Perception of first-order grating acuity and second-order spatial contrast sensitivity in anisometropia amblyopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To study the perception of first-order grating acuity and second-order spatial contrast sensitivity in patients with monocular anisometropia amblyopia.METHODS:A total of 715 children(715 eyes)diagnosed as monocular anisometropia amblyopia in our hospital from January 2018 to December 2022 were collected as amblyopia group, and 745 children(745 eyes)with normal corrected visual acuity were collected. The best corrected visual acuity(BCVA), first-order grating acuity and/or second-order spatial contrast sensitivity were measured, repectively. The perception ability of amblyopia patients to first-order grating acuity and second-order spatial contrast sensitivity were analyzed.RESULTS:There were significant differences between amblyopia group and normal control group in the perception of first-order grating acuity(11.58±6.10 vs. 20.27±3.47, P<0.001)and second-order spatial contrast sensitivity(0.33±0.16 vs 0.12±0.04, P<0.001). And there were significant differences between mild-to-moderate amblyopia and severe amblyopia patients in first-order grating acuity(12.10±6.23 vs. 8.13±3.70, P<0.001)and second-order spatial contrast sensitivity(0.32±0.16 vs. 0.37±0.17, P<0.05).CONCLUSION: The first-order and second-order visual pathway of the cerebral cortex in children with monocular anisometropia amblyopia have different degrees of damage. The injury of severe amblyopia is more serious than that of mild-to-moderate amblyopia.

Objective Assessment of Visual Field Defects Caused by Optic Chiasm and Its Posterior Visual Pathway Injury / 法医学杂志

OBJECTIVES@#To investigate the characteristics and objective assessment method of visual field defects caused by optic chiasm and its posterior visual pathway injury.@*METHODS@#Typical cases of visual field defects caused by injuries to the optic chiasm, optic tracts, optic radiations, and visual cortex were selected. Visual field examinations, visual evoked potential (VEP) and multifocal visual evolved potential (mfVEP) measurements, craniocerebral CT/MRI, and retinal optical coherence tomography (OCT) were performed, respectively, and the aforementioned visual electrophysiological and neuroimaging indicators were analyzed comprehensively.@*RESULTS@#The electrophysiological manifestations of visual field defects caused by optic chiasm injuries were bitemporal hemianopsia mfVEP abnormalities. The visual field defects caused by optic tract, optic radiation, and visual cortex injuries were all manifested homonymous hemianopsia mfVEP abnormalities contralateral to the lesion. Mild relative afferent pupil disorder (RAPD) and characteristic optic nerve atrophy were observed in hemianopsia patients with optic tract injuries, but not in patients with optic radiation or visual cortex injuries. Neuroimaging could provide morphological evidence of damages to the optic chiasm and its posterior visual pathway.@*CONCLUSIONS@#Visual field defects caused by optic chiasm, optic tract, optic radiation, and visual cortex injuries have their respective characteristics. The combined application of mfVEP and static visual field measurements, in combination with neuroimaging, can maximize the assessment of the location and degree of visual pathway damage, providing an effective scheme for the identification of such injuries.

Effects of Acupuncture on Functional Connectivity Changes of What Visual Pathway in the Brain in Children with Monocular Refractive Amblyopia / 中医杂志

