Optic Nerve Disease Research Articles

Repeatability and clinical use of pupillary light reflex measurement using RAPDx® pupillometer.

To evaluate the repeatability of pupillary light reflex metrics measured by the RAPDx® dynamic pupillometer in healthy subjects and clinical application in patients with unilateral optic neuritis (ON). Sixty eyes of 30 healthy volunteers were measured three times consecutively by the same technician. The amplitude of constriction (AC), the latency of constriction (LOC), the velocity of peak constriction (VC) of light-evoked pupillary constriction, RAPD score for amplitude and latency were measured using RAPDx® dynamic pupillometer. The repeatability of above metrics was assessed by the intraclass correlation coefficient (ICC) and coefficient of variation (Cov). Furthermore, pupillary light reflex measurements were performed in 48 eyes of 24 patients diagnosed with unilateral optic neuritis (ON). Interocular symmetry was evaluated both in the healthy subjects and the ON-involved patients. High repeatability of AC, LOC, and VC in healthy subjects was displayed, presenting with the ICC value over 0.80 and the Cov less than 8.00%. But the RAPD score for amplitude (ICC: 0.67) and RAPD score for latency (ICC: 0.65) showed only moderate repeatability. Furthermore, a slight declining trend was found in amplitude and peak velocity when continuous and multiple measurements in the healthy subjects. Good symmetry of the AC, LOC, and VC of pupillary light constriction between the two eyes was displayed in the healthy subjects (P > 0.05). By contrast, there was a distinct decrease of AC and VC (P < 0.01), and a mild increase of LOC (P < 0.01) in the ON-involved eye in direct pupillary light reflex. Pupillary light reflex measured by the RAPDx® pupillometer achieved overall good repeatability and interocular symmetry in healthy subjects. The device also presented decent preliminary results in patients with unilateral ON, suggesting its potential value to be developed as a tool in optic nerve diseases.

7,8-Dihydroxyflavone alleviates apoptosis and inflammation induced by retinal ischemia-reperfusion injury via activating TrkB/Akt/NF-kB signaling pathway.

Retinal ischemia-reperfusion injury (RIRI) is of common occurrence in retinal and optic nerve diseases. The BDNF/TrkB signaling pathway has been examined to be neuroprotective in RIRI. In this study, we investigated the role of a potent selective TrkB agonist 7,8-dihydroxyfavone (DHF) in rat retinas with RIRI. Our results showed that RIRI inhibited the conversion of BDNF precursor (proBDNF) to mature BDNF (mBDNF) and increased the level of neuronal cell apoptosis. Compared with RIRI, DHF+RIRI reduced proBDNF level and at the same time increased mBDNF level. Moreover, DHF administration effectively activated TrkB signaling and and downstream Akt and Erk signaling pathways which increased nerve cell survival. The combined effects of mBDNF/proBDNF increase and TrkB signaling activation lead to reduction of apoptosis level and protection of retinas with RIRI. Moreover, it was also found that astrocytes labeled by GFAP were activated in RIRI and NF-kB mediated the increased expressions of inflammatory factors and these effects were partially reversed by DHF administration. Besides, we also used RNA sequencing to analyze the differently expressed genes (DEGs) and their enriched (Kyoto Encyclopedia of Genes and Genomes) KEGG pathways between Sham, RIRI, and DHF+RIRI. It was found that 1543 DEGs were differently expressed in RIRI and 619 DEGs were reversed in DHF+RIRI. The reversed DEGs were typically enriched in PI3K-Akt signaling pathway, Jak-STAT signaling pathway, NF-kB signaling pathway, and Apoptosis. To sum up, the DHF administration alleviated apoptosis and inflammation induced by RIRI via activating TrkB signaling pathway and may serve as a promising drug candidate for RIRI related ophthalmopathy.

