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Biomedical subjects

T Barrie

Publications and source records attributed to T Barrie.

At least 19 recordsLinked to original sources

Residual debris as a potential cause of postphacoemulsification endophthalmitis.

AIM: To examine residual debris within sterilised instruments prior to cataract surgery. METHODS: (i) Flushings from 32 sets of phacoemulsification instruments, sterilised according to hospital routine protocols, were taken preoperatively and analysed by scanning electron microscopy (SEM). (ii) A total of 16 sets of flushings from a different institute were collected-with separation of samples collected from phacoemulsification and those from irrigation-aspiration (IA) instruments-and analysed in the same way. (iii) A total of 15 sets of flushings were collected from instruments where an automated flushing system was used prior to sterilisation. RESULTS: (i)In the first study, 62% were clean, 16% were moderately contaminated and 22% were severely contaminated. Various contaminants were identified including lens capsule and cells, man-made fibres, squamous cells, bacteria, fungal elements, diatoms, red blood cells and proteinaceous material. (ii) In the second study, the results were similar and contamination of both phacoemulsification and IA instruments was shown. (iii) The third study showed that although a decrease in contamination followed automated flushing, contamination was not completely eliminated. CONCLUSIONS: Although all equipment had been sterilised, pyrogenic material was still present. These findings emphasise the importance of meticulous cleaning of all surgical equipment in which biological debris can remain.

Endophthalmitis↗

National audit of the outcome of primary surgery for rhegmatogenous retinal detachment. I. Sample and methods.

PURPOSE: This national study was designed to audit anatomical outcome and complications relating to primary surgery for rhegmatogenous retinal detachments. This paper presents survey methods, characteristics of participating consultants and the demographic and clinical characteristics of the patient sample. METHODS: Two surveys were undertaken. The first identified consultants who at the time performed retinal detachment surgery in the National Health Service. These surgeons formed the sampling frame for a nationwide cross-sectional clinical study that audited the outcomes of primary surgery for rhegmatogenous retinal detachments. Consultants selected patients according to the study eligibility criteria and data were collected by self-administered postal questionnaires. A validation exercise was carried out to examine selection bias and reporting accuracy. RESULTS: Only 256/671 (38%) of UK consultants, who responded to the first survey, indicated that they performed retinal detachment surgery on NHS patients. Annual activity varied between 0 and 400 primary procedures for rhegmatogenous retinal detachments. Seven hundred and sixty-eight eligible patients from 167 consultants were recruited for the clinical study. Twenty per cent of patients had a single retinal break with less than one quadrant of associated detachment and 45% had single or multiple breaks within the same quadrant and/or less than two quadrants of associated retinal detachment. Over 50% patients had single or multiple horseshoe tears. Validation studies suggested that there was no significant bias from the selection of patients or inaccuracy in reporting outcomes. CONCLUSIONS: This large unselected group of primary rhegmatogenous retinal detachments provides a representative sample for considering variations in re-attachment rates.

Adolescent↗

National audit of the outcome of primary surgery for rhegmatogenous retinal detachment. II. Clinical outcomes.

PURPOSE: This national study was designed to audit anatomical outcome and complications relating to primary surgery for rhegmatogenous retinal detachments. This paper presents success and complication rates, and examines variations in outcome. METHODS: Sampling and recruitment details of this nationwide cross-sectional survey of 768 patients of 167 consultant ophthalmologists having their first operation for rhegmatogenous retinal detachment have been described. The main clinical outcomes detailed here are anatomical reattachment at 3 months after surgery and complications related to surgery. Consultants with a declared special interest in retinal surgery and able to perform pars plana vitrectomy were designated specialists for the analyses. RESULTS: Overall reattachment rate with a single procedure was 77% (95% CI 73.9-80.2). There were significant differences in reattachment rates between specialists and non-specialists. Without allowing for case-mix, specialists had a reattachment rate of 82% (95% CI 77.9-85.7) with a single procedure and non-specialists 71% (95% CI 65.9-76.0). Allowing for case-mix, there was a significant difference between specialists and non-specialists for grade 2 detachments of 87% and 70% respectively (P < 0.0001). Analysing detachments by break type, the largest difference between specialists and non-specialists was observed for retinal detachments secondary to horseshoe tears, 80% and 68% respectively (P < 0.003). Specialists met the standards set for primary reattachment rates, while non-specialists did not. Over a third of patients had at least one complication reported at some point during the audit period. CONCLUSIONS: Significant differences were seen in reattachment rates between specialists and non-specialists, overall and for specific subgroups of patients. This study provides relevant, robust and valid standards to enable all surgeons to audit their own surgical outcomes for primary retinal detachment repair in rhegmatogenous retinal detachments, identify common categories of failure and aim to improve results.

