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Corneal transplantation is the most effective treatment for corneal blindness. Standard planned keratoplasties have a high success rate. Conditions such as active inflammation at the time of surgery, the presence of ocular surface disease, previous graft disease, or neovascularization make them more susceptible to rejection. These are so-called high-risk corneal transplantations. In our study, we selected 52 patients with a higher risk of graft rejection. A total of 78 procedures were performed. The main indications for the first keratoplasty were infections (59.6%) and traumas (21.2%). Visual acuity (VA) significantly improved from 2.05 logMAR on the day of keratoplasty to 1.66 logMAR in the latest examination ( p = 0.003). An analysis of the graft survival showed a 1-year survival of 54% and a 5-year survival of 19.8% of grafts. The mean observation time without complications after the first, second, and third surgery was 23, 13, and 14 months, respectively. The best results were noted among patients with infectious indications for keratoplasty ( p = 0.001). Among them, those with bacterial infection had the best visual outcomes ( p = 0.047).

Age-related macular degeneration (AMD) is an eye disease causing damage to the macular region of the retina where most of the photoreceptors responsible for central visual acuity are located. MicroRNAs (miRNAs) are small single-stranded non-coding RNA molecules that negatively regulate genes by silent post-transcriptional gene expressions. Previous studies have shown that changes in specific miRNAs are involved in the pathogenesis of eye diseases, including AMD. Altered expressions of miRNAs are related to disturbances of regulating oxidative stress, inflammation, angiogenesis, apoptosis and phagocytosis, which are known factors in the pathogenesis of AMD. Moreover, dysregulation of miRNA is involved in drusen formation. Thus, miRNAs may be used as potential molecular biomarkers for the disease and, furthermore, tailoring therapeutics to particular disturbances in miRNAs may, in the future, offer hope to prevent irreversible vision loss. In this review, we clarify the current state of knowledge about the influence of miRNA on the pathogenesis, diagnosis and treatment of AMD. Our study material consisted of publications, which were found in PubMed, Google Scholar and Embase databases using "Age-related macular degeneration", "miRNA", "AMD biomarkers", "miRNA therapeutics" and "AMD pathogenesis" as keywords. Paper search was limited to articles published from 2011 to date. In the section "Retinal, circulating and vitreous body miRNAs found in human studies", we limited the search to studies with patients published in 2016-2021.

Uveal melanoma is the most common primary intraocular malignancy in adults, characterized by an insidious onset and poor prognosis strongly associated with tumor size and the presence of distant metastases, most commonly in the liver. Contrary to most tumor identification, a biopsy followed by a pathological exam is used only in certain cases. Therefore, an early and noninvasive diagnosis is essential to enhance patients' chances for early treatment. We reviewed imaging modalities currently used in the diagnostics of uveal melanoma, including fundus imaging, ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), fundus autofluorescence (FAF), as well as positron emission tomography/computed tomography (PET/CT) or magnetic resonance imaging (MRI). The principle of imaging techniques is briefly explained, along with their role in the diagnostic process and a summary of their advantages and limitations. Further, the experimental data and the advancements in imaging modalities are explained. We describe UM imaging innovations, show their current usage and development, and explain the possibilities of utilizing such modalities to diagnose uveal melanoma in the future.

Confirmation of the biological effectiveness of new ophthalmic preparations introduced in the market is an important element in maintaining the safety of using this type of medications. This study aimed to investigate the activity of Ozodrop ® on human corneal and conjunctival epithelial cells, as well as its antibacterial and antifungal activity. Cytotoxicity analyses of ocular surface epithelial cells were performed in vitro by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) and Neutral Red uptake assays. The level of nitric oxide released by the cells was assessed by the Griess method. The reduction of the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical by the tested formulation was analyzed. Microbiological tests were also performed. It was found that the Ozodrop ® preparation exhibited biological activity, but was less active than the reference antibiotics and the anti-yeast agent. The cytotoxic activity of the Ozodrop ® formulation was dependent on the time of cell exposure to it. No toxic effect was observed in the short-term, for up to 3 h. It appeared after 24 h of exposure of the cells to the preparation. The drops showed antioxidant activity in the specified concentration range. They also stimulated the release of nitric oxide, mainly by corneal epithelial cells. The Ozodrop ® formulation exhibits biological activity that can be considered useful in the treatment of infections in the front part of the eye.

Purpose: The elevation of intraocular pressure (IOP), a major risk factor in glaucoma, is an important parameter tracked in experimental models of this disease. However, IOP measurement in laboratory rodents is challenging and may not correlate with some key pathological events that occur in the development of glaucoma. The aims of this study were to quantify changes in ocular morphology in DBA/2J mice that develop spontaneous, age-dependent, pigmentary glaucoma and to check the possible correlation of these parameters with IOP., Method: Eye morphology was evaluated with MRI in DBA/2J, DBA/2J-Gpnmb + /SjJ, and C57BL/6J female mice ages 3, 6, 9, 12, and 15 months. The animals were anesthetized with isoflurane. A planar receive-only surface coil (inner diameter = 10 mm) was placed over each animal's left eye and the image was acquired with a 7T small animal-dedicated magnetic resonance tomograph and T2-weighted TurboRARE sequence. Ocular dimensions were manually quantitated using OsiriX software. IOP was measured with rebound tonometry., Results: In the control animals, no age-related changes in the ocular morphology were noted. Since 6 months of age, the anterior chamber deepening and elongation of the eyeballs of DBA/2J mice was detectable. We found a significant, positive correlation between IOP and axial length, anterior chamber area, or anterior chamber width in C57BL/6J mice but not in DBA/2J mice. However, after excluding the measurements performed in the oldest DBA/2J mice (i.e. analyzing only the animals ages 3 to 12 months), we demonstrated a significant positive correlation between IOP and anterior chamber width., Conclusion: High-resolution magnetic resonance imaging of the eye area in mice enables reproducible and consistent measures of key dimensions of the eyeball. We observed age-dependent alterations in the eye morphology of DBA/2J mice that mostly affected the anterior chamber. We also demonstrated a correlation between some of the ocular dimensions and the IOP of C57Bl/6J mice and DBA/2J mice with moderately advanced glaucomatous pathology., (Copyright © 2020 Fiedorowicz, Wełniak-Kamińska, Świątkiewicz, Orzeł, Chorągiewicz, Toro, Rejdak, Bogorodzki and Grieb.)

