Objective: To report the frequency of neuro-ophthalmologic cases seen over one working week by a senior neuro-ophthalmologist in Singapore and to determine a pattern in the incidence of neuro-ophthalmic diseases. Methods: A retrospective review of 57 consecutive neuro-ophthalmologic cases seen by one senior neuro-ophthalmologist from June 14 to 18, 2010 was done. All patients underwent a complete neuro-ophthalmologic examination. Demographic data and clinical diagnoses were gathered. Results: A total of 57 patients were seen. Thirty-one percent (18) of these patients were new consultations while the remaining 61% (39) were follow-up visits. Fifty-two percent were females (30) with a mean age of 53 years while 47% were males (27) with a mean age of 49 years. Nineteen cases involved disorders of the optic nerve followed by disorders of ocular motility (11), optic chiasm, visual pathways, and/or visual cortex (14). Among the cases involving the optic nerve, 5 were ischemic optic neuropathy. In respect to disorders of ocular motility, ocular myasthenia gravis (n=5) was the most common condition seen. Pituitary adenomas comprised the bulk of the disorders of the optic chiasm (4). The remaining neuro-ophthalmic cases were almost evenly distributed. A very rare case of Froin’s syndrome was also seen. Conclusion Overall, during the five-day neuro-ophthalmologic clinic, majority of cases were ischemic in nature, reminding readers that systemic diseases, such as hypertension, diabetes mellitus, hyperlipidemia, commonly manifest in the eye. Hence, better systemic control of these diseases is necessary.
Optic Nerve Diseases ; Visual Pathways ; Visual Cortex

How the brain perceives objects and classifies perceived objects is one of the important goals of visual cognitive neuroscience. Previous research has shown that when we see objects, the brain's ventral visual pathway recognizes and classifies them, leading to different ways of interacting with them. In this paper, we summarize the latest research progress of the ventral visual pathway related to the visual classification of objects. From the perspective of the neural representation of objects and its underlying mechanisms in the visual cortex, we summarize the current research status of the two important organizational dimensions of object animacy and real-world size, provide new insights, and point out the direction of further research.
Brain Mapping/methods* ; Magnetic Resonance Imaging ; Pattern Recognition, Visual ; Photic Stimulation ; Visual Cortex ; Visual Pathways

To manifest visual acuity of 20/20 or better, the requirements are good optical imagery, foveal fixation, intact receptor structure and function, and full integrity of the involved neural pathways. Person with hyperopia of 1-10 diopter or astigmatism of 1 diopter may be able to read the line marked 20/20 of Snellen's chart. Non-cycloplegic and cycloplegic subjective manifest refractions were done on 380 normal eyes with visual acuity of 20/20 or more to observe the prevalence, type and degree of the refractive errors. The results were as follows; 1. In non-cycloplegic subjective manifest refraction, 147 eyes(38.7%) had refractive error such as simple hyperopic astigmatism(50.3%), hyperopia(37.4%), simple myopic astigmatism(6.8%) and compound hyperopic astigmatism(5.4%). In cycloplegic subjective manifest refraction, 183 eyes(48.2%) were ametropia such as simple hyperopic astigmatism (49.7%), hyperopia(38.3%), compound hyperopic astigmatism(8.7%) and simple myopic astigmatism(3.2%). 2. As to the type of astigmatisms, "with the rule" astigmatism was 2.5 times more than "against the rule". 3. Average degree of refractive errors were 0.12 diopter in non-cycloplegic refraction and 0.22 diopter in cycloplegic refraction. 4. The degree of hyperopia was less than 1.00 diopter in all cases of noncycloplegic refractions and in most cases(93%) of cycloplegic refractions. 5. Degree of astigmatism were less than 1.00 diopter in the majority(98%).
Astigmatism ; Humans ; Hyperopia ; Neural Pathways ; Prevalence ; Refractive Errors ; Visual Acuity*

BACKGROUND: Sympathetic skin response (SSR) is a transient change in the electrical potential of the skin that is evoked by internal or external stimuli. In the present study, our purpose was to compare electrical and visual stimulation methods of evoking a SSR. METHODS: SSRs evoked by both electrical and visual stimulation were recorded from the palm and sole from 48 healthy volunteers. RESULTS: SSRs were obtained in all normal control subjects following both electrical and visual stimulation. The latency of SSR following electrical stimulation was 1383.75+/-223.56 msec at the palm and 1790.54+/-318.70 msec at the sole, and that following visual stimulation was 1518.75+/-252.64 msec at the palm and 1930.10+/-226.19 msec at the sole. The latencies of SSRs following visual stimulation were prolonged significantly more than those following electrical stimulation. The amplitudes of SSRs following visual stimulation were significantly lower than those following electrical stimulation, and the amplitude of SSRs following both electrical and visual stimulation had marked intersubject and intrasubject variabilities in each of the stimulations. CONCLUSIONS: The SSR evoked by visual stimulation is as reliable as known electrical stimulation for determining sympathetic functions and is a less invasive method. Latencies by visual stimulation are longer than those by electrical stimulation in both the palm and sole. The visual stimulation method of evoking a SSR is not influenced by an ascending somatosensory pathway theoretically, so we can postulate that it reflects a purely autonomic function if there is no problem in the visual pathway.
Electric Stimulation ; Healthy Volunteers ; Photic Stimulation ; Skin* ; Visual Pathways

