Eye and Brain最新文献

Purpose: The retina has potential as a biomarker of brain health and Alzheimer's disease (AD) because it is the only part of the central nervous system which can be easily imaged and has advantages over brain imaging technologies. Few studies have compared retinal and brain measurements in a middle-aged sample. The objective of our study was to investigate whether retinal neuronal measurements were associated with structural brain measurements in a middle-aged population-based cohort.

Participants and methods: Participants were members of the Dunedin Multidisciplinary Health and Development Study (n=1037; a longitudinal cohort followed from birth and at ages 3, 5, 7, 9, 11, 13, 15, 18, 21, 26, 32, 38, and most recently at age 45, when 94% of the living Study members participated). Retinal nerve fibre layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) thickness were measured by optical coherence tomography (OCT). Brain age gap estimate (brainAGE), cortical surface area, cortical thickness, subcortical grey matter volumes, white matter hyperintensities, were measured by magnetic resonance imaging (MRI).

Results: Participants with both MRI and OCT data were included in the analysis (RNFL n=828, female n=413 [49.9%], male n=415 [50.1%]; GC-IPL n=825, female n=413 [50.1%], male n=412 [49.9%]). Thinner retinal neuronal layers were associated with older brain age, smaller cortical surface area, thinner average cortex, smaller subcortical grey matter volumes, and increased volume of white matter hyperintensities.

Conclusion: These findings provide evidence that the retinal neuronal layers reflect differences in midlife structural brain integrity consistent with increased risk for later AD, supporting the proposition that the retina may be an early biomarker of brain health.

Ocular myasthenia gravis (OMG) is a neuromuscular disease characterized by autoantibody production against post-synaptic proteins in the neuromuscular junction. The pathophysiological auto-immune mechanisms of myasthenia are diverse, and this is governed primarily by the type of autoantibody production. The diagnosis of OMG relies mainly on clinical assessment, the use of serological antibody assays for acetylcholine receptors (AchR), muscle-specific tyrosine kinase (MusK), and low-density lipoprotein 4 (LPR4). Other autoantibodies against post-synaptic proteins, such as cortactin and agrin, have been detected; however, their diagnostic value and pathogenic effect are not yet clearly defined. Clinical tests such as the ice test and electrophysiologic tests, particularly single-fiber electromyography, have a valuable role in diagnosis. The treatment of OMG is primarily through cholinesterase inhibitors (pyridostigmine), and steroids are frequently required in cases of ophthalmoplegia. Other immunosuppressive therapies include antimetabolites (azathioprine, mycophenolate mofetil, methotrexate) and biological agents such as B-cell depleting agents (Rituximab) and complement inhibitors (eculizumab). Evidence is scarce on the effect of immunosuppressive therapy on altering the natural course of OMG. Clinicians must be vigilant of a myasthenic syndrome in patients using immune-check inhibitors. Reliable and consistent biomarkers are required to assess disease severity and response to therapy to optimize the management of OMG. The purpose of this review is to summarize the current trends and the latest developments in diagnosing and treating OMG.

Horner's syndrome (HS) is caused by a damage to the oculosympathetic pathway. HS may be congenital, but it is usually acquired and may reveal a life-threatening condition. According to the anatomic location of the underlying pathologic process, HS is classified as central, pre- or postganglionic, when the lesion affects the first, second or third-order neuron, respectively. Pharmacological testing, if available, can be used to differentiate HS from « pseudo-HS » in patients with mild symptoms. Given the financial burden that imaging of the entire oculosympathetic pathway represents, a targeted imaging approach is advised. Although in the majority of cases, clinical examination may predict etiology, in other cases pharmacological testing can help in the localization process. We searched PubMed data base for papers published before December 2022 that concerned Horner's syndrome, its neuro-ophthalmological manifestations and diagnosis. In this article, we describe the main neuro-ophthalmological manifestations of the three types of HS, the most common etiologies, and a targeted diagnostic strategy in each type.

Pineal germinomas can be very complex in terms of presentation, diagnosis, and management. This review attempts to simplify this complexity in an organized manner, addressing the anatomic relationships that provide the basis for the uniqueness of pineal germinoma. Ocular findings and signs and symptoms of elevated intracranial pressure are the keys to suspecting the diagnosis and obtaining the necessary imaging and cerebrospinal fluid studies. Other symptoms can suggest spread beyond the pineal region. Surgery may only be needed to obtain tissue for a definitive diagnosis, as germinoma is highly responsive to chemotherapy and focused radiation therapy. Hydrocephalus, usually related to tumor obstruction of the cerebral aqueduct, may also need to be addressed. Outcome for pineal germinoma is usually excellent, but relapse can occur and may require additional intervention. These issues are detailed in this review.