Adolescent↗

Spatial localization after different types of retinal detachment surgery.

PURPOSE: To compare the effect on spatial localization of two different forms of surgery for primary rhegmatogenous retinal detachment. METHODS: Two groups of 30 patients (one group undergoing conventional external scleral-buckling procedures, the other undergoing vitrectomy procedures) were recruited. They pointed at targets appearing on a computer touchscreen without being able to see their hands, while viewing targets with the non-surgically treated eye. The sizes of the horizontal pointing errors were recorded on three separate occasions: before surgery, on the first postoperative day, and approximately 10 days later. RESULTS: On the first postoperative day a significant change in localization of 2.9 +/- 0.9 degrees [SD]) was observed in the scleral-buckling group, compared with 1.3 +/- 0.6 degrees in the vitrectomy group. These changes resolved by the second postoperative assessment. CONCLUSIONS: These results, particularly in patients in the scleral-buckling group in whom greater manipulation of the extraocular muscles inevitably occurs, are consistent with an alteration in the extraretinal eye position information that is used in spatial localization. This is likely to be a consequence of modified efference copy and/or extraocular muscle proprioception.

Adult↗

Motility and binocularity outcomes in vitrectomy versus scleral buckling in retinal detachment surgery.

BACKGROUND: Ocular motility defects and loss of binocularity are well-recognised problems following retinal detachment surgery. It is presumed that scleral buckling is primarily responsible for these effects. The increasing use of vitrectomy in the management of retinal detachment might be expected to reduce the incidence of these defects. METHOD: Two groups of patients presenting with primary uncomplicated rhegmatogenous retinal detachments were examined following a single surgical repair. The first group underwent vitrectomy (n = 17), the second group, scleral buckling/external surgical techniques (n = 23). RESULTS: Heterotropia was present in 24% (n = 4) of the vitrectomy group and 30% (n = 7) of the "external" group, with suppression reported clinically in 8 of these and diplopia by the other 3. While ocular movements were frequently full (vitrectomy 59%, external 61%), restricted vertical movements were observed in 35% of the vitrectomy group and 26% of the external group, with horizontal and general restrictions being rare (6% and 13% respectively). True motor fusion was more common for the external group (44%) than the vitrectomies (24%), while superimposition was more frequent in the vitrectomies (64%; external 39%). The latter was achieved only with correcting prisms in 18% of vitrectomies and 9% of the external group. The remainder did not demonstrate any potential for binocularity. Visual symptoms were more frequent among the vitrectomy group, with aniseikonia and torsion significantly more common. CONCLUSIONS: The findings confirm that ocular motility problems are not exclusive to scleral buckling, with the incidence being similar in both groups. Slinging of the extraocular muscles and the accompanying dissection, resulting in the 'fat adherence syndrome', must be considered as contributory factors. The visual deficits which inevitably occur as the result of retinal detachment seem to play a more major role in the disruption of binocularity in these cases.

Adolescent↗

How much blame can be placed on laser photocoagulation for failure to attain driving standards?

One hundred consecutive patients who underwent bilateral pan-retinal photocoagulation (PRP) for proliferative diabetic retinopathy were assessed in accordance with the UK Driver and Vehicle Licensing Agency (DVLA) guidelines. Visual acuity was documented, and visual fields were assessed using the Esterman test. Among the 30% of patients who failed to reach the visual standards required for a driving licence, three groups were identified: those who failed to attain either the required binocular visual acuity (n = 4), or visual fields (n = 9), or both (n = 17). Previous studies reveal a large variation in DVLA field test failure following PRP treatment for proliferative diabetic retinopathy. Our results show a 19% failure rate solely attributable to treatment, which is at the lower end of previously reported studies (20-80%). The reasons for this discrepancy are discussed. We conclude that modern treatment procedures for proliferative diabetic retinopathy may be undertaken with the knowledge that in the majority of cases a patient's driving licence is unlikely to be revoked.

Automobile Driver Examination↗

Macular holes.

Explore the source record for details and available documents.

Humans↗

Benefits of training junior physicians to detect diabetic retinopathy--the Glasgow experience.