ObjectiveTo explore the efficacy of acupuncture intervention for children with monocular refractive-parallax amblyopia and the possible mechanisms of brain function based on resting-state functional magnetic resonance （rs-fMRI）. MethodsSeventy-six children with anisometropic amblyopia were randomly divided into routine treatment group （38 cases） and acupuncture treatment group （38 cases）. In the conventional group， the children were given three regular treatments of red flash， grating and visual stimulation for 5 mins each time； in the acupuncture group， on the basis of the conventional treatment， the children were given acupuncture for 20 mins each time on bilateral Jingming （BL 1）， Cuanzhu （BL 2）， Guangming （GB 37） and Fengchi （GB 20）； the children in both groups were treated once every other day and three times a week for 4 weeks. The corrected visual acuity was compared between groups before and after treatment. Fifteen children with left-sided refractive amblyopia were randomly selected from each of the above two groups and underwent brain rs-fMRI scans before and after treatment， and 10 healthy children with normal visual acuity of the matched gender and age were included in the normal group and underwent brain rs-fMRI scans. Based on the activation likelihood estimation （ALE） method， we constructed the what visual pathway network， and compared and analyzed the spherical regions of interest （ROIs） of the children with normal children， and both groups of children with differences in functional connectivity （FC values） within the what pathway in the brain before and after treatment. ResultsTwo cases dropout in the acupuncture group， and finally 36 cases in the acupuncture group and 38 cases in the conventional group were included in the analysis. Compared with before treatment， the best corrected visual acuity of amblyopia in both groups was significantly improved after treatment （P＜0.05）， and the improvement of vision in the acupuncture group was significantly better than that in the conventional group （P＜0.05）. The results of rs-fMRI showed that the FC values of the primary optic cortex and the right fusiform gyrus， the left lingual gyrus and the right fusiform gyrus， and the right infraoccipital gyrus and the right middle temporal gyrus were significantly elevated in the brain of the refractive amblyopia children with the whitepathic amblyopia， compared with that of the normal children （P＜0.05）. The FC values of the left lingual gyrus， the right suboccipital gyrus with the right fusiform gyrus， the left lingual gyrus with the right middle temporal gyrus， the right and left lateral middle occipital gyrus， and the right and left lateral middle occipital gyrus with the right suboccipital gyrus were significantly （P＜0.05） lower in the conventional group compared with those in the conventional group before treatment. Compared with that before acupuncture treatment， the FC values of the right lingual gyrus and the right fusiform gyrus， the primary visual cortex and the right middle temporal gyrus increased significantly after acupuncture treatment （P＜0.05）， and the FC values of the left inferior occipital gyrus and the right middle temporal gyrus， the FC values of the left lingual gyrus and the right middle occipital gyrus decreased significantly （P＜0.05）. Compared between groups after treatment， the FC between the left suboccipital gyrus and the right fusiform gyrus in the acupuncture group was significantly higher than that in the conventional group （P＜0.05）， and the FC between the left middle occipital gyrus and the right and left suboccipital gyrus was significantly lower than that in the conventional group （P＜0.05）. ConclusionAcupuncture can significantly improve the corrected vision of anisometropic amblyopic children， and its effect mechanism may focus on regulating the occipito-temporal interlobular functional connectivity within the what pathway， thus improving the children's visual function of shape and color vision and visual learning and memory ability.

Caracterización de las lesiones compresivas de la vía visualanterior / Characterization of Compressive Lesions of the Anterior VisualPathway

Objetivo: Determinar las características clínico-epidemiológicas de los pacientes diagnosticados con lesiones compresivas de la vía visual anterior. Métodos: Se realizó un estudio descriptivo transversal durante el período comprendido entre mayo de 2018 y marzo de 2020 con 41 pacientes con diagnóstico de síndrome compresivo de la vía visual anterior atendidos en el Servicio de Neuroftalmología del Instituto Cubano de Oftalmología "Ramón Pando Ferrer". Resultados: La mayor frecuencia en cuanto a síntomas fue la disminución progresiva de la visión central. Se encontraron lesiones de tipo tumoral en 39 pacientes para el 95,1 por ciento. Los defectos hemianópticos se detectaron en el campo visual del 45 por ciento de la muestra y el 33 por ciento presentó disminución difusa de la sensibilidad retiniana. Conclusiones: La mayoría de los pacientes fueron del sexo femenino en edades medias de la vida. Predominaron las lesiones tumorales sobre las vasculares. Los macroadenomas de hipófisis y los meningiomas fueron las etiologías más frecuentes y el sitio de compresión más encontrado fue el quiasma óptico. Se detectó disminución del grosor del complejo de células ganglionares maculares en la tomografía de coherencia óptica de la mayoría de los enfermos(AU)

Objective: To determine the clinical-epidemiological characteristics of patients diagnosed with compressive lesions of the anterior visual pathway. Methods: A cross-sectional descriptive study was conducted during the period from May 2018 to March 2020 with 41 patients diagnosed with compressive syndrome of the anterior visual pathway attended at the Neurophthalmology Service of the Cuban Institute of Ophthalmology "Ramón Pando Ferrer". Results: The most frequent symptom was the progressive decrease of central vision. Tumor type lesions were found in 39 patients for 95.1 percent. Hemianoptic defects were detected in the visual field of 45 percent of the sample and 33 percent presented diffuse decrease of retinal sensitivity. Conclusions: The majority of patients were female at middle ages of life. Tumor lesions predominated over vascular lesions. Pituitary macroadenomas and meningiomas were the most frequent etiologies and the most frequent site of compression was the optic chiasm. Decreased thickness of the macular ganglion cell complex was detected in the optical coherence tomography of most of the patients(AU)

