Search PubMed⌕ Search

Biomedical subjects

A J Bron

Publications and source records attributed to A J Bron.

At least 109 records · Page 6Linked to original sources
PubMed1986

Diabetic retinopathy: different risk factors for exudates and haemorrhages.

The retinae of 137 patients were examined ophthalmologically and for visual acuity at diagnosis of non-insulin dependent diabetes and again in 1982 and 1983, approximately 7 and 8 years later, when colour photographs were also taken. In 1983, 46% were without detectable retinopathy, 32% had haemorrhages (including microaneurysms) only, 4% exudates alone and 18% both lesions. Those with haemorrhages were more hyperglycaemic than those without retinopathy and those with exudates only. Indeed, those with exudates alone had lower mean glucose levels than those without retinopathy (p less than 0.05). Patients with exudates (+/- haemorrhages) had a lower percentage of the fatty acids of plasma cholesterol esters as linoleate than those without (p less than 0.05) but this did not hold for those developing haemorrhages. Different risk factors appear to operate in different features of diabetic retinopathy. In some respects exudate formation may be more akin to macro than to micro angiopathy.

Aged↗
PubMed1986

Quantifying early diabetic retinopathy.

A precise and accurate method of numerically quantifying diabetic retinopathy, on standardised retinal colour photographs, has been developed which allows small changes and trends to be monitored. Colour slides are projected onto a screen and features noted on an acetate sheet which provides a permanent record. Sector analysis showed microaneurysms and haemorrhages to occur most often at the temporal-to-macula area, exudates at the macula and cotton wool spots on the nasal side of the retina. Seventy percent of microaneurysms appeared in the previous year, irrespective of the severity of the retinopathy. In proportion to their usual relative prevalences, after normalisation of distribution, the various features can be combined to provide a single value, the Retinopathy Index. This provides an overall assessment of retinopathy which is suitable for comparing the progress of mild retinopathy in prospective studies.

Aneurysm↗
PubMed1986

Cataract and retinopathy: screening for treatable retinopathy.

Diabetes causes cataract and certain physical changes in the lens. The diabetic lens is larger than the non-diabetic and shows greater light scatter and fluorescence. Both hyperglycaemia and lowering of blood glucose case refractive changes and hypermetropia is the most common. Classical 'snow-flake' juvenile cataract associated with hyperglycaemia is now rare. It has an osmotic mechanism. Diabetes is a risk factor for cataract in adults which is duration dependent, more frequent in women and leads to earlier surgery. It resembles non-diabetic senile cataract. Extracapsular cataract extraction is the method of choice for diabetic cataract with a better visual result and less risk of rubeosis iridis. A posterior chamber implant may still permit retinal photocoagulation if necessary. Diabetic retinopathy is still the leading cause of blindness in the working age group. The beneficial effect of photocoagulation has been shown by randomized controlled trials to be long-lasting for both proliferative retinopathy and maculopathy. Therefore there is a need for screening, especially for those with proliferative disease which may be present without symptoms. A knowledge of risk factors will enhance detection rate with duration as the strongest determinant for retinopathy. Any screening modality should be highly sensitive as well as specific. The role of different professionals as potential screeners should be considered. Adequate provisions include facilities for checking vision and for dimming ambient lighting. Mydriasis and a good ophthalmoscope light will increase detection rate. The use of a 45 degrees non-mydriatic camera is unlikely to supplant the use of an ophthalmoscope as a single field is likely to miss important lesions. A 60 degrees camera may confer a large enough field and the use of transparencies will provide magnification when films are projected but the camera is more difficult to use. A list of features chosen by a recent study to characterize sight-threatening retinopathy is included and their presence indicates the need for referral to an ophthalmic clinic for treatment or close observation.

Adolescent↗
PubMed1986

Topical anaesthetic and tear film stability.

The effect of unpreserved topical anaesthetic on tear film stability (0.4% oxybuprocaine hydrochloride) was investigated in a double masked randomised study in 12 healthy volunteers, using a noninvasive tear film break up technique (NIBUT). It was found that the topical anaesthetic did not reduce the pre-corneal tear film stability, contrary to the electron microscopic evidence.

Adult↗
PubMed1986

Non-invasive tear film break-up time: sensitivity and specificity.

The accuracy of a diagnostic technique; non-invasive tear film break-up time (NIBUT) was determined by calculating the sensitivity and specificity of the test. Thirty-three dry eye patients (65 eyes) of varying severity (mild, moderate and severe) and 66 age and sex matched normal subjects (132 eyes) were examined. The results indicate that the critical value of 10 seconds for the NIBUT provides sensitivity of 82% and specificity of 86%.

Adult↗
PubMed1986

Effect of sodium hyaluronate (0.1%) on break-up time (NIBUT) in patients with dry eyes.

We evaluated the effect of 0.1% sodium hyaluronate (unpreserved) in 10 patients with dry eyes. The precorneal tear film break-up time was assessed by the non-invasive technique, and the severity of symptoms was recorded before and after treatment on a 0 to +3 scale. It was found that the tear film stability was significantly increased (p less than 0.05) in eyes treated with sodium hyaluronate. The symptoms of grittiness and burning were also significantly alleviated in the treated eyes.

