Eye Pathology Research Articles

Значение индивидуальной программы реабилитации (абилитации) для детей - инвалидов по зрению

Congenital and hereditary forms of ophthalmic pathology claim over 90 % of cases of vision disability in children. The main functional eye disorders affecting the fundamental categories of life quality of a disabled child are visual acuity and visual field impairment. Child disability is often characterized by the fact that visual defects are accompanied by musculoskeletal pathologies, hearing impairment, diseases of internal organs, and psycho-neurological impairments. The purpose of this paper is to increase the awareness of ophthalmologists in measures taken by various institutions and organizations in accordance with the individual rehabilitation or habilitation program for disabled children developed by the Bureau of the medical social expertise. Medical rehabilitation includes: rehabilitation and reconstructive therapy, prosthetics, provision of technical rehabilitation facilities depending on the child’s visual acuity and visual field state, eye pathology, and age. Psychological and pedagogic rehabilitation of disabled children includes pre-school education, general education and psychological correction. For citation: Egorova T.S. The importance value of an individual rehabilitation (habilitation) program for visually impaired children. Russian ophthalmological journal. 2018; 11 (1): 67-73. doi: 10.21516/2072-0076-2018-11-1-63-73 (In Russian).

Multimodal imaging of linear lesions in the fundus of pathologic myopic eyes with macular lesions.

To detect, using multimodal imaging, lacquer cracks (LCs) and myopic stretch lines (MSLs) in pathologic myopic eyes with macular hemorrhage (MHE) and those without. We collected 18 consecutive pathologic myopic eyes (spherical equivalent ≤ -8.0 diopters) that had presented with linear, yellowish-white lesions in the macula. We categorized the eyes into either the MHE group or the non-MHE group. All underwent fluorescein angiography (FA), near infrared autofluorescence (NIA), indocyanine green angiography (ICGA), and spectral-domain optical coherence tomography (SD-OCT). In all 18 eyes, the linear lesions were hyperfluorescent under NIA imaging, but hypofluorescent under ICGA. All ten eyes in the MHE group had LCs, and two had both LCs and MSLs. None of the eight eyes in the non-MHE group had LCs. Regarding proximity to the MHE, LCs tended to locate closer than MSLs. Incidental perforating scleral vessels were clearly visible on the tracked SD-OCT scanning line, joining the choroid beneath the border of MHE. Sample cases are illustrated using delicate photographs and explanations. NIA imaging combined with SD-OCT and ICGA can detect and differentiate early the subtle difference between the two types of linear lesions in pathological myopic eyes. Notably, MSLs were not associated with MHEs or LCs in our consecutive series.

VISUAL FIELD DEFECTS;

Objectives: To obtain and compare the exact visual status before and afterexcision of sella supra sellar tumors using the computerized perimetry as a standard measuringtools and then compare with the international studies. Background: Sella suprasellar tumorsare though not so common but affect visual acuity of patients and their quality of life drops.These tumors include pituitary adenoma commonest in the adult population, meningioma,Craniopharyngioma, astrocytic glioma, Optic nerve Glioma, Germinoma, Dermoid, Pituitarymetastases. We planned a descriptive case series study to compare the pre and post excisionvisual field defects using computerized perimetry. Study Design: Case series study. Setting:Department of Neurosurgery, Pakistan Institute of Medical Sciences, SZABMU, and Islamabad.Period: 2 years from January 2015 to December 2016. Methods: A total of 73 patients withsella suprasellar tumors were identified and enrolled. Patients between the age of 10 and55 years were selected on the basis of having sella supra sellar tumor on CT/MRI brain withcontrast. Patients whose age was less than 10 years and more than 55 years were excluded.Moreover, patients with post radiation necrosis diagnosed on MRI and MR spectroscopy brain,those operated for other eye pathology and patients with sella supra sellar SOL having comorbiditieslike diabetes mellitus, hypertension etc. were also excluded from the study. Thestudy outcome was measured in terms of comparison of visual field defects after excision ofsella suprasellar tumors using computerized perimetry. Results: The average age of patientswas 42.1 + 6.8 years ranging from 10 to 55 years. Female gender was predominant; therewere 40 (54.8%) female patients. The mean computerized perimetry was 0.65 + 0.34 LogMARbefore surgery which improved to 0.19 + 0.12 LogMAR after surgery. Overall, of the 73 cases,63 (86.4%) had improvement whereas 10 (13.6%) study cases had no improvement in thevisual field on follow-up. Conclusion: It can be concluded that after craniotomy and excisionof sella suprasellar tumors, perimetry showed improvement in the majority of the study cases.

