COVID-19 and myopia. / Koronamyopi.

The everyday lives of children and adolescents have changed drastically during the COVID-19 pandemic. Can increased use of digital devices affect the risk of developing myopia?

Vision-related quality of life in patients with occipital stroke.

OBJECTIVES: The aim of this study was to detect visual field defects (VFDs) after occipital infarction, investigate the rate of recovery and the impact of VFD upon vision-related quality of life (QoL). MATERIALS AND METHODS: Multicenter, prospective study including patients with MRI verified acute occipital infarction (NOR-OCCIP project). Ophthalmological examination including perimetry was performed within 2 weeks and after 6 months. Vision-related QoL was assessed by the National Eye Institute Visual Function Questionnaire 25 (VFQ-25) at one and 6 months post-stroke. RESULTS: We included 76 patients, reliable perimetry results were obtained in 66 patients (87%) at a median of 8 days after admittance and VFD were found in 52 cases (79%). Evaluation of VFD after 6 months revealed improvement in 52%. Patients with VFD had significantly lower composite score in VFQ-25 at both test points (77 vs 96, P = .001 and 87 vs 97, P = .009), in nine out of eleven subscales of VFQ-25 at 1 month and seven subscales after 6 months, including mental health, dependency, near and distance activities. Milder VFD had better results on VFQ-25 modified composite score (95 vs 74, P = .002).VFD improvement was related to improved VFQ-25 modified composite score (9.6 vs 0.8, P = .018). About 10% of patients with VFD reported driving 1 month post-stroke and 38% after 6 months. CONCLUSION: VFD substantially reduces multiple aspects of vision-related QoL. Severity of VFD is related to QoL and VFD improvement results in better QoL. Neglecting visual impairment after stroke may result in deterioration of rehabilitation efforts. Driving post-stroke deserves particular attention.

Visual dysfunction in multiple sclerosis. / Synsproblemer ved multippel sklerose.

Multiple sclerosis can give rise to signs and symptoms from the entire nervous system, including visual impairments. Visual impairments often go unreported because they are not obvious to patients, which means that doctors must ask about them specifically. Regular monitoring of vision is important, however, to provide personalised rehabilitation and assistive technologies, and thereby improve patients' functioning and quality of life.

Maternal myasthenia gravis: a cause for arthrogryposis multiplex congenita.

BACKGROUND: Arthrogryposis multiplex congenita (AMC) is a condition defined as contractures in more than two joints and in multiple body areas. The principal mechanism leading to the development of AMC in utero is decreased fetal movement. OBJECTIVE: Both fetal and maternal factors can lead to this condition, including maternal myasthenia gravis (MG) which is the topic of this review. MG is an autoimmune disease in which antibodies (immunoglobulin G) are formed against acetylcholine receptors. The disease can affect both genders, but women are more prone to develop the disease in early adulthood, a phase of life when the focus of many women is often directed towards founding a family. During pregnancy, maternal antibodies are transmitted to the fetus. RESULTS: Although the child is unaffected in most cases, the constant transmission of antibodies in utero can lead to neonatal myasthenia post-partum, a transient condition characterized by hypotonia and swallowing/respiratory difficulties as well as AMC. CONCLUSION: The maternal antibody profile in mothers with MG seems to play a key role in whether the child develops AMC or not. There are also indications that there may be a relation between neonatal MG and AMC, as well as a high recurrence rate in siblings.

NMR spectroscopy of human eye tissues: a new insight into ocular biochemistry.

BACKGROUND: The human eye is a complex organ whose anatomy and functions has been described very well to date. Unfortunately, the knowledge of the biochemistry and metabolic properties of eye tissues varies. Our objective was to reveal the biochemical differences between main tissue components of human eyes. METHODS: Corneas, irises, ciliary bodies, lenses, and retinas were obtained from cadaver globes 0-1/2 hours postmortem of 6 male donors (age: 44-61 years). The metabolic profile of tissues was investigated with HR MAS 1H NMR spectroscopy. RESULTS: A total of 29 metabolites were assigned in the NMR spectra of the eye tissues. Significant differences between tissues were revealed in contents of the most distant eye-tissues, while irises and ciliary bodies showed minimal biochemical differences. ATP, acetate, choline, glutamate, lactate, myoinositol, and taurine were identified as the primary biochemical compounds responsible for differentiation of the eye tissues. CONCLUSIONS: In this study we showed for the first time the results of the analysis of the main human eye tissues with NMR spectroscopy. The biochemical contents of the selected tissues seemed to correspond to their primary anatomical and functional attributes, the way of the delivery of the nutrients, and the location of the tissues in the eye.

