Severity of Trachomatous Scarring among Adults in Trachoma-Endemic Amhara Region of Ethiopia.

Trachomatous scarring has been shown to progress regardless of active ocular Chlamydia trachomatis infection, indicating that scarring drivers may be unrelated to ongoing transmission. Although scarring prevalence is commonly associated with older age and female sex, less is known about other potential contributors to its development. This study identified and assessed risk factors associated with scarring magnitude in a trachoma-endemic setting, utilizing a five-point photographic scale (S0-S4). During 2017 trachoma surveys of Amhara, Ethiopia, photographers captured left and right conjunctival images of adults (ages 15 years and older) from 10 districts. Subsequently, two graders independently assessed photographs for scarring, with discrepancies adjudicated by an expert grader. Scarring scores for 729 individuals were aggregated from the eye level to the participant level, excluding 17 participants because of poor photograph quality. Among those with scarring, most cases (20.4%) were severe (S4, comprising more than 90% of the tarsal conjunctiva) compared with the prevalence of moderate S3-A/B (11.2%), S2 (8.3%), and mild S1 (19.2%). The youngest group (ages 15-19 years) exhibited all scarring stages. Older participants (60 years and older) experienced a greater burden of severe scarring (S4 prevalence: 32.6%) than their younger (15-19 years) counterparts (6.2%). Multivariate ordinal logistic regression models indicated female sex, increasing age, and district-level trachomatous follicular-inflammation prevalence were significant predictors of scarring severity. Trachomatous scarring and its progression to trichiasis, may prove a barrier to meeting WHO timelines for trachoma elimination and will necessitate ongoing surveillance and interventions after elimination thresholds have been met.

Validation of a New Duplex Real-Time Polymerase Chain Reaction for Chlamydia trachomatis DNA Detection in Ocular Swab Samples.

Trachoma is the world-leading infectious cause of preventable blindness and is caused by the bacteria Chlamydia trachomatis. In developing countries, diagnosis is usually based on clinical evaluation. Serological-based tests are cheaper than molecular-based ones, but the latter are more sensitive and specific. The present study developed a new duplex qPCR which concomitantly detects the C. trachomatis cryptic plasmid and the human 18S rRNA gene, with an LOD95% for C. trachomatis DNA of 13.04 genome equivalents per reaction. The new qPCR was tested using 50 samples from an endemic area and 12 from a non-endemic area that were previously characterized using direct immunofluorescence assay (DFA) and clinical evaluation. Among the 50 endemic samples, 3 were found to be positive by clinical evaluation (6%), 18 were found to be positive by DFA (36%), and 48 were found to be positive by qPCR (96%). Next, the new duplex qPCR was validated using 50 samples previously characterized by qPCR. Validation was carried out on a benchtop instrument (ABI7500) or on a portable point-of-care instrument (Q3-Plus), showing 95% specificity and 100% sensitivity. The ubiquitous presence of C. trachomatis DNA in samples from the endemic region confirms that constant monitoring is of paramount importance for the effective measurement of the elimination of trachoma. The newly developed duplex qPCR presented in this study, along with its validation in a portable qPCR system, constitutes important tools toward achieving this goal.

Comparison of two approaches to measuring clean faces as part of the facial cleanliness component of the SAFE trachoma elimination strategy.

BACKGROUND: The Alliance for the Global Elimination of Trachoma (GET) endorses the full SAFE strategy to eliminate trachoma; Surgery (for trichiasis), Antibiotics (to reduce the community pool of infection, Facial cleanliness, and Environmental improvement (to decrease transmission). There is no accepted measure of facial cleanliness. This study compared two possible metrics for facial cleanliness. METHOD/FINDINGS: Metric one: Clean face was defined as observed absence of ocular and nasal discharge on the face. Metric two: observing a grade of dirtiness (scale 10 = lightest to 0 = darkest) on a standard facial wipe. The reliability of grading a child's face or grading a facial wipe was determined in children in Kongwa Tanzania. We also observed both measurements in a cohort of 202 children ages 1 to <7years prior to face cleaning, immediately afterwards, and 4 hours afterwards. Fifty of the children did not have face cleaning and were controls. Intra-and interobserver reliability was similar for both measures, the latter = 0.53 for observing a clean face and 0.52 for grading a facial wipe. There was no correlation between the two. Both measures detected facial cleaning, compared to control children who were not cleaned, immediately after cleaning; control children with 53% clean faces and wipe score of 6.7 compared to cleaned children with 88% clean faces and wipe score of 8 (p = .0001, p = < .0001, respectively). Both measures also detected face washing 4 hours previously compared to controls. CONCLUSIONS: The two metrics were equally reliable, and both measured the behavior of face washing. They measure different aspects of a clean face; one measures the amount of dirt on wiped area and the other measures ocular and nasal discharge. Both measurements appear to capture the behavior of facial cleaning, and the choice of metric would appear to rest on the measurement that captures the stated objective of the behavior, consideration of costs, training, logistics, and implementation.

