Relationship between visual field loss and contrast threshold elevation in glaucoma

BACKGROUND: There is a considerable body of literature which indicates that contrast thresholds for the detection of sinusoidal grating patterns are abnormally high in glaucoma, though just how these elevations are related to the location of visual field loss remains unknown. Our aim, therefore, has been to determine the relationship between contrast threshold elevation and visual field loss in corresponding regions of the peripheral visual field in glaucoma patients. METHODS: Contrast thresholds were measured in arcuate regions of the superior, inferior, nasal and temporal visual field in response to laser interference fringes presented in the Maxwellian view. The display consisted of vertical green stationary laser interference fringes of spatial frequency 1.0 c deg(-1 )which appeared in a rotatable viewing area in the form of a truncated quadrant extending from 10 to 20° from fixation which was marked with a central fixation light. Results were obtained from 36 normal control subjects in order to provide a normal reference for 21 glaucoma patients and 5 OHT (ocular hypertensive) patients for whom full clinical data, including Friedmann visual fields, had been obtained. RESULTS: Abnormally high contrast thresholds were identified in 20 out of 21 glaucoma patients and in 2 out of 5 OHT patients when compared with the 95% upper prediction limit for normal values from one eye of the 36 normal age-matched control subjects. Additionally, inter-ocular differences in contrast threshold were also abnormally high in 18 out of 20 glaucoma patients who had vision in both eyes compared with the 95% upper prediction limit. Correspondence between abnormally high contrast thresholds and visual field loss in the truncated quadrants was significant in 5 patients, borderline in 4 patients and absent in 9 patients. CONCLUSION: While the glaucoma patients tested in our study invariably had abnormally high contrast thresholds in one or more of the truncated quadrants in at least one eye, reasonable correspondence with the location of the visual field loss only occurred in half the patients studied. Hence, while contrast threshold elevations are indicative of glaucomatous damage to vision, they are providing a different assessment of visual function from conventional visual field tests

Sero-Epidemiology of Rotavirus Gastroenteritis in Children in Ilorin, Kwara State

Rotavirus is responsible for the most severe dehydrating diarrhea among young children due to gastroenteritis. In this study, we aimed to ascertain the occurrence of childhood gastroenteritis caused by Rotavirus among infants and young children who are younger than 5 years of age in Ilorin, Kwara State and determined the risk factors posing the challenges to be susceptible to diarrhea associated with rotavirus in Ilorin, Kwara State. Diarrhea stool samples were collected from children who passed watery stools, who met predetermined inclusion criteria and who presented at the study hospitals Viz: General Hospital and Specialist Hospital Alagbado and Children Specialist Hospital, Igboro. All within Kwara State either on outpatient care basis or those admitted into the pediatric ward. Sample of stool habouring rotavirus antigens was detected by commercial Rotavirus IgM ELISA kit to target recent infections among the participants. Out of three hundred (300) stool samples that were collected from children suffering from acute diarrhea, a total number of eighty-six (86) were found to be Rotavirus positive (28.7 %) and two hundred and fourteen (214) were found to be negative (71.3%). The age group 3-5 years, showed the highest prevalence rate which is in line with some research findings that attribute this age range with certain feeding habits and cultural practices, predisposing them to gastroenteritis. It is therefore advised that parents and guardian alike should ensure that special care is given to children, with emphasis on their feeding habits and sanitation

Earthworms and in vitro physiologically-based extraction tests : complementary tools for a holistic approach towards understanding risk at arsenic-contaminated sites

The relationship of the total arsenic content of a soil and its bioaccumulation by earthworms (Lumbricus rubellus and Dendrodrilus rubidus) to the arsenic fraction bioaccessible to humans, measured using an in vitro physiologically-based extraction test (PBET), was investigated. Soil and earthworm samples were collected at 24 sites at the former arsenic mine at the Devon Great Consols (DGC) in southwest England (UK), along with an uncontaminated site in Nottingham, UK, for comparison. Analysis of soil and earthworm total arsenic via inductively coupled plasma mass spectrometry (ICP-MS) was performed following a mixed acid digestion. Arsenic concentrations in the soil were elevated (204–9,025 mg kg−1) at DGC. The arsenic bioaccumulation factor (BAF) for both earthworm species was found to correlate positively with the human bioaccessible fraction (HBF), although the correlation was only significant (P ≤ 0.05) for L. rubellus. The potential use of both in vitro PBETs and earthworms as complementary tools is explored as a holistic and multidisciplinary approach towards understanding risk at contaminated sites. Arsenic resistant earthworm species such as the L. rubellus populations at DGC are presented as a valuable tool for understanding risk at highly contaminated sites