Aneurisma de la arteria carótida interna como lesión compresiva de la vía visual / Internal carotid artery aneurysm as a compressive lesion of the visual pathway

El diagnóstico temprano de las lesiones compresivas del nervio óptico adquiere cada vez mayor importancia. La descompresión precoz de este o del quiasma puede resultar una mejora significativa de la función visual, mientras que el diagnóstico erróneo puede ocasionar pérdida visual irreversible, disfunción neurológica o la muerte. Las causas de la compresión de la vía visual anterior son increíblemente variadas. Los meningiomas, los tumores hipofisarios y los aneurismas son las lesiones comúnmente más identificadas como causa de neuropatía óptica compresiva sin edema del disco. Presentamos una paciente femenina de 50 años de edad, quien se sometió a la cirugía de catarata congénita del ojo izquierdo, sin mejoría de la función visual, a lo que se sumó el empeoramiento inespecífico de la calidad visual. La psicofísica visual, la campimetría automatizada y la tomografía de coherencia óptica aportaron hallazgos sugestivos de compresión de la vía visual intracraneal. Se indicó imagen por resonancia magnética de cráneo y órbitas para confirmar la sospecha diagnóstica. La angiografía cerebral demostró la presencia de un aneurisma de la arteria carótida interna, que se trató por vía endovascular con resultados satisfactorios(AU)

The importance of early diagnosis of compressive lesions of the optic nerve is on the increase. Timely decompression of the optic nerve or the optic chiasm may bring about significant visual function improvement, whereas erroneous diagnosis may result in irreversible visual loss, neurological dysfunction or death. The causes of compression of the anterior visual pathway are incredibly varied. Meningiomas, pituitary tumors and aneurysms are the lesions most commonly identified as causes of compressive optic neuropathy without disc edema. A case is presented of a female 50-year-old patient undergoing congenital cataract surgery of her left eye without visual function improvement, alongside unspecific visual quality worsening. Visual psychophysical testing, automated campimetry and optical coherence tomography contributed findings suggestive of intracranial visual pathway compression. Magnetic resonance imaging of the brain and orbits was indicated to confirm the diagnostic suspicion. Cerebral angiography revealed the presence of an internal carotid artery aneurysm which was treated by endovascular procedure with satisfactory results(AU)

The Amygdala Responds Rapidly to Flashes Linked to Direct Retinal Innervation: A Flash-evoked Potential Study Across Cortical and Subcortical Visual Pathways / 神经科学通报·英文版

Rapid detection and response to visual threats are critical for survival in animals. The amygdala (AMY) is hypothesized to be involved in this process, but how it interacts with the visual system to do this remains unclear. By recording flash-evoked potentials simultaneously from the superior colliculus (SC), lateral posterior nucleus of the thalamus, AMY, lateral geniculate nucleus (LGN) and visual cortex, which belong to the cortical and subcortical pathways for visual fear processing, we investigated the temporal relationship between these regions in visual processing in rats. A quick flash-evoked potential (FEP) component was identified in the AMY. This emerged as early as in the LGN and was approximately 25 ms prior to the earliest component recorded in the SC, which was assumed to be an important area in visual fear. This quick P1 component in the AMY was not affected by restraint stress or corticosterone injection, but was diminished by RU38486, a glucocorticoid receptor blocker. By injecting a monosynaptic retrograde AAV tracer into the AMY, we found that it received a direct projection from the retina. These results confirm the existence of a direct connection from the retina to the AMY, that the latency in the AMY to flashes is equivalent to that in the sensory thalamus, and that the response is modulated by glucocorticoids.

Advances in the study of visual pathway injury in glaucoma and the neuroplasticity of the visual system after injury / 国际眼科杂志(Guoji Yanke Zazhi)

@#Glaucoma is a group of diseases characterized by progressive optic nerve atrophy and visual field defects. Some evidence demonstrate that glaucoma's pathological damage affects the retina and optic nerve and involves the entire visual pathway. Recent studies have found that the nerve injury is not completely irreversible but has certain plasticity. Furthermore, studies have shown that neurons in the visual pathway of glaucoma can be repaired and remodeled under certain conditions to restore visual function, which offers a new way to treat glaucoma.

