Post-Keratoplasty Microbial Keratitis in the Era of Lamellar Transplants-A Comprehensive Review.

Microbial keratitis in a post-transplant cornea should be considered a distinct entity from microbial keratitis in a non-transplant cornea. Firstly, the use of immunosuppressive treatments and sutures in corneal transplants changes the etiology of keratitis. Secondly, corneal transplant has an impact on corneal biomechanics and structure, which facilitates the spread of infection. Finally, the emergence of lamellar transplants has introduced a new form of keratitis known as interface keratitis. Given these factors, there is a clear need to update our understanding of and management strategies for microbial keratitis following corneal transplantation, especially in the era of lamellar transplants. To address this, a comprehensive review is provided, covering the incidence, risk factors, causes, and timing of microbial keratitis, as well as both clinical and surgical management approaches for its treatment in cases of penetrating and lamellar corneal transplants.

Safety of an Intracameral Fixed Combination for Mydriasis and Intraocular Anaesthesia During Cataract Surgery.

Purpose: To compare the safety of a standardized, commercially available intracameral combination of mydriatics and anesthetic (ICMA) with a reference topical mydriatic regimen for cataract surgery. Patients and Methods: The safety results from two international, randomized, controlled clinical studies were combined to compare ICMA at the beginning of cataract surgery (ICMA group) to the reference topical mydriatic regimen (reference group). Data were collected on ocular and systemic adverse events, corneal and anterior chamber examination, endothelial cell density, retinal thickness and visual acuity. Analysis was performed on a pooled safety set from both studies, preoperatively and up to 1 month postoperatively. Results: 342 patients received ICMA and 318 the reference topical regimen. Ocular adverse events were reported in 17.0% of patients in the ICMA group and 18.6% in the reference group. No difference was shown between groups in endothelial cell density (2208 ± 498 cells/mm2 for ICMA group versus 2241 ± 513 cells/mm2 for the reference group; p=0.547) and retinal thickness (change from baseline less than 50 µm in 94.7% versus 95.0% of patients, respectively) at 1 month postoperatively. At 1-day post-surgery, less patients in the ICMA group had moderate or severe (Grades 2 and 3) superficial punctate corneal staining (3.9% versus 7.0% for the reference group; p=0.064). Postoperatively, some ocular symptoms were also less frequently reported in the ICMA group. Best-corrected visual acuity increased in 96.0% of patients in the ICMA group and 95.8% in the reference group at 1 month. Conclusion: ICMA injection at the beginning of cataract surgery was demonstrated to be safe and may also provide perioperative and postoperative advantages over the standard topical mydriatic regimen.

Therapeutic benefit of idebenone in patients with Leber hereditary optic neuropathy: The LEROS nonrandomized controlled trial.

Leber hereditary optic neuropathy (LHON) is a mitochondrial disease leading to rapid and severe bilateral vision loss. Idebenone has been shown to be effective in stabilizing and restoring vision in patients treated within 1 year of onset of vision loss. The open-label, international, multicenter, natural history-controlled LEROS study (ClinicalTrials.gov NCT02774005) assesses the efficacy and safety of idebenone treatment (900 mg/day) in patients with LHON up to 5 years after symptom onset (N = 199) and over a treatment period of 24 months, compared to an external natural history control cohort (N = 372), matched by time since symptom onset. LEROS meets its primary endpoint and confirms the long-term efficacy of idebenone in the subacute/dynamic and chronic phases; the treatment effect varies depending on disease phase and the causative mtDNA mutation. The findings of the LEROS study will help guide the clinical management of patients with LHON.

Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans.

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Towards Uncovering the Role of Incomplete Penetrance in Maculopathies through Sequencing of 105 Disease-Associated Genes.

Inherited macular dystrophies (iMDs) are a group of genetic disorders, which affect the central region of the retina. To investigate the genetic basis of iMDs, we used single-molecule Molecular Inversion Probes to sequence 105 maculopathy-associated genes in 1352 patients diagnosed with iMDs. Within this cohort, 39.8% of patients were considered genetically explained by 460 different variants in 49 distinct genes of which 73 were novel variants, with some affecting splicing. The top five most frequent causative genes were ABCA4 (37.2%), PRPH2 (6.7%), CDHR1 (6.1%), PROM1 (4.3%) and RP1L1 (3.1%). Interestingly, variants with incomplete penetrance were revealed in almost one-third of patients considered solved (28.1%), and therefore, a proportion of patients may not be explained solely by the variants reported. This includes eight previously reported variants with incomplete penetrance in addition to CDHR1:c.783G>A and CNGB3:c.1208G>A. Notably, segregation analysis was not routinely performed for variant phasing-a limitation, which may also impact the overall diagnostic yield. The relatively high proportion of probands without any putative causal variant (60.2%) highlights the need to explore variants with incomplete penetrance, the potential modifiers of disease and the genetic overlap between iMDs and age-related macular degeneration. Our results provide valuable insights into the genetic landscape of iMDs and warrant future exploration to determine the involvement of other maculopathy genes.

