Anterior Segment OCT for Detection of Narrow Angles: A Community-Based Diagnostic Accuracy Study.

PURPOSE: To assess the diagnostic accuracy of anterior segment OCT (AS-OCT) screening for detecting gonioscopically narrow angles. DESIGN: Population-based cross-sectional study. PARTICIPANTS: A stratified random sample of individuals aged ≥ 60 years, selected from a door-to-door census performed in low-lying Nepal. TESTING: Participants underwent AS-OCT, posterior segment OCT, and intraocular pressure (IOP) testing in the community. Those meeting referral criteria in either eye were invited to have a comprehensive eye examination including gonioscopy. Referral criteria included (i) the lowest 2.5% of AS-OCT measurements, (ii) retinal OCT results suggestive of glaucomatous optic neuropathy, diabetic retinopathy, or age-related macular degeneration, and (iii) elevated IOP. MAIN OUTCOME MEASURES: Sensitivity and specificity of 5 semiautomated AS-OCT parameters relative to gonioscopically narrow angles, defined as the absence of visible trabecular meshwork for ≥ 180° on nonindentation gonioscopy. RESULTS: Of 17 656 people aged ≥ 60 years enumerated from 102 communities, 12 633 (71.6%) presented for AS-OCT testing. Referral was recommended for 697 participants based on AS-OCT criteria and 2419 participants based on other criteria, of which 858 had gonioscopy performed by a glaucoma specialist. Each of the 5 AS-OCT parameters offered good diagnostic information for predicting eyes with gonioscopically narrow angles, with areas under the receiver operating characteristic curve ranging from 0.85 to 0.89. The angle opening distance at 750 µm from the scleral spur (AOD750) provided the most diagnostic information, providing an optimal sensitivity of 87% (95% confidence interval [CI], 75%-96%) and specificity of 77% (71%-83%) at a cutpoint of 367 µm, and a sensitivity of 65% (95% CI, 54%-74%) when specificity was constrained to 90% (cutpoint, 283 µm). CONCLUSIONS: On AS-OCT, the AOD750 parameter detected approximately two-thirds of cases of gonioscopically narrow angles when test specificity was set to 90%. Although such a sensitivity may not be sufficient when screening solely for narrow angles, AS-OCT requires little additional effort if posterior segment OCT is already being performed and thus could provide incremental benefit when performing OCT-based screening. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.

Village-integrated eye workers for prevention of corneal ulcers in Nepal (VIEW study): a cluster-randomised controlled trial.

BACKGROUND: Corneal ulcers are a common cause of blindness in low-income and middle-income countries, usually resulting from traumatic corneal abrasions during agricultural work. Antimicrobial prophylaxis of corneal abrasions can help prevent corneal ulcers, but delays in the initiation of therapy are frequent. We aimed to assess whether a community-based programme for corneal ulcer prevention would reduce the incidence of corneal ulceration. METHODS: A cluster-randomised trial was performed in village development committees (VDCs) in Nepal. VDCs in the catchment area of Bharatpur Eye Hospital, Nepal with less than 15 000 people were eligible for inclusion. We randomly assigned (1:1) VDCs to either an intervention group or a control group. In the intervention VDCs, existing female community health volunteers (FCHVs) were trained to diagnose corneal abrasions and provide a 3-day course of ophthalmic antimicrobials to their patients. In the control VDCs, FCHVs did not provide this intervention. Participants were not masked given the nature of the intervention. Both groups were followed up for 3 years for photographic evidence of corneal ulceration. The primary outcome was the incidence of corneal ulceration, determined by masked assessment of corneal photographs. The analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, NCT01969786. FINDINGS: We assessed 112 VDCs, of which 24 were enrolled. The study was performed between Feb 4, 2014, and Oct 20, 2017. 12 VDCs were randomly assigned to the intervention group and 12 to the control group. 252 539 individuals were included in the study (130 579 in the intervention group and 121 960 in the control group). FCHVs diagnosed and provided antimicrobials for 4777 corneal abrasions. The census identified 289 corneal ulcers among 246 893 person-years in the intervention group (incidence 1·21 cases [95% CI 0·85-1·74] per 1000 person-years) and 262 corneal ulcers among 239 170 person-years in the control group (incidence 1·18 cases [0·82-1·70] per 1000 person-years; incidence rate ratio 1·03 [95% CI 0·63-1·67]; p=0·93). Medication allergy was self-reported in 0·2% of participants. INTERPRETATION: We did not detect a reduction in the incidence of corneal ulceration during the first 3 years of a community-based corneal ulcer prevention programme. Further study might be warranted in more rural areas where basic eye care facilities are not available. FUNDING: National Eye Institute.

