Dataset Information

Comparison of Smartphone Photography, Single-Lens Reflex Photography, and Field-Grading for Trachoma.

ABSTRACT: Conjunctival examination for trachomatous inflammation-follicular (TF) guides public health decisions for trachoma. Smartphone cameras may allow remote conjunctival grading, but previous studies have found low sensitivity. A random sample of 412 children aged 1-9 years received an in-person conjunctival examination and then had conjunctival photographs taken with 1) a single-lens reflex (SLR) camera and 2) a smartphone coupled to a 3D-printed magnifying attachment. Three masked graders assessed the conjunctival photographs for TF. Latent class analysis was used to determine the sensitivity and specificity of each grading method for TF. Single-lens reflex photo-grading was 95.0% sensitive and 93.6% specific, and smartphone photo-grading was 84.1% sensitive and 97.6% specific. The sensitivity of the smartphone-CellScope device was considerably higher than that of a previous study using the native smartphone camera, without attachment. Magnification of smartphone images with a simple attachment improved the grading sensitivity while maintaining high specificity in a region with hyperendemic trachoma.

SUBMITTER: Nesemann JM

PROVIDER: S-EPMC7695070 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

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Comparison of Smartphone Photography, Single-Lens Reflex Photography, and Field-Grading for Trachoma.

Nesemann John M JM Seider Michael I MI Snyder Blake M BM Maamari Robi N RN Fletcher Daniel A DA Haile Berhan A BA Tadesse Zerihun Z Varnado Nicole E NE Cotter Sun Y SY Callahan Elizabeth Kelly EK Emerson Paul M PM Margolis Todd P TP Lietman Thomas M TM Keenan Jeremy D JD

The American journal of tropical medicine and hygiene 20201001 6

Conjunctival examination for trachomatous inflammation-follicular (TF) guides public health decisions for trachoma. Smartphone cameras may allow remote conjunctival grading, but previous studies have found low sensitivity. A random sample of 412 children aged 1-9 years received an in-person conjunctival examination and then had conjunctival photographs taken with 1) a single-lens reflex (SLR) camera and 2) a smartphone coupled to a 3D-printed magnifying attachment. Three masked graders assessed ...[more]

PMID: 33021196

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Project description:BackgroundClinical examination of trachoma is used to justify intervention in trachoma-endemic regions. Currently, field graders are certified by determining their concordance with experienced graders using the kappa statistic. Unfortunately, trachoma grading can be highly variable and there are cases where even expert graders disagree (borderline/marginal cases). Prior work has shown that inclusion of borderline cases tends to reduce apparent agreement, as measured by kappa. Here, we confirm those results and assess performance of trainees on these borderline cases by calculating their reliability error, a measure derived from the decomposition of the Brier score.Methods and findingsWe trained 18 field graders using 200 conjunctival photographs from a community-randomized trial in Niger and assessed inter-grader agreement using kappa as well as reliability error. Three experienced graders scored each case for the presence or absence of trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense (TI). A consensus grade for each case was defined as the one given by a majority of experienced graders. We classified cases into a unanimous subset if all 3 experienced graders gave the same grade. For both TF and TI grades, the mean kappa for trainees was higher on the unanimous subset; inclusion of borderline cases reduced apparent agreement by 15.7% for TF and 12.4% for TI. When we assessed the breakdown of the reliability error, we found that our trainees tended to over-call TF grades and under-call TI grades, especially in borderline cases.ConclusionsThe kappa statistic is widely used for certifying trachoma field graders. Exclusion of borderline cases, which even experienced graders disagree on, increases apparent agreement with the kappa statistic. Graders may agree less when exposed to the full spectrum of disease. Reliability error allows for the assessment of these borderline cases and can be used to refine an individual trainee's grading.

Project description:BackgroundAs the prevalence of trachoma declines worldwide, it is becoming increasingly expensive and challenging to standardize graders in the field for surveys to document elimination. Photography of the tarsal conjunctiva and remote interpretation may help alleviate these challenges. The purpose of this study was to develop, and field test an Image Capture and Processing System (ICAPS) to acquire hands-free images of the tarsal conjunctiva for upload to a virtual reading center for remote grading.Methodology/principal findingsThis observational study was conducted during a district-level prevalence survey for trachomatous inflammation-follicular (TF) in Chamwino, Tanzania. The ICAPS was developed using a Samsung Galaxy S8 smartphone, a Samsung Gear VR headset, a foot pedal trigger and customized software allowing for hands-free photography. After a one-day training course, three trachoma graders used the ICAPS to collect images from 1305 children ages 1-9 years, which were expert-graded remotely for comparison with field grades. In our experience, the ICAPS was successful at scanning and assigning barcodes to images, focusing on the everted eyelid with adequate examiner hand visualization, and capturing images with sufficient detail to grade TF. The percentage of children with TF by photos and by field grade was 5%. Agreement between grading of the images compared to the field grades at the child level was kappa = 0.53 (95%CI = 0.40-0.66). There were ungradable images for at least one eye in 199 children (9.1%), with more occurring in children ages 1-3 (18.5%) than older children ages 4-9 (4.2%) (χ2 = 145.3, p<0.001).Conclusions/significanceThe prototype ICAPS device was robust, able to image 1305 children in a district level survey and transmit images from rural Tanzania to an online grading platform. More work is needed to improve the percentage of ungradable images and to better understand the causes of disagreement between field and photo grading.

Dataset Information

Comparison of Smartphone Photography, Single-Lens Reflex Photography, and Field-Grading for Trachoma.

Publications

Comparison of Smartphone Photography, Single-Lens Reflex Photography, and Field-Grading for Trachoma.

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