English

Objectives: To obtain and compare the exact visual status before and afterexcision of sella supra sellar tumors using the computerized perimetry as a standard measuringtools and then compare with the international studies. Background: Sella suprasellar tumorsare though not so common but affect visual acuity of patients and their quality of life drops.These tumors include pituitary adenoma commonest in the adult population, meningioma,Craniopharyngioma, astrocytic glioma, Optic nerve Glioma, Germinoma, Dermoid, Pituitarymetastases. We planned a descriptive case series study to compare the pre and post excisionvisual field defects using computerized perimetry. Study Design: Case series study. Setting:Department of Neurosurgery, Pakistan Institute of Medical Sciences, SZABMU, and Islamabad.Period: 2 years from January 2015 to December 2016. Methods: A total of 73 patients withsella suprasellar tumors were identified and enrolled. Patients between the age of 10 and55 years were selected on the basis of having sella supra sellar tumor on CT/MRI brain withcontrast. Patients whose age was less than 10 years and more than 55 years were excluded.Moreover, patients with post radiation necrosis diagnosed on MRI and MR spectroscopy brain,those operated for other eye pathology and patients with sella supra sellar SOL having comorbiditieslike diabetes mellitus, hypertension etc. were also excluded from the study. Thestudy outcome was measured in terms of comparison of visual field defects after excision ofsella suprasellar tumors using computerized perimetry. Results: The average age of patientswas 42.1 + 6.8 years ranging from 10 to 55 years. Female gender was predominant; therewere 40 (54.8%) female patients. The mean computerized perimetry was 0.65 + 0.34 LogMARbefore surgery which improved to 0.19 + 0.12 LogMAR after surgery. Overall, of the 73 cases,63 (86.4%) had improvement whereas 10 (13.6%) study cases had no improvement in thevisual field on follow-up. Conclusion: It can be concluded that after craniotomy and excisionof sella suprasellar tumors, perimetry showed improvement in the majority of the study cases.

Efficacy of a Fatty Acids Dietary Supplement in a Polyethylene Glycol-Induced Mouse Model of Retinal Degeneration.

Current knowledge of the benefits of nutrition supplements for eye pathologies is based largely on the use of appropriate animal models, together with defined dietary supplementation. Here, C57BL6 mice were subretinally injected with polyethylene glycol (PEG)-400, an established model of retinal degeneration with a dry age-related macular degeneration (AMD)-like phenotype, an eye pathology that lacks treatment. In response to PEG-400, markers of the complement system, angiogenesis, inflammation, gliosis, and macrophage infiltration were upregulated in both retinas and retinal pigment epithelium (RPE)/choroids, whereas dietary supplementation with a mixture based on fatty acids counteracted their upregulation. Major effects include a reduction of inflammation, in both retinas and RPE/choroids, and an inhibition of macrophage infiltration in the choroid, yet not in the retina, suggesting a targeted action through the choroidal vasculature. Histological analysis revealed a thinning of the outer nuclear layer (ONL), together with dysregulation of the epithelium layer in response to PEG-400. In addition, immunohistofluorescence demonstrated Müller cell gliosis and macrophage infiltration into subretinal tissues supporting the molecular findings. Reduced ONL thickness, gliosis, and macrophage infiltration were counteracted by the diet supplement. The present data suggest that fatty acids may represent a useful form of diet supplementation to prevent or limit the progression of dry AMD.

NAP counteracts hyperglycemia/hypoxia induced retinal pigment epithelial barrier breakdown through modulation of HIFs and VEGF expression.