Association of visual impairment with disability: a population-based study.

OBJECTIVE: To determine the relationship between visual impairment and other disabilities in a developing country. METHODS: In this cross-sectional ancillary study, all individuals 50 years and older in 18 communities in the Chitwan region of Nepal were administered visual acuity screening and the Washington Group Short Set (WGSS) of questions on disability. The WGSS elicits a 4-level response for six disability domains: vision, hearing, walking/climbing, memory/concentration, washing/dressing, and communication. The association between visual impairment and disability was assessed with age- and sex-adjusted logistic regression models. RESULTS: Overall, 4719 of 4726 individuals successfully completed visual acuity and disability screening. Median age of participants was 61 years (interquartile range: 55-69 years), and 2449 (51.9%) were female. Participants with vision worse than 6/60 in the better-seeing eye were significantly more likely to be classified as having a disability in vision (OR 18.4, 95% CI 9.9-33.5), walking (OR 5.3, 95% CI 2.9-9.1), washing (OR 9.4, 95% CI 4.0-21.1), and communication (OR 5.0, 95% CI 1.7-13.0), but not in hearing (OR 0.6, 95% CI 0.006-2.2) or memory (OR 2.2, 95% CI 0.7-5.1). CONCLUSIONS: Visually impaired participants were more likely to self-report disabilities, though causality could not be ascertained. Public health programs designed to reduce visual impairment could use the WGSS to determine unintended benefits of their interventions.

Evaluation of alternate outreach models for cataract services in rural Nepal.

BACKGROUND: Bharatpur Eye Hospital in Chitwan District, a primarily agrarian setting in south-central Nepal, reduced the number of diagnostic screening and treatment (DST) camps by one half (151 to 75) in an attempt to increase both the efficiency of its outreach program and the number of people that go directly to the hospital for service. The Hospital evaluated the two program models in terms of program costs, cataract surgical utilization, hospital direct payment and patient equity. METHODS: The study is a prospective, before and after, study of the impact of an alternate outreach model on cataract service utilization patterns and cost per outreach camp and cost per cataract surgery at Bharatpur Eye Hospital, comparing the service years July 2006 to June 2007, with July 2007 to June 2008. Study findings were based on routinely gathered hospital and outreach administrative data. RESULTS: The total cost of the DST camps decreased by approximately US$2000. The cost per camp increased from US$52 to $78 and the cost per cataract surgery decreased from US$ 3.80 to $3.20. The number of patients who went directly to the hospital, and paid for cataract surgery, increased from 432 (17%) to 623 (25%). The total number of cataract surgical procedures at Bharatpur Eye Hospital remained very similar between the two service years (2501 and 2449, respectively). The presenting visual acuity and sex of the two cataract surgical populations were very similar (favouring women, 53 and 55% in the two years, respectively). A shift toward younger men and women occurred with a 245 (64%) increase in people age 50-59 years, and shift away from people age 70 years and older with a 236 (22%) reduction. The age and sex distribution of the direct paying patients were very similar in the two years. CONCLUSION: The new, more concentrated, more rural DST model of service delivery reduced overall outreach program costs, cost per cataract surgery transported, while increasing direct payments to the hospital, with a significant decrease in the number of people age 70 and older in the first year.

Multiple Chlamydiaceae species in trachoma: implications for disease pathogenesis and control.