Preliminary study of visual pathway in ocular hypertension patients using magnetic resonance diffusion tensor and 3D-OCT / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To study the microscopic changes of visual pathology in ocular hypertension(OHT)patients using magnetic resonance diffusion tensor imaging(DTI)technology and three-dimensional optical coherence tomography(3D-OCT)technology. <p>METHODS: Twenty-six patients with 52 eyes diagnosed as OHT in our hospital from January 2016 to October 2019 were included in the case group. Twenty-six healthy patients who were matched with age and gender in the same period were included in the control group. All eyes were examined for best corrected visual acuity, central corneal thickness(CCT), non-contact intraocular pressure, while all eyes were examined by optical disc 3D-OCT combined optic nerve, optic chiasma, optic tract, and optic radiation DTI. Compared the differences between the two groups. <p>RESULTS: The CCT of the OHT group was thinner than that of the normal control group; the intraocular pressure was higher than that of the normal control group, and the difference was statistically significant(all <i>P</i><0.05). The optic disc area of the OHT group was larger than that of the normal control group, while the optic cup area was increased, and the average CP-RNFL thickness and nasal CP-RNFL thickness were thinner than those of the normal control group(all <i>P</i><0.05). There was no statistic difference in the superior, inferior and temporal CP-RNFL(all <i>P</i>>0.05). The FA values of bilateral optic nerve and optic radiation decreased compared with the normal control group, and the difference was statistically significant(all <i>P</i><0.05). There was no significant difference of optic chiasma, bilateral visual tract's FA value, and bilateral visual pathway ADC value between the two groups(all <i>P</i>>0.05). <p>CONCLUSION: 3D-OCT can obtain the thickness of CP-RNFL and the parameters of optic disc, DTI can reconstruct the intracranial visual pathway and can detect the microscopic changes of optic nerve, optic chiasma, optic tract, and optic radiation at early stage. Combining 3D-OCT and DTI technology can effectively understand the microscopic changes of the visual pathway and provide new models for clinical research of ocular hypertension patients.

Application of diffusion tensor imaging in tracking visual pathway fiber bundles in postoperative intensity-modulated radiotherapy for cerebral gliomas / 中华放射肿瘤学杂志

Objective To analyze the feasibility of incorporation of tracking visual pathway fiber bundles by diffusion tensor imaging ( DTI) in computed tomography ( CT) simulation to develop a protective radiotherapy regimen for cerebral gliomas.Methods A total of 31 patients with cerebral gliomas who were admitted to our hospital from 2013 to 2015 and planed to receive postoperative radiotherapy were enrolled as subjects.All patients underwent CT simulation, conventional or contrast-enhanced magnetic resonance imaging, and DTI.The obtained DTI images of visual pathway fiber bundles were fused with 3DT1 anatomical scans and then imported into the treatment planning system.A protective treatment plan ( setting the entire visual pathway fiber bundles as organs at risk (OARs)) and a conventional treatment plan were made for intensity-modulated radiotherapy ( IMRT) .Comparison of treatment outcomes was made by paired t test.Results There were no significant differences in the conformity index and heterogeneity index of the planning target volume between the two treatment plans ( P=0.875,0.597), both of which had sufficient radiation doses to the target volume and conventional OARs protected.For the patients undergoing the protective treatment plan, the Dmax and Dmean values were reduced to 9.01%and 9.05%, respectively, in the ipsilateral optic tract and to 17.96%and 15.52%, respectively, in the contralateral optic tract;the Dmax and Dmean values were reduced to 5.37%and 5.48%(P=0.000), respectively, in the ipsilateral optic radiation tract and to 12.89%and 11.21%( P=0.000) , respectively, in the contralateral optic radiation tract.Conclusions The protective treatment plan based on CT simulation combined with the display of visual pathway fiber bundles by DTI can reduce the radiation dose to the entire visual pathway fiber bundles, which keeps the risk of visual dysfunction after radiotherapy as low as possible.