Adult↗
PubMed1986

The defences of the ocular surface.

Bacterial infection may be responsible for mild self-limiting disease, chronic disease or acute and devasting ocular destruction. This paper and those that follow deal with some of the clinical forms of disease which are encountered, the bacteria responsible, the mechanism of invasion and the natural defences and clinical management, including selection and delivery of antibiotics.

Anti-Bacterial Agents↗
PubMed1985

Effect of meibomian oils on Schirmer tear test.

The detrimental effect of meibomian oils expressed onto the lid margins on the value of the Schirmer test was investigated in two studies (N = 12 per study): without and with topical anaesthesia. In the 12 subjects studied there was no evidence of external ocular disease. The studies were conducted in a double masked randomised cross-over fashion. It was found that neither expression of meibomian oils nor topical anaesthesia showed any statistically significant (P greater than 0.05) reduction in final tear secretion rates. Thus, the notions that lid manipulation may impede tear flow into the Schirmer strip and that topical anaesthesia reduces apparent tear flow, are not supported.

Adult↗
PubMed1985

Effect of age on contrast sensitivity function: uniocular and binocular findings.

Monocular and binocular contrast sensitivity function for a range of spatial frequencies was measured in two groups of subjects with normal vision. Statistically significant differences in performance between the younger group (age 20-30 years) and the older group (age 50-87 years) were found at all spatial frequencies sampled between 0.40 and 19 X 25 cpd. In the age range 50-87 years there was a linear decline in contrast sensitivity with age for medium and high spatial frequencies, but sensitivity for low spatial frequencies was independent of age.

Adult↗
PubMed1985

Detection of optic nerve damage in ocular hypertension.

Thirty patients with ocular hypertension were tested for contrast sensitivity loss. Seventeen were not on treatment, and thirteen were receiving some form of pressure reducing therapy. The contrast sensitivity results of 63% of ocular hypertensive eyes were abnormal (greater than 2 SDs from the age matched norm). Thus it appears that contrast sensitivity can detect early visual loss in patients who have normal visual fields and it is suggested that this test might be used as a criterion for therapy in ocular hypertension. There was no significant difference in the intraocular pressures between patients who gave abnormal contrast sensitivity results and those who did not in the untreated group (p greater than 0.05), suggesting that intraocular pressure level is a poor predictor of optic nerve fibre damage in patients with ocular hypertension.

Aged↗
PubMed1985

Assessment of bleeding in eye surgery.

A new method for assessing microhaemorrhage in eye surgery was used in 16 patients for cataract extraction. It was shown that bleeding was greatest in the first five minutes and that it correlated with the surgeon's clinical estimate of blood loss. The method was used to assess the effect of two different general anaesthetic induction regimens on intraoperative bleeding.

Aged↗
PubMed1985

The inhibition of bovine lens aldose reductase by Clinoril, its absorption into the human red cell and its effect on human red cell aldose reductase activity.

The protein aldose reductase has been implicated in cataract in diabetes and galactosaemia. Recently it has been suggested that a number of non-steroidal anti-inflammatory agents have inhibitory activity against aldose reductase activity, and therefore might be used to prevent diabetic complications including cataract. Steady state kinetic experiments show that Clinoril (Sulindac sulphoxide) acts as a non-competitive inhibitor of NADPH oxidation with purified bovine lens aldose reductase, with an action that may involve binding to more than one site on the protein. As a preliminary to studying the effect on human lens and cataract, a double-masked, placebo-controlled study using random allocation into parallel groups was conducted on 20 volunteers to determine the penetration of Clinoril (Sulindac) and its metabolites into normal human red cells, and the effect of the drug on red cell NADPH-oxidising activity. It was found that while Clinoril, the sulphoxide form of the drug, and its metabolites the sulphone and the sulphide could be detected in the appropriate plasma samples (up to 36 micrograms of the sulphone/ml of plasma), very little could be detected in the red cells. There was no significant effect on red cell NADPH-oxidising activity.

Absorption↗
PubMed1985

A non-invasive instrument for clinical assessment of the pre-corneal tear film stability.

A simple, non-invasive technique has been developed for assessment of the stability of the pre-corneal tear film. Changes are observed in the reflection of a grid pattern from the tear film surface. Breaks in the tear film appear as random discontinuities in the grid image. Using this non-invasive technique the stability of the pre-corneal tear film was assessed in nine normal subjects and twelve established dry-eye patients. The non-invasive tear film break-up time (NIBUT) of the dry-eye patients was on average only 25% to 32% of normal values. The non-invasive technique provides an alternative approach to diagnosing non-wetting disorders as well as a means of evaluating the efficacy of artificial tear solutions.

Adolescent↗
PubMed1985

Effect of fluorescein instillation on the pre-corneal tear film stability.

Non-invasive tear film break-up time (NIBUT) was measured in nine normal subjects to investigate the effect of fluorescein instillation of tear film stability. It was found that fluorescein instillation reduced the tear film stability in the treated group, compared with the control group (P less than 0.05). It is, therefore likely that the tear film stability may be greater than had hitherto been suggested by the fluorescein method.

Adult↗