An interventional study of fMRI in Dry Eye Syndrome and Photophobia, sponsored by University Hospital, Toulouse. Status unknown at 1 site in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2018-04-18.
Sponsored by University Hospital, Toulouse · Not applicable, Interventional, and Other
Photophobia is a common and disabling symptom in patient with dry eye syndrome. The aim of this study is tried to better understand this complain analyzing brain activation during a luminous stimulation to highlight modification of cortical activation.
Dry eye syndrome is a frequent and underestimated disease whose incidence tends to increase because of the population ageing and behaviors modification (time spent using screens increased, wearing of contact lenses...). Photophobia deteriorates the quality of life in patients with dry eye syndrome decreasing outdoor activities. This symptom is not understood and does not seem to be linked with dry eye syndrome severity. The study will compare cortical activation after luminous stimulation of 16 patients eyes (8 patients with dry eye syndrome and photophobia vs 8 asymptomatic patients) using functional MRI (fMRI).
The primary study endpoint was the extent of magnetic signals in visual cortex after luminous stimulation. Secondary endpoints were the spatial activation extent in the 3 areas of the visual cortex (Brodmann areas 17,18,19).
Exclusion Criteria:
8 symptomatic patients with dry eye (mild to severe) assessed using a validated questionnaire (OSDI score, Appendix 1) associated with a disabling photophobia (need to wear sunglasses permanently outside, restriction of the outputs in case of significant brightness, restriction of the use of the screens because of the visual embarrassment ...). The fMRI will be carried out following the inclusion visit after all the necessary checks
Radiation: fMRI
8 asymptomatic patients presenting neither photophobia (even minimal) or dry eye. The fMRI will be carried out following the inclusion visit after all the necessary checks
Radiation: fMRI
The BOLD (Blood-Oxygen-Level Dependent) signal obtained by fMRI reflects the rate of oxygenation of the blood in the brain. However, the hemodynamic response that corresponds to an inflow of oxygenated blood increases in regions that consume energy. Thus, it is possible, by the study of the BOLD signal, to know with a great precision the regions of the brain specially active during a given task. The recorded signals reflect a neuronal activation. For each eye, recordings with and without flash visual stimulation are performed alternately.
The spatial extent of activation of the visual cortex
Measurement of voxel activation is validated and standardized (SPM8 software (Wellcome Department of Cognitive Neurology, London, UK) . In order to be able to determine the anatomical location of the voxels, a registration of the images on the standard image MNI152 (Montreal National Institute) provided by the Montreal Neurological Institute for which the spatial location of all the areas is known will be realized. It will thus be obtained, the number of activated voxels per visual area (Brodmann 17, 18, 19) for each hemisphere (contralateral and ipsilateral) of a subject with or without complaint.
Time frame: One day
Plan to share: No
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University Hospital, Toulouse