Diabetic macular edema (DME) is a common complication leading to a central vision loss in patients with diabetes. In this eye pathology, the hyperglycaemic/hypoxic microenvironment of pigmented epithelium is responsible for outer blood retinal barrier integrity changes. More recently, we have shown that a small peptide derived from the activity-dependent neuroprotective protein (ADNP), known as NAP, counteracts damages occurring during progression of diabetic retinopathy by modulating HIFs/VEGF pathway. Here, we have investigated for the first time the role of this peptide on outer blood retinal barrier (BRB) integrity exposed to hyperglycaemic/hypoxic insult mimicking a model in vitro of DME. To characterize NAP role on disease's pathogenesis, we have analyzed its effect on HIFs/VEGF system in human retinal pigmented epithelial cells, ARPE-19, grown in high glucose and low oxygen tension. The results have shown that NAP prevents outer BRB breakdown by reducing HIF1α/HIF2α, VEGF/VEGFRs, and increasing HIF3α expression, moreover it is able to reduce the percentage of apoptotic cells by modulating the expression of two death related genes, BAX and Bcl2. Further investigations are needed to determine the possible use of NAP in DME treatment.

Prevalence of eye pathology in a group of diabetic patients at National District Hospital Outpatient Department in Bloemfontein, South Africa.

BackgroundDiabetic retinopathy is the third most common cause of blindness after cataracts and glaucoma in South Africa. Primary healthcare interventions providing eye care services play an important role in preventing complications.AimTo determine the prevalence of eye pathology in a group of diabetic patients at National District Hospital by screening for diabetes-associated ocular pathology.SettingOutpatients Department run by Department of Family Medicine at National District Hospital in Bloemfontein from June to July 2014.MethodsInterviews were used to collect information regarding diabetic patients’ history of diabetes mellitus and if and when previous diabetic retinopathy screening was performed. Visual acuity was assessed, intra-ocular pressure measured and a non-mydriatic digital fundus camera used to screen for retinal pathology.ResultsDuring the last year, only 4.5% of patients had their vision checked with a Snellen chart, and 16.5% were examined with an ophthalmoscope. Since diagnosis of diabetes, only 15.5% of patients were referred to an ophthalmologist. Patient referral was needed for 87 (42.9%) cases for refractive disorders, 37 (18.2%) for suspected glaucoma, 30 (14.8%) for cataracts, and 22 (10.8%) for diabetic retinopathy.ConclusionThis study confirms that glaucoma, cataracts and diabetic retinopathy are prevalent eye conditions among diabetic patients. Offering eye screening at primary healthcare level may contribute to early detection of eye pathology and timeous referral for sight-saving treatment.

Cathepsin B as a potential cystatin M/E target in the mouse hair follicle

Deficiency of the cysteine protease inhibitor cystatin M/E (Cst6) in mice leads to disturbed epidermal cornification, impaired barrier function, and neonatal lethality. We report the rescue of the lethal skin phenotype of ichq (Cst6-deficient; Cst6−/−) mice by transgenic, epidermis-specific, reexpression of Cst6 under control of the human involucrin (INV) promoter. Rescued Tg(INV-Cst6)Cst6ichq/ichq mice survive the neonatal phase, but display severe eye pathology and alopecia after 4 mo. We observed keratitis and squamous metaplasia of the corneal epithelium, comparable to Cst6−/−Ctsl+/− mice, as we have reported in other studies. We found the INV promoter to be active in the hair follicle infundibulum; however, we did not observe Cst6 protein expression in the lower regions of the hair follicle in Tg(INV-Cst6)Cst6ichq/ichq mice. This result suggests that unrestricted activity of proteases is involved in disturbance of hair follicle biology, eventually leading to baldness. Using quenched activity-based probes, we identified mouse cathepsin B (CtsB), which is expressed in the lower regions of the hair follicle, as an additional target of mouse Cst6. These data suggest that Cst6 is necessary to control CtsB activity in hair follicle morphogenesis and highlight Cst6-controlled proteolytic pathways as targets for preventing hair loss.—Oortveld, M. A. W., van Vlijmen-Willems, I. M. J. J., Kersten, F. F. J., Cheng, T., Verdoes, M., van Erp, P. E. J., Verbeek, S., Reinheckel, T., Hendriks, W. J. A. J., Schalkwijk, J., Zeeuwen, P. L. J. M. Cathepsin B as a potential cystatin M/E target in the mouse hair follicle.

