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Biomedical subjects

J Weatherill

Publications and source records attributed to J Weatherill.

10 recordsLinked to original sources
PubMed1991

Loss of visual function associated with microalbuminuria in diabetes mellitus: a pilot study.

Visual function loss has been documented in diabetes mellitus in relation to flicker and contrast. However, no direct correlation between the degree of loss in sensitivity and the level of retinopathy has been established. It has been suggested that such non-invasive psychophysical procedures actually reflect metabolic disturbances within the diabetic retina. This study investigates the possibility of whether early nephropathy demonstrated by microalbuminuria, is an indicator of microangiopathy which may be a cause of retinal disturbance leading to a loss of visual function. The visual function of a group of diabetics showing microalbuminuria was studied. Contrast and flicker threshold were measured and the results compared with those obtained with an age-matched control diabetic group. The procedures used effectively separated the two groups and raises the issue of incorporating psychophysics in retinal screening programmes.

Albuminuria↗
PubMed1990

Comparing clinical tests of visual function in cataract with the patient's perceived visual disability.

Conventional techniques for assessing the visual function of cataract patients include visual acuity (VA), contrast sensitivity (CS) and glare disability (GD). The extent to which these measurements provide accurate information about a patient's perceived visual disability is not known. In this study, binocular and monocular VA and CS and monocular GD measurements were made using commercially available techniques on 33 cataract patients. VA was measured using a Ferris-Bailey LogMAR chart and CS by the Pelli-Robson letter CS chart. Glare disability was measured using the Mentor Brightness Acuity Tester in conjunction with both the LogMAR and Pelli Robson charts. Each patient's perceived visual disability was quantified using a 20-point questionnaire about the effect of vision on everyday activities. There was little correlation between subjective visual disability and monocular or binocular VA measurements. Measurements of binocular CS, however, were highly correlated with the patient's perceived visual disability, particularly their subjective assessment of the effect of vision on their mobility-orientation. We suggest that binocular CS measurements using the Pelli-Robson chart provide useful additional information regarding the need for surgery in cataract patients.

Activities of Daily Living↗
PubMed1989

The subjective assessment of cataract.

The medical treatment of cataract now appears to be a distinct possibility. A number of anti-cataract formulations are being clinically tested, and more clinical trials are being planned. To obtain a true assessment of a drug's efficacy, a battery of tests are needed which can accurately assess cataract progress. A clinical trial of the proposed anti-cataract drug Bendalina is being conducted. The six subjective methods used to assess cataract progression in the trial are presented. These are refractive error, LogMAR visual acuity, contrast sensitivity, glare sensitivity, retinal visual acuity and displacement threshold hyperacuity. The reasons for using each technique and their method of measurement is explained.

Aged↗
PubMed1989

Causes of blindness and partial sight in the Bradford Metropolitan District from 1980 to 1985.

A retrospective review of the BD8 forms submitted for the period 1980-85 in the Bradford Metropolitan District was conducted to ascertain the incidence and causes of blindness and partial sight. A total of 1485 cases were registered in this period of which 755 (50%) were included in the Blind register and 730 (49.2%) in the Partially Sighted register. Age-related macular degeneration was the most important cause of visual handicap, accounting for 43.9% of all registrations, followed by glaucoma (16.2%), diabetic retinopathy (6.3%), myopic degeneration (6.1%), optic atrophy (4.4%), cerebrovascular disease (3.8%), cataracts (3.6%), retinal vascular occlusive disease (3.2%), corneal opacities (3.0%), congenital anomalies (2.7%), retinitis pigmentosa/tapeto-retinal degeneration (1.9%), retinal detachment (1.8%) and others (3.1%). The ratio of female to male registrations was 1.8:1. Eighty-four per cent of this sample population was above the age of 60 years at the time of registration.

Adolescent↗
PubMed1987

Psychophysical measurement of the foveal avascular zone.

The size of the foveal avascular zone (FAZ) reflects the condition of the microcapillary circulation in the foveal area. A number of studies have shown a significant increase in FAZ size in conditions of vascular pathology including diabetes. A non-invasive method of estimating FAZ size may be a valuable addition to a psychophysical test battery. We used a blue-light field to reveal the activity of the retinal leucocytes to two groups of normal subjects with average ages 24 and 61 years. Two methods were used to estimate the FAZ size, making use of the fact that subjects could see their own FAZ as the area free of leucocyte activity. The first method required subjects to indicate when leucocyte activity stopped as the field size was decreased and when it reappeared as field size was increased. The second required subjects to match the size of the leucocyte-free area with a white circle superimposed on the field. A search algorithm was used to change circle size according to subjects' responses. Results show a significant difference in FAZ size between the two age groups with both methods of measurement, and estimates were comparable to those reported using angiographic methods.

Adult↗