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Biomedical subjects

R Holden

Publications and source records attributed to R Holden.

At least 19 recordsLinked to original sources

A clinical evaluation of ophthalmic assessment in children with sensori-neural deafness.

BACKGROUND: Since 1991, children with sensori-neural deafness and their families within Southern Derbyshire have been supported by a multiagency approach to their diagnosis and management. RESULTS: One hundred and twenty-two children were seen at the Child Development Centre for an holistic assessment, and 110 of these children have had an ophthalmic assessment, of whom 48 (43.6%) were found to have ophthalmic abnormalities. These included 43 children (39.1%) with refractive errors, ranging from mild to severe. Of 82 children with uncomplicated deafness, 26 (31.7%) had refractive errors. The prevalence of ophthalmic problems was higher than the prevalence in hearing school children in the literature and in local pre-school children. There were six cases of Usher syndrome. Twenty-one children had more than one eye defect. The findings indicate that deaf and hearing impaired children are two to three times more likely to develop ophthalmic abnormalities than their hearing peers, which makes early detection of paramount importance. An important local outcome has been the establishment of guidelines for ophthalmic assessment to include assessment of vision and screening for Usher syndrome by electro-physiological testing at aged 7 years and above. Screening has been completed to date in 78 children with congenital sensori-neural deafness. CONCLUSIONS: Sensitive and efficient ophthalmic assessment and management are essential for all deaf and hearing impaired children and national guidelines need to be established for both assessment of vision and screening for Usher syndrome, based on further evaluated research.

Child↗

The use of surgical facemasks during cataract surgery: is it necessary?

AIM: To assess whether facemask utilisation by the surgeon during cataract surgery has any effect on the bacterial load falling onto the operative site. METHOD: Prospective randomised masked study. Consent was obtained from 221 patients. Cases were randomised to wearing a new mask or not wearing any mask throughout the procedure. Blood agar settle plates were placed adjacent to the patient's head in the operative field. Duration of procedure was noted. Plates were incubated and read at 48 hours. Colony forming bacteria were counted and identified. RESULTS: There were significantly fewer organisms cultured when the surgeon used a facemask (p=0.0006). The majority of organisms were Staphylococcus epidermidis, Bacillus spp, and Diphtheroid spp; however Staphylococcus aureus and Pseudomonas aeruginosa were cultured on several occasions. There were no cases of infective complication. CONCLUSIONS: The main purpose of an operating mask is to prevent bacteria falling on to the operative site from the surgeon's oropharynx or nasopharynx with the concomitant theoretical risk of infective complication. Operating masks were shown to have a significant effect on the volume of bacterial organisms falling to the operative site; however, whether this is clinically significant is unknown.

Bacterial Infections↗

The effect of sub-Tenon's anaesthesia on intraocular pressure.

PURPOSE: To assess the effect of sub-Tenon's anaesthesia on intraocular pressure (IOP) prior to cataract surgery. METHODS: Fifty consecutive patients undergoing phacoemulsification of cataract were recruited. Routine sub-Tenon's anaesthesia was administered with 5 ml unpreserved 2% lignocaine. IOPs were measured immediately prior to and at 1, 3, 5 and 10 min after injection. Efficacy was assessed subjectively by the operating surgeon. No ocular compression was used. Pre- and post-injection IOPs were compared using the Wilcoxon signed rank test, whereas all other results were compared with baseline using Student's two-tailed paired t-tests. RESULTS: All patients achieved good analgesia and akinesis. There was no significant difference between the IOP prior to and 1 min after injection. At all time intervals after 3 min there was a significant reduction in IOP compared with the pre-injection measurement. At 5 min, the mean IOP reduction was 2.72 mmHg and at 10 min IOP was lowered by 2.92 mmHg. Both reductions were statistically significant compared with baseline. CONCLUSIONS: Sub-Tenon's anaesthesia does not cause any significant rise in IOP, thereby possibly making it the anaesthetic technique of choice when an increase in IOP is undesirable. There is no indication for the use of an ocular pressure-reducing device when sub-Tenon's anaesthesia is employed.

Aged↗

Characteristics of voluntary visual sampling of the environment for safe locomotion over different terrains.