Acupuncture Therapy for the Treatment of Optic Nerve Atrophy

Objective: Optical Nerve Atrophy is one of the most common causes of blindness worldwide. The condition is linked to several pathologies, which contribute to the damage of the optic nerve. The presence of a tumor on the optic nerve, improper formation of the optic nerve, glaucoma, hereditary and central nervous system diseases, and anterior ischemic optic neuropathy promote deterioration of the optic nerve. The purpose of this review is to examine the efficacy of acupuncture therapy for ONA. Method: Clinical trials (case control-trials), and randomized control trials (RCTs) were assessed to observe the efficacy of acupuncture as well as the safety of acupuncture, needling manipulation, and acupoints selection. The data collected in this research include scientific research papers from China National Knowledge Infrastructure (CNKI), PUBMED library, National Library of Medicine (NLM), EMBASE, Cochrane Library, Chinese Biomedical Literature Database, and other literature library date present. Ophthalmoscope, OCT, pupils test, ocular alignment, nystagmus, and visual acuity check were the diagnostic tools used for ONA in the included study. ONA treatment has been a challenge to ophthalmologists over the past decades. At present, western approaches have no fixed treatment mechanism for the condition. Early diagnosis, the use of magnifying lenses, and reduction of increased fluid around the spinal cord and brain are the multiple disciplinary approaches used in western medicine for ONA. On the other hand, Acupuncture, a branch of traditional Chinese medicine, which stimulates the body’s natural healing ability to promote physical and emotional well-being, has reported some significant treatment effects for ONA. Result: The overall result shows that Acupuncture greatly improved patients’ visual acuity, visual field, and visual function in the included study. Acupuncture acting alone showed significant superiority over other treatments for optical nerve atrophy. Acupuncture combined with medication could improve a patient’s condition more rapidly than medications alone. Conclusion: Optic nerve atrophy is a threatening condition to the vision, which is a leading cause of blindness worldwide. Acupuncture has improved the condition of patients with ONA more effectively than other treatment mechanisms in the included study. However, more clinical trials need to be carried out to substantiate stronger evidence of acupuncture for ONA.

An observational study of the correlation between axial length and retinal nerve fibre layer thickness in myopic eyes in a tertiary care centre in south india

Objective: To assess the correlation between axial length and retinal nerve fibre layer (RNFL) thickness in myopic eyes in a tertiary care hospital in a two-year period (August 2017 to June 2019). Methods: Institutional ethics committee approval was obtained. Written and informed consent was obtained from all the participants. One hundred eyes of 58 patients were screened. Myopic patients with > -0.50 D myopia in the age group of 18 to 40 years with intraocular pressure (IOP) <20 mm Hg were included in the study. Patients with a history of ocular trauma, glaucoma, ocular surgeries, optic nerve or macular diseases, pathological myopia, and media opacities were excluded from the study. An ophthalmic evaluation was done by assessing the visual acuity, IOP, slit-lamp examination, and perimetry using Humphrey field analyser II (Swedish interactive threshold algorithm SITATM testing strategy). After dilating the pupils with Tropicamide plus, posterior segment evaluation was done using a 90 D lens with slit lamp bio-microscopy as well as indirect ophthalmoscopy and 20 D lens. The axial length was measured using Lenstar LS 900. Optical Coherence Tomography (OCT) images were obtained using a 3 D OCT 1 Maestro machine by a single observer. Results: There was a statistically significant association between axial length and RNFL thickness in myopic eyes (P = 0.0003). As the axial length of the eyeball increases, the RNFL thickness decreases in all four quadrants except the temporal quadrant, producing a statistically significant negative correlation (r = -0.3551). Conclusion: There is a statistically significant association between axial length and RNFL thicknesses in all quadrants except the temporal quadrant. The negative correlation between axial length and RNFL thickness would be useful in avoiding misdiagnosis of glaucoma since RNFL thickness is low in both glaucoma and myopia.

Visual Function and Visual Perception among Senior Citizens with Mild Cognitive Impairment in Taiwan.

Purpose: With the benefits of advanced medical technology, Taiwan has gradually changed from an aged society to a super-aged society. According to previous studies, the prevalence rate of mild cognitive impairment (MCI) over the age of 60 is 15% to 20%. Therefore, the main purpose of our study was to analyze the correlation of cognitive function with visual function (specifically, binocular vision and visual perception) in Taiwanese volunteers aged 60 years or older. Methods: Thirty-six healthy participants who were not taking psychiatric medications and who had not been diagnosed with any retinal or optic nerve diseases were enrolled. Addenbrooke’s cognitive examination III (ACE-III), binocular visual function, and visual perception evaluation were performed, and the data analyzed statistically by t-test, χ2, linear regression, and MANOVA. Results: Cognitive function was closely correlated with visual function and visual perception; the horizontal adjustment time of binocular eye movement, stereopsis, the motor-free visual perception test-4 (MVPT-4), and peripheral awareness actually displayed higher explanatory power in predicting cognitive function. In addition, various interactive parameters between visual function and visual perception were found to affect specific aspects of ACE-III. Discussion: Our study revealed that there was a close correlation of cognitive function with visual function; as such, it may be possible to predict visual function deficits in patients with mild cognitive impairment.

