Salzmann's nodular degeneration.

Salzmann nodular corneal degeneration is a non-inflammatory, progressive corneal degeneration characterized by bluish-white nodules of varying shapes classically located in the mid-peripheral cornea. It was first described by Maximilian Salzmann in 1925 and was noted at that time to be associated with "eczematous keratoconjunctivitis". Since then, significant progress has been made to understand environmental and genetic risk factors associated with SND. However, etiopathogenesis remains poorly understood. A review of the literature was performed to highlight our recent understanding of SND and its management.

POSITION OF IN-THE-BAG POSTERIOR CHAMBER INTRAOCULAR LENSES RELATIVE TO THE LIMBUS: Applications to Scleral-Sutured Lenses.

PURPOSE: To characterize the true position of in-the-bag intraocular lenses (IOLs) relative to the limbus using ultrasound biomicroscopy and estimate scleral-sutured IOL positioning. METHODS: This prospective single-center study included 70 eyes of 41 patients with in-the-bag posterior chamber IOLs. Four vertical ultrasound biomicroscopy captures were performed in each eye in the superior, inferior, nasal, and temporal quadrants. Postoperative biometric data were collected. The primary outcome was the vertical distance of the in-the-bag IOL from the sclerocorneal limbus. Secondary outcomes included anterior shift and refractive change of a theoretical scleral-sutured IOL using sclerotomies at 2.5 mm and 3 mm posterior to the limbus. RESULTS: A total of 265 ultrasound biomicroscopy images were analyzed, including 64 superior, 69 inferior, 66 nasal, and 66 temporal. The true in-the-bag IOL position measured as distance posterior to the sclerocorneal limbus was 4.23 ± 0.56 mm superiorly, 4.22 ± 0.46 mm inferiorly, 3.95 ± 0.48 mm nasally, and 3.86 ± 0.52 mm temporally. The anterior shift of a theoretical scleral-sutured IOL was 0.60 mm for a 3-mm sclerotomy and 0.93 mm for a 2.5-mm sclerotomy, resulting in a theoretical myopic shift of 0.45 diopter (D) and 0.79 D, respectively, assuming a 15-D IOL. Larger biometric measurements correlated with a more posterior in-the-bag position. CONCLUSION: True in-the-bag IOL position was found to be more posterior than estimates of scleral-sutured IOLs. Additional corrections in scleral-sutured IOL calculations may improve refractive outcomes.

Preoperative evaluation for cataract surgery.

PURPOSE OF REVIEW: To provide a consolidated update regarding preoperative evaluation for cataract surgery. RECENT FINDINGS: Visual acuity alone is a poor gauge of cataract disability. Modalities such as wave front aberrometry, lens densitometry, and light-scatter assessments can quantify optical aspects of cataract and may prove clinically useful in surgical evaluation. Advances in biometry are driving improvements in refractive outcomes, which in turn have increased patient expectations. Future advances in biometry technology may include three-dimensional imaging of the cornea and lens. Screening for ocular comorbidities has become increasingly important, particularly to guide lens selection. Risk stratification systems can help guide surgical decisions and may decrease intraoperative complication rate. A comprehensive medical history and physical is currently mandated for all Medicare patients undergoing cataract surgery but may be of limited utility for low-risk patients. SUMMARY: Rising patient expectations and a growing number of surgical choices have expanded the cataract preoperative evaluation. A systematic and comprehensive examination which includes identifying any ocular comorbidity is essential for surgical planning and counseling on visual prognosis. New technologies will continue to inform, but not replace, sound clinical judgment.

Coniochaeta mutabilis keratitis with an unusual mode of transmission treated with penetrating keratoplasty and systemic antifungals.