Is Primary Open-Angle Glaucoma a Vascular Disease? Assessment of the Relationship between Retinal Arteriolar Morphology and Glaucoma Severity Using Adaptive Optics.

BACKGROUND: Retinal vascular abnormalities may be associated with glaucomatous damage. Adaptive optics (AO) is a new technology that enables the analysis of retinal vasculature at the cellular level in vivo. The purpose of this study was to evaluate retinal arteriolar parameters using the rtx1 adaptive optics fundus camera (AO-FC) in patients with primary open-angle glaucoma (POAG) at different stages and to investigate the relationship between these parameters and changes in spectral-domain optical coherence tomography (SD-OCT) and perimetry. METHODS: Parameters of the retinal supratemporal and infratemporal arterioles (wall thickness (WT), lumen diameter (LD), total diameter (TD), wall-to-lumen ratio (WLR), and cross-sectional area of the vascular wall (WCSA)) were analysed with the rtx1 in 111 POAG eyes, which were divided into three groups according to the severity of the disease, and 70 healthy eyes. The associations between RTX1 values and the cup-to-disk ratio, SD-OCT parameters, and visual field parameters were assessed. RESULTS: Compared with the control group, the POAG groups showed significantly smaller TD and LD values (p < 0.05) and significantly higher WLR and WT values (p < 0.05) for the supratemporal and infratemporal arterioles. TD was significantly positively correlated with the retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) (p < 0.05). LD was significantly positively correlated with the RNFL, GCC, and rim area (p < 0.05). The WLR was significantly negatively correlated with the RNFL, GCC, rim area, and MD (p < 0.05), while it was significantly positively correlated with the cup-to-disc ratio and PSD (p < 0.05). CONCLUSIONS: The results suggest that vascular dysfunction is present in POAG, even at a very early stage of glaucoma, and increases with the severity of the disease.

Clinical Application of Adaptive Optics Imaging in Diagnosis, Management, and Monitoring of Ophthalmological Diseases: A Narrative Review.

Visualization of the retinal structure is crucial for understanding the pathophysiology of ophthalmic diseases, as well as for monitoring their course and treatment effects. Until recently, evaluation of the retina at the cellular level was only possible using histological methods, because the available retinal imaging technology had insufficient resolution due to aberrations caused by the optics of the eye. Adaptive optics (AO) technology improved the resolution of optical systems to 2 µm by correcting optical wave-front aberrations, thereby revolutionizing methods for studying eye structures in vivo. Within 25 years of its first application in ophthalmology, AO has been integrated into almost all existing retinal imaging devices, such as the fundus camera (FC), scanning laser ophthalmoscopy (SLO), and optical coherence tomography (OCT). Numerous studies have evaluated individual retinal structures, such as photoreceptors, blood vessels, nerve fibers, ganglion cells, lamina cribrosa, and trabeculum. AO technology has been applied in imaging structures in healthy eyes and in various ocular diseases. This article aims to review the roles of AO imaging in the diagnosis, management, and monitoring of age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma, hypertensive retinopathy (HR), central serous chorioretinopathy (CSCR), and inherited retinal diseases (IRDs).

Retinal Photoreceptors and Microvascular Changes in the Assessment of Diabetic Retinopathy Progression: A Two-Year Follow-Up Study.

BACKGROUND: With the increasing global incidence of diabetes mellitus (DM), diabetic retinopathy (DR) has become one of the leading causes of blindness in developed countries. DR leads to changes in retinal neurons and microcirculation. Rtx1TM (Imagine Eyes, Orsay, France) is a retinal camera that allows histological visualisations of cones and retinal microcirculation throughout the DM duration. OBJECTIVE: This study aimed to analyse the cones and retinal microvascular changes in 50 diabetic individuals and 18 healthy volunteers. The patients participated in the initial visit and two follow-up appointments, one and two years after the study, beginning with Rtx1TM image acquisition, visual acuity assessment, macular OCT scans and blood measurements. RESULTS: The study revealed significant differences in the cone density, mosaic arrangement and vascular morphology between healthy and diabetic patients. The final measurements showed decreased photoreceptor and microvascular parameters in the DR group compared with the control group. Furthermore, in the 2-year follow-up, both groups' Rtx1TM-acquired morphological changes were statistically significant. CONCLUSIONS: Rtx1TM technology was successfully used as a non-invasive method of photoreceptors and retinal vasculature assessment over time in patients with diabetic retinopathy. The study revealed a trend toward more vascular morphological changes occurring over time in diabetic patients.

