John P. Whitcher

Corneal blindness: a global perspective

Diseases affecting the cornea are a major cause of blindness worldwide, second only to cataract in overall importance. The epidemiology of corneal blindness is complicated and encompasses a wide variety of infectious and inflammatory eye diseses that cause corneal scarring, which ultimately leads to functional blindness. In addition, the prevalence of corneal disease varies from country to country and even from one population to another. While cataract is responsible for nearly 20 million of the 45 million blind people in the world, the next major cause is trachoma which blinds 4.9 million individuals, mainly as a result of corneal scarring and vascularization. Ocular trauma and corneal ulceration are significant causes of corneal blindness that are often underreported but may be responsible for 1.5-2.0 million new cases of monocular blindness every year. Causes of childhood blindness (about 1.5 million worldwide with 5 million visually disabled) include xerophthalmia (350,000 cases annually), ophthalmia neonatorum, and less frequently seen ocular diseases such as herpes simplex virus infections and vernal keratoconjunctivitis. Even though the control of onchocerciasis and leprosy are public health success stories, these diseases are still significant causes of blindness--affecting a quarter of a million individuals each. Traditional eye medicines have also been implicated as a major risk factor in the current epidemic of corneal ulceration in developing countries. Because of the difficulty of treating corneal blindness once it has occurred, public health prevention programmes are the most cost-effective means of decreasing the global burden of corneal blindness.

American College of Rheumatology classification criteria for Sjögren's syndrome: a data-driven, expert consensus approach in the Sjögren's International Collaborative Clinical Alliance cohort.

We propose new classification criteria for Sjögrens syndrome (SS), which are needed considering the emergence of biologic agents as potential treatments and their associated comorbidity. These criteria target individuals with signs/symptoms suggestive of SS.

Epidemiology and aetiological diagnosis of corneal ulceration in Madurai, south India

AIMS/BACKGROUND To determine the epidemiological characteristics and risk factors predisposing to corneal ulceration in Madurai, south India, and to identify the specific pathogenic organisms responsible for infection. METHODS All patients with suspected infectious central corneal ulceration presenting to the ocular microbiology and cornea service at Aravind Eye Hospital, Madurai, from 1 January to 31 March 1994 were evaluated. Sociodemographic data and information pertaining to risk factors were recorded, all patients were examined, and corneal cultures and scrapings were performed. RESULTS In the 3 month period 434 patients with central corneal ulceration were evaluated. A history of previous corneal injury was present in 284 patients (65.4%). Cornea cultures were positive in 297 patients (68.4%). Of those individuals with positive cultures 140 (47.1%) had pure bacterial infections, 139 (46.8%) had pure fungal infections, 15 (5.1%) had mixed bacteria and fungi, and three (1.0%) grew pure cultures ofAcanthamoeba. The most common bacterial pathogen isolated was Streptococcus pneumoniae, representing 44.3% of all positive bacterial cultures, followed by Pseudomonas spp (14.4%). The most common fungal pathogen isolated was Fusariumspp, representing 47.1% of all positive fungal cultures, followed by Aspergillus spp (16.1%). CONCLUSIONS Central corneal ulceration is a common problem in south India and most often occurs after a superficial corneal injury with organic material. Bacterial and fungal infections occur in equal numbers with Streptococcus pneumoniaeaccounting for the majority of bacterial ulcers and Fusariumspp responsible for most of the fungal infections. These findings have important public health implications for the treatment and prevention of corneal ulceration in the developing world.

Epidemiologic Characteristics, Predisposing Factors, and Etiologic Diagnosis of Corneal Ulceration in Nepal

Corneal ulceration is one of the most frequent causes of blindness in developing countries. Between September 1985 and August 1987, 405 patients with corneal ulceration were examined at Tribhuvan University Teaching Hospital in Kathmandu, Nepal. Males and females were equally affected. The most common predisposing cause of ulceration was corneal trauma, usually with organic agricultural materials. Microorganisms were grown from 324 (80%) of the ulcers. Pure bacterial cultures were obtained from 256 (63.2%) of the patients, whereas pure fungal cultures were obtained from 27 (6.7%) of the patients. In 41 patients (10.1%), corneal cultures yielded a mixed growth of bacteria and fungi. Of a total of 398 bacterial isolates, 124 (31.1%) were positive for Streptococcus pneumoniae, the most commonly isolated organism in the series. Other frequently isolated bacteria included Staphylococcus epidermidis, S. aureus, and Pseudomonas species. Of 68 positive fungal isolates obtained, 32 (47.0%) were identified as Aspergillus species. Candida species and Fusarium species were less commonly seen.