Idh2 deficiency accelerates renal dysfunction in aged mice

The free radical or oxidative stress theory of aging postulates that senescence is due to an accumulation of cellular oxidative damage, caused largely by reactive oxygen species (ROS) that are produced as by-products of normal metabolic processes in mitochondria. The oxidative stress may arise as a result of either increased ROS production or decreased ability to detoxify ROS. The availability of the mitochondrial NADPH pool is critical for the maintenance of the mitochondrial antioxidant system. The major enzyme responsible for generating mitochondrial NADPH is mitochondrial NADP+-dependent isocitrate dehydrogenase (IDH2). Depletion of IDH2 in mice (idh2-/-) shortens life span and accelerates the degeneration of multiple age-sensitive traits, such as hair grayness, skin pathology, and eye pathology. Among the various internal organs tested in this study, IDH2 depletion-induced acceleration of senescence was uniquely observed in the kidney. Renal function and structure were greatly deteriorated in 24-month-old idh2-/- mice compared with wild-type. In addition, disruption of redox status, which promotes oxidative damage and apoptosis, was more pronounced in idh2-/- mice. These data support a significant role for increased oxidative stress as a result of compromised mitochondrial antioxidant defenses in modulating life span in mice, and thus support the oxidative stress theory of aging.

Comparative ocular pathology and animal models used in eye research

SummaryThis lecture dealing with comparative eye pathology will present various interesting animal eyes seen from a basic anatomical point of view but also seen as a potential animal eye model used for research. Anatomical differences in different animal eyes will be presented and nature's way of solving different eye problems is discussed.

Electro-optic control of photographic imaging quality through ‘Smart Glass’ windows in optics demonstrations

An experimental setup allowing the modeling of conditions in optical devices and in the eye at various degrees of scattering such as cataract pathology in human eyes is presented. The scattering in cells of polymer-dispersed liquid crystals (PDLCs) and ‘Smart Glass’ windows is used in the modeling experiments. Both applications are used as optical obstacles placed in different positions of the optical information flow pathway either directly on the stimuli demonstration computer screen or mounted directly after the image-formation lens of a digital camera. The degree of scattering is changed continuously by applying an AC voltage of up to 30–80 V to the PDLC cell. The setup uses a camera with 14 bit depth and a 24 mm focal length lens. Light-emitting diodes and diode-pumped solid-state lasers emitting radiation of different wavelengths are used as portable small-divergence light sources in the experiments. Image formation, optical system point spread function, modulation transfer functions, and system resolution limits are determined for such sample optical systems in student optics and optometry experimental exercises.

Dopamine 2 Receptor Activation Entrains Circadian Clocks in Mouse Retinal Pigment Epithelium

Many of the physiological, cellular, and molecular rhythms that are present within the eye are under the control of circadian clocks. Experimental evidence suggests that the retinal circadian clock, or its output signals (e.g., dopamine and melatonin), may contribute to eye disease and pathology. We recently developed a retinal pigment ephithelium (RPE)-choroid preparation to monitor the circadian clock using PERIOD2 (PER2)::LUC knock-in mouse. In this study we report that dopamine, but not melatonin, is responsible for entrainment of the PER2::LUC bioluminescence rhythm in mouse RPE-choroid. Dopamine induced phase-advances of the PER2::LUC bioluminescence rhythm during the subjective day and phase-delays in the late subjective night. We found that dopamine acts exclusively through Dopamine 2 Receptors to entrain the circadian rhythm in PER2::LUC bioluminescence. Finallly, we found that DA-induced expression of core circadian clock genes Period1 and Period2 accompanied both phase advances and phase delays of the RPE-choroid clock, thus suggesting that – as in other tissues – the rapid induction of these circadian clock genes drives the resetting process. Since the RPE cells persist for the entire lifespan of an organism, we believe that RPE-choroid preparation may represent a new and unique tool to study the effects of circadian disruption during aging.