Efficacy of Single-Dose Azithromycin for Ocular Chlamydial Infection: A Longitudinal Study.

Millions of doses of azithromycin are distributed each year for trachoma, yet the treatment efficacy of a single dose of azithromycin for ocular Chlamydia infection has not been well characterized. In this study, four villages in Niger received a mass azithromycin distribution for trachoma. All 426 children aged 0-5 years residing in the study villages were offered conjunctival swabbing every 6 months to test for ocular Chlamydia trachomatis. Among the children infected with ocular Chlamydia before treatment, 6% (95% CI: 2-15%) tested positive for ocular Chlamydia infection 6 months later, and 15% (95% CI: 7-28%) tested positive 12 months later. The most important predictor of post-treatment ocular Chlamydia infection was pretreatment ocular Chlamydia infection (relative risk: 3.5, 95% CI: 1.3-9.4). Although the 6-monthly monitoring schedule was suboptimal for testing the treatment efficacy of an antibiotic, these findings are nonetheless consistent with high treatment efficacy of a single dose of azithromycin and suggest that additional interventions might be most effective if targeted to those children infected prior to treatment.

Visual Impairment and Real-World Home Physical Activity With Home Environment in an Older Population.

Importance: Physical activity levels are lower in visual impairment. However, additional factors, such as home environmental features, which can modify physical activity in this group, are unknown. Objective: To investigate the association between home environment features and home physical activity in patients with visual impairment. Design, Setting, and Participants: This cross-sectional study of clinical patients included participants with glaucoma suspect and primary glaucoma who were 60 years or older with varying degrees of visual field damage. Study participants were recruited from the Johns Hopkins Wilmer Eye Institute Glaucoma Clinic, Baltimore, Maryland, from September 2013 through March 2015. Data were analyzed from December 19, 2022, through December 25, 2022. Main Outcomes and Measures: Total in-home steps taken per day was the primary outcome measure; time in daily home physical activity and nonsedentary activity were secondary outcomes. Results: A total of 153 participants were included in analyses with mean age of 71 (SD, 7.8) years and 71 were female (46%). Sixty percent had more than 1 comorbid illness, about one-third took 5 or more prescription drugs, and median daily home steps were 1137. Median integrated visual field sensitivity was 28 dB. Better-eye median visual acuity in logMAR was 0.05 (20/22 Snellen equivalent). For every 0.1-log unit increment in average measured home lighting, participants took 5% more daily steps (rate ratio [RR], 1.05; 95% CI, 1.00-1.10; P = .04) and had a 3% faster average daily peak cadence (RR, 1.03; 95% CI, 1.01-1.05; P = .01). The average number of nonsedentary activity minutes (RR, 1.04; 95% CI, 1.00-1.07; P = .06), average bout duration (ß = 0.03; 95% CI, 0.00-.07; P = .06), and activity fragmentation (ß = -0.06; 95% CI, -0.13 to 0.00; P = .06) showed associations with home lighting. The number of hazards was not associated with any activity metric (steps: RR, 1.14; 95% CI, 0.96-1.34; P = .13; peak cadence: RR, 1.00; 95% CI, 0.93-1.08; P = .98; and nonsedentary time: RR, 1.11; 95% CI, 0.98-1.26; P = .11), nor was the frequency of hazards. Conclusions and Relevance: In this study, results demonstrated that home environment features, particularly lighting, may influence home activity metrics in older adults with visual impairment. Further prospective studies would be needed to confirm if home modifications can improve at-home activity.

