Clinical trial NCT03322930: Rod Sensitivity in Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP)
Official title: Rod Sensitivity in Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP)
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Retinitis Pigmentosa
AMD
Keywords: microperimetry
rod visual fields
Lead sponsor: Retina Foundation of the Southwest
Sponsor class: OTHER
First posted: 2017-10-26
Enrollment: 40
Sex: ALL
Minimum age (years): 10
Maximum age (years): 85
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_ONLY
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: 50 subjects with retinitis pigmentosa 50 patients with AMD 10 normal volunteers ages 18 to 40 and 10 normal volunteers ages over age 55 years

Brief summary: A new fundus-guided microperimeter (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.

Detailed description: 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.

Eligibility criteria: 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

Primary outcomes:
measure: Rod Sensitivity Within the Central Retina as Measured on the Nidek MP-3S
timeFrame: through study completion, an average of 1 year
Secondary outcomes:
Other outcomes:
Locations:
city: Dallas
country: United States
facility: Retina Foundation of the Southwest
state: Texas
Study officials:
affiliation: Retina Foundation of the Southwest
name: David G Birch, PhD
role: PRINCIPAL_INVESTIGATOR
References: