Search PubMed⌕ Search

Biomedical subjects

G N Dutton

Publications and source records attributed to G N Dutton.

At least 91 records · Page 5Linked to original sources
PubMed1991

The characteristics of midfacial fractures and the association with ocular injury: a prospective study.

Ocular injuries commonly occur in patients with facial fractures. This prospective study was set up to determine the incidence of ocular injuries, as assessed by an ophthalmologist, in patients who had sustained midfacial fractures. Over a 2-year period, a study of 363 patients who had sustained midfacial trauma sufficient to lead to a facial bone fracture (438 fractures) was undertaken and patients received a comprehensive examination by an ophthalmologist and an orthoptist within 1 week of injury. The characteristics of the eye injuries sustained were related to the aetiology of the fracture, the type of fracture, and the sex and age of each patient. Ninety percent of patients sustained ocular injuries of various severities. Sixty three percent of patients sustained only minor or transient ocular injuries, 16% suffered moderately severe ocular injury and 12% experienced severe eye injuries. Road traffic accident was associated with the highest incidence of severe ocular disorder (9/45 = 20%) whilst assaults had the second highest incidence at 11% (20/181). One third of all patients with comminuted malar fracture suffered a severe ocular disorder (9/27) whilst blow-out fracture came second at 16.7% (6/36). Fifty six patients (15.4%) had a decrease in their visual acuity and 9 patients (2.5%) had significant traumatic optic neuropathy. Decrease in visual acuity was the main clinical finding accompanying the majority of significant eye injuries. When ocular injuries were related to aetiology, it was apparent that road traffic accidents and assaults associated with alcohol abuse showed the highest incidence of major ocular dysfunction. It is suggested that all patients sustaining midfacial fracture associated with a significant decrease in visual acuity either pre- or postoperatively should have an early ophthalmological review.

Accidental Falls↗
PubMed1991

Diplopia following midfacial fractures.

Over a period of 2 years, 363 patients who had sustained a total of 438 midfacial fractures due to blunt trauma received a full ophthalmological examination within 1 week of injury. Of these, 72 patients (19.8%) developed diplopia. Diplopia was most common following road traffic accidents (31%) and least common with simple falls (10%). Blow-out fractures of the orbit led to double vision in 58% of cases. Eighty two percent of patients recovered from diplopia within 6 months of injury; only 1 patient required squint surgery for double vision. The principal risk factors for diplopia comprise road traffic accidents, blow-out fractures and comminuted malar fractures. Early surgical reconstruction of midfacial fractures with conservative management of concomitant motility disorders has, in our series, resulted in very few patients having diplopia in the long term.

Accidents, Occupational↗
PubMed1991

Low vision aids--is our service cost effective?

A questionnaire and telephone survey was carried out on a Scottish population of patients with impaired vision, in order to ascertain the proportion of patients who gain benefit from Low Vision Aids (LVA) and to determine the number of LVAs which are retained but unused. One third of the patients who answered the questionnaire never use their LVAs, and one half were not satisfied with the service provided. A cost analysis indicated that approximately (pounds) 8,000 worth of LVAs are neither used nor returned each year to a single LVA service. The patients' ages, diagnoses, and visual acuities were related to the compliance rate. It appears that increasing age and decreasing visual acuity may be factors which decrease compliance. However none of the factors analysed could be used as a reliable predictor of patient satisfaction or of eventual benefit. Other health services which provide intensive training in the use of LVAs reportedly achieve a higher level of compliance. We conclude that our present service could probably be improved by the employment of additional staff specifically trained to teach patients how to make best use of the LVAs provided.

Adolescent↗
PubMed1991

Etretinate and visual function: a 1-year follow-up study.

Concern has been expressed in the literature that the drug etretinate may be potentially retinotoxic. Four patients are reported who have received long-term treatment with etretinate and who have undergone detailed evaluation for the development of visual dysfunction over a 1-year period. Despite prolonged treatment and high total doses no evidence of ocular toxicity attributable to the drug was found in any of the patients.

Ectodermal Dysplasia↗
PubMed1991

Gonioscopic findings in Greek patients with exfoliation glaucoma.

A prospective gonioscopic evaluation was carried out upon a cohort of Greek patients who had undergone trabeculectomy for open-angle glaucoma. Sixty-five patients were found to show clinical evidence of exfoliation glaucoma (EXG), whilst nine patients were deemed to have primary open angle glaucoma (POAG). The gonioscopic features of these eyes and of 43 non-operated eyes from the same patients with either exfoliation syndrome (EXS) or EXG are presented. The median degree of angle pigmentation was significantly higher in the operated eyes with EXG when compared with the POAG cases. In the operated eyes, deposition of exfoliation was found on the ciliary processes in 82% of cases and on the zonules in 52%.

Anterior Eye Segment↗
PubMed1991

Optic foraminal radiography--a redundant investigation?

A retrospective study of all plain radiographs taken of optic foramina during the six years 1984-9 inclusive, comprising a total of 318 examinations, was carried out in order to determine the role of this investigation in patients with ophthalmic disorders. All but one of the radiographs were reported as showing no abnormality. However, for this exception, review of the radiographs showed that the optic foramina were asymmetrical but fell within the normal range. This study indicates that plain radiographs of the optic foramina have little or no useful function. Abandoning the use of these views as a routine will result both in a reduction in radiation hazard and in considerable financial saving.

Eye Diseases↗
PubMed1991

Reappraisal of the ratio of disc to macula/disc diameter in optic nerve hypoplasia.

The ratio of disc to macula/disc diameter is characteristically increased in eyes with optic nerve hypoplasia. We present the largest reported series of patients with a definitive diagnosis of optic nerve hypoplasia for whom this ratio has been determined. All measurements were made by an independent masked observer. Our results are in accordance with previous reports. A ratio of 2.94 provides a one-tailed upper population limit of 95%. An attempt has been made to correlate optic disc size and visual acuity. In 75% of bilateral cases the eye with the relatively smaller optic disc was found to have a better Snellen visual acuity than the fellow eye. This suggests that additional pathogenic mechanism(s) may have determined the eventual visual outcome in such eyes. Such mechanisms include macular hypoplasia, high refractive error, refractive amblyopia, central scotoma, and optic atrophy.

Adolescent↗
PubMed1991

Optimum technique of light brightness assessment in control subjects and patients with ocular hypertension and glaucoma.

The light brightness test is an investigation in which crossed polarizing lenses placed in front of each eye are rotated with respect to one another to ellicit any disparity in perception of a diffusely illuminated screen. A number of different strategies can be employed to achieve the aim of determining the degree of disparity which is perceived as equal by the patient. A cohort of 45 control subjects was assessed in order to determine the ranges of brightness disparity accepted as equal for six methods of assessment. The method which gave the optimal confidence limit was to preset one pair of lenses at 0 degrees (maximum transmission) and the other as a fixed reference at 45 degrees. Rotation of the lens set at 0 degrees was carried out until the brightness of an X-ray box is perceived as equal. The strategy was then reversed. A disparity in one or both recordings greater than 76.5% is outside 99% confidence limits for the whole population studied. One of 14 patients with ocular hypertension gave a consistently 'positive' results. For the optimal method, over 60% of patients with glaucoma fell outside 95% condidence limits for normal controls indicating that a disparity in brightness perception between eyes is a common feature in glaucoma, in which the disease process usually affects one eye more than the other. For the patients with chronic glaucoma there was a positive correlation between the difference in brightness perception and the difference in central visual field score, indicating that brightness perception may be subserved by the central 30 degrees of the retina. When combined with visual acuity assessment this easily performed test warrants evaluation as a potential screening test for chronic glaucoma.

Chronic Disease↗
PubMed1991

Quantitative mechanical assessment of the extraocular muscles.

The active and passive behaviour of the extraocular muscles can be investigated by measuring the force that must be applied to rotate the eyeball when the muscles are relaxed (the forced duction test) or the force required to maintain the eyeball stationary while the contralateral eye follows a moving target (the force generation test). Apparatus and test procedures for carrying out both tests are described. Normal values and confidence intervals for the tests have been obtained and the results of muscle entrapment and palsy illustrated.

Adolescent↗
PubMed1990

Automatic chart reader--an example of computer systems for patients' data interpretation.

A new approach to the processing of circular medical charts based on "odd symmetry digital subtraction" is presented. The technique allows automatic digitisation of these charts using an image processing system based on a flat bed scanner. This approach is simple, fast, and reliable; and provides a system in which the digitised image is processed by a microcomputer to extract and quantify the plotted information. The main features and the potential applications of this approach in medical and nonmedical fields are discussed.

Algorithms↗
PubMed1990

Acquired Brown's syndrome: iatrogenic causes.

Two cases of iatrogenic acquired Brown's syndrome are presented, and other causes of this disorder and its treatment are discussed. Care should be taken not to cause damage when operating in the region of the trochlea.

Adult↗
PubMed1990

Penetration of synthetic corticosteroids into human aqueous humour.

The penetration of prednisolone acetate (1%) and fluorometholone alcohol (0.1%) into human aqueous humour following topical application was determined using the very sensitive and specific technique of Gas Chromatography with Mass Spectrometry (GCMS). Prednisolone acetate afforded peak mean concentrations of 669.9 ng/ml within two hours and levels of 28.6 ng/ml in aqueous humour were detected almost 24 hours post application. The peak aqueous humour level of fluorometholone was 5.1 ng/ml. The results are compared and contrasted with the absorption of dexamethasone alcohol (0.1%), betamethasone sodium phosphate (0.1%) and prednisolone sodium phosphate (0.5%) into human aqueous humour.

Aged↗
PubMed1990

Penetration of topically applied betamethasone sodium phosphate into human aqueous humour.

Gas Chromatography combined with Negative Chemical Ionisation Mass Spectrometry (GCMS) was used to determine the absorption of topically applied beta-methasone sodium phosphate into the aqueous humour of human subjects undergoing routine intraocular surgery. The Betamethasone concentration was greatest in the interval 91-120 minutes following topical administration (mean peak concentration = 7.7 ng/ml). At twelve hours post instillation the mean concentration of Betamethasone was 2.5 ng/ml and detectable levels were recorded in the aqueous humour 24 hours after application (mean concentration 0.4 ng/ml).

Administration, Topical↗
PubMed1990

Brightness discrimination and contrast sensitivity in chronic glaucoma--a clinical study.

The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma.

Adult↗
PubMed1990

Optic nerve hypoplasia in children.

Optic nerve hypoplasia (ONH) is characterised by a diminished number of optic nerve fibres in the optic nerve(s) and until recently was thought to be rare. It may be associated with a wide range of other congenital abnormalities. Its pathology, clinical features, and the conditions associated with it are reviewed. Neuroendocrine disorders should be actively sought in any infant or child with bilateral ONH. Early recognition of the disorder may in some cases be life saving.

Abnormalities, Multiple↗
PubMed1989

Recent developments in the prevention and treatment of congenital toxoplasmosis.

The manifestations of congenital toxoplasmosis vary considerably in degree, characteristics and time of onset. Options for prevention of the disease include the appropriate disposal of cat litter and the avoidance of ingestion of both contaminated food and undercooked meat by pregnant women. Immunisation of the domestic cat population is a consideration for the future. Alternatively, immunisation of sero-negative pregnant women awaits the introduction of an effective and safe reagent. Current treatment modalities are not universally effective and new drugs are the subject of active development and research. Screening of pregnant women or perhaps newborn infants are potential options but the cost effectivity has yet to be established in many countries and the results of treatment during pregnancy and early childhood are encouraging but are as yet unproven. The majority of patients with congenital toxoplasmosis eventually develop toxoplasmic retinochoroiditis. Current treatment options for this condition are outlined. Acquired immune deficiency syndrome (AIDS) may, in some cases, represent a recrudescence of congenital intracerebral infection. Current treatment strategies for this condition are discussed.

Acquired Immunodeficiency Syndrome↗