Rod Sensitivity in Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP)
| Status: | Enrolling by invitation |
|---|---|
| Conditions: | Ocular |
| Therapuetic Areas: | Ophthalmology |
| Healthy: | No |
| Age Range: | 10 - 85 |
| Updated: | 10/29/2017 |
| Start Date: | October 1, 2017 |
| End Date: | July 1, 2019 |
A new fundus-guided microperimeter, the MP-3S, has been developed by Nidek, Inc. to track the
fundus of the patient and present stimuli in specific anatomically-defined locations.
Furthermore, this tracking means that exactly the same locations can be tested on subsequent
(follow-up) visits. The investigators will use a method called two-color perimetry to map rod
and cone sensitivity on this device. With this technique, the sensitivity difference
(blue-red) to chromatic test stimuli can be used to determine whether rods, cones or both
photoreceptor systems mediate the threshold at a given location in the macula.
fundus of the patient and present stimuli in specific anatomically-defined locations.
Furthermore, this tracking means that exactly the same locations can be tested on subsequent
(follow-up) visits. The investigators will use a method called two-color perimetry to map rod
and cone sensitivity on this device. With this technique, the sensitivity difference
(blue-red) to chromatic test stimuli can be used to determine whether rods, cones or both
photoreceptor systems mediate the threshold at a given location in the macula.
Despite recent advances in understanding the pathogenesis of retinitis pigmentosa (RP) and
age-related macular degeneration (AMD), precise characterization of the disease phenotype
remains elusive. In both diseases, much of the focus has necessarily been on the loss of cone
function, since visual fields, acuity and contrast sensitivity are typically measured under
photopic conditions. In RP, we need a greater understanding of patterns of rod loss since
most disease-causing mutations affect primarily rods. In AMD, recent findings have shown that
scotopic sensitivity can be much more affected than conventional photopic measurements such
as visual acuity. For patients, however, it is difficult to maintain stable fixation,
especially when central vision is compromised. A new fundus-guided microperimeter, the MP-3S,
has been developed by Nidek, Inc. to circumvent this problem. The investigators will evaluate
the value of this device for following rod and cone loss in patients with either RP or AMD.
age-related macular degeneration (AMD), precise characterization of the disease phenotype
remains elusive. In both diseases, much of the focus has necessarily been on the loss of cone
function, since visual fields, acuity and contrast sensitivity are typically measured under
photopic conditions. In RP, we need a greater understanding of patterns of rod loss since
most disease-causing mutations affect primarily rods. In AMD, recent findings have shown that
scotopic sensitivity can be much more affected than conventional photopic measurements such
as visual acuity. For patients, however, it is difficult to maintain stable fixation,
especially when central vision is compromised. A new fundus-guided microperimeter, the MP-3S,
has been developed by Nidek, Inc. to circumvent this problem. The investigators will evaluate
the value of this device for following rod and cone loss in patients with either RP or AMD.
Inclusion Criteria:
- clear media
- diagnosis of RP or non neovascular AMD
- normal volunteers
Exclusion Criteria:
- exudative AMD
- other eye diseases that could cause vision loss
- physical ailments that would preclude comfortable testing
- unable to provide informed consent
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