Optic Nerve Tilt, Crescent, Ovality, and Torsion in a Multi-Ethnic Cohort of Young Adults With and Without Myopia.

PurposeThe purpose of this article is to evaluate optic nerve head (ONH) characteristics in an ethnically diverse cohort of young U.S. adults.MethodsIn this study, 409 myopes and 206 nonmyopes (median age 22 years) completed measures including biometry and spectral domain optical coherence tomography from enface (ovality and torsion) and cross-sectional (tilt and crescent width) scans. Associated factors were evaluated using multivariable models.ResultsIn myopic versus nonmyopic right eyes, median tilt (6.0° vs. 2.4°; P < 0.0001) and frequency of crescents (49% vs. 10%; P < 0.0001) were higher in myopes. Right eyes with crescents had higher median tilts (8.8° [myopic], 9.0° [nonmyopic]) than those without crescent (2.5° [myopic], 2.1° [nonmyopic]), irrespective of refractive group (both P < 0.0001). Torsion was similar between groups, with a slight difference in ovality (0.89 vs. 0.91; P < 0.03). Data in the left eyes were similar, and modeling was done only for the right myopic eyes. Multivariable models showed that an increased tilt was associated with ethnicity (P < 0.001), the presence of crescent (P < 0.001), and smaller ONH diameter (P < 0.0031), with interactions between ethnicity and crescent (P = 0.002). Specifically, ONH tilt was significantly higher in Asian eyes without crescent (P < 0.0001 for all comparisons), and crescent width was associated with increased tilt in non-Asian eyes (P < 0.02). Crescent width was associated with ethnicity (greatest in Asians) and disc tilt. Interactions were observed between tilt and ethnicity, whereby tilt had a greater effect on crescent width in non-Asian eyes, and crescent width was associated with increased tilt in non-Asian eyes.ConclusionsThe data clarify the influence of ethnicity and myopia on ONH characteristics in young adults and may inform future studies of biomechanical properties or of retinal pathology of the myopic eye.

Fatigue and cognition: Pupillary responses to problem-solving in early multiple sclerosis patients.

IntroductionIn early multiple sclerosis (MS) patients, cognitive changes and fatigue are frequent and troublesome symptoms, probably related to both structural and functional brain changes. Whether there is a common cause of these symptoms in MS is unknown. In theory, an altered regulation of central neuropeptides can lead to changes in regulation of autonomic function, cognitive difficulties, and fatigue. Direct measurements of central neuropeptides are difficult to perform, but measurements of the eye pupil can be used as a reliable proxy of function.MethodsThis study assesses pupil size during problem‐solving in early MS patients versus controls. A difference in pupil size to a cognitive challenge could signal altered activity within the autonomic system because of early functional brain changes associated with cognitive load. We recruited MS patients (mean disease duration: 2.6 years, N = 41) and age‐matched healthy controls (N = 43) without eye pathology. Neurological impairment, magnetic resonance imaging, visual evoked potentials, depression, and fatigue were assessed in all of the patients. In both groups, we assessed processing speed and retinal imaging. Pupil size was recorded with an eye‐tracker during playback of multiplication tasks.ResultsBoth groups performed well on the cognitive test. The groups showed similar pupillary responses with a mean of 0.55 mm dilation in patients and 0.54 mm dilation in controls for all the tasks collapsed together. However, controls (N = 9) with low cognitive scores (LCS) had an increased pupillary response to cognitive tasks, whereas LCS MS patients (N = 6) did not (p < .05). There was a tendency toward a smaller pupillary response in patients with fatigue.ConclusionsThis is the first study to investigate pupillary responses to cognitive tasks in MS patients. Our results suggest that MS‐related changes in cognition and fatigue may be associated with changes in arousal and the autonomic regulation of task‐related pupillary responses. This supports the theory of a link between cognition and fatigue in MS.

Deep image mining for diabetic retinopathy screening.