Purpose: To identify ophthalmic findings in Alzheimer's type dementia (ATD) compared to normal subjects.

Patients and methods: This comparative descriptive study included participants from the institution's cognitive fitness center. Complete ophthalmic examinations were performed. Optical coherence tomography (OCT) and OCT angiography (OCTA) were used to analyze retinal thickness and vascular density. The Ocular Surface Disease Index (OSDI) score and tear breakup time (TBUT) were used to assess dry eye. The blink rate was counted by a well-trained observer. Cognitive function was evaluated using the Thai Mental State Examination (TMSE) score. Correlation analysis was performed to compare OCT, OCTA parameters, and TMSE.

Results: We included 24 ATD patients and 39 normal participants as a control group by age and sex-matched. The prevalence of dry eye using the Asia Dry Eye Society criteria was 15% and 13% in normal and ATD patients, respectively. The differences in OSDI scores, TBUT, and blink rate between the two groups were not statistically significant. The parafoveal and perifoveal macular thickness of the ATD group were significantly lower than that of the control group (p<0.01). All parameters of the vessel density of the ATD group were significantly lower than in the control group, including the whole macular vessel density (p<0.01), optic disc vessel density at the nerve head level (p<0.01), and optic disc vessel density at the radial peripapillary capillary level (p<0.05). After age adjustment, there were no statistically significant differences in all the OCT and OCTA parameters. There was a positive correlation between retinal thickness and vessel density in the macular and optic disc region and TMSE scores.

Conclusion: Perifoveal and parafoveal retinal thickness might be more sensitive than peripapillary RNFL thickness to detect neurodegenerative changes in patients with ATD. Macular thickness and vessel density reduction were also positively correlated with cognitive decline.

Glaucoma is one of the main causes of irreversible blindness in the world. The most common form, primary open-angle glaucoma, is an optic neuropathy that is characterized by a progressive loss of retinal ganglion cells and their axons, leading to structural changes in the optic nerve head and associated visual field defects. Elevated intraocular pressure remains the most important modifiable risk factor for primary open-angle glaucoma. However, a significant proportion of patients develop glaucomatous damage in the absence of increased intraocular pressure, a condition known as normal-tension glaucoma (NTG). The pathophysiology underlying NTG remains unclear. Several studies have revealed that vascular and cerebrospinal fluid (CSF) factors may play significant roles in the development of NTG. Vascular failure caused by functional or structural abnormalities, and compartmentation of the optic nerve subarachnoid space with disturbed CSF dynamics have been shown to be associated with NTG. In the present article, based on the concept of the glymphatic system and observations in patients with NTG, we hypothesize that failure of fluid transport via the glymphatic pathway in the optic nerve may be involved in the pathogenesis of some if not many cases of NTG. According to this hypothesis, vascular and CSF factors may share reduced glymphatic transport and perivascular waste clearance in the optic nerve as a final common pathway leading to the development of NTG. In addition, we speculate that some cases of NTG may reflect glymphatic dysfunction in natural brain aging and central nervous system diseases, such as Alzheimer's disease. Clearly, further studies are needed to gain additional insight into the relative contribution of these factors and conditions to reduced glymphatic transport in the optic nerve.

Purpose: We improve pupillary responses and diagnostic performance of flicker pupil perimetry through alterations in global and local color contrast and luminance contrast in adult patients suffering from visual field defects due to cerebral visual impairment (CVI).

Methods: Two experiments were conducted on patients with CVI (Experiment 1: 19 subjects, age M and SD 57.9 ± 14.0; Experiment 2: 16 subjects, age M and SD 57.3 ± 14.7) suffering from absolute homonymous visual field (VF) defects. We altered global color contrast (stimuli consisted of white, yellow, cyan and yellow-equiluminant-to-cyan colored wedges) in Experiment 1, and we manipulated luminance and local color contrast with bright and dark yellow and multicolor wedges in a 2-by-2 design in Experiment 2. Stimuli consecutively flickered across 44 stimulus locations within the inner 60 degrees of the VF and were offset to a contrasting (opponency colored) dark background. Pupil perimetry results were compared to standard automated perimetry (SAP) to assess diagnostic accuracy.

Results: A bright stimulus with global color contrast using yellow (p= 0.009) or white (p= 0.006) evoked strongest pupillary responses as opposed to stimuli containing local color contrast and lower brightness. Diagnostic accuracy, however, was similar across global color contrast conditions in Experiment 1 (p= 0.27) and decreased when local color contrast and less luminance contrast was introduced in Experiment 2 (p= 0.02). The bright yellow condition resulted in highest performance (AUC M = 0.85 ± 0.10, Mdn = 0.85).