Purpose: Kynurenine aminotransferases (KATs) catalyze the synthesis of kynurenic acid (KYNA), a compound of significant biological activity. The aim of this study is to investigate the presence and distribution of KAT immunoreactivity in the healthy human cornea., Methods: Data on gene expression in human eye structures were extracted from public microarray experiments using Genevestigator software. Immunohistochemistry was conducted using polyclonal antibodies against KAT I, II, and III on sections of eight enucleated eyes from patients with choroidal melanoma., Results: Bioinformatics analysis showed that all four KAT isoforms were actively transcribed in the cornea and the conjunctiva. Immunohistochemical analysis revealed the presence of KAT I, II, and III in all examined corneal sections. The corneal endothelium showed the strongest reactivity for all three KAT isoforms. There was a slight positive staining of the corneal stroma for KAT I and II. KAT III immunoreactivity was found only in the stroma of the limbal region. In the corneal epithelium, the expression of all three KAT isoforms showed a specific pattern of the stain with fine squatter granules throughout the cytoplasm. This reactivity was more pronounced in the basal cell layers. The intermediate cell layers showed only faint immunoreactivity, and occasionally, there was no staining. KAT I, II, and III were also present in the adjacent limbal conjunctiva., Conclusions: The results indicate that kynurenine can be metabolized to KYNA in the corneal epithelium, stroma, and endothelium.

Background: Open globe injuries complicated with the presence of an intraocular foreign body constitute a vision threatening condition., Purpose: To present the results of pars plana vitrectomy in patients with intraocular foreign body., Material and Methods: Medical records of 22 patients were analyzed. Retrospective analysis of data included visual acuity, age, gender and type of injury., Results: All patients were men and the mean age was 37 years. All injuries occurred while working with a hammer. All patients were treated with pars plana vitrectomy combined with intraocular foreign body removal and internal limiting membrane peeling. The visual acuities improved in 9 cases (41%), in 13 cases (59%) the deterioration of visual acuity was observed, no eye was enucleated. In 14 eyes pars plana vitrectomy was combined with lens removal, in 14 eyes silicone oil was used as a tamponade., Conclusions: Surgical intervention with pars plana vitrectomy combined with intraocular foreign body removal and cataract extraction may preserve severely traumatized eyes and maintain or even improve vision. ocular trauma, vitrectomy, intraocular foreign body.

Targeting mechanisms that result in increased concentrations of kynurenic acid (KYNA) in the brain has been considered as a therapeutic approach for the treatment of epilepsy and certain neurodegenerative disorders. Recently, KYNA has been implicated in the effects produced by the high-fat and low-protein/carbohydrate ketogenic diet (KD) in a report demonstrating an increased production of KYNA in vitro by one of the ketone bodies, β-hydroxybutyrate, elevated by the KD. To further explore this association, brain concentrations of KYNA were compared in young (3 weeks old) and adult (8-10 weeks old) rats that were chronically exposed to the KD and regular diet. Exposure to the KD resulted in the anticipated elevations of β-hydroxybutyrate with accompanying decreases in glucose concentrations. In comparison to rats fed the regular diet, KYNA concentrations were significantly (p < 0.05) increased in the hippocampus (256 and 363% increase in young and adult rats, respectively) and in the striatum (381 and 191% increase in young and adult rats, respectively) in KD-fed rats. KD-induced increases in KYNA concentrations in young versus adult rats in the hippocampus and striatum were comparable (p > 0.05). Exposure to the KD had no effect on KYNA concentrations in the cortex of young and adult rats (p > 0.05). In summary, chronic exposure to the KD resulted in several-fold increases in KYNA concentrations in discrete brain structures in the rats. Thus, the relevant clinical question for further exploration is whether KD-induced increases in KYNA concentrations can translate into clinically significant improvements in neuropsychiatric diseases associated with KYNA hypofunction.

The kynurenine aminotransferases (KATs) KAT I and KAT II are pivotal to the synthesis of kynurenic acid (KYNA), the only known endogenous glutamate receptor antagonist and neuroprotectant. KAT I and II have been found in avian, rodent, and human retina. Expression of KAT I in Müller cell endfeet and KAT II in retinal ganglion cells has been documented. Developmental changes in KAT expression and KYNA concentration in the avian and rodent retina have also been found. Studies of retinal neurodegeneration have shown alterations in KYNA synthesis in the retina in response to retinal ganglion cell loss. In DBA/2J mice, a model of ocular hypertension, an age-dependent decrease of retinal KYNA and KATs was found. In the corpora amylacea in the human retina intensive KAT I and II immunoreactivity was demonstrated. In summary, these findings point to the potential involvement of KYNA in the mechanisms of retinal aging and neurodegeneration.