Visual recovery demonstrated by functional MRI and diffusion tensor tractography in bilateral occipital lobe infarction / 영남의대학술지

We report on a patient who showed visual recovery following bilateral occipital lobe infarct, as evaluated by follow up functional magnetic resonance imaging (fMRI) and diffusion tensor tractography (DTT). A 56-year-old female patient exhibited severe visual impairment since onset of the cerebral infarct in the bilateral occipital lobes. The patient complained that she could not see anything, although the central part of the visual field remained dimly at 1 week after onset. However, her visual function has shown improvement with time. As a result, at 5 weeks after onset, she notified that her visual field and visual acuity had improved. fMRI and DTT were acquired at 1 week and 4 weeks after onset, using a 1.5-T Philips Gyroscan Intera. The fiber number of left optic radiation (OR) increased from 257 (1-week) to 353 (4-week), although the fiber numbers for right OR were similar. No activation in the occipital lobe was observed on 1-week fMRI. By contrast, activation of the visual cortex, including the bilateral primary visual cortex, was observed on 4-week fMRI. We demonstrated visual recovery in this patient in terms of the changes observed on DTT and fMRI. It appears that the recovery of the left OR was attributed more to resolution of local factors, such as peri-infarct edema, than brain plasticity.

The study of visual pathway of gloucoma patients with DTI / 实用放射学杂志

Objective To study the microstructural characteristics of white matter fiber tracts of visual pathways using diffusion tensor imaging (DTI)in the patients with primary glaucoma.Methods Twenty patients with primary bilateral glaucoma and 30 nor-mal adults were recruited and scanned with visual pathways magnetic resonance imaging (MRI)and DTI,obtaining T1 FLAIR ima-ges and directionally encoded color (DEC)images.On DEC images,ROIs were put in the anterior,middle and posterior part of bi-lateral optic nerve,optic tract and optic radiation,to calculate the average FA and MD value of each region.Results T1 FLAIR and DEC images could clearly show the optic nerve,optic tract and optic radiation.In patients with glaucoma,the FA values of optic nerve,optic tract and optic radiation were:0.372±0.040,0.340±0.036,0.31 5±0.026,while the MD values were:1.760±0.1 1, 1.831±0.09,1.927±0.10.The FA values of optic nerve,optic tract and optic radiation of normal adults were:0.538 ±0.073, 0.460±0.082,0.455±0.083,whilst the MD values were:0.995 ±0.27,1.312 ±0.40,1.347 ±0.37.Compared with the normal controls,FA values of all parts are deceased whereas the MD values of all parts are increased in patients.Conclusion Glaucoma is a central nervous system disease involving the whole visual pathways.Use DTI can evaluate the microstructural characteristics of white matter fiber tracts of visual pathways in the patients with glaucoma.

Expression of neurofilament 200 in different sections of neurons of the visual pathway after retinal ischemia reperfusion injury / 中华实验眼科杂志

Background Neurofilament 200 (NF200) is an indirect indicator of the specific distribution of axons.It reflects the condition of the maintenance of neuronal morphology.Whether NF200 is involved in the damage of the visual pathway after retinal ischemia reperfusion injury (RIRI) should be further examined.Objective The present study was to investigate the expression of NF200 in retinal ganglion cells (RGCs),lateral geniculate nucleus (LGN),superior colliculus and visual cortex following RIRI.Methods Forty SD rats were randomized into the RIRI 1-,2-,3-,4-,6-,8-week groups,sham operation group and control group.Acute intraocular hypertension was induced in the right eye by anterior chamber perfusion of normal saline solution for 60 minutes to elevate the intraocular pressure to 110 mmHg.The animals were sacrificed at different time points for the preparation of the retina,LGN,superior colliculus and visual cortex sections.The expression of NF200 in RGCs,LGN,superior colliculus and visual cortex was assayed by immunohistochemistry.Results The expression level (A value) of NF200 in the RGCs was significantly different among the 8 groups after reperfusion (F =78.855,P =0.000),and that in the 1-week group was significantly lower than in the control group (t =36.563,P＜0.01).In the RIRI 1-week group,the expression of NF200 in the contralateral LGN in the experimental group was significantly lower than that in the control group (t =6.483,P＜0.01).In the 4-week group and 6-week group,the expression of NF200 in the contralateral LGN was significantly higher than that in the control group (t =2.904,4.313,P＜0.01).One week after RIRI,the expression of NF200 in contralateral superior celliculus in the experimental group was significantly lower than that in the control group (t =2.966,P＜0.05),and in the 2-week group,the expression of NF200 in the contralateral superior colliculus was significantly higher than that in the control group (t =7.397,P＜0.01).In the 2-week group,3-week group and 4-week group,the expression of NF200 in bilateral visual cortex was significantly higher in the experimental group than that in the control group (contralateral ∶ t =18.728,18.213,15.088,P＜0.01 ; ipsilateral ∶ t =8.690,5.704,7.805,P＜0.01).Conclusions RIRI can induce axonal damage of RGCs,contralateral LGN,superior colliculus and bilateral visual cortex neurons.

