Visual signs and symptoms of Parkinson's disease

Parkinson's disease (PD) is a common disorder of middle-aged and elderly people, in which there is degeneration of the extra-pyramidal motor system. In some patients, the disease is associated with a range of visual signs and symptoms, including defects in visual acuity, colour vision, the blink reflex, pupil reactivity, saccadic and smooth pursuit movements and visual evoked potentials. In addition, there may be psychophysical changes, disturbances of complex visual functions such as visuospatial orientation and facial recognition, and chronic visual hallucinations. Some of the treatments associated with PD may have adverse ocular reactions. If visual problems are present, they can have an important effect on overall motor function, and quality of life of patients can be improved by accurate diagnosis and correction of such defects. Moreover, visual testing is useful in separating PD from other movement disorders with visual symptoms, such as dementia with Lewy bodies (DLB), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). Although not central to PD, visual signs and symptoms can be an important though obscure aspect of the disease and should not be overlooked.

Gallium-transferrin binding in treated and untreated Parkinson's disease

The binding of gallium (Ga) to transferrin (Tf) was studied in plasma from control patients, in patients with untreated Parkinson's disease (PD) and in patients with PD treated either with levodopa (L-dopa) alone or in combination with selegiline. Mean percentage Ga-Tf binding was significantly reduced in untreated and treated PD compared with controls. Binding, however, was significantly greater in treated than in untreated patients. There was no difference in binding between patients treated with L-dopa alone and those treated with L-dopa and selegiline. The data support the hypothesis that oxidation reactions may be of pathogenic significance in PD.

The visual complications of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder affecting middle-aged and elderly people. The disorder is of particular interest to Optometrists because it is associated with a range of visual problems including defects in eye movement and pupillary function. This article reviews the visual complications of PD and the pathological changes in the eye and brain which may explain these symptoms.

Parkinson's disease Part 1: symptoms, diagnosis and changes in the brain

Parkinson's disease is a common neurodegenerative disorder of middle-aged and elderly people. There are two aspects of the disease of special interest to optometrists. First, visual problems may be present in a proportion of patients with the disease. In addition, the disease is treated by a variety of drugs, some of which may have ocular complications. This article describes the incidence, symptoms, diagnosis, causes and changes in the brain in Parkinson's disease.

Parkinson's disease Part 2: visual aspects

There are two aspects of Parkinson's disease specifically discussed in this article. First, visual symptoms are present in a proportion of patients with the disease and it is important that these are recognised. Second, Parkinson's disease can be successfully treated with drugs, but some of the drugs have ocular side effects and optometrists need to be aware of the signs of ocular complication in these patients.

Serum neopterin levels and gallium transferrin binding in Parkinson's disease

The unconjugated pterin neopterin is secreted by macrophages activated by interferon-gamma and hence, the level of neopterin in serum may be used as a marker of a cellular immune response in a patient. Serum neopterin levels were measured by high performance liquid chromatography (HPLC) in 28 Parkinson's disease (PD) patients and 28 age and sex matched controls. The level of serum neopterin was significantly elevated in PD compared with controls suggesting immune activation in these patients. The level of neopterin was negatively correlated with the level of binding of gallium to transferrin (Tf) but unrelated to the level of iron binding. Hence, in PD, it is possible that a cellular immune response may be important in the pathogenesis of the disease. One effect of the cellular immune response may be a reduction in the binding of metals other than iron to Tf and this could also be a factor in PD.

Visual signs and symptoms of Parkinson's disease

There are two aspects of PD of particular interest to optometrists. First, PD patients can develop a range of visual problems including those affecting eye movement, pupillary function, and in complex visual functions involving the ability to judge distance or make out the shape of an object. Second, the symptoms of PD can be treated successfully using a variety of drugs, some of which have significant ocular adverse reactions (OAR). This article describes the general features of PD, the dopamine neurotransmitter system and its relevance to eye symptoms, the visual symptoms reported in PD, and the OAR that have been reported.

Metal binding to transferrin and immune reactions in Parkinson's disease

The binding of iron (59Fe) and gallium (67Ga) to the plasma protein transferrin (Tf) was investigated by G75 gel filtration chromatography in control patients and treated and untreated patients with Parkinson's disease (PD). Fe-Tf binding was 100% in all controls and PD patients suggesting that a defect in Fe-Tf binding was not involved in the aetiology of PD. Ga-Tf binding was significantly reduced in both untreated and treated PD patients compared to controls. In addition, treated PD patients had significantly higher Ga-Tf binding than untreated patients. A reduction in metal binding to Tf could result in the increase of a low molecular weight species which may more readily enter the CNS. Alternatively, it could lead to a decrease in the transport of essential metals into the brain via the Tf receptor system. A significant elevation in neopterin was demonstrated within the plasma of untreated PD patients compared to controls suggesting the activation of a cellular immune response. Furthermore, plasma neopterin was lower in treated compared to untreated PD patients, although the difference was not significant. There was no evidence for the activation of the humoral immune response in untreated or treated PD patients as measured by circulating immune complex (CIC) levels within the plasma. An inverse relationship between Ga-Tf binding and neopterin was observed in untreated PD patients. The addition of oxidants in the form of potassium permanganate and activated manganese dioxide reduced Ga-Tf binding in control plasma. However, relatively little response was observed using monocyte preparations. The results suggest that oxidants produced by activation of the cellular immune system could damage the Tf molecule thereby reducing its ability to bind metals.