The characteristics of visual sampling required for successful locomotion over various terrains is the focus of this work. In the first experiment we directly address the role of continuous visual monitoring of the environment in guiding locomotion by allowing the subjects to choose when and where to take a visual sample of the terrain and examine the effects of different terrains on characteristics of visual sampling. Young subjects walked over travel paths of varying difficulties while wearing opaque liquid crystal eyeglasses and pressed a hand-held switch to make the glasses transparent when they needed to sample the environment. Travel time and visual sampling characteristics were recorded. Results show that intermittent sampling (less than 50%) of the environment is adequate for safe locomotion, even over a novel travel path. The frequency, duration and timing of visual samples are dependent on terrain characteristics. Visual sampling of the environment is unaffected by preview restriction of the travel path and is increased when specific foot placement is required and there is a potential hazard in the travel path. In the second experiment we dissociated steering control and obstacle avoidance from specific foot placement and examined visual sampling demands prior to the initiation of the swing phase and during the swing phase. The results show that steering control and obstacle avoidance do influence the visual sampling time, which is scaled to the magnitude of change. Vision was used in a feedforward control mode to plan for and initiate appropriate changes in the swing limb trajectory: its use during the swing phase to provide on-line control was minimal.

Adult↗

Delusional phenomenology--dimensions of change.

Although the application of cognitive techniques to both the measurement and modification of delusional beliefs has recently been developed in more theoretical detail (e.g. Chadwick & Lowe, 1994, Behaviour Research and Therapy, 32, 355-367) there has not been an effort to examine the variability of delusional phenomenology across time. In the present study we report on the treatment of 6 individuals who fulfilled DSM-III-R (American Psychiatric Association, 1987) criteria for Delusional Disorder and who received cognitive therapy targeted specifically on the single symptom of their delusional belief(s). Single-case time-series methodology was used to examine the associations between different aspects of delusional phenomenology through baseline and intervention study phases. Belief maintenance factors were found to be significantly associated with conviction in all 3 individuals who responded to the intervention. Negative behaviours, affect associated with the belief, preparedness to talk to others about the belief and insight were associated with conviction in some individuals but not others. Preoccupation and acting on the belief were aspects of delusional phenomenology that were found to systematically vary independent of belief conviction. The results support a multidimensional view of delusional phenomenology and the process of change during cognitive intervention.

Adult↗

Preventable delays in the treatment of intraocular melanoma in the UK.

Intraocular melanoma should be treated urgently to improve the chances of survival and of conserving the eye and vision. The aims of this study were to determine the mode of presentation of intraocular melanoma in the United Kingdom and to identify any preventable causes of delay in treatment. A total of 112 patients were included and questioned about their initial symptoms, the type of practitioner consulted and their subsequent management. Thirty per cent of patients were asymptomatic and detected on routine ophthalmoscopy. Symptomatic patients presented with blurred vision (52%), photopsia (26%), visual field loss (9%) and miscellaneous symptoms (13%). Patients presented to an optometrist in 66 cases (59%), to a general practitioner in 30 cases (27%) and to an ophthalmologist in 16 cases (14%). The tumour was misdiagnosed in 12% of patients presenting to an optometrist and in 27% of cases presenting to a GP. The period from the time of onset of symptoms or detection of an abnormality to the time when the patient was referred to the Ocular Oncology Service averaged 6 months (range 0-36 months). Patients waited an average of 4 months if referred urgently as compared with 7.7 months if referred non-urgently (Mann-Whitney U-test, p = 0.0003). Patients were likely to be treated sooner if they were referred directly to the ophthalmologist rather than via the GP (7.8 months vs 4.8 months; Mann-Whitney U-test, p = 0.02).

Adult↗

Quantitation of vitamin E and a carotenoid pigment in cataractous human lenses, and the effect of a dietary supplement.

The quantitation of tocopherols and carotenoids in lipid extracts of cataractous human lenses was performed in parallel with those of matched samples of plasma, which was also analysed at the same time. Alpha-tocopherol in cataractous lenses from elderly human subjects was present at 4.4 mumoles/kg wet weight, much less than the mean of 33 mumoles/l in plasma from these subjects. The mean ratio of alpha- and gamma-tocopherols was 3.5 in the lenses, and 11.3 in plasma. Lens extracts contained no detectable alpha- or beta-carotene, lycopene, or beta-cryptoxanthin. However, all the lens extracts contained a pigment with the retention time and spectrum of lutein and zeaxanthin. Using the molar extinction coefficient of lutein this was present at ca. 0.03 microM, compared with 0.2 microM in plasma. Seven patients with bilateral cataracts had one of their cataractous lenses removed and analysed, and were then given either an oral placebo, or an oral supplement of ascorbate, alpha-tocopherol and beta-carotene. Three months later, the second cataractous lens, and a blood sample, were analysed. Three of the seven had received the active supplement, as confirmed by substantially raised blood levels of alpha-tocopherol and beta-carotene, and raised aqueous humour levels of vitamin C. However, lens tocopherol levels remained unchanged, and no beta-carotene could be detected in the lenses after supplementation. This preliminary evidence needs to be confirmed in larger studies.

Aged↗

Central corneal light scatter in long-term diabetics.