LINAC-Based Radiosurgery of Arteriovenous Malformation involving Visual Pathway: A Report of Two Cases / 대한뇌혈관외과학회지

The authors present two cases of arteriovenous malformation (AVM) involving the visual pathway following linear accelerator (LINAC) stereotactic radiosurgery. Both patients were treated with 18 Gy (marginal dose, 70-80% isodose line, 3 isocenter) delivered to the malformed vascular mass involving the optic tract on the right side. For both patients, however, less than 8 Gy were irradiated onto the ipsilateral optic chiasm and optic nerve, and 4.5 Gy were irradiated onto the contralateral optic nerve (20% isodose line). On the five-year follow-up MRI scan and angiogram, the AVM was totally obliterated in one patient and the AVM was markedly decreased in size in the other patient. Their visual fields were well preserved and visual acuities were even improved for both patients. We report here with on two cases of AVM involving the visual pathway that were effectively and safely treated with 18 Gy using LINAC-based radiosurgery, and we also attempt to define the safe and effective radiation dosage for the patients with AVM involving visual apparatus.

The Effect of Unilateral Orbital Enucleation on Acetylcholine and Muscarinic Receptors in Visual Pathway, and Physical Activity of Rats

Acetylcholine is one of the major neurotransmitters in visual system of rats. Cholinergic, serotonergic and gamma-aminobutyric acid(GABA) ergic projections are known as modulators of visual processing. The purpose of this study was to examine the effects of unilateral orbital enucleation on the amount of acetylcholine and its receptor bindings in dorsolateral geniculate body, superior colliculus and visual cortex of rats, and on motor activites. The amount of acetylcholine was measured by gas chromatography; whereas [3H]quinuclidinyl benzilate(QNB) bindings to muscarinic receptors were examined by autoradiography. Motor activity was measured by activity meter for 24 hours. The results of this study were as follows: 1. The amount of acetylcholine in superior colliculus significantly increased at 1 week after enucleation, but it decreased at 2 and 4 weeks after enucleation. In visual cortex, the amount of acetylcholine did not change at 1 week after enucleation, but it significantly decreased at 2 and 4 weeks after enucleation. 2. After enucleation, [3H]-QNB binding to muscarinic receptors gradually decreased over the 4 weeks in dorsolateral geniculate body, superior colliculus and visual cortex. 3. Locomotor activity of rats did not show any change at 1 week after enucleat ion, but it decreased at 2 and 4 weeks after enucleation. In conclusion, unilateral orbital enucleation resulted in a reduction in the amount of acetylcholine and muscarinic receptors in rat visual system, which was speculated to be a major cause of a decrease in physical activity.

Is glaucoma a central never system disease? / 眼科

Studies on glaucoma have been focused only on optic nerve damage and aqueous humor dynamic for many years. In recent years, with the advances in understanding of glaucoma and visual sciences, and the development of a neurological cross-discipline, new interdisciplinary problems have been raised. Notably, the question of whether glaucoma is only an optic nerve disease. Is it a disease that begins from the eye, and then involves the whole visual pathway? Or is it a particular central nervous system disease, which manifests itself in the eye? The answers to these problems are inconclusive so far, but there are reasons to believe that glaucoma is a disease with multi-level, multi-factor damage to the entire visual pathway involved. Its mechanisms are complex and involve cross-synaptic damage, visual pathway blood disorders, blood-brain barrier disorders, and so on. As we come to understand that glaucoma is an ocular and central never system neurodegenerative disease, we may better understand the pathogenesis of glaucoma and therefore establish comprehensive treatment strategies for this disease.

2 Cases of Anterior Communicating Artery Aneurysms Associated with Visual Symptoms

Interference with visual pathways is usually not caused by intracranial aneurysms. Aneurysms of the anterior communicating artery rarely produce visual symptoms and signs in spite of their proximity to the visual pathways. The reason may be that these aneurysms rupture and present with subarachnoid hemorrhage before becoming large enough to exert significant pressure on the chiasm or optic nerves. The visual symptoms would be presented as visual field defect or impaired vision. These can be explained as the result of direct compression of the optic pathways, ischemic changes in the visual pathways caused by severe vasospasm after subarachnoid hemorrhage, or intraocular pathology such as retinal hemorrhage. 2 cases of anterior communicating artery aneurysms associated with visual symptoms are presented with a brief review of literatures.