A simplified quantitative method for assessing keratoconjunctivitis sicca from the Sjögren's Syndrome International Registry.

PURPOSE To describe, apply, and test a new ocular grading system for assessing keratoconjunctivitis sicca (KCS) using lissamine green and fluorescein. DESIGN Prospective, observational, multicenter cohort study. METHODS The National Institutes of Health-funded Sjögrens Syndrome International Registry (called Sjögrens International Collaborative Clinical Alliance [SICCA]) is developing standardized classification criteria for Sjögren syndrome (SS) and is creating a biospecimen bank for future research. Eight SICCA ophthalmologists developed a new quantitative ocular grading system (SICCA ocular staining score [OSS]), and we analyzed OSS distribution among the SICCA cohort and its association with other phenotypic characteristics of SS. The SICCA cohort includes participants ranging from possibly early SS to advanced disease. Procedures include sequenced unanesthetized Schirmer test, tear break-up time, ocular surface staining, and external eye examination at the slit lamp. Using statistical analyses and proportional Venn diagrams, we examined interrelationships between abnormal OSS (>or=3) and other characteristics of SS (labial salivary gland [LSG] biopsy with focal lymphocytic sialadenitis and focus score >1 positive anti-SS A antibodies, anti-SS B antibodies, or both). RESULTS Among 1208 participants, we found strong associations between abnormal OSS, positive serologic results, and positive LSG focus scores (P < .0001). Analysis of the overlapping relationships of these 3 measures defined a large group of participants who had KCS without other components of SS, representing a clinical entity distinct from the KCS associated with SS. CONCLUSIONS This new method for assessing KCS will become the means for diagnosing the ocular component of SS in future classification criteria. We find 2 forms of KCS whose causes may differ.

Corneal ulceration in the developing world--a silent epidemic.

Anyone who has spent time in Asia or Africa can invariably recall a vivid image of a blind beggar, sometimes an elderly person but frequently a child with opaque corneas, haunting the bazaars and marketplaces of cities and villages. The spectre is so common that it almost passes unnoticed, but these individuals who are bilaterally blind represent only a small fraction of the millions who suffer monocular blindness as a result of corneal trauma and subsequent microbial keratitis. With the global figure of blindness rapidly approaching 40 million, attention naturally is focused on cataract, which is responsible for 50% or more of all visual disability, and trachoma which is still an enormous public health problem affecting 500 million people worldwide and responsible for 25% of all bilaterally blind individuals.1 Xerophthalmia, onchocerciasis, and glaucoma account for several millions more of the 85% of the world’s blind individuals who live in developing countries in Asia and Africa.2 While corneal blindness in the developing world has traditionally been attributed to trachoma, xerophthalmia, …

Incidence of corneal ulceration in Madurai District, South India

OBJECTIVE To determine the incidence of corneal ulceration in Madurai District, South India. DESIGN Retrospective incidence study. SETTING General community. PATIENTS All patients who reside in Madurai District and presented to an ophthalmologist in 1993 with corneal ulceration. MAIN OUTCOME MEASURE Cases of corneal ulceration. RESULTS 1148 cases of corneal ulceration were recorded in the medical records of those ophthalmologists who maintained records. Based upon the recorded number of cases, the annual incidence per 10,000 population was 3.4. The ratio of male to female patients was 1.6:1.0. When the estimated number of cases from those without records was added to the total number of recorded cases the annual incidence was 11.3 per 10,000 population. CONCLUSION Corneal ulceration is a common occurrence in South India. While the true incidence of this problem is impossible to determine because of the lack of medical records, we believe our estimation of the incidence to be close to the true incidence in this community.