Successive Acanthamoeba Corneal Isolates Identified in Poland Monitored in Terms of In Vitro Dynamics.

BACKGROUND: Amoebae of the genus Acanthamoeba cause a sight-threatening infection called Acanthamoeba keratitis. It is considered a rare disease in humans but poses an increasing threat to public health worldwide, including in Poland. We present successive isolates from serious keratitis preliminary examined in terms of the identification and monitoring of, among others, the in vitro dynamics of the detected strains. METHODS: Clinical and combined laboratory methods were applied; causative agents of the keratitis were identified at the cellular and molecular levels; isolates were cultivated in an axenic liquid medium and regularly monitored. RESULTS: In a phase-contrast microscope, Acanthamoeba sp. cysts and live trophozoites from corneal samples and in vitro cultures were assessed on the cellular level. Some isolates that were tested at the molecular level were found to correspond to A. mauritanensis, A. culbertsoni, A. castellanii, genotype T4. There was variability in the amoebic strain dynamics; high viability was expressed as trofozoites' long duration ability to intense multiply. CONCLUSIONS: Some strains from keratitis under diagnosis verification and dynamics assessment showed enough adaptive capability to grow in an axenic medium, allowing them to exhibit significant thermal tolerance. In vitro monitoring that was suitable for verifying in vivo examinations, in particular, was useful to detect the strong viability and pathogenic potential of successive Acanthamoeba strains with a long duration of high dynamics.

Pupil diameter during cataract surgery after intracameral injection of the first ready-to-use combination of mydriatics and anaesthetic at the beginning of surgery in patients with a preoperative pupil diameter <6 mm.

PURPOSE: We evaluated, in a real-life setting, the effect of Mydrane® (ready-to-use combination of tropicamide, phenylephrine hydrochloride and lidocaine, injected into the anterior chamber at the beginning of cataract surgery to induce mydriasis and intraocular anaesthesia) on the pupil diameter during cataract surgery in patients with a preoperative pupil diameter <6 mm after the use of topical mydriatics. METHODS: We collected and analysed the data of 59 consecutive patients whose pupils dilated to a diameter <6 mm after the administration of mydriatic eye drops during the preoperative visit and who received Mydrane® during cataract surgery. RESULTS: In the group of 59 patients with a preoperative pupil diameter <6 mm after topical mydriatics, cataract surgery was performed in 36 patients (61.0%) using only Mydrane® to obtain mydriasis, with no additional drug or medical device. The mean pupil diameters in this group (36 of 59) during the preoperative assessment after topical mydriatics and just before capsulorhexis when Mydrane® was injected during surgery were 5.1 ± 0.74 and 6.15 ± 1.14 mm. Additional drugs were used in 23 patients (39%). In this group, the mean pupil diameters after topical mydriatics and just before capsulorhexis using Mydrane® were 4.58 ± 1.06 and 5.6 ± 1.26 mm, respectively. CONCLUSION: In a real-life setting, the mean pupil diameter achieved during cataract surgery after the intracameral injection of Mydrane® in patients with a preoperative pupil diameter <6 mm was over 1 mm larger than the mean pupil diameter after topical mydriatics, despite the trauma caused by the operation.

ASSOCIATED FACTORS AND SURGICAL OUTCOMES OF MICROCYSTOID MACULAR EDEMA AND CONE BOUQUET ABNORMALITIES IN EYES WITH EPIRETINAL MEMBRANE.