The accuracy and appropriateness of 115 consecutive referrals by non-consultant physicians to a specialist Diabetic Retinopathy Clinic were assessed in a retrospective study. The source of the referrals was masked throughout the study. Referrals were classed as 'appropriate' or 'inappropriate' for patient management, and the referral diagnosis (where specified) was compared with the ophthalmologist's initial assessment. It was graded as 'correct', 'partly correct' and 'incorrect'. Referrals from physicians who had received 40-50 hours of outpatient training in the Diabetic Retinopathy Clinic (group A, n = 49) were compared with referrals from doctors without this special instruction (group B, n = 66). Referral was deemed 'appropriate' in 32 (65%) of group A referrals, but in only 22 (33%) of group B (chi 2 = 11.54, df = 1, P less than 0.001). Referral diagnosis (when expressed) was graded as 'correct' in 28 (67%) of group A referrals compared with only 12 (30%) of group B, being 'incorrect' in 10 (25%) of group B referrals and just two (4.5%) of group A (chi 2 = 12.9, df = 2, P less than 0.005). Regular fundoscopy with accurate assessment and appropriate action is vital to prevent loss of vision in diabetic patients. Short-term outpatient training in a Diabetic Eye Clinic leads junior physicians to more appropriate referral and more accurate referral diagnosis.

Diabetic Retinopathy↗

Autonomic mechanisms underlying intraocular pressure changes during insulin-induced hypoglycaemia in normal human subjects: effects of pharmacological blockade.

1. A fall in intraocular pressure is induced by acute hypoglycaemia in humans. The role of the autonomic nervous system in mediating this response was investigated in 24 normal volunteers in whom hypoglycaemia was induced with intravenous soluble insulin, under four experimental conditions: (1) control (n = 6), (2) non-selective alpha-adrenoceptor blockade (phentolamine) (n = 6), (3) non-selective beta-adrenoceptor blockade (propranolol) (n = 6) and (4) cholinergic blockade (atropine) (n = 6). Intraocular pressure was measured by using an applanation tonometer. In 12 subjects intraocular pressure was measured during each type of pharmacological blockade of similar duration without induction of hypoglycaemia, to assess the effects of individual antagonists. 2. In the control study intraocular pressure fell during hypoglycaemia from 15 +/- 1.0 to 10 +/- 1.3 mmHg (P less than 0.01) 10 min after the autonomic reaction. beta-Adrenoceptor blockade caused a reduction in intraocular pressure from 15 +/- 1.1 to 9 +/- 1.0 mmHg (P less than 0.001) before the administration of insulin, and when hypoglycaemia was induced intraocular pressure decreased further to 7 +/- 1.0 mmHg (P less than 0.05, compared with immediately before insulin). A decrease in intraocular pressure of similar magnitude was observed with propranolol alone (16 +/- 1.0 to 10 +/- 1.0 mmHg, P less than 0.05). 3. Cholinergic blockade had no immediate effect on intraocular pressure, and the reduction in intraocular pressure during hypoglycaemia was of similar magnitude to that observed during the control study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Contact lens related problems presenting in casualty.

The use of contact lenses in preference to spectacles has gained much popularity over recent years. This, however, is not without its complications and eye departments are now seeing an increasing number of contact lens related eye disease. This study seeks to show the range of complications seen, their treatment and outcome. It also outlines the types of contact lens in popular use, the reason for wear, the duration of wear and the sex, age and professional distribution of contact lens wearers.

Adolescent↗

How effective is the referral chain for diabetic retinopathy?

Despite the availability of effective photocoagulation treatment, diabetic retinopathy remains the main cause of blindness in persons aged between 20 and 64 years. We have examined the effectiveness of the referral chain for retinopathy by auditing medical records for a representative sample being 226 diabetic patients (35% of attenders) referred to a special photocoagulation clinic. Patients were classified as 'late' or 'not late' by using an algorithm which accounted for the state of retinopathy at referral and the previous frequency of eye examination. Forty-four patients (19%) were considered to have been referred late. These were mainly younger onset patients, aged between 30 and 40, and not attending a diabetic clinic. Patients not attending any other outpatient clinic were 27 times more likely to be referred late.

Adult↗

The place of elective vitrectomy in the management of patients with Candida endophthalmitis.

A general review of the treatment of Candida endophthalmitis is undertaken, with particular emphasis on the efficacy of various drugs currently in use. Their absorption by the eye when given systemically is also considered. The limitations of medical treatment for this condition are discussed and the theoretical reasons for vitrectomy considered. Six cases that underwent vitrectomy are reviewed, and the indications for vitrectomy in Candida endophthalmitis are discussed. A tentative overall plan for the management of such cases is given.

Amphotericin B↗