV group and 252 in the control group. Statistically significant differences between the two groups were observed in systemic immune-related corneal lesions [CMV group: 38 (30.2%), control group: 26 (10.3%)], local immune and inflammatory corneal lesions [CMV group: 46 (36.5%), control group: 40 (15.9%)], congenital corneal opacity [CMV group: 46 (36.5%), control group: 48 (19.0%)] total number of corneal transplants (CMV group: 178 times, control group: 276 times), corneal deep neovascularization crossing the graft [CMV group: 104 (82.5%), control group: 68 (27.0%)] and severe opacity [CMV group: 44 (34.9%), control group: 30 (11.0%)]. Binary logistic regression analysis showed that systemic immune-related corneal lesions (OR=4.044, 95%CI 1.810-9.033, P<0.001), local immune and inflammatory corneal lesions (OR=3.554, 95%CI 1.569-8.052, P=0.002), congenital corneal opacity (OR=2.606, 95%CI 1.216-5.589, P=0.014), total number of corneal transplants (OR=3.206, 95%CI 1.753-5.864, P<0.001), corneal deep neovascularization crossing the graft (OR=8.347, 95%CI 3.967-17.559, P<0.001), and severe opacity (OR=3.063, 95%CI 1.221-7.682, P=0.017) were independent risk factors for CMV infection after corneal transplant. Conclusions: CMV infection was present in more than 1/5 of corneal transplant recipients who experienced transplant failure. CMV infection after corneal transplant may be related to immune rejection reactions and ocular inflammatory responses. Inflammatory corneal lesions associated with systemic or local immune abnormalities, congenital corneal opacity, and multiple corneal transplants may exacerbate the levels of inflammatory factors during the perioperative period of corneal transplant, increasing the risk of post-transplant CMV infection, leading to the infiltration of deep neovascularization and severe opacity in the cornea.

Attach importance to the orderly development of different corneal transplant procedures

There are various surgical methods for corneal transplantation, each requiring precise treatment tailored to the characteristics and different layers of corneal opacity or lesions. These layers include the corneal epithelium, stroma (lamellar), and corneal endothelium, with options for full-thickness (penetrating) corneal transplantation or artificial corneal transplantation. However, a current issue in clinical practice is that, regardless of the degree of corneal disease, the availability of corresponding eye bank support, or surgical conditions, classic penetrating (full-thickness) corneal transplantation is universally performed. Alternatively, there is a trend toward adopting technically demanding procedures such as endothelial transplantation and artificial corneal transplantation. This trend has led to increased postoperative complications and the wastage of corneal donor materials. Choosing the appropriate corneal transplant procedure can offer advantages such as preserving more healthy corneal tissue, conserving corneal donors, facilitating rapid vision recovery, and minimizing the risk of immune rejection. Corneologists need to master the indications for various corneal transplant surgeries and systematically perform different corneal transplant procedures based on the surgeon's skills, hospital conditions, and eye bank conditions. This approach aims to enhance the success rate of the surgery.

Research progress on ocular complications caused by type 2 diabetes mellitus and the function of tears and blepharons.

The purpose of this study was to explore the related research progress of ocular complications (OCs) caused by type 2 diabetes mellitus (T2DM), tear and tarsal function, and the application of deep learning (DL) in the diagnosis of diabetes and OCs caused by it, to provide reference for the prevention and control of OCs in T2DM patients. This study reviewed the pathogenesis and treatment of diabetes retinopathy, keratopathy, dry eye disease, glaucoma, and cataract, analyzed the relationship between OCs and tear function and tarsal function, and discussed the application value of DL in the diagnosis of diabetes and OCs. Diabetes retinopathy is related to hyperglycemia, angiogenic factors, oxidative stress, hypertension, hyperlipidemia, and other factors. The increase in water content in the corneal stroma leads to corneal relaxation, loss of transparency, and elasticity, and can lead to the occurrence of corneal lesions. Dry eye syndrome is related to abnormal stability of the tear film and imbalance in neural and immune regulation. Elevated intraocular pressure, inflammatory reactions, atrophy of the optic nerve head, and damage to optic nerve fibers are the causes of glaucoma. Cataract is a common eye disease in the elderly, which is a visual disorder caused by lens opacity. Oxidative stress is an important factor in the occurrence of cataracts. In clinical practice, blood sugar control, laser therapy, and drug therapy are used to control the above eye complications. The function of tear and tarsal plate will be affected by eye diseases. Retinopathy and dry eye disease caused by diabetes will cause dysfunction of tear and tarsal plate, which will affect the eye function of patients. Furthermore, DL can automatically diagnose and classify eye diseases, automatically analyze fundus images, and accurately diagnose diabetes retinopathy, macular degeneration, and other diseases by analyzing and processing eye images and data. The treatment of T2DM is difficult and prone to OCs, which seriously threatens the normal life of patients. The occurrence of OCs is closely related to abnormal tear and tarsal function. Based on DL, clinical diagnosis and treatment of diabetes and its OCs can be carried out, which has positive application value.