Purpose: To report a case of fungal keratitis caused by Coniochaeta mutabilis along with its treatment and discuss the possibility of an unusual mode of transmission. Only a few cases of ocular C. mutabilis infection have been reported, and this is the first presenting domestic fowl as a potential source of infection. Observations: A 52-year-old woman presented with a corneal ulcer following a week of increasing eye pain. Five months prior, she had a corneal abrasion in the same eye that resulted from trauma during yard work. Two weeks before presentation, she cared for a chicken with ocular infection. Culture of the corneal scraping identified Coniochaeta mutabilis, a rarely described fungal pathogen. After multiple treatment modalities were attempted, the patient ultimately underwent penetrating keratoplasty. No signs of infection recurrence were present during follow-up after the procedure. Conclusions and Importance: C. mutabilis keratitis is a rare condition that typically presents with an aggressive nature and requires multiple forms of treatment. Here, we report direct contact with an infected chicken cornea as a possible mode through which the disease was acquired. Early suspicion of fungal etiology in cases of keratitis allows directed treatment, which may improve visual outcomes. Acknowledging unusual modes of transmission may help bring this differential diagnosis into consideration. Furthermore, given the scarcity of literature about this disease, individual case reports are informative for guiding future treatment and research.

Marginal corneal infiltrates as an ocular manifestation of acute generalized exanthematous pustulosis.

Purpose: To report a case of keratoconjunctivitis with marginal corneal infiltrates in a patient with acute generalized exanthematous pustulosis (AGEP) secondary to trimethoprim-sulfamethoxazole. Observations: A 63-year-old female presented with a diffuse pustular skin rash and bilateral keratoconjunctivitis with marginal corneal infiltrates. Skin biopsy led to the diagnosis of AGEP secondary to trimethoprim-sulfamethoxazole use. Treatment of the ocular findings with topical corticosteroids and lubrication led to near-full resolution after two weeks. Conclusions and Importance: To the best of our knowledge, this is the first reported association between AGEP and keratoconjunctivitis with marginal corneal infiltrates. A hypersensitivity reaction to a foreign antigen is implicated in the pathogenesis of both AGEP and sterile marginal infiltrates, and we suggest that the patient's underlying hypersensitivity process associated with AGEP accounted for the ocular findings.

Surgical excision and distilled water lysis of a congenital corneal intrastromal cyst.

PURPOSE: To describe imaging findings and encourage the use of distilled water as an adjuvant osmolytic in the surgical management of corneal intrastromal cysts. OBSERVATIONS: A five-year-old female with no history of ocular trauma presented with a visually significant corneal opacity of the left eye. She was diagnosed with a presumed corneal intrastromal cyst and underwent surgical excision with distilled water osmolysis of the cyst cavity. CONCLUSIONS AND IMPORTANCE: Optical coherence tomography (OCT) can confirm diagnosis of intrastromal cysts. Presumed epithelial cell nests remain visible at post-operative month eight, with no evidence for cyst recurrence. The authors propose that OCT findings are pathognomonic for corneal intrastromal cysts and that cyst excision combined with distilled water osmolysis at the time of debridement may be beneficial in conserving tissue integrity.

The Effect of Mass Azithromycin Distribution on Childhood Mortality: Beliefs and Estimates of Efficacy.

A cluster-randomized trial demonstrated that mass oral azithromycin distribution reduced childhood mortality 49.6% (Trachoma Amelioration in Northern Amhara [TANA]). The relative risk of childhood mortality was then estimated using two approaches: an expert survey and a Bayesian analysis. The survey asked public health experts to estimate the true effect of mass azithromycin distribution on childhood mortality. The Bayesian estimation used the TANA study's results and prior estimates of the efficacy of other effective population-level interventions. The experts believed mass azithromycin reduces childhood mortality (relative risk = 0.83, 95% credible intervals [CrI] = 0.70-1.00). The Bayesian analysis estimated a relative risk of 0.71 (95% CrI = 0.39-0.93). Both estimates suggest that azithromycin may have a true mortality benefit, though of a smaller magnitude than found in the single available trial. Prior information about nonantibiotic, population-level interventions may have informed the expert's opinions. Additional trials are needed to confirm a mortality benefit from mass azithromycin.

Reliability of measurements performed by community-drawn anthropometrists from rural Ethiopia.