Maf1 regulates axonal regeneration of retinal ganglion cells after injury

Retinal ganglion cells (RGCs) are the sole output neurons that carry visual information from the eye to the brain. Due to various retinal and optic nerve diseases, RGC somas and axons are vulnerable to damage and lose their regenerative capacity. A basic question is whether the manipulation of a key regulator of RGC survival can protect RGCs from retinal and optic nerve diseases. Here, we found that Maf1, a general transcriptional regulator, was upregulated in RGCs from embryonic stage to adulthood. We determined that the knockdown of Maf1 promoted the survival of RGCs and their axon regeneration through altering the activity of the PTEN/mTOR pathway, which could be blocked by rapamycin. We further observed that the inhibition of Maf1 prevented the retinal ganglion cell complex from thinning after optic nerve crush. These findings reveal a neuroprotective effect of knocking down Maf1 on RGC survival after injury and provide a potential therapeutic strategy for traumatic optic neuropathy.

Effect of Electrical Stimulation on Ocular Cells: A Means for Improving Ocular Tissue Engineering and Treatments of Eye Diseases.

Tissue engineering is biomedical engineering that uses suitable biochemical and physicochemical factors to assemble functional constructs that restore or improve damaged tissues. Recently, cell therapies as a subset of tissue engineering have been very promising in the treatment of ocular diseases. One of the most important biophysical factors to make this happen is noninvasive electrical stimulation (ES) to target ocular cells that may preserve vision in multiple retinal and optic nerve diseases. The science of cellular and biophysical interactions is very exciting in regenerative medicine now. Although the exact effect of ES on cells is unknown, multiple mechanisms are considered to underlie the effects of ES, including increased production of neurotrophic agents, improved cell migration, and inhibition of proinflammatory cytokines and cellular apoptosis. In this review, we highlighted the effects of ES on ocular cells, especially on the corneal, retinal, and optic nerve cells. Initially, we summarized the current literature on the in vitro and in vivo effects of ES on ocular cells and then we provided the clinical studies describing the effect of ES on ocular complications. For each area, we used some of the most impactful articles to show the important concepts and results that advanced the state of these interactions. We conclude with reflections on emerging new areas and perspectives for future development in this field.

Normative data assessment of age-related changes in macular and optic nerve head vessel density using optical coherence tomography angiography

ObjectiveTo investigate macular and optic nerve head vessel density in healthy individuals using optical coherence tomography angiography (OCTA), and determine their relationship with age. MethodThis retrospective study included 153 eyes of 153 individuals aged between 20 and 80 years, who had no systemic diseases, optic disk, or retinal pathologies. The retinal (6 × 6 mm) and optic disk (4.5 × 4.5 mm) OCTA images were evaluated for superficial capillary plexus (SCP), deep capillary plexus (DCP) and radial peripapillary capillary plexus (RPCP) vessel density, foveal avascular zone (FAZ) area, and choriocapillaris flow area and compared among 5 age groups. ResultsThe SCP vessel density was significantly associated with age for the whole image (P = 0.001), parafovea (P = 0.038), and perifovea (P/ce:italic>= 0.001). The DCP vessel density significantly varied with age in the whole image (P = 0.004), parafovea (P = 0.001), and perifovea (P = 0.002). The SCP and DCP vessel densities were significantly lower in the older age groups, and more prominently so after 50 years of age. The FAZ area increased with age; however, this finding was not statistically significant (P = 0.660). The choriocapillaris flow area decreased with age (P = 0.002). The RPCP vessel density in the inside disk significantly decreased with age (P = 0.038). ConclusionAge should be taken into consideration when using OCTA in the diagnosis and follow-up of retinal and optic nerve diseases. It is believed that the results here in can be used as a reference baseline for future studies.