Impact of donor health on corneal biochemistry--an unexpected caveat from a pilot study.

BACKGROUND: To test the possibility that some chronic systemic maladies not directly related to the function of the eye may significantly and permanently disturb corneal metabolism. MATERIAL/METHODS: Contents of selected low molecular weight metabolites were compared among corneas collected from donors who died suddenly of an accident or non-poisoning suicide, or met a sudden non-accidental death from unidentified causes, or died of a chronic cardiovascular disease or of idiopathic liver cirrhosis (N=4 for each group). Corneal buttons were halved; one half was snap-frozen and stored at -80°C, and the other half was stored at +4°C in Eusol-C for 8 days and then was snap-frozen and stored at -80°C until analyzed. Metabolite contents were assessed using high-resolution magic angle spinning proton NMR spectroscopy. RESULTS: Significant between-group differences in corneal biochemical profiles were identified. Most of them were reduced or nullified by the Eusol-C storage, suggesting their link to differences in in vivo corneal environment. The corneas from donors with liver cirrhosis or cardiovascular diseases differed considerably from the remaining ones, both before and after the Eusol-C storage. CONCLUSIONS: Various chronic systemic diseases that are not directly related to the function of the eye markedly affect corneal biochemistry. Some of the alterations are likely related to a permanent aberration in corneal metabolism. A study is warranted in larger donor groups on the effect of idiopathic liver cirrhosis and cardiovascular diseases on corneal metabolism and/or a retrospective analysis of the long-term outcome of keratoplasty and other grafting procedures employing materials from these donor groups.

Metabolic profile of keratoconic cornea.

PURPOSE: To investigate the difference in metabolic profile of keratoconic and normal corneas using two different analysis methods. METHODS: Keratoconic corneas were obtained from patients (aged 19-27) during transplantation surgery. Control samples were obtained from human donors (aged 61-75) 1-8 h post-mortem. The metabolic profile of tissues was investigated with high-resolution magic angle spinning (1)H nuclear magnetic resonance (NMR) spectroscopy and high performance liquid chromatography (HPLC). RESULTS: Nine amino acids and 20 metabolites were assigned with HPLC and NMR spectroscopy, respectively. No significant biochemical difference was revealed between keratoconic and control samples, which represent distant age groups. CONCLUSIONS: It suggests that development of keratoconus might be related to the accelerated ageing of the cornea. This issue warrants further studies.

Influence of donor age, post-mortem time and cold storage on metabolic profile of human cornea.

PURPOSE: Limited knowledge exists about the influence of donor age and death-to-preservation interval (DPI) on the metabolic properties of the cornea. The aim of this study is to investigate the relationship between both factors and metabolite content of the cornea. METHODS: Corneas from 15 human donors (age: 41-78 years) were obtained within 16 hrs post-mortem and kept in cold storage for 8 days. The metabolic profiles of the samples were investigated using high-resolution, magic angle spinning (1) H nuclear magnetic resonance spectroscopy before and after 8 days of preservation. RESULTS: Twenty-two metabolites were detected and assigned in the corneal spectra. The significant metabolic differences before and after hypothermic storage were revealed between younger and older donors. DPI-related significant differences revealed before preservation of the corneas were not displayed after 8 days of cold storage. CONCLUSIONS: Age of donor as well as post-mortem time influences the biochemical properties of the cornea. Cold storage decreases the metabolite differences between the tissues collected at different post-mortem time.

Impact of organ culturing on metabolic profile of human corneas: preliminary results.

PURPOSE: It is suggested that the quality of corneal graft may depend on modifications that appear in the tissue during culturing. The aim of this study was to investigate the differences in the metabolic profile between cultured and noncultured human corneas. METHODS: Corneas from 12 donors were obtained post-mortem and cultured for 6-20 days. Control corneas were obtained from four patients with malignant melanoma of the chorioidea and were kept frozen at -80 °C until analysed. The metabolic profiles of the samples were investigated using high-resolution, magic angle spinning (1) H nuclear magnetic resonance spectroscopy and special software for: (i) analysis of complex mixtures, (ii) principal component analysis and (iii) specialized statistical analysis. RESULTS: Twenty metabolites were detected and assigned in the corneas. Significant differences in metabolic profiles between cultured and noncultured corneas were revealed. It was also shown in samples kept in culture for 9-14 days that the levels of (i) alanine, formate, lactate and (ii) acetate, alanine, arginine, lactate were elevated in comparison with the samples kept for <9 and more than 14 days, respectively. CONCLUSIONS: Corneal culturing affects the metabolic profile of the tissue. The increases in the levels of some metabolites within the second week of culturing likely result from variations in tissue metabolic or enzymatic activity caused by changed (organ culture) environment. As the mechanisms responsible for these changes are not clear, further research is indicated.