Gender differences in trachomatous scarring prevalence in a formerly trachoma hyperendemic district in Tanzania.

BACKGROUND: Trachoma is a chronic conjunctivitis caused by the bacterium Chlamydia trachomatis. Repeated infections lead to trachomatous conjunctival scarring which can progress to potentially blinding trachomatous trichiasis (TT). In trachoma hyperendemic conditions, women compared to men have an increased risk of scarring and TT, which can progress to blinding corneal opacification. This study determined if there were gender differences in scarring prevalence and severity when trachoma prevalence approaches elimination, in a formerly trachoma hyperendemic region. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional prevalence study was conducted amongst adults age 15 years and older in Kongwa district, Tanzania in 2019. 3168 persons over age 15 years agreed to be examined and had at least one eye with a gradable image. Ocular photographs were graded for scarring according to a published four-step severity scale. Overall, about half of all study participants had scarring. However, more females (52.3%) had any scarring compared to males (47.2%), OR = 1.22 (95% CI = 1.05-1.43). For every year increase in age, there was a 6.5% increase in the odds of having more severe scarring (95% CI: 5.8%, 7.2%). Women were more likely than men to have severe scarring, OR 2.36 (95% CI: 1.84-3.02). Residence in a community with TF≥10% was associated with a 1.6-fold increased odds of any scarring. CONCLUSIONS/SIGNIFICANCE: Overall scarring prevalence and more severe scarring prevalence was higher in females compared to males, even adjusting for age and community TF prevalence. The data suggest that processes occur that lead to women preferentially progressing towards more severe scarring compared to men.

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.

Expanding a photographic grading system for trachomatous scarring.

BACKGROUND: The purpose was to assess an expansion of a previously published photographic four-step severity grading scale for trachomatous scarring (TS). METHODS: Images of everted eyelids of adult women in Tanzania were graded for the presence and severity of TS. The previous S3 grade was subdivided into two categories: S3A, one-third to <50% of the upper eyelid conjunctiva scarred; and S3B, 50% to <90%. The reliability and ease of use were evaluated. This new categorisation was then applied to images taken of the same women 5 y prior to evaluate whether it could help detect previously undetected progression. RESULTS: In total, 142 eyes at baseline and 418 eyes at follow-up after 5 y were graded as S3. Interobserver agreement using the expanded scarring grading scale was a kappa of 0.86. At baseline, 51 (35.9%) eyes were S3A and 91 (64.1%) were S3B. At follow-up after 5 y, 36.6% of the eyes that were previously documented as not having progressed were now detected as having progressed from S3A to S3B. S3B images were more likely to progress to S4 compared with S3A (OR 4.6, 95% CI 2.1 to 9.9). CONCLUSIONS: Adding S3A and S3B is reliable and detects more scarring progression. It will be beneficial for future studies analysing TS in photographs.

Relationship Between Intraocular Pressure and Age: A Population-Based Study in Nepal.

PRCIS: Intraocular pressure (IOP) decreased with age in a population-based study in Nepal, from a mean of 14.1 mm Hg among those 60-64 years old to 13.0 mm Hg among those 80 years old or older. PURPOSE: Few studies have assessed the distribution of IOP from the Indian subcontinent, despite its large population and high burden of glaucoma. The objective of this study was to assess the distribution of IOP measurements from adults living in a lowland region of Nepal. METHODS: In a population-based cross-sectional study, all individuals aged 60 years and older from an area of lowland Nepal were invited for an IOP assessment with a rebound tonometer. RESULTS: Of 160 communities (28,672 people aged ≥60 y) enrolled, 79 (13,808 people aged ≥60 y) were randomly selected for IOP testing. Of those eligible, 10,017 (72.5%) individuals underwent tonometry. Mean IOP decreased monotonically over 5-year age groups, from 14.1 mm Hg (SD: 3.6) among those aged 60-64 years to 13.0 mm Hg (SD: 4.2) among those 80 years or older. The 97.5th percentile IOP measurement was 21.0 mm Hg for all age groups. In adjusted analyses, younger age, self-reported diabetes, and higher population density were each associated with higher IOP, and self-reported cataract surgery was associated with lower IOP. CONCLUSIONS: Mean IOP was lower among older individuals in Nepal, consistent with many studies from East Asia and in contrast to many studies from western populations. These results suggest that ethnic background might be a consideration when diagnosing ocular hypertension.