The Role of IL-6, IL-10, and TNF-α in Ocular GVHD Following Allogeneic Transplantation

ABSTRACT Purpose To figure out the roles of tear inflammatory cytokines in Ocular graft-versus-host disease (oGVHD) symptoms by analyzing tear cytokine levels and related factors. Methods This prospective study involved 27 post-HSCT patients and 19 controls with dry eye disease. Analyses included tear cytokine (IL-6, IL-10, and TNF-α), ocular surface evaluation, and conjunctival impression cell examination. Tear cytokine levels were evaluated in three grades of corneal epithelial lesions. The study also analyzed the correlation between tear cytokine levels and ocular surface parameters. Tear cytokine levels were then used in a Receiver Operating Characteristic (ROC) curve and linear regression model to predict oGVHD related factors. Results IL-6 has good diagnostic efficacy in oGVHD related dry eye. Elevated levels of tear IL-6 and TNF-α were observed in the group with severe corneal epithelial lesions. IL-6 levels were positively correlated with corneal fluorescein staining (CFS), eyelid margin hyperemia, conjunctival lesions, and meibum secretion. IL-6 showed excellent predictive ability with Area Under the Curve (AUC) values all greater than 0.70 (p < 0.05). IL-10 and TNF-α were negatively correlated with the meibomian gland proportion and conjunctival goblet cell (GC) density, while TNF-α was positively correlated with CFS and eyelid margin hyperemia. Conclusion Dry eye symptoms related to ocular GVHD, can be partly diagnosed and assessed using various tear cytokine level detection methods.

Review of ocular alterations in bats in America and notes on a new case for Saccopteryx bilineata (Chiroptera: Emballonuridae)

Abstract Morphological abnormalities in bats are rarely reported and, particularly, ocular problems are relatively scarce in the literature. We present a review of the records of ocular alterations in bats of the American continent and document for the first time a case of ocular alteration in the species Saccopteryx bilineata in northern Colombia. In this study we found cases of corneal opacity (5/19 individuals), lesions and trauma, microphthalmia (4/19 individuals), anophthalmia (4/19 individuals) and adnexal diseases (2/19 individuals). We encourage researchers to report their observations of bats with ocular anomalies, as this information could be useful for estimating occurrence rates and addressing questions associated with the social behaviour of the species and on their effects on natural populations.

INTRAOCULAR PRESSURES OF AQUARIUM-HOUSED COWNOSE RAYS (RHINOPTERA BONASUS) WITH NORMAL AND ABNORMAL OPHTHALMIC EXAMS.

Cownose rays (Rhinoptera bonasus) are common elasmobranchs in zoos and aquaria; however, there is a lack of published information regarding ocular findings in this species. Intraocular pressure (IOP) was measured in a total of 52 cownose rays (Rhinoptera bonasus) from two unrelated aquaria (n = 22 from A1, n = 30 from A2) using a TonoVet rebound tonometer on two settings (dog = D, and unidentified species = P) as part of a full ophthalmologic examination. Adult (n = 38) and juvenile (n = 14) rays were sampled out of water briefly in sternal recumbency. Intraocular pressure (mean ± SD [range]) in the D setting (9.10 ± 2.57 [4-18] mmHg) was higher than the P setting (5.21 ± 2.32 [0-12] mmHg) (P<0.001). Statistical analysis revealed no difference in IOP between right and left eyes, and no correlation between body weight and IOP. No differences in IOP between sex, age group, and location were identified in either setting. However, a significant difference was observed between levels of severity of corneal disease in IOP D setting (P=0.006) and P setting (P=0.024), and levels of severity of intraocular disease in IOP D setting (P=0.034) only. This study provides baseline IOP values using rebound tonometry in aquarium-housed cownose rays with apparent corneal and intraocular lesions and reveals that the D setting may be more sensitive in identifying IOP changes in eyes with intraocular disease.

