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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Videokeratoscopy techniques rely on a number of factors in order to achieve accurate estimates of corneal surface topography. Good tear film quality, minimal reflections from eyelashes, and minimal eye movements are essential for corneal topography estimates to be reliable. However, in practice, these ideal conditions may not always be fulfilled, especially in cases of subjects diagnosed with dry eye syndrome, having narrow palpebral apertures, long eyelashes, or nystagmus (uncontrolled eye movements). Such nonoptimal conditions of image acquisition result in poorer estimates of corneal topography. The aim of this paper was to devise a technique that would provide more accurate estimation of corneal topography in such situations and particularly when the source of signal interference is strong. This was achieved by developing a set of algorithms that extract the interference from the acquired raw videokeratoscopic image and filter the topography according to the interference location. The experiments carried out with test surfaces and real corneas showed that this new technique leads to a significant improvement in the topography estimator. Additionally, it is an interference indication procedure that, in the future, could be used for the purpose of tear film quality estimation.
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PMID:Estimating corneal surface topography in videokeratoscopy in the presence of strong signal interference. 1883 63

Although visual function is thought to be preserved in patients with locked-in syndrome (LIS), enabling them to communicate through vertical or lateral eye movements or blinking of the upper eyelid, nothing is known about the actual visual function of patients with LIS. The goal of this study is to evaluate the visual function of patients with LIS which may enable better evaluation of the state of consciousness of these patients. Patients with LIS seen in a single neurovascular unit of a tertiary center between 1997 and 2013 were retrospectively reviewed. Each patient had a specialized neuro-ophthalmological evaluation under optimal environmental conditions (light, contrast, examination distance, head position, best ergonomic adaptation, and establishment of a means of communication with help from the patient's friends/family). Visual acuity, extraocular eye movements, confrontational visual field, slit lamp and fundus examination were performed. Thirteen patients (6M/7F) were included in this study. Mean visual acuity was 20/60. Oculomotor examination was abnormal in 77%. Forty-six percent of patients presented binocular diplopia mainly related to a VIth nerve palsy. One patient presented complete ophthalmoplegia. Forty-six percent of patients had nystagmus responsible for oscillopsia (oculopalatal tremor). An abnormal visual field was observed in 17% of patients, and abnormal pupillary light response leading to photophobia was present in 22% of patients. Keratitis or dry eye syndrome was present in most patients and was a major cause of pain and visual impairment. Our results suggest that the visual function is impaired in all patients with LIS. This impairment is multifactorial including mostly binocular diplopia or oscillopsia but also refractive errors, dry eye syndrome, keratitis or visual field defect. This altered visual function may alter the ability of the patient to interact with his environment and lead to underestimation of their state of consciousness. An ophthalmologic evaluation would allow for improvement of these patients' comfort, their ability to communicate, and the assessment of their state of consciousness.
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PMID:Evaluation of the visual function of patients with locked-in syndrome: Report of 13 cases. 2715 1