Changes in corneal thickness have been correlated with severity of diabetic retinopathy. Measuring light scatter at the central cornea may reflect the changes in corneal thickness and hence the retinopathy. This study compared the peak central corneal light scatter between 22 insulin-dependent diabetic patients with disease of at least 10 years' duration and 29 controls. No significant difference was found in the light-scattering properties of the central cornea between the two groups. This technique does not offer an alternative method of screening for diabetic retinopathy.

Cornea↗

Measuring pain in pediatric oncology ICU patients.

Thirty patients (ages 5 to 13) hospitalized in a pediatric oncology intensive care unit (ICU) rated the presence and severity of their pain on the Faces Pain Scale (FPS) and the Poker Chip Tool (PCT). Parents independently rated the child's pain on these scales and each patient's nurse completed the Objective Pain Scale (OPS). Patients' ratings on the FPS correlated significantly with parents' ratings on this scale (tau = .48, P = .002) but not on the PCT (tau = .23, P = .16). Nurses' ratings on the OPS were moderately correlated with patients' FPS ratings (tau = .37, P = .02) but were only weakly associated with PCT ratings (tau = .27, P = .09). The majority of patients, parents, and nurses expressed a preference for the FPS over the PCT. The FPS appears to be a clinically useful and accurate approach for measuring the pain of pediatric oncology patients in an ICU but is limited to those who can participate in a self-report measurement.

Adolescent↗

Analysis of retro-illumination photographs for use in longitudinal studies of cataract.

Retro-illumination photography has potential for the monitoring of cortical and posterior subcapsular cataract formation. Variations in the individual illumination results have limited accurate quantification of opacities within such images. We present a new image analysis technique which minimises the effect of uneven and varying retro-illumination. The new technique has been tested for variation between photographers and over a short time period. We believe it is of value in lens assessment in combination with a semi-quantitative grading system.

Cataract↗

Visual performance and objectively measured grades of cataract. A correlation of methods designed for use in longitudinal trials.

Objective quantification of cataract and subjective assessment of visual performance are essential features of anticataract or cataractogenic drug trials. The constrains of a longitudinal trial require a compromise in contrast sensitivity measurement between sensitivity and speed. Such a system has been developed for use in longitudinal anticataract trials. An objective cataract assessment system has also been developed for these trials. Visual performance parameters and objectively measured grades of cataract using these systems were correlated in a group of patients with early lens opacities. Overall the correlation was poor in all three morphological types of cataract. Possible reasons for this and implications for future anticataract trials are discussed.

Aged↗

The effects of adrenaline, hyaluronidase and age on peribulbar anaesthesia.

In a prospective, randomised, masked trial, 91 patients undergoing intraocular surgery received an anaesthetic mixture containing lignocaine hydrochloride 2% and bupivacaine hydrochloride 0.5%. In addition group 1 had hyaluronidase (50 i.u./ml) and adrenaline (1:200,000), group 2 had hyaluronidase alone, group 3 had adrenaline alone and group 4 had neither. The groups were compared regarding the quality of operating conditions. Hyaluronidase had a substantial beneficial effect though there was no significant difference related to the use of adrenaline. Anaesthesia was less effective in patients under the age of 65 years.

Age Factors↗

External ocular trauma in instrumental and normal deliveries.

OBJECTIVE: To compare the occurrence of external ocular trauma in instrumental and normal deliveries. DESIGN: Prospective controlled study. SETTING: University Hospital of Wales, Cardiff. SUBJECTS: 133 babies born consecutively with the use of forceps and 133 control babies born without instrumentation to women matched for parity. INTERVENTIONS: External ocular examination. MAIN OUTCOME MEASURES: The presence within 24 h of birth of corneal oedema, corneal abrasion, conjunctival chemosis, subconjunctival haemorrhage and lid oedema. RESULTS: Lid oedema and multiple minor external ocular trauma occurred in 52 and 22 babies, respectively, in the instrumental delivery group and in 13 and 8 babies, respectively in the control group (P less than 0.001). Corneal abrasion occurred in two babies and corneal oedema in one baby after forceps delivery but in none of the control group. No more serious injuries occurred. All injuries resolved without long term sequelae. CONCLUSION: The frequency of sight threatening corneal trauma in instrumental deliveries is low. Specialist ophthalmic screening of these babies is not justified.

Birth Injuries↗

Ocular fundus lesions in sports divers using safe diving practices.

Ocular fundus fluorescein angiography was performed on 26 divers, who had used safe diving practices for at least 10 years, and on seven controls. There was no significant difference in the incidence of macular abnormalities between these groups and those of a previous study. Adherence to safe diving practice confers some protection against the macular abnormalities known to occur in divers with a history of decompression sickness.

Adult↗