Retinal nerve fibre layer attenuation: clinical indicator for vigabatrin toxicity.

PURPOSE: To investigate whether persistent visual field defects among patients exposed once to the antiepileptic drug vigabatrin (VGB) were associated with peripapillary retinal nerve fibre layer thickness (RNFLT) attenuation. METHODS: Nine individuals with partial epilepsy and VGB-attributed visual field loss (group 1; 18 eyes) and seven age- and gender-matched individuals with epilepsy and no previous VGB exposure (group 2; 14 eyes) were included in the study. Full-field 120 point screening perimetry out to 60 degrees from central fixation using the Humphrey Field Analyzer was performed. RNFLT was quantified by optical coherence tomography (OCT) using Fast RNFLT protocol, Stratus OCT (3.0) after pupillary dilation. The results from the right eye are presented in this article. RESULTS: Among the patients with VGB-attributed visual field loss, five patients had only peripheral field defect (group 1a) and the remaining four had advanced field defects both in the periphery and within 30° from central fixation (group 1b). None of the patients in the control group had manifest visual field loss. The mean RNFLT among the patients with VGB-attributed visual field loss was significantly attenuated compared to the controls [mean total RNFLT: group 1: 75.6 ± 12.7 µm, group 2: 103.5 ± 9.7 µm, mean difference 27.9 µm, (CI 15.9-39.9; p < 0.001)]. RNFLT values classified as borderline according to normative database (Stratus OCT) occurred more frequently among individuals with VGB-attributed visual field loss than in controls (frequency in group 1: 6/9; group 2: 0/7, p = 0.011). The nasal, superior and inferior quadrants of RNFLT in individuals with VGB-attributed visual field loss were significantly attenuated, while no difference was detected in temporal quadrants compared to controls. Both individuals with peripheral and those with advanced visual field losses in the VGB group had attenuated mean total RNFLT compared to controls (p = 0.006, p = 0.002, respectively). Occurrence of borderline classification of total RNFLT ≤5th percentile was more frequent among individuals with advanced visual field loss than among controls (p = 0.048). CONCLUSION: Persistent visual field loss attributed to VGB is associated with reduced peripapillary RNFLT and was detected both among patients with advanced and among patients with only peripheral visual field defects. Measurements of RNFLT with OCT might be considered as a diagnostic supplement in the follow-up of patients exposed to vigabatrin.

Acute visual loss after spinal surgery.

PURPOSE: To report visual loss after prone spinal surgery. METHODS: Computed tomography scan, fundus photography, optical coherence tomography (OCT). RESULTS: A 56-year-old man demonstrated loss of vision in the left eye after cervical spinal surgery. Clinical examination revealed loss of vision to finger counting, severe visual field defect and blurred neural rim area around the optic disc in the left eye. Six weeks later, visual acuity in the left eye was 6/9 and there was inferior visual field defect. Six months after the surgery, significant reduction of retinal nerve fibre layer thickness around the optic nerve head was measured with OCT, consistent with the visual field defect. CONCLUSION: Ischemic optic neuropathy is the most common cause of visual loss after spine surgery and special emphasis should be given to protect the eye against possible pressure during the surgery.

Metabonomics--a new approach in ophthalmology.

Metabonomics is a new technology providing broad information about dynamic metabolic responses in living systems to pathophysiological stimuli or genetic modification. Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful methods in metabonomics; it is utilized to establish the metabolic profiles of biofluids, and is practically the only method capable of examining intact tissue samples. Experience with the application of metabonomics in eye research is still limited, yet this method provides the possibility of exploring metabolic processes in the eye in vivo. This article presents a brief background to the usefulness of metabonomics, and the possible applications of an NMR-based technique in eye research and clinical practice.

The effect of single and repeated UVB radiation on rabbit lens.