Deep learning is quickly becoming the leading methodology for medical image analysis. Given a large medical archive, where each image is associated with a diagnosis, efficient pathology detectors or classifiers can be trained with virtually no expert knowledge about the target pathologies. However, deep learning algorithms, including the popular ConvNets, are black boxes: little is known about the local patterns analyzed by ConvNets to make a decision at the image level. A solution is proposed in this paper to create heatmaps showing which pixels in images play a role in the image-level predictions. In other words, a ConvNet trained for image-level classification can be used to detect lesions as well. A generalization of the backpropagation method is proposed in order to train ConvNets that produce high-quality heatmaps. The proposed solution is applied to diabetic retinopathy (DR) screening in a dataset of almost 90,000 fundus photographs from the 2015 Kaggle Diabetic Retinopathy competition and a private dataset of almost 110,000 photographs (e-ophtha). For the task of detecting referable DR, very good detection performance was achieved: Az=0.954 in Kaggle's dataset and Az=0.949 in e-ophtha. Performance was also evaluated at the image level and at the lesion level in the DiaretDB1 dataset, where four types of lesions are manually segmented: microaneurysms, hemorrhages, exudates and cotton-wool spots. For the task of detecting images containing these four lesion types, the proposed detector, which was trained to detect referable DR, outperforms recent algorithms trained to detect those lesions specifically, with pixel-level supervision. At the lesion level, the proposed detector outperforms heatmap generation algorithms for ConvNets. This detector is part of the Messidor® system for mobile eye pathology screening. Because it does not rely on expert knowledge or manual segmentation for detecting relevant patterns, the proposed solution is a promising image mining tool, which has the potential to discover new biomarkers in images.

Diabetes Type 4: A Paradigm Shift in the Understanding of Glaucoma, the Brain Specific Diabetes and the Candidature of Insulin as a Therapeutic Agent

In the present analysis, we aim at probing into many important mechanisms that serve to bridge conceptual gaps to fill up the mosaic of a picture revealing that glaucoma indeed is brain specific diabetes and more appropriately "Diabetes Type 4". Based on this conceptual substance, we weave a novel idea of insulin being a potential remedy for glaucoma. This analysis synthesizes upon the published literature on brain changes in glaucoma, possibility of isolated brain diabetes, insulin signaling glitches in glaucoma pathology, mitochondrial dysfunction and insulin resistance in glaucomatous eyes, insulin mediated regulation of intraocular pressure and its dysregulation in mitochondrial dysfunction. We also look into the role of amyloidopathy and taupathy in glaucoma pathogenesis vis-à-vis insulin signaling. At every step, the discussion reveals that insulin and other allied moieties are a sure promise for glaucoma treatment and management. In this article, we aim at synthesizing a persuasive and all inclusive picture of glaucoma etiopathomechanism centered on "insulin-hypofunctionality" in the central nervous system (i.e. brain specific diabetes). We start with considering the possibility of neurodegenerative diabetes that exists independent of the peripheral diabetes. Once that condition is met, then a metabolic conglomeration of this brain specific diabetes is deliberated upon leading us to understand the development of retinal ganglion cell apoptosis, intraocular pressure elevation, optic cupping and mitochondrial dysfunction. All these are the hallmarks and sufficient conditions to satisfy the diagnostic criteria for glaucoma. Immediate application of this analysis points towards glaucoma therapy centered upon improving what we have termed insulin-hypofunctionality.

Multi-channel MRI segmentation of eye structures and tumors using patient-specific features.