BACKGROUND: Undernutrition is an important risk factor for childhood mortality, and remains a major problem facing many developing countries. Millennium Development Goal 1 calls for a reduction in underweight children, implemented through a variety of interventions. To adequately judge the impact of these interventions, it is important to know the reproducibility of the main indicators for undernutrition. In this study, we trained individuals from rural communities in Ethiopia in anthropometry techniques and measured intra- and inter-observer reliability. METHODS AND FINDINGS: We trained 6 individuals without prior anthropometry experience to perform weight, height, and middle upper arm circumference (MUAC) measurements. Two anthropometry teams were dispatched to 18 communities in rural Ethiopia and measurements performed on all consenting pre-school children. Anthropometry teams performed a second independent measurement on a convenience sample of children in order to assess intra-anthropometrist reliability. Both teams measured the same children in 2 villages to assess inter-anthropometrist reliability. We calculated several metrics of measurement reproducibility, including the technical error of measurement (TEM) and relative TEM. In total, anthropometry teams performed measurements on 606 pre-school children, 84 of which had repeat measurements performed by the same team, and 89 of which had measurements performed by both teams. Intra-anthropometrist TEM (and relative TEM) were 0.35 cm (0.35%) for height, 0.05 kg (0.39%) for weight, and 0.18 cm (1.27%) for MUAC. Corresponding values for inter-anthropometrist reliability were 0.67 cm (0.75%) for height, 0.09 kg (0.79%) for weight, and 0.22 kg (1.53%) for MUAC. Inter-anthropometrist measurement error was greater for smaller children than for larger children. CONCLUSION: Measurements of height and weight were more reproducible than measurements of MUAC and measurements of larger children were more reliable than those for smaller children. Community-drawn anthropometrists can provide reliable measurements that could be used to assess the impact of interventions for childhood undernutrition.

Diagnostic characteristics of tests for ocular Chlamydia after mass azithromycin distributions.

PURPOSE: Although trachoma control programs frequently use the World Health Organization (WHO) simplified grading system for trachoma to monitor the clinical response after repeated mass azithromycin treatments, the programmatic relevance of this evaluation after multiple rounds of antibiotic treatments is unclear. METHODS: Three rounds of annual mass azithromycin were distributed to 12 villages in Ethiopia. Twelve months after the third treatment, children were assessed for follicular trachomatous inflammation (TF) and intense trachomatous inflammation (TI) using the WHO simplified grading system and for ocular chlamydial infection using DNA-based and RNA-based tests. Test characteristics for predicting chlamydial infection were computed assuming a chlamydial RNA-based gold standard. As a secondary analysis, test characteristics were also assessed using a latent class analysis. RESULTS: The prevalence of RNA evidence of ocular chlamydia was 7.1% (95% confidence interval [CI], 2.7-17.4). A DNA-based test and TF had sensitivities of 61.0% (95% CI, 47.1-73.3) and 65.9% (95% CI, 41.6-83.9), specificities of 100% (95% CI, 99.3-100) and 67.5% (95% CI, 61.0-73.5), and positive predictive values of 100% (95% CI, 86.3-100) and 13.4% (95% CI, 5.5-29.3) compared with an RNA-based gold standard. The latent class analysis confirmed that the RNA-based test was a reasonable choice for a gold standard, with a sensitivity of 100% (95% CI, 67.1-100) and specificity of 99.6% (95% CI, 98.1-100). CONCLUSIONS: Basing treatment decisions after mass azithromycin distributions on the WHO simplified grading system will maximize the treatment of infected persons compared with a DNA-based test but will also result in more uninfected persons being treated. The RNA-based test was considerably more sensitive, and almost equivalently specific, compared with a DNA-based test. (ClinicalTrials.gov number, NCT00322972.).

Prior elicitation and Bayesian analysis of the Steroids for Corneal Ulcers Trial.