Surgeon effects on cataract refractive outcomes are minimal compared with patient comorbidity and gender: an analysis of 490 987 cases

AimTo investigate effect of patient age, gender, comorbidities and surgeon on refractive outcomes following cataract surgery.MethodsStudy population: patients on UK national ophthalmic cataract database on cataract operations undertaken between 1...

Evaluation of the Relationship Between Preferential Looking Testing and Visual Evoked Potentials as a Biomarker of Cerebral Visual Impairment.

Cerebral visual impairment (CVI) is a leading cause of visual impairment in children in developed countries, but diagnostic tools to detect CVI are limited. We sought to analyze the visual acuity of children with CVI as assessed by visual evoked potentials (VEPs) and preferential looking test (PLT) to determine whether the relationship between the visual outcomes on these two testing methods may serve as a biomarker of CVI. We performed a retrospective chart review of patients with a confirmed diagnosis of CVI and at least one ophthalmological assessment with visual acuity measured by VEP and PLT. Of the 218 patients included in the study, the most common condition associated with CVI was an underlying genetic disorder (36%, 79/218). Treatment for seizures occurred in the majority of the entire cohort of patients (80%, 175/218). Ophthalmic comorbidities included retinal disease in 23 patients, optic nerve disease in 68 patients, nystagmus in 78 patients, and strabismus in 176 patients. When assessed by either VEP or PLT, visual acuity in children with CVI fell below expected norms. At initial and final presentations, VEP acuity exceeded PLT acuity by one or more octaves, and this difference was greater than expected compared with normal visual development. We propose utilizing this quantifiable disparity between VEP and PLT as a biomarker of CVI.

Quantifying inter-organelle membrane contact sites using proximity ligation assay in fixed optic nerve sections

Membrane contact sites (MCS) play crucial roles in cell physiology with dysfunction in several MCS proteins being linked with neurological and optic nerve diseases. Although there have been significant advances in imaging these interactions over the past two decades with advanced electron microscopy techniques, super-resolution imaging and proximity-dependent fluorescent reporters, a technique to observe and quantify MCS in mammalian optic nerve tissues has not yet been reported. We demonstrate for the first time that proximity ligation assay (PLA), a technique already used in mammalian cell lines, can be used as an efficient method of quantifying inter-organelle contact sites, namely mitochondria-endoplasmic reticulum (ER) and mitochondria-late-endosomes, in mammalian optic nerve tissues treated with adeno-associated virus (AAV) gene therapy with wild-type or phosphomimetic (active) protrudin. PLA utilises complementary single-stranded DNA oligomers bound to secondary antibodies that hybridise and complete a circular piece of DNA when the primary antibodies of interest interact. These interactions can be detected by amplifying the circular DNA and adding fluorescent probes. We show that PLA is a useful method that can be used to quantify MCS in optic nerve tissues. We have found that upregulation of protrudin with gene therapy significantly increases the number of mitochondria-ER and mitochondria-Rab7-late endosomes contact sites in optic nerves.

Retinal Diseases and Parkinson Disease: A Population-Based Study.

IntroductionPatients with Parkinson disease (PD) tend to have ophthalmic symptoms. Retinal diseases are associated with central nervous system diseases, especially neurodegenerative diseases. Here, we investigated the association of retinal diseases with PD, especially the temporal relationship before and after PD diagnosis.MethodsData were obtained from the National Health Insurance Research Database of Taiwan. In total, 21,845 patients with newly diagnosed PD were matched with four controls each on the basis of propensity score. This study was bidirectional. A case–control study evaluated the adjusted odds ratio (aOR) of retinal disease before PD diagnosis by using conditional logistic regression. Furthermore, a cohort study evaluated the adjusted subdistribution hazard ratio (aSHR) for new-onset retinal and optic nerve diseases after PD diagnosis by using competing risk analysis. The association between PD with optic nerve diseases and glaucoma (another common ophthalmic diseases with the consequence of retinal dysfunction) were also analyzed as reference.ResultsIn the case–control study, PD was found to be significantly comorbid with recent and remote retinal disease [recent: ≤ 5 years, aOR: 1.12, 95% confidence interval (CI): 1.03–1.23; remote: > 5 years, aOR: 1.18, 95% CI: 1.04–1.34]. No similar association was identified between optic nerve disease or glaucoma with PD. In the cohort study, patients with PD were found to have a low risk of retinal disease in short-term (≤ 5 years, aSHR: 0.81, 95% CI: 0.71–0.93) and long-term (> 5 years, aSHR: 0.82, 95% CI: 0.72–0.93) follow-up.ConclusionThe study findings demonstrated that patients with prediagnostic PD were at greater risk of retinal disease than non-PD participants, but the risk reversed afterward. Thus, retinal disease may be a premotor manifestation of PD, and there may be some possible effect of dopamine supplements on retina.