Периферические язвы роговицы в ассоциации с ревматической патологией

Background: peripheral ulcerative keratitis (PUK) is a polyetiological disease. The pathogenesis of PUK is attributed to a combination of factors, including the anatomy of the peripheral cornea, the activation of autoimmune reactions, and the corneal destruction caused by autoan- tibodies and matrix metalloproteinases. Aim: to describe the clinical symptoms of PUK, its association with rheumatic diseases (RD), its course, and the efficacy of treatment options. Patients and Methods: а total of 32 patients (9 men and 23 women, mean age 59.3±9.4 years) with PUK associated with RD were under surveillance. The diagnosis was established based on the results of eye examinations, tear production test, and multidisciplinary examination. Treatment was performed in an outpatient or inpatient setting based on the severity of corneal lesions. Results: the most common association between PUK and RD was established with rheumatoid arthritis (56.2%). Clinical hallmarks of PUK included mild infiltration and perifocal corneal edema, accompanied by the appearance of an oval or sickle-shaped epithelial and stromal defect 2–4 mm from the limbus. Additionally, rapid corneal lysis and perforation (18.7%) and association with perilimbal vasculitis and scleritis (31.2%) were observed. Bilateral corneal lesions were observed in 56.2%. Tear production, as measured by Schirmer's test, was 6±2 mm, while tear film stability was 2±1 mm. Conservative management was found to be effective in 59.4% (outpatient treatment in 40.6% and inpatient treatment in 18.7%). Surgical interventions were performed for emergent indications, including tectonic keratoplasty (21.9%) and deep anterior lamellar keratoplasty (15.6%). Conclusion: PUK represents a severe clinical manifestation of visual disorders in RD. Treatment for PUK involves local and systemic steroids in the acute period, basic immunosup-pressive therapy, and, when necessary, keratoplasty. Systemic rheumatological therapy, regular use of tear substitutes and reparative preparations are prescribed to prevent recurrences. KEYWORDS: keratitis, corneal ulcer, limbus, autoimmune diseases, rheumatoid arthritis, keratoplasty. FOR CITATION: Drozdova E.A. Peripheral corneal ulcers in association with rheumatic diseases. Russian Journal of Clinical Ophthalmology. 2024;24(2):88–93 (in Russ.). DOI: 10.32364/2311-7729-2024-24-2-8.

Long-Term Observation of Prognostic Factors and Clinical Outcome of Vernal Keratoconjunctivitis in Childhood.

Vernal keratoconjunctivitis (VKC) is a refractory ocular allergic disorder that mainly affects boys. Long-term follow-up has been rarely reported for VKC. We investigated the long-term clinical outcome of VKC to identify relevant clinical features of prognostic value based on follow-up for a median of 70 months. In total, 45 consecutive patients clinically diagnosed with VKC aged 4 to 12 years at onset at the Department of Ophthalmology of Fukuoka University Hospital were included. Patients were treated with immunosuppressive eye drops without simultaneous corticosteroid eye drops, except for the occurrence of exacerbations. Collated variables were gender, age at onset, clinical score of ocular lesions (conjunctival giant papillae, limbal edema and corneal epithelial lesions) at the first visit, and clinical score of atopic dermatitis (AD) at baseline. Cumulative cure rate was estimated using Kaplan-Meier method. A binomial logistic predictive model was used to determine the most reliable clinical predictors of VKC outcome. The observation period ranged from 24 to 188 months, with median of 70 months. Among the 45 cases enrolled, all non-cured cases (14 cases) observed clinically were complicated by AD. Cumulative cure rate was 74.5% and 84.9% at eight- and ten-year follow-up, respectively. Ten-year cumulative cure rates of cases with and without AD were 50.5% and 100%, respectively, and a significant difference was found between these cumulative cure curves. Binomial regression analysis revealed that AD and gender were significantly related to worse outcome, and this binomial regression model had high sensitivity and specificity. This study demonstrated that th eclinical outcomeof VKC might be predicted by several factors that can beobtained in the early clinical phase. Information on the long-term prognosis of VKC patients might play an important role for precision medicine for VKC in childhood.

