Bullseye Center Method

Foveal Adaptation After 100 Years Wait

by Albert J. Hofeldt, MD.

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     Can you imagine, using an iPhone to measure your vision? We have waited 100 years to capturing foveal vision, the very center of vision. Foveal Dark Adaptation measures light bleaching of the fovea and recovery of the foveal photoreceptors. The iPhone, iPad and MacBook are the first instruments developed to detect slow recovery from foveal bleaching. Simple automated iPhone testing on MacHealth.pro is easy outside the doctor’s office, even at home. This is AMA Optics, Inc. first remote testing for macular diseases that does not duplicate eye doctor’s tests. Download the app from Apple store, play it on the iPhone. The professional group listed below found it fast, easy and accurate to use with built-in tutorial teaching. In USA, there are there are listed 35 million diabetics and 22 million with AMD retinopathy, patients awaiting early diagnosis now and regularly.

     A dark adaptation test of the fovea was impossible in the late 1800s when ERG (electroretinogram) became able to measure the peripheral rods and cones. The cones of the fovea were very different, thought by experts to be too fast to measure.

     In 1921, Selig Hecht, PhD at Columbia University in NYC was the first to measure the foveal function, called Foveal Dark Adaptation, which measured 7.1 seconds in duration 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 use as 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 target having a white center and a peripheral white annulus. While the subject observes the bleaching light on the iPhone which is aligned with the center disc of the bullseye, changed the subject’s fovea from active to passive function. After 30 seconds of bleaching, the light dimmed and the view expands to the diameter that allows the subject to see the complete bullseye target, the center fovea and the surrounding non-foveal rod and cones. With bleaching, the center disc turns from white to dark and the covered peripheral annulus remains white. As the fovea recovers, the center starts turning from dark to white while the annulus starts turning from white to darker, the endpoint is the moment the center appears whiter than the annulus. Shifting the white anchor from the peripheral annulus to the center disc is in accordance with Weber’s law, “There is one bright object per visual field, the brightest point”.

     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 Apple app, 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. 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.

     A new patent is in application at USPTO, this patent allows color light bleaching that will expand the application of the Foveal Dark Adaptation test. Foveal dark adaptation measures the recovery time of photoreceptors which provides means to study the healthy and diseased. The test is fast, easy and accurate, which makes it applicable for identifying macular disease by iPhone/ iPad/ MacBook at home, the first test to screen for macular disease by patients at home.

     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)