Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report a patient with pathologically proven idiopathic Parkinson's disease (IPD) who developed diplopia secondary to convergence insufficiency during his motor "off" periods. Diplopia resolved with onset of motor benefit from levodopa. Neuro-ophthalmologic examination demonstrated convergence insufficiency during motor "off" periods that was alleviated after onset of motor benefit from levodopa. This is the first reported case of convergence insufficiency in IPD responsive to levodopa.
Strabismus 1999 Sep
PMID:Convergence insufficiency in idiopathic Parkinson's disease responsive to levodopa. 1052 Feb 42

Diplopia is sometimes reported by patients with Parkinson's disease (PD) without apparent oculomotor disorders. We assessed clinical features and associated oculomotor and perceptual performance in 14 patients (6 male, 8 female) with PD with a peculiar type of selective diplopia. Duplication of images was confined to single objects or persons, occurred repetitively, and lasted few seconds in all subjects. Frequency of episodes ranged from several episodes per day to three episodes per year. In six of seven subjects undergoing comprehensive ophtalmological examination, subtle ocular disorders (heterophoria, strabism, etc.) were found. Nine of 14 patients were suffering from current or previous visual hallucinations and 3 more patients developed hallucinations within 3 years of diplopia onset. Selective diplopia of isolated single objects and persons in PD is possibly related to hallucinosis and minor ocular disturbances seem to be a triggering factor for this peculiar type of misperception.
 ...
PMID:Selective diplopia in Parkinson's disease: a special subtype of visual hallucination? 1723 Apr 66

Although visual processing impairments are common in schizophrenia, it is not clear to what extent these originate in the eye vs. the brain. This review highlights potential contributions, from the retina and other structures of the eye, tovisual processing impairments in schizophrenia and high-risk states. A second goal is to evaluate the status of retinal abnormalities as biomarkers for schizophrenia. The review was motivated by known retinal changes in other disorders (e.g., Parkinson's disease, multiple sclerosis), and their relationships to perceptual and cognitive impairments, and disease progression therein. The evidence reviewed suggests two major conclusions. One is that there are multiple structural and functional disturbances of the eye in schizophrenia, all of which could be factors in the visual disturbances of patients. These include retinal venule widening, retinal nerve fiber layer thinning, dopaminergic abnormalities, abnormal ouput of retinal cells as measured by electroretinography (ERG), maculopathies and retinopathies, cataracts, poor acuity, and strabismus. Some of these are likely to be illness-related, whereas others may be due to medication or comorbid conditions. The second conclusion is that certain retinal findings can serve as biomarkers of neural pathology, and disease progression, in schizophrenia. The strongest evidence for this to date involves findings of widened retinal venules, thinning of the retinal nerve fiber layer, and abnormal ERG amplitudes. These data suggest that a greater understanding of the contribution of retinal and other ocular pathology to the visual and cognitive disturbances of schizophrenia is warranted, and that retinal changes have untapped clinical utility.
 ...
PMID:Schizophrenia and the eye. 2634 25

Maintaining proper eye alignment is necessary to generate a cohesive visual image. This involves the coordination of complex neural networks, which can become impaired by various neurodegenerative diseases. When the vergence system is affected, this can result in strabismus and disorienting diplopia. While previous studies have detailed the effect of these disorders on other eye movements, such as saccades, relatively little is known about strabismus. Here, we focus on the prevalence, clinical characteristics, and treatment of strabismus and disorders of vergence in Parkinson's disease, spinocerebellar ataxia, Huntington disease, and multiple system atrophy. We find that vergence abnormalities may be more common in these disorders than previously thought. In Parkinson's disease, the evidence suggests that strabismus is related to convergence insufficiency; however, it is responsive to dopamine replacement therapy and can, therefore, fluctuate with medication "on" and "off" periods throughout the day. Diplopia is also established as a side effect of deep brain stimulation and is thought to be related to stimulation of the subthalamic nucleus and extraocular motor nucleus among other structures. In regards to the spinocerebellar ataxias, oculomotor symptoms are common in many subtypes, but diplopia is most common in SCA3 also known as Machado-Joseph disease. Ophthalmoplegia and vergence insufficiency have both been implicated in strabismus in these patients, but cannot fully explain the properties of the strabismus, suggesting the involvement of other structures as well. Strabismus has not been reported as a common finding in Huntington disease or atypical parkinsonian syndromes and more studies are needed to determine how these disorders affect binocular alignment.
 ...
PMID:Vergence and Strabismus in Neurodegenerative Disorders. 2986 16