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Biomedical subjects

N P Strong

Publications and source records attributed to N P Strong.

At least 19 recordsLinked to original sources
PubMed2006

Distance stereoacuity in intermittent exotropia.

BACKGROUND: Studies of distance stereoacuity in intermittent exotropia suggest that normal stereoacuity corresponds to good control of the deviation and that reduced or negative stereoacuity signifies poorer control. AIM: : To evaluate distance stereoacuity in intermittent exotropia using the Frisby Davis Distance stereo test (FD2). METHODS: Children with intermittent exotropia where the near angle was less than or equal to distance were eligible for recruitment. Standardised prospective data collection included FD2 distance stereoacuity. This was a longitudinal study in which outcomes are reported for baseline, last follow-up (> or =6 months before any surgery) or preoperative and last postoperative visits for those undergoing surgery. RESULTS: 110 children with intermittent exotropia had FD2 stereoacuity tested at baseline: 70 comprehended the test. Mean (standard deviation (SD)) age was 4.6 (1.7) years (range 2-10 years). 41/70 (59%) showed positive responses: mean (SD) stereoacuity 30 (12) s of arc. The mean follow-up period before any surgery was 13 months (range 6-27 months). At follow-up, mean (SD) stereoacuity was 24 (11) s of arc. Preoperative and postoperative stereoacuity were not significantly different from those not undergoing surgery. CONCLUSION: This study was the first to report distance stereoacuity in intermittent exotropia using the FD2 stereo test: patients with intermittent exotropia can achieve normal levels of distance stereoacuity, but a considerable proportion, despite comprehending, showed a negative response. This suggests that using the FD2, distance stereoacuity in intermittent exotropia is either absent or normal rather than reduced. Possible reasons for this and its implications are discussed.

Child↗
PubMed2004

Clinical outcomes and complications of intraocular lens exchange in patients with opacified hydrophilic acrylic lenses SC600-2.

BACKGROUND: The purpose of this study was to present the outcomes of intraocular lens exchange in patients with opacified hydrophilic acrylic intraocular lenses. PATIENTS AND METHODS: Fifteen patients, who underwent uncomplicated phacoemulsification and hydrophilic acrylic intraocular lens (model SC600-2) implantation with good visual recovery, were re-referred to our department 76 - 188 weeks post-surgery due to progressive visual loss resulting from opacification of the implant. Intraocular lens exchange followed. The method of lens exchange is described. The effect on the best corrected visual acuity and on their refraction, the operative and postoperative complications are reported. RESULTS: All 15 patients underwent intraocular lens exchange. Twelve patients (80 %) had improvement of their best corrected visual acuity, in two cases (13 %) the best corrected visual acuity did not change, and in one case (7 %) the best corrected visual acuity deteriorated, this being attributed to progression of her age-related macular degeneration. None of the patients developed zonular dehiscence; in one patient the exchange was complicated with posterior capsule rupture, and an anterior chamber intraocular lens was implanted. One patient required cutting of the haptics before removal of the opacified intraocular lens. The mean Snellen (decimal) visual acuity was 0.35 (range 0.1 to 0.6) before lens exchange and 0.49 (range 0.1 to 0.6) six weeks after; the difference was significant (P < 0.05). Excluding the patient with the deterioration of her age-related macular degeneration, mean visual acuity of the remaining fourteen patients after the intraocular lens exchange was even better (0.56). CONCLUSION: Exchange of opacified hydrophilic acrylic intraocular lenses seems to be the only currently available effective treatment, leading to improvement of visual acuity.

Acrylates↗
PubMed2004

The Newcastle Control Score: a new method of grading the severity of intermittent distance exotropia.