Epidemiology of ulcerative keratitis in Northern California

OBJECTIVE To determine the incidence and associated risk factors for ulcerative keratitis in northern California. METHODS In this large-population, retrospective, cohort study, all medical records with diagnosis coding for corneal ulcers during a consecutive 12-month period were reviewed. Incidence rates were calculated using a dynamic population model. Multivariate relative risk regression was conducted to evaluate potential risk factors for ulcerative keratitis. RESULTS Within the target population of 1 093 210 patients, 302 developed ulcerative keratitis. The incidence of ulcerative keratitis was 27.6 per 100 000 person-years (95% confidence interval, 24.6-30.9). The incidence of corneal ulceration in contact lens wearers was 130.4 per 100 000 person-years (95% confidence interval, 111.3-151.7), with an adjusted relative risk of 9.31 (7.42-11.7; P < .001) compared with non-contact lens wearers, who had an incidence of ulcerative keratitis of 14.0 per 100 000 person-years (11.7-16.6). Seven of 2944 people known to be infected with human immunodeficiency virus developed ulcerative keratitis, with 5 being contact lens wearers. The incidence of ulcerative keratitis in human immunodeficiency virus-positive patients was 238.1 per 100 000 person-years (95% confidence interval, 95.7-490.5), with an odds ratio of 9.31 (7.42-11.7; P < .001) compared with human immunodeficiency virus-negative patients, who had an incidence of ulcerative keratitis of 27.1 per 100 000 person-years (24.1-30.3). CONCLUSIONS The incidence of ulcerative keratitis in this population is higher than previously reported. This may be owing to the increasing prevalence of contact lens wear.

Comparison of Annual and Biannual Mass Antibiotic Administration for Elimination of Infectious Trachoma

CONTEXT Treatment recommendations assume that repeated mass antibiotic distributions can control, but not eradicate or even locally eliminate, the ocular strains of chlamydia that cause trachoma. Elimination may be an important end point because of concern that infection will return to communities that have lost immunity to chlamydia after antibiotics are discontinued. OBJECTIVE To determine whether biannual treatment can eliminate ocular chlamydial infection from preschool children and to compare results with the World Health Organization-recommended annual treatment. DESIGN, SETTING, AND PARTICIPANTS A cluster-randomized clinical trial of biannual vs annual mass azithromycin administrations to all residents of 16 rural villages in the Gurage Zone, Ethiopia, from March 2003 to April 2005. INTERVENTIONS At scheduled treatments, all individuals aged 1 year or older were offered a single dose of oral azithromycin either annually or biannually. MAIN OUTCOME MEASURE Village prevalence of ocular chlamydial infection and presence of elimination at 24 months in preschool children determined by polymerase chain reaction, correcting for baseline prevalence. Antibiotic treatments were performed after sample collections. RESULTS Overall, 14,897 of 16,403 eligible individuals (90.8%) received their scheduled treatment. In the villages in which residents were treated annually, the prevalence of infection in preschool children was reduced from a mean of 42.6% (range, 14.7%-56.4%) to 6.8% (range, 0.0%-22.0%) at 24 months. In the villages in which residents were treated biannually, infection was reduced from 31.6% pretreatment (range, 6.1%-48.6%) to 0.9% (range, 0.0%-4.8%) at 24 months. Biannual treatment was associated with a lower prevalence at 24 months (P = .03, adjusting for baseline prevalence). At 24 months, no infection could be identified in 6 of 8 of those treated biannually and in 1 of 8 of those treated annually (P = .049, adjusting for baseline prevalence). CONCLUSION Local elimination of ocular chlamydial infection appears feasible even in the most severely affected areas, although it may require biannual mass antibiotic distributions at a high coverage level. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00221364.

The Antioxidants in Prevention of Cataracts Study: effects of antioxidant supplements on cataract progression in South India.

Aim: To determine if antioxidant supplements (β carotene and vitamins C and E) can decrease the progression of cataract in rural South India. Methods: The Antioxidants in Prevention of Cataracts (APC) Study was a 5 year, randomised, triple masked, placebo controlled, field based clinical trial to assess the ability of interventional antioxidant supplements to slow cataract progression. The primary outcome variable was change in nuclear opalescence over time. Secondary outcome variables were cortical and posterior subcapsular opacities and nuclear colour changes; best corrected visual acuity change; myopic shift; and failure of treatment. Annual examinations were performed for each subject by three examiners, in a masked fashion. Multivariate modelling using a general estimating equation was used for analysis of results, correcting for multiple measurements over time. Results: Initial enrolment was 798 subjects. Treatment groups were comparable at baseline. There was high compliance with follow up and study medications. There was progression in cataracts. There was no significant difference between placebo and active treatment groups for either the primary or secondary outcome variables. Conclusion: Antioxidant supplementation with β carotene, vitamins C and E did not affect cataract progression in a population with a high prevalence of cataract whose diet is generally deficient in antioxidants.