The Association Between the Severity of Trachomatous Scarring and Trachomatous Trichiasis Severity in Surgical Patients in Tanzania.

PURPOSE: To determine the association between the severity of trachomatous conjunctival scarring (TS) of the upper eyelid conjunctiva and trachomatous trichiasis (TT) severity in TT surgical patients. METHODS: A cross-sectional study was conducted amongst adults with TT who were referred to surgical camps in Bahi District, Tanzania, for TT surgery. Participants underwent ocular examination. The presence and severity of TS was evaluated in photographs of the everted upper eyelid. TT severity was assessed at the time of the ocular exam based on the number of lashes touching the globe and/or evidence and extent of epilation. Ordinal logistic models were used to examine the association between the severity of TS and TT severity. RESULTS: A total of 627 eyes of 388 participants were included. Mean age was 65 years (ranging from 21-98), 81% were females, and 62% had bilateral TT. 93% of eyes with any TT had at least moderate TS; 62% of eyes had severe TS. An increase in TS severity was associated with an increase in the severity of TT. Using as a reference eyes with none to mild TS, in eyes with moderate TS the odds of increased severity of TT was 1.30 (95% CI 0.67-2.51), in eyes with severe TS the odds was 4.20 (95% CI 2.23-7.92). CONCLUSION: In cases of trachomatous trichiasis presenting for surgery, the severity of TT was significantly associated with the severity of TS with almost all cases of TT having moderate or severe scarring.

Monitoring transmission intensity of trachoma with serology.

Trachoma, caused by ocular Chlamydia trachomatis infection, is targeted for global elimination as a public health problem by 2030. To provide evidence for use of antibodies to monitor C. trachomatis transmission, we collated IgG responses to Pgp3 antigen, PCR positivity, and clinical observations from 19,811 children aged 1-9 years in 14 populations. We demonstrate that age-seroprevalence curves consistently shift along a gradient of transmission intensity: rising steeply in populations with high levels of infection and active trachoma and becoming flat in populations near elimination. Seroprevalence (range: 0-54%) and seroconversion rates (range: 0-15 per 100 person-years) correlate with PCR prevalence (r: 0.87, 95% CI: 0.57, 0.97). A seroprevalence threshold of 13.5% (seroconversion rate 2.75 per 100 person-years) identifies clusters with any PCR-identified infection at high sensitivity ( >90%) and moderate specificity (69-75%). Antibody responses in young children provide a robust, generalizable approach to monitor population progress toward and beyond trachoma elimination.

A Virtual Reading Center Model Using Crowdsourcing to Grade Photographs for Trachoma: Validation Study.

BACKGROUND: As trachoma is eliminated, skilled field graders become less adept at correctly identifying active disease (trachomatous inflammation-follicular [TF]). Deciding if trachoma has been eliminated from a district or if treatment strategies need to be continued or reinstated is of critical public health importance. Telemedicine solutions require both connectivity, which can be poor in the resource-limited regions of the world in which trachoma occurs, and accurate grading of the images. OBJECTIVE: Our purpose was to develop and validate a cloud-based "virtual reading center" (VRC) model using crowdsourcing for image interpretation. METHODS: The Amazon Mechanical Turk (AMT) platform was used to recruit lay graders to interpret 2299 gradable images from a prior field trial of a smartphone-based camera system. Each image received 7 grades for US $0.05 per grade in this VRC. The resultant data set was divided into training and test sets to internally validate the VRC. In the training set, crowdsourcing scores were summed, and the optimal raw score cutoff was chosen to optimize kappa agreement and the resulting prevalence of TF. The best method was then applied to the test set, and the sensitivity, specificity, kappa, and TF prevalence were calculated. RESULTS: In this trial, over 16,000 grades were rendered in just over 60 minutes for US $1098 including AMT fees. After choosing an AMT raw score cut point to optimize kappa near the World Health Organization (WHO)-endorsed level of 0.7 (with a simulated 40% prevalence TF), crowdsourcing was 95% sensitive and 87% specific for TF in the training set with a kappa of 0.797. All 196 crowdsourced-positive images received a skilled overread to mimic a tiered reading center and specificity improved to 99%, while sensitivity remained above 78%. Kappa for the entire sample improved from 0.162 to 0.685 with overreads, and the skilled grader burden was reduced by over 80%. This tiered VRC model was then applied to the test set and produced a sensitivity of 99% and a specificity of 76% with a kappa of 0.775 in the entire set. The prevalence estimated by the VRC was 2.70% (95% CI 1.84%-3.80%) compared to the ground truth prevalence of 2.87% (95% CI 1.98%-4.01%). CONCLUSIONS: A VRC model using crowdsourcing as a first pass with skilled grading of positive images was able to identify TF rapidly and accurately in a low prevalence setting. The findings from this study support further validation of a VRC and crowdsourcing for image grading and estimation of trachoma prevalence from field-acquired images, although further prospective field testing is required to determine if diagnostic characteristics are acceptable in real-world surveys with a low prevalence of the disease.