AIM: To describe the development and application of a novel scoring system for grading the severity of intermittent distance exotropia (IDEX) and its potential application as an intervention criterion for surgical intervention. METHODS: The Newcastle Control Score (NCS) for IDEX was developed by incorporating both subjective (home control) and objective (clinic control) criteria into a scale to grade severity. The score structure described was evaluated for interobserver and test-retest reliability. To determine an optimal score threshold for surgical intervention, 170 cases of IDEX were scored retrospectively. Cure rates for surgical and non-surgical cases were then compared according to preoperative or presenting scores. RESULTS: Interobserver and test-test reliability were good (r = 0.82 and r = 0.89 respectively). Total cure rate with surgery was 54% and without surgery 18% (chi(2) = 23.093, df = 1, p<0.001). Significantly fewer patients with NCS >/=3 achieved cure without surgery than those with NCS 2 (chi(2) = 3.362, df = 1, p<0.047). CONCLUSIONS: The NCS is a reliable method for grading the severity of IDEX and aids decisions regarding intervention. Patients with a score of 3 or more are unlikely to attain a cure without surgery.

Child↗
PubMed2002

Effect of prior steroid treatment on temporal artery biopsy findings in giant cell arteritis.

AIM: To examine the effect of up to 6 weeks of corticosteroid treatment on the positive temporal artery biopsy rate in giant cell arteritis (GCA). METHODS: Prospective comparative clinical study of 11 patients meeting the American College of Rheumatology criteria for diagnosis of GCA. Patients underwent temporal artery biopsy within 1 week, at 2-3 weeks, or after 4 weeks of corticosteroid treatment. RESULTS: Overall, nine of 11 (82%) patients had positive temporal artery biopsies. Six of seven (86%) biopsies performed after 4 or more weeks of steroid treatment were positive. CONCLUSION: Temporal artery biopsy is useful several weeks after institution of steroids.

Administration, Oral↗
PubMed1999

Risk factors for strabismus in children born before 32 weeks' gestation.

AIM: To investigate risk factors associated with strabismus in children born prematurely. METHODS: Prospective study of all children born before 32 weeks' gestation between 1 January 1990 and 31 December 1991 in a geographically defined population of approximately 3 million in the Northern Region of the United Kingdom. All children were examined aged 2 years by the same ophthalmologist and paediatrician. RESULTS: 558 children (98.6% of study group) were examined. Logistic regression showed an increased risk of strabismus in children with cicatricial retinopathy of prematurity (p=0.02), refractive error (p=0.003), family history of strabismus (p<0.0001), and poor neurodevelopmental outcome (p<0.0001), in particular impaired locomotor skills (p=0.008) and hand-eye coordination (p=0. 001). Gestational age and regressed acute ROP were not independent risk factors for strabismus (p=0.92 and 0.85 respectively). CONCLUSIONS: This study has identified factors which are independently related to strabismus (although not necessarily causative) and others which are related only indirectly. This may contribute both to the management of children born prematurely and to future studies of the aetiology of strabismus.

Child Development↗
PubMed1998

New generation hydroxypropyl methylcellulose (HPMC-Ophtal H) for intraocular surgery: a confocal laser scanning microscopy study.

PURPOSE: To determine the abundance and variety of particulate debris in new generation hydroxypropyl methylcellulose (HPMC) samples. METHOD: Three samples of sterile HPMC-Ophtal H were examined using a confocal laser scanning microscope, scanning electron microscope and mass spectrometry. RESULTS: Confocal laser scanning microscopy of the samples showed that particulate matter in HPMC was less than 30 microns in size and at a density of less than 1000 particles per millilitre. No discernible details were seen by the scanning electron microscope, and mass spectrometry did not identify and bands. CONCLUSION: Improved methods of preparation including filtration may be responsible for decreased particulate debris in new generation HPMC.

Cataract Extraction↗
PubMed1997

Refractive errors in children born before 32 weeks gestation.

PURPOSE: To document the refractive errors in a cohort of children born before 32 weeks gestation. METHODS: All children born before 32 weeks gestation between 1 January 1990 and 31 December 1991 to mothers resident in the Northern Region of the National Health Service were examined at 2 years old (n = 558). RESULTS: Stage 3 or worse retinopathy of prematurity (ROP) was associated with myopia. In those not developing stage 3 or worse ROP, the refractive errors were myopia in 1.5%, hypermetropia > 4 dioptres (D) in 5.4%, anisometropia > 1 D in 1.1% and astigmatism > 1.25 D in 5.7%. CONCLUSION: The incidence of refractive errors in those not developing stage 3 or worse ROP was similar to that in the general population.

