Retina Disorder Clinical Trial
Official title:
A Multimodal Approach Towards an Objective Assessment of Macular Function at Retinal and Cortical Levels
Research questions/hypotheses: About 15% of the population over 40 years of age are affected
by diseases of the retina. Accurate measurement of the extent of visual field impairment is
of highest importance for disease subtype diagnosis and severity classification. The current
gold-standard approach for the assessment of macular sensitivity is microperimetry (MP) where
the patient is asked to report whether or not visual stimuli presented at different positions
within the visual field are detected. While this technique is a very straightforward approach
and simple in its application, it is important to note that MP is psychophysical in nature
and requires constantly high attentional performance of the patient throughout the
examination period. As many patients suffering from retinal diseases are well over 65 years
of age, they are unable to maintain such high levels of attention over longer periods and,
thus, MP results may be biased. Retinotopic assessment using population receptive field (pRF)
mapping based on functional magnetic resonance imaging (fMRI) offers an alternative by
allowing for objective visual field testing, independent of patient performance. We have
shown previously in healthy subjects that pRF allows for accurate detection of simulated
central scotomata down to 2.35 degrees radius. Also, pilot data in patients with retinal
scotomata showed strong correspondence between pRF and MP results, i.e. macular regions with
reduced macular sensitivity and atrophy of outer retinal layers correlated well with pRF
coverage maps showing reduced density of activated voxels. The aim of this project is to
determine whether pRF mapping could serve as an alternative visual field testing method by:
(1) assessing test-retest reproducibility of pRF and MP in clinical populations with stable
retinal diseases (Stargardt disease, geographic atrophy) over a four-week period; (2)
assessing visual field changes over a one-year period in patients suffering from acute
retinal scotomata (branch retinal artery occlusions, full-thickness macular holes). All pRF
mapping will be accompanied by MP measurements to allow for a direct comparison of the two
techniques.
Scientific/scholarly innovation/originality of the project: The present project applies a
novel approach for linking retinal function assessed with MP and pRF mapping in a
representative patient population with acute and chronic retinal diseases. The project seeks
to contribute to best practice methods for using fMRI to assess macular dysfunction both for
documentation of the natural course of the disease and during therapy in a study setting.
Methods: fMRI uses pRF mapping to provide retinotopic data (pRF coverage maps) that are then
correlated with the results of conventional ophthalmic testing including MP, visual acuity
and contrast sensitivity testing, reading performance, optical coherence tomography and
autofluorescence imaging.
Status | Not yet recruiting |
Enrollment | 100 |
Est. completion date | June 15, 2020 |
Est. primary completion date | March 16, 2020 |
Accepts healthy volunteers | Accepts Healthy Volunteers |
Gender | All |
Age group | N/A and older |
Eligibility |
Inclusion Criteria: - 20 patients clinically diagnosed with GA secondary to AMD. - 20 patients clinically and genetically diagnosed with STGD. - 20 patients clinically diagnosed with BRAO. - 20 patients clinically diagnosed with acute FTMH before and after macular surgery. - 20 healthy control subjects. Visual acuity of 20/16- 20/32 Exclusion Criteria: - Presence of any other ophthalmological or neurological disease affecting visual function - Cataract > grade 2 (according to lens opacities system) - All routine exclusion criteria that apply to MRI scans including pacemakers, metallic implants, prostheses or coils, claustrophobia - Pregnancy - Dyslexia |
Country | Name | City | State |
---|---|---|---|
n/a |
Lead Sponsor | Collaborator |
---|---|
Medical University of Vienna |
Type | Measure | Description | Time frame | Safety issue |
---|---|---|---|---|
Primary | Correspondence between coverage maps originating from microperimetry and population-receptive field mapping of the primary visual cortex measured by functional magnetic resonance imaging. | Qualitative and quantitative assessment of the correspondence between conventional functional assessment of retinal scotomata (microperimetry) and population-receptive field (pRF) mapping of the primary visual cortex measured by functional magnetic resonance imaging in patients clinically diagnosed with geographic atrophy secondary to age-related macular degeneration, Stargardts disease, branch retinal artery occlusions and full thickness macular holes before and after macular surgery. The microperimetry test grid (retinal sensitivity measured in Decibel, dB) willl be correlated with the pRF coverage maps calculated from fMRI data. Each dot represents the centre of a receptive field of a single voxel and every pRF centre is associated with a 2D Gaussian which together constitute the coverage map. Correspondence between coverage maps will be quantified by calculating the matching coefficient. | 2 years | |
Secondary | Correspondence between coverage maps originating from structural imaging (optical coherence tomography and autofluorescence imaging) and population-receptive field mapping of the primary visual cortex measured by functional magnetic resonance imaging. | Qualitative and quantitative assessment of the correspondence between conventional structural assessment of retinal scotomata (optical coherence tomography and autofluorescence imaging) and population-receptive field (pRF) mapping of the primary visual cortex measured by functional magnetic resonance imaging in patients clinically diagnosed with geographic atrophy secondary to age-related macular degeneration, Stargardts disease, branch retinal artery occlusions and full thickness macular holes before and after macular surgery. The retinal layer thickness maps (measured in micometer, µm) willl be correlated with the pRF coverage maps calculated from fMRI data. Each dot represents the centre of a receptive field of a single voxel and every pRF centre is associated with a 2D Gaussian which together constitute the coverage map.Correspondence between coverage maps will be quantified by calculating the matching coefficient. | 2 years | |
Secondary | Reproducibility assessment | Reproducibility of population-receptive field mapping of the primary visual cortex and of conventional ophthalmic assessment (microperimetry, visual acuity and contrast sensitivity testing, reading performance, optical coherence tomography and autofluorescence imaging) in patients with retinal scotomata secondary to Stargardt disease and geographic atrophy compared with normal control participants with artificial scotomata. | 1 year |
Status | Clinical Trial | Phase | |
---|---|---|---|
Completed |
NCT05229094 -
EVA Nexus Vitrectomy Device Field Observation Study
|
||
Recruiting |
NCT05491798 -
A Big Data-based Cohort Study for Cataract Patients
|
||
Recruiting |
NCT04718532 -
A New Technique For Retinal Disease Treatment
|
||
Completed |
NCT04068207 -
Minocycline Treatment in Retinitis Pigmentosa
|
Phase 2 |