Cornea Verticillata – a Rare Complication of Chloroquine Toxicity. Case Report

IntroductionCornea verticillata is characterized by bilateral grayish or golden-brown linear opacities in a typical vortex shape, mainly in the lower segments of the corneal epithelium, without covering the corneal stroma. It is most often associated with taking amiodarone but can be induced by other medications. Chloroquine is commonly used in treatment and prevention of protozoal diseases. Additionally, it has applications in dermatology and rheumatology as an anti-inflammatory agent in collagenosis, rheumatoid arthritis or lupus erythematosus. Its ophthalmic side effects and their management are noteworthy and are briefly summarized in this paper.Material and MethodsWe present a case of a 62-year-old female patient who was referred to the clinic for diagnosis of corneal lesions detected incidentally during a follow-up examination 6 months after starting treatment with chloroquine for rheumatoid arthritis.ResultsThe patient was diagnosed with cornea verticillata and informed that it does not affect visual acuity and is not an indication for changes in therapy. Discontinuation of medication results in partial or, in some cases, complete resolution of changes.DiscussionIt is important to closely monitor patients taking drugs that are known to have ophthalmic side effects for the first time in new indications. We should consider eye side effects when treating systemic disease and recommend screening tests.ConclusionsA baseline ophthalmic examination should be performed on all patients before initiating use of chloroquine. Moreover, chloroquine can lead to permanent loss of visual acuity contributing to bull’s eye maculopathy, which is irreversible.

A case series study: Corneal lesions and subsequent needs for Corneal Grafting

Background: Corneal lesions handicap all age groups and corneal grafts, provided by do-nors, treat most of the isolated corneal lesions that has wide diverse etiologies. Methods and patients: This study analyzed corneal lesion etiologies and determined the percentage of candidates that required corneal grafts. This study was conducted in Al-Thawra Modern General hospital (ATGMH) in 2004. We enrolled all new patients with cor-neal lesions attending the clinic during the study period. The corneal lesions were either isolated or combined with other eye lesions. We determined the demography, etiology, and visual acuity by Snellen's E- chart, slit lamp, ultrasound, and accordingly documented the plan of treatment. Those that had trauma and/or inflammation were treated with followed up for two months to plan their potential need for corneal graft. Results: From 1440 ophthalmic patients visiting the eye clinic in 2004, the incidence rates of eyes affected by corneal lesions were 9.41% (N=135). Among the causes requiring primary and secondary level intervention were trauma (61) 4.236% and inflammation (18) 1.25%. Among the treated suffers, 15% obtained visual acuity 6/36 and better. Tertiary intervention by corneal graft was required among degenerative lesions (9) 0.625%, keratoconus (12) 0.833%, edema (12) 0.833%, dryness (7) 0.278%, dystrophy (6) 0.416%. Meanwhile, the fourth level required cosmetic treatment and rehabilitation. The lesions were bilateral in (27) 20%, congenital in (6) 0.416% and tumors found in (2) 0.138%. Conclusion: The incidence of corneal lesions was high (9.4%) among our patients, 63.94% were due to preventable trauma and inflammation and 69% were candidates for corneal graft.

Suitability of Slaughterhouse-Acquired Pig Eyes as Model Systems for Refractive Ultraviolet and Infrared Femtosecond Laser Research

Purpose To elucidate whether it is feasible to use porcine eyes from scalded, abattoir-acquired animals for refractive femtosecond laser research. Methods An infrared laser (FS 200) and an ultraviolet laser (prototype version) were tested for their applicability on scalded pig eyes. Fifty porcine eyes were divided into two equally-sized groups and assigned to either the infrared or the ultraviolet laser. Both laser groups were comprised of five subgroups of n = 5 eyes each. Group A: non-scalded eyes (negative control); group B: eyes taken from tunnel-scalded animals; group C1: eyes taken from tank-scalded animals without opaque corneal lesion; group C2: eyes taken from animals with opaque corneal lesion; group D: eyes scalded in toto in the laboratory (positive control). In each group the lasers were employed to create a stromal flap. The quality of the laser cuts and the resulting flap beds, as well as of the porcine corneas themselves, was examined by anterior segment optical coherence tomography and scanning electron microscopy. Results All scalded specimens exhibited substantial corneal swelling, most pronounced in group C2. After ultraviolet laser application, the tank- and tunnel-scalded samples displayed marked irregularities and an increased degree of surface roughness in the flap beds. After infrared laser application, this was only the case in the tank-scalded specimens. Conclusion It is not recommended to use eyes taken from scalded pigs for ultraviolet femtosecond laser experiments. For infrared femtosecond lasers, eyes taken from tunnel-scalded animals may represent an acceptable alternative, if non-scalded eyes are not available.