Acute Disease↗
PubMed1996

Primary ocular relapse in acute lymphoblastic leukemia.

Relapse of acute lymphoblastic leukaemia (ALL) occurred in the anterior segment of four children. All cases had been treated according to the Medical Research Council's UK Acute Lymphoblastic Leukaemia trial protocol (UKALL) including 2 years of continuation chemotherapy. In three cases the diagnosis was confirmed by anterior chamber aspirate while in one case the diagnosis was presumed on clinical grounds alone. All four cases experienced isolated leukaemic relapse in the anterior segment within 2 months of stopping therapy. The months immediately following cessation of continuation chemotherapy as part of the UKALL regime appear to represent a 'high-risk' period for primary anterior segment relapse of ALL. Children with ALL presenting with uveitis should be regarded as having leukaemic relapse and anterior chamber taps with or without an iris biopsy should be considered to confirm this diagnosis. Early diagnosis and treatment of ocular leukaemic relapse is likely to give these children the best chance of ultimate cure.

Anterior Chamber↗
PubMed1996

Retinopathy of prematurity in a controlled trial of prophylactic surfactant treatment.

AIMS: To investigate the incidence of acute and cicatricial retinopathy of prematurity (ROP) in a cohort of premature neonates entered into a randomised, multicentre trial of prophylactic exogenous surfactant for respiratory distress syndrome (RDS) compared with controls receiving surfactant only if severe RDS developed. METHODS: The incidence of acute and cicatricial ROP was assessed in 304 neonates born at less than 30 weeks' gestation in a geographically defined population of approximately three million. RESULTS: There was a trend towards improved survival in the group receiving prophylactic surfactant with 102/151 (67.5%) surviving compared with 82/141 controls (58.2%, p = 0.12). The prophylactic surfactant group would be expected to have an increased risk of ROP due to improved survival, particularly of the most premature infants. However, there was no statistically significant difference in the incidence of acute ROP between the two groups and the incidence of cicatricial ROP was lower in the group receiving prophylactic surfactant (4/100 survivors, 4.0%) compared with neonates receiving rescue surfactant as required (6/81, 7.4%). This difference did not reach statistical significance (p = 0.35). CONCLUSION: The trend for a lower incidence of cicatricial ROP in those neonates treated with prophylactic surfactant compared with the rescue surfactant group, despite improved survival, suggests that the use of prophylactic surfactant also had a beneficial effect on the development of cicatricial ROP.

Drug Combinations↗
PubMed1995

Vitreous loss in planned extracapsular cataract extraction does lead to a poorer visual outcome.

Forty-six cases of vitreous loss during planned extracapsular cataract extraction salvaged by anterior vitrectomy and primary anterior chamber lens implantation were compared in a retrospective cohort study with 92 individually matched controls. The postoperative visual outcome for cases with vitreous loss was significantly poorer than that for controls even after adjustment for confounding variables. Part of this visual morbidity was explained by cystoid macular oedema and retinal detachment, but even after adjusting for these two complications visual outcome remained worse among cases than controls. There was a significantly higher incidence of clinically apparent cystoid macular oedema amongst cases compared with controls (20% versus 1%). Two retinal detachments occurred among the cases but this difference in incidence was not statistically significant.

Aged↗
PubMed1995

Ocular outcome in children born before 32 weeks gestation.

Ocular outcome was assessed in a 2 year cohort of all children born before 32 weeks gestation within a geographically defined population of approximately 3 million. Five hundred and sixty-five children were born within the study period; 558 children (98.8% of the study group) were assessed at approximately 2 years old. There was a high incidence of abnormalities, particularly strabismus (70, 12.5%), cortical visual loss (7, 1.3%), sequelae of retinopathy of prematurity (16, 2.9%) and other significant refractive errors (69, 12.7%). These data provide a recent estimate of gestational age-specific prognosis and suggest that follow-up yields a significant proportion of children with visual abnormalities who could benefit from treatment.

