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     The novel article published in EYE, Nature’s Magazine: Relative Foveal Dark Adaptation: A Potential Method for Assessing Macular Health. 2024, J S Kane, M Gaspich, A Gold, H Pichardo, S A Kane. This study (Eye; https://doi.org/10.1038/s41433-024-03201-2), describes MacDx.pro app provided by AMA Optics, Inc.A novel method for measuring dark adaptation of foveal cones relative to perifoveal rods and cones that utilizes the shift of a visual anchor at the endpoint after a recovery period to normal vision. Relative foveal dark adaptation was studied in 6 normal subjects ranging in age from 20 to 81 years and across differing testing conditions. Testing time in normal subjects was typically less than a minute per test. An anchor shifting endpoint from surround to center of a bullseye stimulus following 30 seconds of foveal bleaching was reproducible and unaffected by ambient room lighting, pupil size, and light attenuation. Repeating fovea dark adaptation at 15,30,60, and 90 seconds of white light bleaching is seen in the figure below which illustrates increased recovery time with increase bleaching time and age. Repeat, sequential testing was similarly reproducible except after long bleaching times. This paradigm more directly assesses macular health than currently available methods of dark adaptation that assess peripheral retinal health. Foveal dark adaptation is intuitive and reproducible, and testing times are brief, requiring only an iPhone screen positioned at reading distance. Relative foveal dark adaptation may be a useful tool to assess macular health. One case of cystoid macular edema post-cataract was detected and treated in the study.

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​        In 1921, Selig Hecht, PhD at Columbia University in NYC was the first to measure the foveal function, called Foveal Dark Adaptation, that measured recovery time at 7.1 seconds using a red-cross target. Testing averaged 1.5 hours per test, the pupil size and room luminance were important variables. Methodology was too difficult to convert to a clinical test.
     In 2021, 100 years after Dr Hecht’s report, Albert J. Hofeldt, MD, was granted the US Patent: Relative Focal Photo-Stress, US Patent 9,089,257. Hofeldt studies focused on the psychophysical properties of the bullseye having a white center and a surrounding white annulus. While the subject observes the bleaching light on the fovea, the center disc of the bullseye focuses on active to passive foveal function, causing the bullseye center to turn from white to grey. After 30 seconds of white light bleaching, the view expanded to the diameter of the bullseye which allowed the fovea to fuse within the center of the surrounding non-foveal rod and cones. As the fovea recovers, the center turns from dark to white while the surrounding annulus starts turning from white to grey. The endpoint is the moment the bullseye center appears whiter than the annulus. Shifting the white anchor from the peripheral annulus to the bullseye center disc is in accordance with Weber’s law, “The brightest point of a visual field is the brightest spot".

     A new patent is allowed by USPTO, which provides color light bleaching to expand the application of the Relative Foveal Dark Adaptation. MacHealth.pro and MacDx.pro are fast, easy and accurate, which makes it applicable for identifying macular disease by iPhone/iPad/MacBook at home, the first test for patients at home to screen for macular disease.

     The app has two models, MacHealth (99¢ for 30 tests) for all people and MacDx® for professionals ($99.00/month), both available from The Apple Store. CPT code is 92284, billing as advised by your provider. The devices: Federal Drug Authority, Product Code QUM, #886.1050, AMA Optics, Inc.

     Those interested in registered research, please call 305 389 0928. (Albert Hofeldt, MD)

     Those wishing testing help, please call 305 538 7696 (MacHealth)