PURPOSE: To elicit expert opinion on the use of adjunctive corticosteroid therapy in bacterial corneal ulcers. To perform a Bayesian analysis of the Steroids for Corneal Ulcers Trial (SCUT), using expert opinion as a prior probability. METHODS: The SCUT was a placebo-controlled trial assessing visual outcomes in patients receiving topical corticosteroids or placebo as adjunctive therapy for bacterial keratitis. Questionnaires were conducted at scientific meetings in India and North America to gauge expert consensus on the perceived benefit of corticosteroids as adjunct treatment. Bayesian analysis, using the questionnaire data as a prior probability and the primary outcome of SCUT as a likelihood, was performed. For comparison, an additional Bayesian analysis was performed using the results of the SCUT pilot study as a prior distribution. RESULTS: Indian respondents believed there to be a 1.21 Snellen line improvement, and North American respondents believed there to be a 1.24 line improvement with corticosteroid therapy. The SCUT primary outcome found a non-significant 0.09 Snellen line benefit with corticosteroid treatment. The results of the Bayesian analysis estimated a slightly greater benefit than did the SCUT primary analysis (0.19 lines verses 0.09 lines). CONCLUSION: Indian and North American experts had similar expectations on the effectiveness of corticosteroids in bacterial corneal ulcers; that corticosteroids would markedly improve visual outcomes. Bayesian analysis produced results very similar to those produced by the SCUT primary analysis. The similarity in result is likely due to the large sample size of SCUT and helps validate the results of SCUT.

The epidemiological dynamics of infectious trachoma may facilitate elimination.

INTRODUCTION: Trachoma programs use mass distributions of oral azithromycin to treat the ocular strains of Chlamydia trachomatis that cause the disease. There is debate whether infection can be eradicated or only controlled. Mass antibiotic administrations clearly reduce the prevalence of chlamydia in endemic communities. However, perfect coverage is unattainable, and the World Health Organization's goal is to control infection to a level where resulting blindness is not a public health concern. Here, we use mathematical models to assess whether more ambitious goals such as local elimination or even global eradication are possible. METHODS: We fit a class of non-linear, stochastic, susceptible-infectious-susceptible (SIS) models which allow positive or negative feedback, to data from a recent community-randomized trial in Ethiopia, and make predictions using model averaging. RESULTS: The models predict that reintroduced infection may not repopulate the community, or may do so sufficiently slowly that surveillance might be effective. The preferred model exhibits positive feedback, allowing a form of stochastic hysteresis in which infection returns slowly after mass treatment, if it returns at all. Results for regions of different endemicity suggest that elimination may be more feasible than earlier models had predicted. DISCUSSION: If trachoma can be eradicated with repeated mass antibiotic distributions, it would encourage similar strategies against other bacterial diseases whose only host is humans and for which effective vaccines are not available.

How reliable are tests for trachoma?--a latent class approach.

PURPOSE: Tests for ocular Chlamydia trachomatis have not been well characterized, because there is no gold standard test. Latent class analysis (LCA) was performed to estimate the sensitivity and specificity of laboratory and clinical tests for trachoma in the absence of a gold standard. METHODS: Individual data from pretreatment, hyperendemic areas in Ethiopia were used. A clustered LCA was performed for three diagnostic tests: PCR and WHO simplified criteria grades of follicular trachoma (TF) and intense trachomatous inflammation (TI). RESULTS: Data from 2111 subjects in 40 villages were available. TF was estimated to be 87.3% (95% CI, 83.3-90.1) sensitive and 36.6% (95% CI, 23.6-40.3) specific; TI was estimated to be 53.6% (95% CI, 46.1-88.0) sensitive and 88.3% (95% CI, 83.3-92.0) specific, and PCR was estimated to be 87.5% (95% CI, 79.9-97.2) sensitive and 100% (95% CI 69.3-100) specific. CONCLUSIONS: LCA allows for an estimate of test characteristics without prior assumption of their performance. TF and TI were found to act in a complementary manner: TF is a sensitive test and TI is a specific test. PCR is highly specific but lacks sensitivity. The performance of these tests may be due to the time course of ocular chlamydial infection, and for this reason, results may differ in areas of low prevalence or recent mass treatment (ClinicalTrials.gov number, NCT00221364).