Association of Optic Nerve Head and Macular Optical Coherence Tomography Measures With Glaucoma-Related Disability.

PRCIS: Optical coherence tomography (OCT) estimated retinal nerve fiber layer (RNFL) thickness associated with glaucoma-related disability independent of the visual field (VF) damage and thus may provide additional patient-relevant disability information beyond what is captured by standard VF testing. PURPOSE: To examine whether OCT metrics [peripapillary RNFL thickness and macular ganglion cell/inner plexiform layer (GCIPL) thickness] are associated with quality of life (QoL) measures and additional disability metrics, and whether these associations are independent of VF damage. METHODS: In this cross-sectional study, 156 patients with glaucoma or suspected glaucoma received VF testing and OCT scans to measure RNFL and GCIPL thickness. QoL was assessed using the Glaucoma Quality-of-Life 15 and additional disability measures including fear of falling, reading speed, and steps per day were assessed. Multivariable regression models adjusting for relevant covariates tested whether RNFL or GCIPL thickness from the less-impaired eye were associated with disability measures and whether associations were independent of VF damage. RESULTS: Greater VF damage is associated with worse QoL (95% CI=0.4-1.4; P <0.001) and slower reading speed (CI=-0.06 to -0.02; P <0.001). Lower RNFL and GCIPL thicknesses were associated with lower QoL scores, but not with QoL scores or other disability metrics after correcting for VF damage. However, post hoc analyses in patients with better eye thicknesses between 55 and 75 µm demonstrated associations between lower RNFL thickness and worse QoL (CI=-2.2 to -0.1; P =0.04) and greater fear of falling (CI=-6.1 to -0.4; P =0.03) even after accounting for VF damage. No such associations were observed for GCIPL thickness. CONCLUSIONS: OCT RNFL, but not GCIPL, thickness is associated with multiple disability measures independent of VF damage severity.

Global Trends in Blindness and Vision Impairment Resulting from Corneal Opacity 1984-2020: A Meta-analysis.

TOPIC: We provide global estimates of the prevalence of corneal blindness and vision impairment in adults 40 years of age and older and examine the burden by age, sex, and geographic region from 1984 through 2020. CLINICAL RELEVANCE: Corneal opacities (COs) are among the top 5 causes of blindness worldwide, yet the global prevalence, regional differences, and risk factors are unclear. METHODS: Abstracted data from the published literature and surveys were obtained from the Global Burden of Disease Vision Loss Expert Group. We supplemented this by an independent systematic literature search of several databases. Studies that provided CO vision impairment data based on population-based surveys for those 40 years of age or older were included, for a total of 244. For each of the 4 outcomes of blindness and moderate to severe vision impairment (MSVI) caused by trachomatous and nontrachomatous CO (NTCO), time trends and differences in prevalence by region, age, and sex were evaluated using a Poisson log-linear model with a generalized estimating equation method. Age-standardized estimates of global prevalence of blindness and MSVI were calculated using the 2015 United Nations standard populations. RESULTS: The global prevalence of blindness resulting from NTCO in those 40 years and older was 0.081% (95% confidence interval [CI], 0.049%-0.315%); that of MSVI was 0.130% (95% CI, 0.087%-0.372%). A significant increase with age was found (prevalence rate ratio, 2.15; 95% CI, 1.99-2.32). Latin America and Europe showed the lowest rates, with 2- to 8-fold higher rates of blindness or MSVI in other regions. The global prevalence of blindness resulting from trachomatous CO in those 50 years and older was 0.0094% (95% CI, 0%-0.0693%); that from MSVI was 0.012% (95% CI, 0%-0.0761%). Blindness resulting from trachomatous CO and MSVI increased with age and female sex, and rates were significantly higher in the African regions. A decrease in trachomatous blindness rates over time was found (prevalence rate ratio, 0.91; 95% CI, 0.86-0.96). DISCUSSION: An estimated 5.5 million people worldwide are bilaterally blind or have MSVI resulting from CO, with an additional 6.2 million unilaterally blind. Blindness resulting from trachomatous CO is declining over time, likely because of the massive scaleup of the global trachoma elimination program and overall socioeconomic development. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Monitoring transmission intensity of trachoma with serology.