PURPOSE: To investigate the associated features and the surgical outcomes in eyes with microcystoid macular edema (MME) and cone bouquet abnormalities (CBA) undergoing epiretinal membrane peeling. METHODS: Retrospective study including patients who underwent pars plana vitrectomy for idiopathic epiretinal membrane. Factors associated with MME and CBA at baseline and their regression were identified with logistic regression models. Postoperative visual acuity was evaluated with linear mixed models from baseline to 12 months. Risk factors for new or worsened macular edema were explored with a Cox regression model. RESULTS: One hundred and eighty-seven eyes are included in this study; 30 eyes (16%) had MME and 53 eyes (28%) had CBA preoperatively. Microcystoid macular edema was associated with severe epiretinal membrane stage (odds ratio [95% confidence interval] = 3.6 [1.3-12.7], P = 0.02); CBA was inversely associated with ectopic inner foveal layer thickness (odds ratio [95% confidence interval] = 0.97 [0.97-0.99] for each 1- µ m EIFL increase, P = 0.006). Eyes with MME had worse visual acuity after epiretinal membrane peeling ( P = 0.01) and were at risk of macular edema worsening (hazard ratio [95% confidence interval] = 2.22 [1.01-5.16], P = 0.04). Older age was associated with MME persistence (odds ratio [95% confidence interval] = 2.46 [1.06-6.82] for each 10-year increase, P = 0.04). No significant associations were found for CBA. CONCLUSION: Although CBA had no prognostic consequences, MME was associated with suboptimal visual recovery and less efficient control of inflammation after surgery. Degeneration of Müller cells may have an alleged role, and further imaging and functional tests are warranted.

Regional analysis of diabetic retinopathy and co-existing social and demographic factors in the overall population of Poland.

Introduction: The aim of our study was to analyse the regional differences in diabetic retinopathy (DR) prevalence and its co-existing social and demographic factors in the overall population of Poland in the year 2017. Material and methods: Data from all levels of healthcare services at public and private institutions recorded in the National Health Fund database were evaluated. International Classification of Diseases codes were used to identify patients with type 1 and type 2 diabetes mellitus (DM) and with DR. Moran's I statistics and Spatial Autoregressive (SAR) model allowed us to understand the distribution of DR prevalence and its possible association with environmental and demographic exposures. Results: In total, 310,815 individuals with diabetic retinopathy (DR) were diagnosed in the year 2017 in Poland. Of them, 174,384 (56.11%) were women, 221,144 (71.15%) lived in urban areas, and 40,231 (12.94%) and 270,584 (87.06%) had type 1 and type 2 DM, respectively. The analysis of the SAR model showed that the significant factors for the occurrence of DR in particular counties were a higher level of average income and a higher number of ophthalmologic consultations per 10,000 adults. Conclusions: The analyses of social, demographic, and systemic factors co-existing with DR revealed that level of income and access to ophthalmologic and diabetic services are crucial in DR prevalence in Poland.

Canaloplasty - Efficacy and Safety in an 18-Month Follow Up Period, and Analysis of Outcomes in Primary Open Angle Glaucoma Pigmentary Glaucoma and Pseudoexfoliative Glaucoma.

PURPOSE: Open-angle glaucoma (OAG), accounting for 90% of all glaucoma cases, is a progressive optic nerve neuropathy. It may lead to irreversible loss of visual field and complete blindness. When conservative treatment becomes insufficient to stop OAG progression, a surgical intervention is considered. Currently, canaloplasty procedure is being introduced instead of conventional trabeculectomy for invasive OAG treatment. The aim of the study is to asses safety and efficacy of canaloplasty. METHODS: This prospective study included 67 eyes that received 360° canaloplasty with placement of a tensioning suture. Primary OAG (n = 35), secondary OAG in pseudoexfoliative syndrome (n = 13), and pigmentary glaucoma (n = 19) patients were included. Control check-ups were conducted pre-operatively and in a 18-month follow-up time. Study endpoints involved reduction in IOP values and in the number of glaucoma medications after the intervention. RESULTS: The intervention led to a significant 38% reduction in IOP value from the preoperative baseline to 18 months after the intervention. The number of medications decreased significantly by 89%. At 18 months postoperative, 79% eyes did not require any glaucoma medications. The incidence of complications after canaloplasty was low, and none of the adverse effects were vision threatening. A surgically-induced astigmatism was the most frequent complication. Pigmentary glaucoma patients were the most beneficial subgroup, with 50% reduction in IOP, the highest success rate, and 98% reduction in the number of medications used. CONCLUSION: This study proved that canaloplasty is an efficient and safe procedure in OAG eyes.

Changes in Nuclear Gene Expression Related to Mitochondrial Function Affect Extracellular Matrix, Collagens, and Focal Adhesion in Keratoconus.

