Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Apr 1;15(4):2671-2681.
doi: 10.21037/qims-24-2146. Epub 2025 Mar 10.

Choroidal thinning can be assessed through facial video analysis

Qinghua He #  1 , Yi Zhang #  1 , Mengxi Shen  2 , Giovanni Gregori  2 , Philip J Rosenfeld  2 , Ruikang K Wang  1   3
Affiliations

Choroidal thinning can be assessed through facial video analysis

Qinghua He et al. Quant Imaging Med Surg. .

Abstract

Background: Different features of skin are associated with various medical conditions and provide opportunities to evaluate and monitor body health. This study created a strategy to assess choroidal thinning through the video analysis of facial skin.

Methods: Videos capturing the entire facial skin were collected from 48 participants with age-related macular degeneration (AMD) and 12 healthy individuals. These facial videos were analyzed using video-based trans-angiosomes imaging photoplethysmography (TaiPPG) to generate facial imaging biomarkers that were correlated with choroidal thickness (CT) measurements. The CT of all patients was determined using swept-source optical coherence tomography (SS-OCT).

Results: The results revealed the relationship between relative blood pulsation amplitude (BPA) in three typical facial angiosomes (cheek, side-forehead, and mid-forehead) and the average macular CT (r=0.48, P<0.001; r=-0.56, P<0.001; r=-0.40, P<0.01). When considering a diagnostic threshold of 200 µm for CT, the newly developed facial video analysis tool effectively distinguished between cases of choroidal thinning and normal cases, yielding areas under the curve of 0.75, 0.79, and 0.69.

Conclusions: These findings shed light on the connection between choroidal blood flow and facial skin hemodynamics, which suggests the potential for predicting vascular diseases through widely accessible skin imaging data.

Keywords: Photoplethysmography; blood pulsation amplitude (BPA); choroidal thinning prediction; facial skin video; swept-source optical coherence tomography (SS-OCT).

PubMed Disclaimer

Conflict of interest statement

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-2146/coif). R.K.W. serves as a Deputy Editor of Quantitative Imaging in Medicine and Surgery. R.K.W. discloses intellectual property owned by the Oregon Health and Science University and the University of Washington. R.K.W. also receives research support from Research to Prevent Blindness, Inc., Carl Zeiss Meditec Inc., Colgate Palmolive Company, and Estee Lauder Inc. He is a consultant to Carl Zeiss Meditec and Cyberdontics. G.G. receives research support from Carl Zeiss Meditec, Inc. He and the University of Miami co-owned a patent that is licensed to Carl Zeiss Meditec, Inc. P.J.R. received research support from Research to Prevent Blindness, Inc., Carl Zeiss Meditec, Inc., and Gyroscope Therapeutics. P.J.R. and the University of Miami co-own a patent that is licensed to Carl Zeiss Meditec, Inc. P.J.R. is also a consultant for Abbvie, Annexon, Apellis, Boehringer-Ingelheim, Carl Zeiss Meditec, Chengdu Kanghong Biotech, Genentech/Roche, InflammX Therapeutics, Ocudyne, Regeneron Pharmaceuticals, and Unity Biotechnology. He also has equity interest in Apellis, InflammX, Ocudyne, and Valitor. The other authors have no conflicts of interest to declare.

Figures

Figure 1
Figure 1
TaiPPG measurements and CT measurement workflows. (A) Clinical setup for TaiPPG, including facial skin illumination by a ring LED and imaging with a 16-bit camera. (B) Regions of the cheek, side-forehead, and mid-forehead selected using a modified 81-point face landmark detection algorithm. (C) Regional PPG pulses extracted from video data and processed with a lock-in amplification algorithm. (D) Calculated BPA. (E) Relative BPA normalized by the whole face: yellow indicates relative cheek BPA, dark blue represents relative side-forehead BPA, and light blue corresponds to relative central-forehead BPA. (F) Photograph of OCT scanning in clinical settings. (G) OCT B-scans to measure CT. (H) En-face projection map of CT based on OCT B-scans. LED, light-emitting diode; OCT, optical coherence tomography; CT, choroidal thickness; BPA, blood pulsation amplitude; TaiPPG, trans-angiosomes imaging photoplethysmography; PPG, photoplethysmography.
Figure 2
Figure 2
Relative BPA and CT maps in six typical cases. (A) Relative BPA maps for cases with increasing relative cheek BPA values. The top row shows pixelated facial BPA maps, and the bottom row displays relative BPA values in the outlined central forehead, side forehead, and cheek regions. (B) Corresponding SS-OCT B-frames and CT maps for the cases shown in (A). CT maps are generated by measuring the distance between the Bruch’s membrane (blue line) and the choroid-sclera interface (yellow line). Representative B-frames are extracted from positions marked with black dotted lines on the CT maps. BPA, blood perfusion amplitude; CT, choroidal thickness; OD, right eye; OS, left eye; SS-OCT, swept-source optical coherence tomography.
Figure 3
Figure 3
Analysis of the correlation between MCT and facial BPA. (A-C) Plots of correlation between MCT and relative BPA values in the (A) cheek, (B) side forehead, and (C) central forehead. (D-F) AUROC for distinguishing choroidal thinning (<200 µm) from non-thinning (≥200 µm) groups, based on BPA values from the (D) cheek, (E) side forehead, and (F) central forehead. AUROC values are reported as mean ± standard deviation. MCT, mean choroidal thickness; BPA, blood perfusion amplitude; AUROC, area under the receiver operating characteristic curve.
Figure 4
Figure 4
Illustration of our proposed collateral circulation mechanism depicting the correlation between CT and relative cheek BPA levels. Blue indicates decreased perfusion; red indicates increased perfusion. OA, ophthalmic artery; FA, facial artery; DNA, dorsal nasal arteries; ICA, internal carotid artery; ECA, external carotid artery; CT, choroid thickness; BPA, blood pulsation amplitude.
See this image and copyright information in PMC

References

    1. Nickla DL, Wallman J. The multifunctional choroid. Prog Retin Eye Res 2010;29:144-68. 10.1016/j.preteyeres.2009.12.002 - DOI - PMC - PubMed
    1. Parver LM, Auker C, Carpenter DO. Choroidal blood flow as a heat dissipating mechanism in the macula. Am J Ophthalmol 1980;89:641-6. 10.1016/0002-9394(80)90280-9 - DOI - PubMed
    1. Grunwald JE, Metelitsina TI, Dupont JC, Ying GS, Maguire MG. Reduced foveolar choroidal blood flow in eyes with increasing AMD severity. Invest Ophthalmol Vis Sci 2005;46:1033-8. 10.1167/iovs.04-1050 - DOI - PubMed
    1. Langham ME, Grebe R, Hopkins S, Marcus S, Sebag M. Choroidal blood flow in diabetic retinopathy. Exp Eye Res 1991;52:167-73. 10.1016/0014-4835(91)90256-E - DOI - PubMed
    1. Margolis R, Spaide RF. A pilot study of enhanced depth imaging optical coherence tomography of the choroid in normal eyes. Am J Ophthalmol 2009;147:811-5. 10.1016/j.ajo.2008.12.008 - DOI - PubMed

LinkOut - more resources