Trachoma, caused by ocular Chlamydia trachomatis infection, is targeted for global elimination as a public health problem by 2030. To provide evidence for use of antibodies to monitor C. trachomatis transmission, we collated IgG responses to Pgp3 antigen, PCR positivity, and clinical observations from 19,811 children aged 1- 9 years in 14 populations. We demonstrate that age-seroprevalence curves consistently shift along a gradient of transmission intensity: rising steeply in populations with high levels of infection and active trachoma and becoming flat in populations near elimination. Seroprevalence (range: 0-54%) and seroconversion rates (range: 0-15 per 100 person-years) correlate with PCR prevalence (r: 0.87, 95% CI: 0.57, 0.97). A seroprevalence threshold of 13.5% (seroconversion rate 2.75 per 100 person-years) identifies clusters with any PCR-identified infection at high sensitivity (>90%) and moderate specificity (69-75%). Antibody responses in young children provide a robust, generalizable approach to monitor population progress toward and beyond trachoma elimination.

Comparison of Five Camera Systems for Capturing and Grading Trachoma Images.

PURPOSE: As training of trachoma graders using live participants grows increasingly difficult and expensive, alternative ways are needed possibly through replacement of field grading with photography. However, minimum specifications for a camera system capable of capturing high quality images have not been defined. This study compared images captured using four smartphones with those from a Nikon SLR camera for image quality and assessment of trachomatous inflammation - follicular (TF). METHODS: The smartphones - Samsung Galaxy S8 (S8), Techno Camon 17 pro (TC), Infinix Note 10 pro (IN), Huawei p30 pro (HP) - were chosen for their availability and likelihood of good performance based on specifications without external attachments. All smartphones were used in random order for each participant. RESULTS: 129 children in Kongwa, Tanzania were enrolled (32.8% TF prevalence). The SLR camera had the least percent of ungradable images (3.1%), followed by the S8 (14%), HP (23.4%), IN (65.9%), and TC (71.2%). The S8 and the HP were significantly more likely to take ungradable images if they were used toward the end of the camera rotation. Agreement between the SLR and field grade was kappa = 0.73. Agreement between the field grade and gradable images from the S8 (0.68) and HP (0.8) was measured. CONCLUSIONS: Published specifications did not predict the success of using different smartphones for everted eyelid photographs; proprietary post-processing software likely influenced gradeability. Smartphones, though we cannot recommend those tested in this study, may be viable for capturing images for trachoma provided the quality of images from the field are adequate.

Progression of Stargardt Disease as Determined by Fundus Autofluorescence Over a 24-Month Period (ProgStar Report No. 17).

