Comparing image quality and trachoma detection across three camera types from a survey in Kongwa, Tanzania.

BACKGROUND: There is an increasing demand for photography for trachoma prevalence surveys. In previous studies, digital single lens reflex (DSLR) images were superior to smartphone images, but newer-model smartphones and/or lens attachments may be able to bridge this gap. This study compares the image quality and ability to detect trachomatous inflammation - follicular (TF) of three camera types: a DSLR Nikon camera, an iPhone SE and an iPhone 13 Pro with a cell scope. METHODS: We surveyed 62 children ages 1-7 y from two Tanzanian communities. Upper tarsal conjunctiva images of both eyes were graded for TF by two standardized graders. The McNemar's test and a logistic regression model were used for analyses. RESULTS: The DSLR camera malfunctioned during the study, thus the iPhone SE and iPhone 13 Pro with cell scope were both more likely to take high-quality, gradable photographs (88% and 86%, respectively) compared with the DSLR camera (69%) (p<0.001 and p=0.02, respectively). TF was detected in gradable images from the iPhone SE (8.8%) and iPhone 13 Pro with cell scope (9.0%) at the same rate (p=1.0) as images from the DSLR camera (9.7%). CONCLUSION: Smartphones with high-quality image capture, like the iPhone SE/13 Pro, have the potential for use in trachoma surveys if the proportion of gradable images can be improved.

Sensitivity and specificity of computer vision classification of eyelid photographs for programmatic trachoma assessment.

BACKGROUND/AIMS: Trachoma programs base treatment decisions on the community prevalence of the clinical signs of trachoma, assessed by direct examination of the conjunctiva. Automated assessment could be more standardized and more cost-effective. We tested the hypothesis that an automated algorithm could classify eyelid photographs better than chance. METHODS: A total of 1,656 field-collected conjunctival images were obtained from clinical trial participants in Niger and Ethiopia. Images were scored for trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense (TI) according to the simplified World Health Organization grading system by expert raters. We developed an automated procedure for image enhancement followed by application of a convolutional neural net classifier for TF and separately for TI. One hundred images were selected for testing TF and TI, and these images were not used for training. RESULTS: The agreement score for TF and TI tasks for the automated algorithm relative to expert graders was κ = 0.44 (95% CI: 0.26 to 0.62, P < 0.001) and κ = 0.69 (95% CI: 0.55 to 0.84, P < 0.001), respectively. DISCUSSION: For assessing the clinical signs of trachoma, a convolutional neural net performed well above chance when tested against expert consensus. Further improvements in specificity may render this method suitable for field use.

Meibography of Eyes With Sequelae of Trachoma.

PURPOSE: To study the effect of trachoma on meibomian glands using infrared meibography and to correlate the results with tear film parameters. METHODS: This is a prospective cohort study in which 86 eyes of healthy volunteers and 90 eyes with trachoma were included. Clinical assessment was performed including the following: slit-lamp examination looking for signs of sequelae of trachoma, tear breakup time (TBUT), superficial punctate keratopathy (SPK), Schirmer II test (with anesthesia), and meibum score. Noncontact meibography was performed on both upper and lower eyelids separately using the meibograde system, which involved distortion of the meibomian gland, shortening, and dropout. RESULTS: Lid margin abnormalities (telangiectasia, lid margin swelling, and hyperemia) were all significantly higher in the trachoma group. The mean SPK (1.36), meibum score (1.76), meibography dropout, distortion, shortening, and total meibography (8.19 for upper eyelids and 3.81 for lower eyelids) were all significantly higher in the trachoma group (P < 0.001) compared with the normal group were SPK (0.88), meibum score (0.16), and total meibography (1.24 for upper eyelids and 0.92 for lower eyelids). Mean TBUT (4.2 s) was significantly shorter in the trachoma group than in the normal group (10.3 s) (P < 0.001). There was no significant difference between both groups in the Schirmer II test. CONCLUSIONS: Meibography of patients with sequelae of trachoma was in agreement with the histopathologic studies. Upper eyelids were much more affected than the lower eyelids. TBUT, SPK, and meibum score were correlated with the status of meibomian glands and meibography, which were significantly different in the trachoma group.

Use of an inexpensive magnifier with light source in the diagnosis of trichiasis among community-based case finders in Nigeria.

PURPOSE: Trichiasis case finding is challenging in many trachoma endemic countries. We sought to determine how the use of an inexpensive hand-held magnifier with light source aids in the diagnosis of people with trichiasis. METHODS: We undertook a study on the use of the "Wilson", an inexpensive hand-held magnifier with light source between two groups of trained case finders: community drug distributors (CDD) volunteers and non-health volunteers. Each group was randomly allocated to be provided a Wilson or not. We compared the number of people with suspected trichiasis and the proportion of true cases referred by each group. Focus group discussions explored the perceptions of the case finders that used the Wilson on its utility in the diagnosis of trichiasis and its ease of use. RESULTS: Among the 121 case finders, 61 were CDD volunteers (31 were provided the Wilson) and 60 were non-health worker volunteers (30 were provided the Wilson). Case finders that used the Wilson were 4.57 times (95% CI 2.46-8.47) more likely to have patients presenting confirmed as trichiasis compared to those not using the Wilson. Case finders that used the Wilson felt the instrument was easy to use, enlarged the eyelashes and made diagnoses of trichiasis easier. DISCUSSION: In Nigeria it appears that the Wilson is easy to handle and use among trichiasis case finders enhances the diagnosis of trichiasis.