Professor Antoniades who is leading the OxQUIP Study said: 'There has been great interest in the precise measurement of abnormalities of eye movements as a way of determining the severity of Parkinson’s disease. We are delighted to be able to share the first results from this study and express our gratitude to our lovely patients for their enormous commitment and support'.
The ability to interpret such measurements is critically dependent on having a good understanding of how they are affected by medication as well as by the disease. In some situations (e.g. the development of a new symptomatic treatment) a marker that is sensitive to medication effects is desirable. In other settings (e.g. the development of a disease modifying treatment) we would like a marker that is relatively unaffected by medication so we can see the state of the underlying condition.
The most commonly reported measure of eye movements in Parkinson’s disease is called ‘prosaccadic latency’. This is the time taken to move your eyes to look at something that appears in your field of view to one side or the other. Studies have given widely differing values for how this is affected by medication, differing not just in magnitude but also direction. Our researchers working on the OxQUIP Study have shown in a large group of patients that this measure is sensitive to the presence of medication, which significantly increases it.
The group also analysed several other aspects of fast eye movements. One of these was the time taken to do the opposite of the above, i.e. to look deliberately away from a visual stimulus, which is called ‘antisaccadic latency’. They found that this is clearly abnormal in Parkinson’s disease yet not significantly affected by the presence of medication. It is therefore likely to be useful in future trials to measure the effects of drugs designed to slow disease progression.