Retinoblastoma and uveal melanoma are fast spreading eye tumors usually diagnosed by using 2D Fundus Image Photography (Fundus) and 2D Ultrasound (US). Diagnosis and treatment planning of such diseases often require additional complementary imaging to confirm the tumor extend via 3D Magnetic Resonance Imaging (MRI). In this context, having automatic segmentations to estimate the size and the distribution of the pathological tissue would be advantageous towards tumor characterization. Until now, the alternative has been the manual delineation of eye structures, a rather time consuming and error-prone task, to be conducted in multiple MRI sequences simultaneously. This situation, and the lack of tools for accurate eye MRI analysis, reduces the interest in MRI beyond the qualitative evaluation of the optic nerve invasion and the confirmation of recurrent malignancies below calcified tumors. In this manuscript, we propose a new framework for the automatic segmentation of eye structures and ocular tumors in multi-sequence MRI. Our key contribution is the introduction of a pathological eye model from which Eye Patient-Specific Features (EPSF) can be computed. These features combine intensity and shape information of pathological tissue while embedded in healthy structures of the eye. We assess our work on a dataset of pathological patient eyes by computing the Dice Similarity Coefficient (DSC) of the sclera, the cornea, the vitreous humor, the lens and the tumor. In addition, we quantitatively show the superior performance of our pathological eye model as compared to the segmentation obtained by using a healthy model (over 4% DSC) and demonstrate the relevance of our EPSF, which improve the final segmentation regardless of the classifier employed.

Swept-source optical coherence tomography to screen for macular pathology in eyes having routine cataract surgery

To determine the incremental benefit of swept-source optical coherence tomography (SS-OCT) in identifying occult macular disease preoperatively in patients scheduled for routine cataract surgery. Shahzad Eye Hospital, Karachi, Pakistan. Prospective case series. Preoperative SS-OCT scans were performed in all patients scheduled to have cataract surgery between January and March 2016. Scans were subsequently reviewed for the presence of macular abnormalities. Patients with clinically detectable retinal pathologies were excluded. Of the 179 eligible patients, 155 were included in the study. Macular pathology was noted in 17 patients (10.9%). The most commonly identified conditions were age-related macular degeneration (n=5), idiopathic epiretinal membrane (n=4), and vitreomacular interface abnormalities (n=4). Other abnormalities included cystoid macular edema (n=2) and ellipsoid zone abnormalities (n=2). Media opacities precluded interpretation of 9 scans (4.7%). Swept-source OCT was an effective noninvasivemodality for detecting macular structural abnormalities, especially in the presence media opacities. Optical coherence tomography imaging should be considered as an adjunct toroutine dilated fundus examination for macular evaluation,particularly if premium intraocular lenses are being considered.

Visual Impairments and Mobile Touchscreen Interaction: State-of-the-Art, Causes of Visual Impairment, and Design Guidelines

ABSTRACTThis article identifies, catalogues, and discusses factors that are responsible for causing visual impairment of either a pathological or situational nature for touch and gesture input on smart mobile devices. Because the vast majority of interactions with touchscreen devices are highly visual in nature, any factor that prevents a clear, direct view of the mobile device’s screen can have potential negative implications on the effectiveness and efficiency of the interaction. This work presents the first overview of such factors, which are grouped in a catalogue of users, devices, and environments. The elements of the catalogue (e.g., psychological factors that relate to the user, or the social acceptability of mobile device use in public that relates to the social environment) are discussed in the context of current eye pathology classification from medicine and the recent literature in human–computer interaction on mobile touch and gesture input for people with visual impairments, for which a state-of-the-art survey is conducted. The goal of this work is to help systematize research on visual impairments and mobile touchscreen interaction by providing a catalogue-based view of the main causes of visual impairments affecting touch and gesture input on smart mobile devices.

Preliminary Data Regarding Decreased Catalase Specific Activity in the Tears as a Result of Environmental Stress

Oxidative stress represents the imbalance between the production of reactive oxygen species and the organism�s capacity to produce antioxidants. This phenomenon has captured lately a lot of attention, with an additional increased interest being manifested towards the relationship between psychological stress and oxidative stress. In the present study we decided to observe the changes which occur in stress environmental conditions applied to rats subjected to swimming and treadmill exercises, by focusing on a preliminary determination of (CAT) specific activity, an enzyme known to catalyse the decomposition of hydrogen peroxide into water and oxygen, and a valuable antioxidant protector, with possible implications into the dry eye pathology. Our results could suggest a possible dry eye animal model induced through stress and a possible implication of the oxidative stress markers in the occurrence of this ocular pathology, as suggested by the significant decrease in the CAT activity registered in rat tears collected after the application of environmental stressors (e.g. swimming and running) versus the control group.