PURPOSE: To estimate the progression rate of atrophic lesions in Stargardt disease derived from fundus autofluorescence (FAF). DESIGN: International, multicenter, prospective cohort study. METHODS: A total of 259 participants aged ≥6 years with disease-causing variants in the ABCA4 gene were enrolled from 9 centers and followed over a 24-month period. FAF images were obtained every 6 months, and areas of definitely decreased autofluorescence (DDAF) and decreased autofluorescence (DAF) were quantified. Progression rates were estimated from linear mixed models with time as the independent variable. RESULTS: A total of 488 study eyes of 259 participants (88.8% with both eyes) were enrolled and images from 432 eyes were followed for 24 months. The overall estimated progression of DDAF was 0.74 mm2/y (95% CI 0.64-0.85, P < .0001) and that of DAF was 0.64 mm2/y (95% CI 0.57-0.71) over a 24-month period in univariate analysis. Growth rates were strongly dependent on baseline lesion area. After square root transformation, the DDAF growth rate was not dependent on baseline lesion radius (P = .11), whereas the DAF growth rate was dependent (P < .0001). Genotype was not found to significantly impact the growth rate of DDAF or DAF lesions. CONCLUSIONS: FAF may serve as a convenient monitoring tool and suitable end point for interventional clinical trials that aim to slow disease progression. DDAF and DAF lesion sizes at baseline are strong predicting factors for lesion area growth and can be partially accounted for by square root transformation.

The Impact of Neighborhood Factors on Physical Activity in Older Adults With Visual Impairment.

PURPOSE: To investigate the associations of neighborhood-level socioeconomic and environmental characteristics with physical activity in persons with glaucoma. DESIGN: Cross-sectional study (N = 230). METHODS: Home addresses were used to extract neighborhood factors (NFs): Area Deprivation Index, crime rate, and the proportion of racial and ethnic minorities, poverty, college graduates, and park area in their census tract. Participants' average number of daily steps and nonsedentary minutes were collected over 7 days using an accelerometer. Visual field (VF) loss was quantified as integrated VF sensitivity. Multivariable negative binomial regression models and additional models with an interaction term evaluated the effect of NF on physical activity and whether these relationships differed by VF loss severity. RESULTS: Participants were on average 70.6 years of age, 51.7% were male, and 27.8% were black. A higher Area Deprivation Index or poverty share was associated with fewer NSM (incidence rate ratio [IRR] = 0.96 per 1 Area Deprivation Index decile increment, P = .01; IRR = 0.92 per 10% poverty share increment, P = .02), while higher share of college graduates was associated with greater NSM (IRR = 1.03 per 10% increment; P = .03). Stronger associations were noted between both high crime rate and poverty share with NSM in individuals with severe VF damage as opposed to no/mild VF damage (IRR = 0.44, P = .001; IRR = 0.81, P = .02). CONCLUSIONS: Select NFs (poverty share and crime rate) may disproportionately affect physical activity in patients with severe VF loss. Interventions to overcome activity limitations within the context of poverty and high socioeconomic disadvantage are important for addressing glaucoma-related disability, particularly in those with severe VF loss.

Detection of trachoma using machine learning approaches.

BACKGROUND: Though significant progress in disease elimination has been made over the past decades, trachoma is the leading infectious cause of blindness globally. Further efforts in trachoma elimination are paradoxically being limited by the relative rarity of the disease, which makes clinical training for monitoring surveys difficult. In this work, we evaluate the plausibility of an Artificial Intelligence model to augment or replace human image graders in the evaluation/diagnosis of trachomatous inflammation-follicular (TF). METHODS: We utilized a dataset consisting of 2300 images with a 5% positivity rate for TF. We developed classifiers by implementing two state-of-the-art Convolutional Neural Network architectures, ResNet101 and VGG16, and applying a suite of data augmentation/oversampling techniques to the positive images. We then augmented our data set with additional images from independent research groups and evaluated performance. RESULTS: Models performed well in minimizing the number of false negatives, given the constraint of the low numbers of images in which TF was present. The best performing models achieved a sensitivity of 95% and positive predictive value of 50-70% while reducing the number images requiring skilled grading by 66-75%. Basic oversampling and data augmentation techniques were most successful at improving model performance, while techniques that are grounded in clinical experience, such as highlighting follicles, were less successful. DISCUSSION: The developed models perform well and significantly reduce the burden on graders by minimizing the number of false negative identifications. Further improvements in model skill will benefit from data sets with more TF as well as a range in image quality and image capture techniques used. While these models approach/meet the community-accepted standard for skilled field graders (i.e., Cohen's Kappa >0.7), they are insufficient to be deployed independently/clinically at this time; rather, they can be utilized to significantly reduce the burden on skilled image graders.