BACKGROUND: Chlamydia trachomatis is a unique obligate intracellular bacterium that remains the leading cause of sexually transmitted bacterial diseases and preventable blindness worldwide. Chronic ocular infections are referred to as trachoma, and predominate in developing countries. Since 2001, the World Health Organization has promoted control strategies including antibiotics, improved hygiene, and environmental measures with limited success. Consequently, a vaccine is urgently needed. Integral to vaccine design is an understanding of the interactions of the pathogen and host immune response. Various animal models of trachoma show that urogenital C. trachomatis strains and other species of the family Chlamydiaceae produce severe conjunctival inflammation and scarring similar to that of the ocular C. trachomatis strains. However, we do not know the extent of organisms that may be involved in human trachoma. Furthermore, C. trachomatis heat shock protein 60 (Hsp60) has been implicated in inflammation and conjunctival scarring but the role of other Chlamydiaceae Hsp60 in disease pathogenesis has not been examined. In this study, we set out to identify whether other Chlamydiaceae species are present in trachoma, and determine their association with severity of clinical disease and with mucosal and systemic immune responses to Chlamydiaceae species-specific Hsp60 to further investigate the immunopathogenesis of this blinding disease. METHODS AND FINDINGS: We randomly selected nine of 49 households in a trachoma-endemic region of Nepal. Trachoma was graded, and real-time, quantitative (k)PCR was used to detect genomic DNA and cDNA (from RNA) for Chlamydiaceae ompA and 16S rRNA genes, respectively, from conjunctival swabs. IgG antibody responses to recombinant (r) Chlamydiaceae species-specific Hsp60 were determined for tears and sera. Surprisingly, all three species-C. trachomatis, Chlamydophila psittaci, and Chlamydophila pneumoniae-were detected in eight (89%) study households; one household had no members infected with C. pneumoniae. Of 80 (63%; n = 127) infected individuals, 28 (35%) had infection with C. psittaci, or C. pneumoniae, or both; single and dual infections with C. psittaci and C. pneumoniae were significantly associated with severe conjunctival inflammation (OR 4.25 [95% confidence interval (CI), 2.9-11.3], p = 0.009] as were single infections with C. trachomatis (OR 5.7 [95% CI, 3.8-10.1], p = 0.002). Of the 80 infected individuals, 75 (93.8%) were also positive for 16S rRNA by kPCR for the same organism identified by ompA. Individuals with tear IgG immunoreactivity to Chlamydiaceae rHsp60 were eight times more likely than individuals without tear immunoreactivity to be infected (95% CI 6.4-15.1; p = 0.003), 6.2 times more likely to have severe inflammation (95% CI 4.4-12.6; p = 0.001), and 5.7 times more likely to have scarring (95% CI 3.9-11.1; p = 0.019) while individuals with serum IgG immunoreactivity were 4.1 times more likely to be infected (95% CI 3.1-10.1; p = 0.014). CONCLUSIONS: We provide substantial evidence for the involvement of C. psittaci and C. pneumoniae, in addition to C. trachomatis, in trachoma. The distribution of Chlamydiaceae species by household and age suggests that these infections are widespread and not just sporadic occurrences. Infection with multiple species may explain the failure to detect chlamydiae among active trachoma cases, when only C. trachomatis is assayed for, and the failure of clinically active cases to resolve their disease following what would be considered effective C. trachomatis treatment. The evidence for viable (RNA-positive) organisms of all three species in single and coinfections, the significant association of these infections with severe inflammation, and the significant association of tear and serum IgG responses to Chlamydiaceae Hsp60 with inflammation and scarring, support the role of all three species in disease pathogenesis. Thus, while our findings should be confirmed in other trachoma-endemic countries, our data suggest that a reevaluation of treatment regimens and vaccine design may be required. Understanding the full impact of Chlamydiaceae species on the epidemiology, immunopathology, and disease outcome of trachoma presents a new challenge for Chlamydiaceae research.

Risk factors for recurrence of postoperative trichiasis: implications for trachoma blindness prevention.

BACKGROUND: Trachoma is the leading worldwide cause of preventable blindness. Surgery can alleviate trachomatous trichiasis (TT), the blinding sequelae of trachoma, but recurrence rates are high. OBJECTIVE: To investigate risk factors for TT recurrence. METHODS: We conducted a prospective case-control cohort study in Nepal that included patients with TT who were undergoing bilamellar tarsal-rotation surgery and control subjects who have scarring but no TT. Conjunctivae were graded for trachoma and swabbed to detect Chlamydia trachomatis by in-house and commercial (Roche Amplicor; Roche Diagnostics Corp, Indianapolis, Ind)-polymerase chain reaction. Univariate and multivariate analyses were performed for associations with chlamydiae and other risk factors. RESULTS: Postoperative TT recurrence rates were 11.1% (4 cases) at 6 months and 25.0% (11 cases) at 12 months while no controls developed TT. Significantly, 5 (45.5%) of 11 patients with TT recurrences at 12 months had chlamydial infection at baseline (odds ratio, 6.0; 95% confidence interval, 1.5-24.3; P =.01), 8 (72.7%) at 6 months (odds ratio, 28; 95% confidence interval, 4.3-181.0; P <.001), and 9 (81.8%) at 12 months (odds ratio, 48; 95% confidence interval, 7.5-302.6; P =.00). No controls were infected during this time. Active trachoma and the baseline number of eyelashes touching the globe were also risk factors for TT recurrence. MAIN OUTCOME MEASURES: The outcome variable was TT recurrence at 6 and 12 months. CONCLUSION: To our knowledge, this is the first study to demonstrate that chlamydial infection at the time of surgery and at follow-up is a significant risk factor for postoperative TT recurrence.