Study of the effect of anaesthesia onthecanine ultrasonographic optic nerve sheath diameter.

To investigate the effects of anaesthetic duration and serial anaesthetic events on optic nerve sheath diameter in a population of dogs without intracranial disease using point-of-care ultrasonography. Client-owned dogs requiring advanced head imaging were prospectively enrolled. Exclusion criteria included signs of elevated intracranial pressure, glaucoma and optic nerve disease. Using a transpalpebral technique, two optic nerve sheath diameter measurements were recorded for each eye at three timepoints: following premedication, after induction within 7minutes and before discontinuing isoflurane. Mixed model analysis was used to characterise optic nerve sheath diameter behaviour and investigate the effects of anaesthetic duration, bodyweight and anaesthetic protocol, age and sex. Fourteen dogs of various ages, breeds and bodyweights were enrolled. A positive linear relationship was detected between body weight and optic nerve sheath diameter. In 12 of 14 dogs, the optic nerve sheath diameter increased from measurements taken after premedication when compared to measurements taken after induction within 7minutes. In a subset of patients, measurements subsequently decreased when anaesthetic duration exceeded 120 minutes. Age, side, sex, final body temperature, blood pressure and anaesthetic protocol did not significantly affect optic nerve sheath diameter. No significant association was noted between optic nerve sheath diameter and end-tidal carbon dioxide after induction and before discontinuing isoflurane. When using point-of-care ultrasound, a transient increase in optic nerve sheath diameter occurs between premedication and within 7 minutes following induction, regardless of bodyweight. This should be taken into consideration when serial monitoring is performed.

The Influence of Mitochondrial Dynamics and Function on Retinal Ganglion Cell Susceptibility in Optic Nerve Disease.

The important roles of mitochondrial function and dysfunction in the process of neurodegeneration are widely acknowledged. Retinal ganglion cells (RGCs) appear to be a highly vulnerable neuronal cell type in the central nervous system with respect to mitochondrial dysfunction but the actual reasons for this are still incompletely understood. These cells have a unique circumstance where unmyelinated axons must bend nearly 90° to exit the eye and then cross a translaminar pressure gradient before becoming myelinated in the optic nerve. This region, the optic nerve head, contains some of the highest density of mitochondria present in these cells. Glaucoma represents a perfect storm of events occurring at this location, with a combination of changes in the translaminar pressure gradient and reassignment of the metabolic support functions of supporting glia, which appears to apply increased metabolic stress to the RGC axons leading to a failure of axonal transport mechanisms. However, RGCs themselves are also extremely sensitive to genetic mutations, particularly in genes affecting mitochondrial dynamics and mitochondrial clearance. These mutations, which systemically affect the mitochondria in every cell, often lead to an optic neuropathy as the sole pathologic defect in affected patients. This review summarizes knowledge of mitochondrial structure and function, the known energy demands of neurons in general, and places these in the context of normal and pathological characteristics of mitochondria attributed to RGCs.

Results of clinical approbation of information leaflet for patients treated with intravitreal injections of drugs