Strigid herpesvirus-1 as a differential for chronic keratitis in owls

An adult free-ranging great horned owl was referred for evaluation of chronic ulcerative keratitis in the left eye that had been treated for several months. In vivo confocal microscopy confirmed that the corneal lesion was an inactive scar, and histopathology and molecular testing of a proliferative palpebral conjunctival lesion in the same eye confirmed infection with strigid herpesvirus- 1. Resolution of the conjunctivitis occurred following the biopsy and the owl was released. Four months later the owl re-presented with presumed rodenticide poisoning, and there was no evidence of recurrence of ocular disease.

Accuracy of artificial intelligence model for infectious keratitis classification: a systematic review and meta-analysis.

Infectious keratitis (IK) is a sight-threatening condition requiring immediate definite treatment. The need for prompt treatment heavily depends on timely diagnosis. The diagnosis of IK, however, is challenged by the drawbacks of the current "gold standard." The poorly differentiated clinical features, the possibility of low microbial culture yield, and the duration for culture are the culprits of delayed IK treatment. Deep learning (DL) is a recent artificial intelligence (AI) advancement that has been demonstrated to be highly promising in making automated diagnosis in IK with high accuracy. However, its exact accuracy is not yet elucidated. This article is the first systematic review and meta-analysis that aims to assess the accuracy of available DL models to correctly classify IK based on etiology compared to the current gold standards. A systematic search was carried out in PubMed, Google Scholars, Proquest, ScienceDirect, Cochrane and Scopus. The used keywords are: "Keratitis," "Corneal ulcer," "Corneal diseases," "Corneal lesions," "Artificial intelligence," "Deep learning," and "Machine learning." Studies including slit lamp photography of the cornea and validity study on DL performance were considered. The primary outcomes reviewed were the accuracy and classification capability of the AI machine learning/DL algorithm. We analyzed the extracted data with the MetaXL 5.2 Software. A total of eleven articles from 2002 to 2022 were included with a total dataset of 34,070 images. All studies used convolutional neural networks (CNNs), with ResNet and DenseNet models being the most used models across studies. Most AI models outperform the human counterparts with a pooled area under the curve (AUC) of 0.851 and accuracy of 96.6% in differentiating IK vs. non-IK and pooled AUC 0.895 and accuracy of 64.38% for classifying bacterial keratitis (BK) vs. fungal keratitis (FK). This study demonstrated that DL algorithms have high potential in diagnosing and classifying IK with accuracy that, if not better, is comparable to trained corneal experts. However, various factors, such as the unique architecture of DL model, the problem with overfitting, image quality of the datasets, and the complex nature of IK itself, still hamper the universal applicability of DL in daily clinical practice.

In the eye of the ophthalmologist: the corneal microbiome in microbial keratitis.

To describe the bacterial findings by a targeted sequencing approach from corneal samples of patients with microbial keratitis and factors influencing culture outcome of indirectly inoculated corneal specimen. Prospective inclusion of patients fulfilling predefined criteria of microbial keratitis. Samples from the corneal lesion were collected and dispensed in liquid transport medium, from which both culture and targeted amplification and sequencing of the V3-V4 region of the 16S rRNA gene were carried out. Additional standard corneal culture from the corneal lesions was also performed. Factors influencing culture outcome of indirectly inoculated corneal samples were identified by a multivariate regression model incorporating quantitative data from sequencing. Among the 94 included patients with microbial keratitis, contact lens wear (n = 69; 73%) was the most common risk factor. Contact lens wearers displayed significant differences in the bacterial community composition of the corneal lesion compared to no lens wearers, with higher abundance of Staphylococcus spp., Corynebacterium spp., and Stenotrophomonas maltophilia. Targeted sequencing detected a potential corneal pathogen in the highest proportional abundance among 9 of the 24 (38%) culture-negative patients with microbial keratitis. Age, bacterial density in the sample, and prior antibiotic treatment significantly influenced culture outcome of indirectly inoculated corneal samples. Targeted sequencing may provide insights on pathogens in both culture negative episodes of microbial keratitis and among subgroups of patients with microbial keratitis as well as factors influencing culture outcome of indirectly inoculated corneal samples.