Purpose: Mitochondrial DNA (mtDNA) abnormalities were previously found to be causative in the pathogenesis of various diseases. Here, comprehensive mitochondrial and nuclear sequence and transcript analyses, along with analyses of the methylation aspects of nuclear genes related to mitochondrial function, were performed in patients with keratoconus (KTCN) to evaluate their contribution to the KTCN pathogenesis. Methods: Blood mtDNA of 42 KTCN and 51 non-KTCN individuals was Sanger sequenced and analyzed along with the previously obtained corneal RNA-sequencing data of 20 KTCN and 21 non-KTCN individuals. In addition, the expression and methylation of mtDNA genes and 1223 mitochondria-related nuclear genes were evaluated. Results: The mtDNA sequence alterations detected in blood coincided with variants identified in transcripts of the matched corneal tissues. In KTCN corneas, 97 mitochondria-related genes were deregulated, including TGFB1, P4HB, and BCL2, which are involved in the extracellular matrix (ECM) organization, collagen formation, and focal adhesion pathways. No changes in the expression of mtDNA transcripts and no differentially methylated genes among the assessed mitochondrial-nuclear gene sets were found. Conclusions: The absence of corneal-specific mtDNA variants indicates that there is no direct relationship between mitochondrial sequence variability and KTCN phenotype in the studied individuals. However, the identified KTCN-specific transcriptomic alterations of the nuclear genes directly related to the mitochondria functioning point to their possible involvement in the ECM organization, collagen formation, and focal adhesion. Translational Relevance: The identification of abnormalities within nuclear genes regulating ECM formation, collagen synthesis, and/or focal adhesion may form the basis of future treatment strategies or predict the progression of corneal changes in KTCN.

First Report of a Case of Ocular Infection Caused by Purpureocillium lilacinum in Poland.

This report describes the first case of an ocular infection induced by Purpureocillium lilacinum in Poland. The patient was a 51-year-old immunocompetent contact lens user who suffered from subacute keratitis and progressive granulomatous uveitis. He underwent penetrating keratoplasty for corneal perforation, followed by cataract surgery due to rapid uveitic cataract. A few weeks later, intraocular lens removal and pars plana vitrectomy were necessary due to endophthalmitis. The patient was treated with topical, systemic, and intravitreal voriconazole with improvement; however, the visual outcome was poor. The pathogen was identified by MALDI-TOF MS.

Characterization of Ocular Surface Microbial Profiles Revealed Discrepancies between Conjunctival and Corneal Microbiota.

The ocular microbiome composition has only been partially characterized. Here, we used RNA-sequencing (RNA-Seq) data to assess microbial diversity in human corneal tissue. Additionally, conjunctival swab samples were examined to characterize ocular surface microbiota. Short RNA-Seq reads, obtained from a previous transcriptome study of 50 corneal tissues, were mapped to the human reference genome GRCh38 to remove sequences of human origin. The unmapped reads were then used for taxonomic classification by comparing them with known bacterial, archaeal, and viral sequences from public databases. The components of microbial communities were identified and characterized using both conventional microbiology and polymerase chain reaction (PCR) techniques in 36 conjunctival swabs. The majority of ocular samples examined by conventional and molecular techniques showed very similar microbial taxonomic profiles, with most of the microorganisms being classified into Proteobacteria, Firmicutes, and Actinobacteria phyla. Only 50% of conjunctival samples exhibited bacterial growth. The PCR detection provided a broader overview of positive results for conjunctival materials. The RNA-Seq assessment revealed significant variability of the corneal microbial communities, including fastidious bacteria and viruses. The use of the combined techniques allowed for a comprehensive characterization of the eye microbiome's elements, especially in aspects of microbiota diversity.

The Relation between Body Mass Index and Retinal Photoreceptor Morphology and Microvascular Changes Measured with Adaptive Optics (rtx1) High-Resolution Imaging.

BACKGROUND: Overweight and obese patients are at risk for diabetes, cardiovascular disorders, and microvascular complications. The rtx1TM (Imagine Eyes, France) is a microscope that allows near histological visualizations of cones and retinal microcirculation. OBJECTIVE: This study analysed the cones and retinal microvascular changes in a group of 47 healthy women with different BMI values. Participants were divided into 2 groups: the BMI group (28 women with BMI >/25) and the control group (19 lean women with BMI <25). RESULTS: The lumen and diameter of retinal arteries were not significantly different between groups. There were significant differences in the thickness of arteriole walls. The WLR and WCSA values differed significantly between the control and BMI groups (for WLR 0.25 ± 0.03 vs. 0.29 ± 0.03, p < 0.001; for WCSA 4136.7 ± 1140.0 vs. 5217.3 ± 944.0, respectively, p < 0.001). In healthy eyes, cone density and morphology were not affected by weight. CONCLUSIONS: Retinal image analysis with rtx1 offers a novel noninvasive measurement of early changes in retinal vasculature that are not detectable during routine clinical examination. Abnormalities of retinal arterioles found by rtx1™examination should be considered as a strong risk factor for cardiovascular changes resulting from overweight and obesity.