BACKGROUND: In our previous investigations, a significant cumulative effect of ultraviolet radiation (UVR) on the corneal and aqueous humour metabolic profiles was revealed. The purpose of the present study was to monitor the alterations in the rabbit lenses under the same experimental design and thereby supplement and complete prior findings. METHODS: Albino rabbit eyes were exposed to single (312 nm, 3.12 J/cm2) or repeated (312 nm, 3 x 1.04 J/cm2) UVB irradiations of the same overall doses. Lenticular samples were analysed by high resolution magic angle spinning proton nuclear magnetic resonance (HR-MAS 1H NMR) spectroscopy. Special grouping patterns between the UVB-irradiated and untreated control samples were evaluated using principal component analysis (PCA). Percentage alterations in the lenticular metabolite concentrations from UVR-B exposed rabbits were calculated relative to the levels in the control group. RESULTS: UVB irradiation of the albino rabbit lenses resulted in a significant decrease in the concentrations of antioxidants (glutathione), osmolytes (taurine, myoinositol) and amino acids (alanine), and a concomitant elevation in the contents of a sugar-related compound, sorbitol. Repeated UVR-B exposure of the rabbit eye had a stronger effect on the lenticular metabolic profile than a single irradiation of the same overall dose. CONCLUSIONS: This study reveals the cumulative effect of repeated UVB irradiations, and shows that even a 48-hour interval between subsequent UVR-B exposures is not sufficient for the healing processes to restore lenticular integrity.

Changes in aqueous humour following single or repeated UVB irradiation of rabbit cornea.

BACKGROUND: Aqueous humour is the main nutritive source for corneal and lenticular tissues, and knowledge of a possible cumulative effect of ultraviolet radiation (UVR) on its metabolic profile might be of great help in the assessment of cataract risks. By using high-resolution (1)H nuclear magnetic resonance (NMR) spectroscopy, it was possible to evaluate the effect of a single and repeated UVB radiation of the rabbit eye with the same overall dose on the aqueous humour. METHODS: Samples of aqueous humour from twenty-four albino white rabbit eyes were examined for the effects of UVB exposure (312 nm). In the first group (UVB1), four animals were irradiated with a single dose 3.12 J/cm(2) (21 minutes) of UVB radiation. The animals in the second group (UVB2, n = 4) were irradiated three times for 7 minutes every 2nd day (dose of 1.04 J/cm(2); days 1, 3, 5) to give the same overall dose (3.12 J/cm(2)). The third group (n = 4) served as an untreated control group. (1)H NMR spectra of aqueous humour from all eyes were obtained. Special grouping patterns among the tissue samples and relative percentage changes in particular metabolite concentrations were evaluated using appropriate statistical methods (multivariate analysis, Independent sample t-test). RESULTS: Significant alterations in the metabolic profile of aqueous humour from UVR-B exposed rabbit eyes and an apparent cumulative effect of repeated UVB irradiation were observed. CONCLUSIONS: Application of a Carr-Purcell-Meiboom-Gill spin echo pulse sequence was found to have a great advantage for correct analysis of the results obtained with NMR spectroscopy of aqueous humour from eyes where increase of protein level due to an inflammatory process could not be excluded.

Postnatal biochemical changes in rat lens: an important factor in cataract models.

PURPOSE: Administration of several cataractogenic agents is effective during the first 21 days of rat lens development, a period of the highest sensitivity of the tissue. Thus, cataract formation and lens maturation affect the biochemical profile of rat lens simultaneously and might be difficult to evaluate separately. The purpose of this study was to use high-resolution magic angle spinning proton nuclear magnetic resonance (HR-MAS 1H NMR) to investigate exclusively the effect of maturation on the metabolic profile of rat lens. METHODS: Albino Sprague-Dawley rats (n = 15) were divided into five groups of three animals and sacrificed at designated times (7, 14, 20, 30, and 60 days). The lenses were dissected, frozen, and thereafter analyzed with HR-MAS 1H NMR spectroscopy. Special grouping patterns among the tissue samples of different age and the relative percentage changes in particular metabolite concentrations were evaluated using appropriate statistical methods (principal components, one-way ANOVA). RESULTS: Time-dependent alterations in the metabolic profile of the rat lens tissue were dominated by a significant increase in taurine, hypo-taurine, and myoinositol concentrations at the age of 30 days. Contents of the energy metabolites and amino acids were nearly constant between the ages of 14 and 30 days, showing a significant decrease in the 60-day-old rat lenses. CONCLUSIONS: HR-MAS 1H NMR spectroscopy showed its suitability to assess the natural alterations in the metabolic profile of maturing rat lens. The results can be used in future cataract research designed to evaluate the metabolic effect of different cataractogenic agents during this postnatal period.