A unilated cataract had been reported to cause a relative afferent pupillary defect (RAPD) in the contralateral eye. After extraction of the cataract, the RAPD disappeared in every case. The ability of cataracts to induce an RAPD in the opposite eye is presumed to increased intraocular scatter of light by the cataract, stimulating more peripheral photoreceptors. This observation has not been reported in Korea. The authors have also observed RAPD in the contralateral eye to the unilateral cataract in six patients, disappearing after cataract surgery. Thus, when an RAPD is seen in an eye with a cataract, a visual pathway defect in that eye should definitely be suspected. In addition, it would be better to hold the brain imaging study when an RAPD is noticed in the contralateral eye to the unilateral cataract and to confirm the normal pupillary reflex in both eyes after the cataract surgery.
Cataract* ; Humans ; Korea ; Neuroimaging ; Pupil Disorders* ; Reflex, Pupillary ; Visual Pathways

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.
Aneurysm ; Arteries ; Intracranial Aneurysm* ; Optic Nerve ; Pathology ; Retinal Hemorrhage ; Rupture ; Subarachnoid Hemorrhage ; Visual Fields ; Visual Pathways

A small beam or slit of light focused at the pupillary margin will induce regular, persistent oscillations of the pupil. The period of these cycles is the pupil cycle time that can be easily measured and expressed in milliseconds. When the efferent part of the light reflex of the pupil is normal, determination of the period of these cycles in milliseconds provides a number which may be correlated with conduction time in the anterior visual pathway. Cox and Drews reoorded pupillary response to alternating half-field visual stimuli and found that stimulation of the temporal visual field (nasal retina) caused more pupillary constriction than did equivalent stimulation of the nasal field(temporal retina). These findings imply an asymmertric decussation of pupillomotor pathways in the midbrain in humans as well as greater sensitivity of the nasal retina. We measured nasal and temporal pupil cycle time on 200 normal eyes of Koreans by half-field stimulation of the nasal and temporal retina. And we found that: 1. The mean temporal pupil cycle time was 1071 +/- 92m sec, in right eye and 1068 +/- 81m sec, in left eye. The mean nasal pupil cycle time was 894 +/- 63m sec, in right eye and 899 +/- 57m sec, in left eye. Difference between nasal and temporal pupil cycle time was 177 +/- 73m sec, in right eye and 169 +/- 64m sec, in left eye. 2. The difference of pupil cycle time between the right and left eyes was 3 +/- 84m sec, in temporal retina and 5 +/- 61m sec, in nasal retina. The difference of pupil cycle time between the two eyes was not significant statistically. 3. The mean temporal pupil cycle time of the two eyes was 1069 +/- 85m sec, and the mean nasal pupil cycle time was 897 +/- 62m sec. Difference between nasal and temporal pupil cycle time was 172 +/- 74m sec. In 95% of normal population, the discrepancy between temporal and nasal pupil cycle time was shorter than 253m sec. 4. The mean temporal pupil cycle time was 1066 +/- 86m sec, in male and 1072 +/- 83m sec, in female. The mean nasal pupil cycle time 901 +/- 63m sec, in male and 894 +/- 59m sec, in female. The difference of pupil cycle time between the male and female was not significant statistically.
Constriction ; Female ; Humans ; Male ; Mesencephalon ; Pupil* ; Reflex ; Retina ; Visual Fields ; Visual Pathways

70%-80% of our sensory input comes from vision. Light hit the retina at the back of our eyes and the visual information is relayed into the dorsal lateral geniculate nuclei (dLGN) and primary visual cortex (V1) thereafter, constituting the image-forming visual circuit. Molecular cues are one of the key factors to guide the wiring and refinement of the image-forming visual circuit during pre- and post-embryonic stages. Distinct molecular cues are involved in different developmental stages and nucleus, suggesting diverse guidance mechanisms. In this review, we summarize molecular guidance cues throughout the image-forming visual circuit, including chiasm determination, eye-specific segregation and refinement in the dLGN, and at last the reciprocal connections between the dLGN and V1.
Animals ; Geniculate Bodies ; metabolism ; Humans ; Visual Cortex ; metabolism ; Visual Pathways ; metabolism

PURPOSE: To report a case of optic tract syndrome in which optical coherence tomography (OCT) demonstrated the specific findings of the retinal nerve fiber layer (RNFL). CASE SUMMARY: A 32-year-old male patient visited the hospital with right side visual field defect in both eyes that occurred immediately after a traffic accident 8 months prior. The visual acuity of both eyes was normal, and a relative afferent papillary defect was evident in the right eye. In addition, suspicious band atrophy of the right optic disc and thinning of the superior and inferior arcuate bundle were observed in the left eye. On visual field examination, homonymous hemianopia was present. Optic tract syndrome was suspected, although there was no abnormality of the visual tract on MRI. On fast RNFL thickness 3.4 scan, a thinning of RNFL in the nasal and temporal segments in the right eye and superior and inferior segments in the left eye were observed. Based on the findings, optic tract syndrome was diagnosed in the left eye. CONCLUSIONS: We report specific OCT findings which can be useful when making a diagnosis of optic tract syndrome.
Accidents, Traffic ; Atrophy ; Eye ; Hemianopsia ; Humans ; Male ; Nerve Fibers ; Retinaldehyde ; Tomography, Optical Coherence ; Visual Acuity ; Visual Fields ; Visual Pathways

This review summarizes objective assessment of visual function using visual electrophysiology. Objective assessment of visual acuity using pattern visual evoked potential (PVEP) and sweep pattern visual evoked potential (SPVEP), objective assessment of visual field using multifocal visual evoked potential (MVEP).
Electrophysiology ; Evoked Potentials, Visual ; Humans ; Photic Stimulation ; Vision Tests/methods* ; Vision, Ocular/physiology* ; Visual Acuity/physiology* ; Visual Field Tests ; Visual Pathways/physiology*