Neuroprotective Factors of the Retina and Their Role in Promoting Survival of Retinal Ganglion Cells: A Review.

Retinal ganglion cells (RGCs) play a crucial role in the visual pathway. As their axons form the optic nerve, apoptosis of these cells causes neurodegenerative vision loss. RGC death could be triggered by increased intraocular pressure, advanced glycation end products, or mitochondrial dysfunction. In this review, we summarize the role of some neuroprotective factors in RGC injury: ciliary neurotrophic factor (CNTF), nerve growth factor (NGF), brain-derived neurotrophic factor, vascular endothelial growth factor, pigment epithelium-derived factor, glial cell line-derived neurotrophic factor, and Norrin. Each, in their own unique way, prevents RGC damage caused by glaucoma, ocular hypertension, ischemic neuropathy, and even oxygen-induced retinopathy. These factors are produced mainly by neurons, leukocytes, glial cells, and epithelial cells. Neuroprotective factors act via various signaling pathways, including JAK/STAT, MAPK, TrkA, and TrkB, which promotes RGC survival. Many attempts have been made to develop therapeutic strategies using these factors. There are ongoing clinical trials with CNTF and NGF, but they have not yet been accepted for clinical use.

Common ALDH3A1 Gene Variant Associated with Keratoconus Risk in the Polish Population.

BACKGROUND: ALDH3A1 protein is important in maintaining corneal physiology and protecting the eye from UV damage. However, none of the genome-wide association studies has indicated that the ALDH3A1 locus is associated with keratoconus. In this study, we examined the potential role of ALDH3A1 variants as risk factors for keratoconus incidence and severity in a large group of Polish keratoconus patients. METHODS: In the first stage we analyzed the coding region sequence of the ALDH3A1 in a subgroup of keratoconus. Then, we genotyped three selected ALDH3A1 variants in a larger KC group of patients (n = 261) and healthy controls (n = 317). RESULTS: We found that the rs1042183 minor allele A is a risk factor for keratoconus in the dominant model (OR = 2.06, 95%CI = 1.42-2.98, p = 0.00013). The rs2228100 variant genotypes appear to be associated with an earlier age of KC diagnosis in the Polish population (p = 0.055 for comparison of three genotypes and p = 0.022 for the dominant inheritance model). CONCLUSIONS: The rs1042183 variant in ALDH3A1 is associated with keratoconus risk in the Polish population. The differences in the allele frequency between both populations could be partially responsible for the difference in the disease prevalence.

High expression of Matrix Gla Protein in Schnyder corneal dystrophy patients points to an active role of vitamin K in corneal health.

PURPOSE: Schnyder corneal dystrophy (SCD) is a rare autosomal dominant disorder characterized by corneal lipid accumulation and caused by UBIAD1 pathogenic variants. UBIAD1 encodes a vitamin K (VK) biosynthetic enzyme. To assess the corneal and vascular VK status in SCD patients, we focused on matrix Gla protein (MGP), a VK-dependent protein. METHODS: Conformation-specific immunostainings of different MGP maturation forms were performed on corneal sections and primary keratocytes from corneal buttons of two SCD patients with UBIAD1 p.Asp112Asn and p.Asn102Ser pathogenic variants and unrelated donors. Native or UBIAD1-transfected keratocytes were used for gene expression analysis. Plasma samples from SCD patients (n = 12) and control individuals (n = 117) were subjected for inactive desphospho-uncarboxylated MGP level measurements with an ELISA assay. RESULTS: Substantial amounts of MGP were identified in human cornea and most of it in its fully matured and active form. The level of mature MGP did not differ between SCD and control corneas. In primary keratocytes from SCD patients, a highly increased MGP expression and presence of immature MGP forms were detected. Significantly elevated plasma concentration of inactive MGP was found in SCD patients. CONCLUSION: High amount of MGP and the predominance of mature MGP forms in human cornea indicate that VK metabolism is active in the visual system. Availability of MGP seems of vital importance for a healthy cornea and may be related to protection against corneal calcification. Systemic MGP findings reveal a poor vascular VK status in SCD patients and indicate that SCD may lead to cardiovascular consequences.