Intravitreal injection (IVI) is a drug delivery method, widely used in modern ophthalmology. To increase the awareness of patients receiving treatment in the healthcare system of the Russian Federation, the Expert Council on Retinal and Optic Nerve Diseases of the Association of Ophthalmologists, an All-Russian Public Organization in 2020 proposed a leaflet “Intravitreal injections (information for patients)”.Purpose: to conduct a clinical assessment of the leaflet by multicenter anonymous surveying of patients.Material and methods. Patients who had experienced IVI treatment were asked to read the leaflet for 20 minutes and then answer 12 questions of the specially designed questionnaire. 93 patients were interviewed in clinics in Moscow, St. Petersburg, Yekaterinburg and Novosibirsk: of these, 57 (61.3%), the average age of all patients was 63.9 years, the most common diagnosis was neovascular age-related macular degeneration (52 cases, 55.9%), the experience of previous treatment ranged from 1 to 104 months.Results. The leaflet had a positive response from the patients (91.4% of the questionnaires received “excellent” and “good” ratings), 90.3% patients reported that the information contained was fully or largely consistent with their experience of IVI treatment. The overwhelming majority of respondents (88.2%) did not experience any difficulties in reading the leaflet. At the same time, the patients revealed insufficient awareness on issues related to the treatment. Also, the patients showed insufficient awareness of issues concerning their health: only 20 (21.5%) respondents could answer all five questions of the questionnaire about the understanding of the relevant information, and 31 patients (33.3%) could answer four questions. This fact emphasizes the importance of information support for the patient.Conclusion. The clinical assessment of the leaflet “Intravitreal injections (information for patients)”, which contains brief information about what the procedure is, contraindications, preparation details, symptoms of the postoperative period that require urgent assistance, allows us to recommend the leaflet for use in the clinical healthcare practice of the Russian Federation.

An information leaflet for patients receiving treatment by intravitreal drug injections. Recommendations of the Expert Council on retinal and optic nerve diseases of the Association of Ophthalmologists, an All-Russian public organization

The widespread introduction of intravitreal drug injections into clinical practice has highlighted a number of issues to be solved, including the risk of serious complications, the treatment burden on patients and the patient’s insufficient adherence to treatment, as well as a significant effect on the healthcare cost and effort. One of the ways to resolve the issues is to increase the patients’ awareness concerning the therapy they are about to receive, which contributes to the patients’ understanding of the details of treatment and enables them to make correct decisions. The best option of presenting such information to the patient is to provide them with a written document. The Expert Council on Retinal and Optic Nerve Diseases of the All-Russian Association of Ophthalmologists has developed, approved and tested an information brochure for patients who receive intravitreal injections. It offers brief information on what the procedure is, contraindications, details of preparation, and symptoms, both common ones and those requiring emergency assistance. The paper outlines the results of the study and presents a layout of an information leaflet for patients recommended for use in the Russian Federation.

Cell Replacement Therapy for Retinal and Optic Nerve Diseases: Cell Sources, Clinical Trials and Challenges.

The aim of this review was to provide an update on the potential of cell therapies to restore or replace damaged and/or lost cells in retinal degenerative and optic nerve diseases, describing the available cell sources and the challenges involved in such treatments when these techniques are applied in real clinical practice. Sources include human fetal retinal stem cells, allogenic cadaveric human cells, adult hippocampal neural stem cells, human CNS stem cells, ciliary pigmented epithelial cells, limbal stem cells, retinal progenitor cells (RPCs), human pluripotent stem cells (PSCs) (including both human embryonic stem cells (ESCs) and human induced pluripotent stem cells (iPSCs)) and mesenchymal stem cells (MSCs). Of these, RPCs, PSCs and MSCs have already entered early-stage clinical trials since they can all differentiate into RPE, photoreceptors or ganglion cells, and have demonstrated safety, while showing some indicators of efficacy. Stem/progenitor cell therapies for retinal diseases still have some drawbacks, such as the inhibition of proliferation and/or differentiation in vitro (with the exception of RPE) and the limited long-term survival and functioning of grafts in vivo. Some other issues remain to be solved concerning the clinical translation of cell-based therapy, including (1) the ability to enrich for specific retinal subtypes; (2) cell survival; (3) cell delivery, which may need to incorporate a scaffold to induce correct cell polarization, which increases the size of the retinotomy in surgery and, therefore, the chance of severe complications; (4) the need to induce a localized retinal detachment to perform the subretinal placement of the transplanted cell; (5) the evaluation of the risk of tumor formation caused by the undifferentiated stem cells and prolific progenitor cells. Despite these challenges, stem/progenitor cells represent the most promising strategy for retinal and optic nerve disease treatment in the near future, and therapeutics assisted by gene techniques, neuroprotective compounds and artificial devices can be applied to fulfil clinical needs.

Non-invasive detection of intracranial pressure related to the optic nerve.