Child, Preschool↗
PubMed1992

Medical management of ocular malakoplakia.

A 14-year-old girl had a granulomatous conjunctival lesion, proven histologically to be malakoplakia. This is the first reported case of malakoplakia arising from conjunctiva, although three others have involved the ocular adnexa. Malakoplakia is a rare disease often associated with immunodeficiency and is characterized by the presence of intracellular inclusions and organisms due to deficient intracellular bacteriolysis. Medical management is difficult because an effective antibacterial agent requires three properties: activity against the organism involved, good intracellular penetration, and the capacity to maintain its effectiveness in the intracellular milieu. Escherichia coli was isolated from a biopsy specimen and from conjunctival swabs. Treatment with systemic ciprofloxacin, which has good intracellular penetration and activity, led to rapid resolution of the lesion. This is the first report concerning the successful use of this drug to treat malakoplakia of any organ.

Adolescent↗
PubMed1992

Factors related to the final visual outcome of 425 patients with traumatic hyphema.

A retrospective study of the visual outcome of 425 in-patients with traumatic hyphaema has been conducted. A multivariate analysis demonstrated that after adjusting for age, sex and pre-existing poor vision, the size of hyphaema on presentation and the presence of retinal damage were significant predictors of a worse final visual outcome (p = 0.00003 and 0.00001 respectively). Topical steroid and/or cycloplegic medication, and the occurrence of secondary haemorrhage did not influence the final visual outcome after adjustment for the other variables. These data illustrate, in an unselected sequential population of patients, the role of these factors in terms of final visual outcome following hyphaema from blunt ocular trauma.

Eye Injuries↗
PubMed1992

Factors related to the incidence of secondary haemorrhage in 462 patients with traumatic hyphema.

In a retrospective study of 462 in-patients with traumatic hyphema, secondary haemorrhage occurred in 8.7% of patients. A multivariate analysis demonstrated that the size of hyphaema on presentation and the presence of retinal damage did not affect the probability of secondary haemorrhage. The incidence of secondary haemorrhage was found to decrease by approximately half with the use of topical steroid (p = 0.005), but did not appear to be influenced by the use of cycloplegics. These data indicate in an unselected sequential population of patients, the therapeutic importance of topical steroid in the treatment of blunt ocular trauma.

Administration, Topical↗
PubMed1992

Contrast sensitivity and glare in cataract using the Pelli-Robson chart.

There is a need for a convenient, clinically applicable test of glare disability which can be used in the preoperative evaluation of patients with cataract. In this study, contrast sensitivity (using the Pelli-Robson letter chart), near vision, and visual acuity were compared, with and without the introduction of a glare source in 70 patients with cataract, 15 with intraocular lenses, and 19 controls. A disposable pen torch was shone at the pupillary margin to induce glare. Contrast sensitivity demonstrated the most marked reduction during glare testing. Cortical cataracts were most affected followed by posterior subcapsular opacities. The glare disability was significantly less in pseudophakic patients and was absent from patients with non-cataractous phakic eyes. Glare testing with a disposable pen torch and a Pelli-Robson contrast sensitivity letter chart provides a rapid test of glare disability which can be easily incorporated into the clinical appraisal of patients with cataract.

Aged↗
PubMed1992

How optometrists screen for glaucoma: a survey.

All optometrists registered and practising in Leicestershire were surveyed to find out what facilities they have for glaucoma screening, how patients are selected for screening, what tests are performed, and the criteria used for referring patients to the hospital ophthalmic service. All respondents examine the optic disc of all patients: 99% have tonometry available, but most use it selectively, on the basis of age, family history and disc appearance. Although 88% have field testing apparatus, this is usually not of a type likely to be effective in screening a general population: 38% have automated or semiautomated perimetry. The criterion level of IOP at which 80% of respondents would refer was 27 mm Hg in the absence of disc cupping, falling to 24 mm Hg if cupping was suspected. Over 80% would refer any patient with a field defect irrespective of IOP.

Adolescent↗