This is a Phase I, single center, open-label study of the dietary supplement calcium formate in normal, healthy female subjects. The purpose of the study is to determine whether daily use of calcium formate is safe and whether it accumulates in the eye.
This is a Phase I, single center, open-label study of the dietary supplement calcium formate in normal, healthy female subjects. The purpose of the study is to determine whether daily use of calcium formate is safe and whether it accumulates in the eye.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
PREVENTION
Masking
NONE
Enrollment
12
Calcium formate - Each uncoated white tablet will contain 650 mg of calcium formate, (equivalent to 200 mg elemental calcium). Nephro-Tech, LLC, will formulate and provide the calcium formate tablets for the study.
University of Wisconsin Hospital and Clinics
Madison, Wisconsin, United States
Vision Testing (refraction) over baseline
Participants will be refracted at baseline and the resultant lens correction will be used for testing visual acuity at all subsequent visits. If a participant's visual acuity drops 10 letters or more at any visit, the participant will be re-refracted and the visual acuity will be tested again with the new lens correction in place.
Time frame: Up to 15 days
Change in Serum Formate Levels over baseline
To test for accumulation of formate, morning blood samples for determination of formate will be obtained at screening, prior to administration of the first dose of calcium formate on Study Days 1, 2, 3, and 8 and on day 15. Blood samples for determination of formate will also be obtained approximately 40-60 minutes after ingestion of the second dose on Study Days 1, 2 and 3.
Time frame: Up to 15 days
Change in Visual Acuity over baseline
Based on retroilluminated Chart R from Ferris-Bailey Early Treatment Diabetic Retinopathy Study (ETDRS) distance visual acuity chart set.
Time frame: Up to 15 days
Change in 100 Hue Vision Testing results over baseline
The FM-100 Hue test will be utilized to assess color vision at baseline and at the conclusion of the study. This test requires the arrangement of 100 discs of varying hues in an orderly sequence. The test requires 15 minutes to complete and is noninvasive. The test is scored by a computer.
Time frame: Up to 15 days
Change in ERG/VEP over baseline
Change in electroretinography (ERG) and visual-evoked potential will be monitored over baseline.
Time frame: Up to 15 days
Change in Visual Fields over baseline
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Automated standardized Humphrey 24-2 visual fields will be performed using the SITA (Swedish Interactive Threshold Algorithm) protocol. This test is standard of care for the assessment and follow-up of optic nerve disorders such as glaucoma or optic neuropathy. It will be performed in the customary manner for evaluation of mean defect.
Time frame: Up to 15 days
Fundus Photography
Stereoscopic color fundus photographs of both eyes will be taken with a 30 degree fundus camera at baseline, at day 2 and day 8 of study tablet administration 40-60 minutes after the second dose, and at study completion (day 15), early termination, or if a vision drop or AE occurs. These will be compared individually for changes including macular edema, retinal or optic nerve abnormalities or other abnormalities occurring from baseline.
Time frame: Up to 15 days