Intracranial pressure (ICP) is associated with a variety of diseases. Early diagnosis and the timely intervention of elevated ICP are effective means to clinically reduce the morbidity and mortality of some diseases. The detection and judgment of reduced ICP are beneficial to glaucoma doctor and neuro ophthalmologist to diagnose optic nerve disease earlier. It is important to evaluate and monitor ICP clinically. Although invasive ICP detection is the gold standard, it can have complications. Most non-invasive ICP tests are related to the optic nerve and surrounding tissues due to their anatomical characteristics. Ultrasound, magnetic resonance imaging, transcranial Doppler, papilledema on optical coherence tomography, visual evoked potential, ophthalmodynamometry, the assessment of spontaneous retinal venous pulsations, and eye-tracking have potential for application. Although none of these methods can completely replace invasive technology; however, its repeatable, low risk, high accuracy, gradually attracted people's attention. This review summarizes the non-invasive ICP detection methods related to the optic nerve and the role of the diagnosis and prognosis of neurological disorders and glaucoma. We discuss the advantages and challenges and predict possible areas of development in the future.

Intraocular epidermal growth factor concentration, axial length, and high axial myopia

PurposeVarious molecules such as dopamine have been found to be associated with axial elongation in experimental studies. Here, we examined whether intraocular EGF is associated with axial length in myopic patients.MethodsThe hospital-based investigation included patients of European descent without optic nerve, retinal, or macular diseases except for myopic maculopathy. Using aqueous humor samples collected during surgery, the EGF concentration was examined applying a cytometric bead array. High myopia was defined by an axial length of ≥ 27.0 mm.ResultsThe study included a non-highly myopic group of 11 patients (mean age, 72.9 ± 10.8 years; mean axial length, 24.3 ± 1.1 mm) and a highly myopic group of three patients (age, 81.11 ± 12.3 years; axial length, 29.5 ± 1.3 mm), with one of them having pathologic myopic maculopathy. In multivariable linear regression analysis, higher EGF concentration was correlated with the highly myopic versus non-highly myopic group (beta, 1.24; non-standardized correlation coefficient B, 6.24; 95% confidence interval (CI), 0.10,12.4;P = 0.047) after adjusting for axial length. The amount of intraocular EGF was significantly higher in the highly myopic group than in the non-highly myopic group (89.1 ± 40.8 pg versus 34.1 ± 13.2 pg; P = 0.005), and it was highest in the eye with myopic maculopathy (135 pg).ConclusionsThe intraocular amount of EGF is higher in highly myopic versus non-highly myopic eyes.

7,8-Dihydroxyflavone protects retinal ganglion cells against chronic intermittent hypoxia-induced oxidative stress damage via activation of the BDNF/TrkB signaling pathway.

Chronic intermittent hypoxia (CIH) plays a key role in the complications of obstructive sleep apnea (OSA), which is strongly associated with retinal and optic nerve diseases. Additionally, the brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling pathway plays an important protective role in neuronal injury. In the present study, we investigated the role of 7,8-dihydroxyflavone (7,8-DHF) in regulating CIH-induced injury in mice retinas and rat primary retinal ganglion cells (RGCs). C57BL/6 mice and in vitro primary RGCs were exposed to CIH or normoxia and treated with or without 7,8-DHF. The mice eyeballs or cultured cells were then taken for histochemistry, immunofluorescence or biochemistry, and the protein expression of the BDNF/TrkB signaling pathway analysis. Our results showed that CIH induced oxidative stress (OS) in in vivo and in vitro models and inhibited the conversion of BDNF precursor (pro-BDNF) to a mature form of BDNF, which increased neuronal cell apoptosis. 7,8-DHF reduced the production of reactive oxygen species (ROS) caused by CIH and effectively activated TrkB signals and downstream protein kinase B (Akt) and extracellular signal-regulated kinase (Erk) survival signaling pathways, which upregulated the expression of mature BDNF. ANA-12 (a TrkB specific inhibitor) blocked the protective effect of 7,8-DHF. In short, the activation of the BDNF/TrkB signaling pathway alleviated CIH-induced oxidative stress damage of the optic nerve and retinal ganglion cells. 7,8-DHF may serve as a promising agent for OSA related neuropathy.