Conclusion: Pupillary responses and pupil perimetry's diagnostic accuracy both benefit from high luminance contrast and global but not local color contrast.

Purpose: To investigate the impact of attention orientation in young myopic adults with astigmatism.

Methods: The effect of attention on foveal meridional performance and anisotropy was measured in corrected myopes with various levels of astigmatism (with-the-rule astigmatism ≤ -0.75D, Axis: 180 ± 20) using orientation-based attention. Attention was manipulated by instructing subjects to attend to either the horizontal or the vertical line of a central pre-stimulus (a pulsed cross) along separate blocks of trials. For each attention condition, meridional acuity and reaction times were measured via an annulus Gabor target situated remotely from the cross and presented at random horizontally and vertically in a two-alternative forced-choice employing two interleaved staircase procedures (one-up/one-down). Attention modulations were estimated by the difference in performance between horizontal and vertical attention.

Results: Foveal meridional performance and anisotropy were strongly affected by the orientation of attention, which appeared critical for the enhancement of reaction times and resolution. Under congruent orienting of attention, foveal meridional anisotropy was correlated with the amount of defocus for both reaction time and resolution, demonstrating greater vertical performance than horizontal performance as myopia increased. Compatible with an attentional compensation of blur through optimal orienting of attention, vertical attention enhanced reaction times compared to horizontal attention and was accompanied by an increase in overall acuity when myopia increased. Increased astigmatism was associated with smaller attention effects and asymmetry, suggesting potential deficits in the compensation of blur in astigmatic eyes.

Conclusion: Collectively, attention to orientation plays a significant role in horizontal-vertical foveal meridional anisotropy and can modulate the asymmetry of foveal perception imposed by the optics of the eye in episodes of uncorrected vision. Further work is necessary to understand how attention and refractive errors interact during visual development. These results may have practical implications for methods to enhance vision with attention training in myopic astigmats.

Purpose: Prenatal growth restriction is associated with impaired neurodevelopment in childhood. This study investigated the effects of being born small for gestational age (SGA) on peripapillary retinal nerve fiber layer (pRNFL) thickness in adults born at term.

Methods: A retrospective cohort study was conducted with a prospective ophthalmologic examination of participants born at full-term (gestational age ≥37 weeks) between 1969 and 2002. All participants were examined with spectral-domain optical coherence tomography and grouped according to their birth weight in correlation to gestational age as former moderate (birth weight (BW) percentile 3rd to <10th) and severe SGA (<3rd percentile), normal (10th-90th percentile, AGA), and moderately (>90th to 97th percentile) and severely (>97th percentile) large for gestational age (LGA) adults (18 to 52 years).

Results: Overall, 547 eyes of 285 individuals (age 29.9±9.4 years, 151 females) born at term were included. Multivariable regression analyses revealed a strong association between a lower global pRNFL thickness in the severe SGA (B=-8.99 [95%-CI: -12.68; -5.30] µm; p<0.001) and in the moderate SGA groups (B=-6.40 [95%-CI: -10.29; -2.50] µm; p=0.001) compared to the reference AGA group.

Conclusion: Our results indicate that restricted fetal growth affects neurologic tissue development of the optic nerve head, particularly in individuals born severely SGA at term. This indicates that fetal growth restriction may exert disturbances in the development of neurologic tissue, which persists in adulthood.

Background: Ultrasonographic measurement of optic nerve sheath diameter is a simple, non-invasive, and reliable method of detecting elevated intracranial pressure (ICP) in critical patients. Optic nerve sheath communicates with the dura mater covering the brain and contains cerebrospinal fluid, allowing pressure transmission from the cranium. Therefore, changes in cerebrospinal fluid (CSF) pressure have been shown to produce changes in ONSD.

Objective: This study aimed to assess the accuracy of optic nerve sheath diameter (ONSD) in diagnosis and follow-up patients with disturbed conscious levels compared with CT brain and fundus examination.

Patients and methods: One hundred forty-one participants were included in the study, classified into 76 cases admitted with disturbed conscious levels due to elevated ICP and 65 controls. All patients were subjected to CT brain and optic nerve US and fundus examination at the time of admission and follow-up after 48 h after proper management.

Results: The current study showed that ONSD is significant in predicting elevated ICP at the cut-off point of average ONSD of 5.19 mm with 97% sensitivity and 98% specificity, and the area under the curve (AUC) was 0.996. The present study revealed a significant inverse correlation between ONSD and GCS in patients with increased ICP.

Conclusion: Ultrasonic measurement of ONSD is a promising technique in diagnosing and following patients with disturbed conscious levels.