eprintid: 10204534 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/20/45/34 datestamp: 2025-02-11 10:07:14 lastmod: 2025-02-11 10:07:14 status_changed: 2025-02-11 10:07:14 type: article metadata_visibility: show sword_depositor: 699 creators_name: Wemyss, Thomas Alan creators_name: Rana, Anubhuti creators_name: Hillman, Sara L creators_name: Nixon-Hill, Miranda creators_name: Yadav, Kapil creators_name: Dadhwal, Vatsla creators_name: Leung, Terence S title: Diagnosing anaemia via smartphone colorimetry of the eye in a population of pregnant women ispublished: pub divisions: UCL divisions: B02 divisions: B04 divisions: D11 divisions: F42 divisions: G12 note: Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 license, https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. abstract: Objective. Screening for disease using a smartphone camera is an emerging tool for conditions such as jaundice and anaemia, which are associated with a colour change (yellowing in jaundice; pallor in anaemia) of the external tissues. Based on this, we aimed to test a technique to non-invasively screen for anaemia in a population highly affected by anaemia: pregnant women in India. In this group, anaemia can have severe health consequences for both the mother and child. Approach. Over 3 years of data collection, in 486 pregnant women in India, we attempted to replicate a previously successful smartphone imaging technique to screen for anaemia. Using smartphone images of the eye and eyelid, we compared two techniques (white balancing and ambient subtraction) to control for variation in ambient lighting, and then extracted 'redness' features from images, which we used as features to predict anaemia via statistical modelling. Main results. We found that we were not able to predict anaemia with enough accuracy to be clinically useful, at 89.6% sensitivity and 26.1% specificity. We consider the hypothesis that this may be due to pigmentation on the sclera and palpebral conjunctiva. Visual judgement showed that pigmentation on the sclera, which may affect the measured colour, is more prevalent in pregnant women in India than in preschool aged children in Ghana (a population previously studied in this context). When participants with subjectively judged visible scleral pigmentation are removed, ability to screen for anaemia using the smartphone images slightly improves (93.1% sensitivity, 28.6% specificity). Significance. These findings provide evidence to reinforce that applying smartphone imaging techniques to understudied populations in the real world requires caution—a promising result in one group may not necessarily transfer to another demographic. date: 2025-01 date_type: published publisher: IOP Publishing official_url: https://doi.org/10.1088/1361-6579/adab4d oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2354057 doi: 10.1088/1361-6579/adab4d medium: Print-Electronic lyricists_name: Wemyss, Thomas lyricists_name: Leung, Terence lyricists_name: Hillman, Sara lyricists_id: TAWEM65 lyricists_id: TSTLE21 lyricists_id: SMANN54 actors_name: Leung, Terence actors_id: TSTLE21 actors_role: owner full_text_status: public publication: Physiological Measurement volume: 13 number: 1 article_number: 01NT01 event_location: England issn: 0967-3334 citation: Wemyss, Thomas Alan; Rana, Anubhuti; Hillman, Sara L; Nixon-Hill, Miranda; Yadav, Kapil; Dadhwal, Vatsla; Leung, Terence S; (2025) Diagnosing anaemia via smartphone colorimetry of the eye in a population of pregnant women. Physiological Measurement , 13 (1) , Article 01NT01. 10.1088/1361-6579/adab4d <https://doi.org/10.1088/1361-6579%2Fadab4d>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10204534/1/Wemyss_2025_Physiol._Meas._13_01NT01.pdf