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Biomedical subjects

A R Fielder

Publications and source records attributed to A R Fielder.

At least 109 records · Page 6Linked to original sources
PubMed1988

Is the geniculostriate system a prerequisite for nystagmus?

The time of onset of congenital horizontal nystagmus is usually known. We present a group of infants in whom this was determined objectively. In two, vertical nystagmus in the neonatal period became horizontally directed, at 4 months in one, and between 7 and 9 months of age in the second. Two infants (one an oculocutaneous albino) had no visual response initially but subsequently developed horizontal nystagmus as the vision improved at 5 and 6 1/2 months: Type III delayed visual maturation. An infant totally blind due to Norrie's disease was examined in the first week of life but did not develop nystagmus for a further 3 months. Two children with cortical visual impairment never developed nystagmus. In early infancy, vision is thought to be predominantly subcortical. Therefore the development of nystagmus at a time when the geniculostriate system is emerging functionally (around 3 months), and its absence in cortical visual impairment, has led us to propose a hypothesis suggesting that a functioning geniculostriate system is a prerequisite for the development of horizontal nystagmus.

Blindness↗
PubMed1988

Light transmission through the human eyelid: in vivo measurement.

We describe an in vivo measurement technique for determining the transmission of light through the human eyelid and present data from three human subjects. The relevance of the transmission measurements are discussed in relation to (1) clinical electrophysiology and (2) the effects of light on the developing visual system.

Adult↗
PubMed1988

Grating and recognition acuities of young amblyopes.

The visual acuities of 36 young amblyopes were determined by (a) conventional recognition tests (near and distance) and (b) an adapted grating acuity card procedure. Considerable agreement between the estimates of acuity obtained with each method was demonstrated, which was generally less than, or equal to, the mean difference between adjacent Snellen lines (4.5 c deg-1). Estimates of grating acuity obtained with vertical gratings did not differ significantly from those obtained with horizontal gratings. There was no difference between the subjects' ability to detect the grating (acuity) and accurately to discriminate target orientation (horizontal or vertical). The results of the experiment are discussed in relation to previous findings of a discrepancy between grating and recognition acuities in amblyopia, and the clinical use of the acuity card procedure.

Amblyopia↗
PubMed1988

Do we need to measure the vision of children?

With the advent of the acuity card procedure, it is now possible to measure quantitatively the vision of infants and young children in a routine clinical setting. Over a 19 month period 1177 tests were performed on 586 patients; ages ranged from 0.5 weeks to 23 years. Overall 1102 (93%) were successful, as were 588 of the 627 (94%) tests performed on children under the age of two years when no conventional acuity test is possible. The results serve as a background on which the argument for and against the need to measure the vision of children is considered.

Adolescent↗
PubMed1987

Retinopathy of prematurity in the United Kingdom.

Retinopathy of prematurity (ROP) continues to be a problem for some preterm infants who survive the neonatal period. We review changes which have occurred in the premature infant population and methods of ophthalmological examination since the last survey of ROP in the United Kingdom was conducted between 1951 and 1953. We have analysed data from a retrospective study, and from our current prospective survey of ROP in the East Midlands, to determine the age at onset of acute ROP. The results show that the ophthalmoscopically visible signs of ROP develop over a narrow postmenstrual age range suggesting that acute ROP occurs only after the retina and/or its vasculature have reached a certain stage of development.

England↗
PubMed1987

Sudden-onset squint.

Differentiating a sudden-onset concomitant squint from a paralytic squint in an ill child can be difficult, but the distinction is important in view of the neurological implications of the latter. Furthermore, the two types may co-exist, and four such cases are described. The causes of sudden-onset squint are discussed. Methods of examination are described which may help to distinguish a paretic squint, with its neurological implications, from a concomitant deviation with no such systemic associations.

Abducens Nerve↗
PubMed1987

Microcornea associated with retinopathy of prematurity.

Eight children with retinopathy of prematurity (ROP) in whom the corneal diameters were abnormally small in one or both eyes are reported. The mechanisms for microcornea in ROP are discussed. The differential diagnosis of microphthalmos is briefly considered.

Cornea↗
PubMed1987

Microcephaly, microphthalmos, and retinal folds: report of a family.

A retarded boy with microcephaly, microphthalmos, and retinal folds is described. His mother and sister showed microphthalmos and the sister was also microcephalic. Another family showing similar findings has been described, indicating that this combination of abnormalities constitutes a discrete entity showing single gene inheritance.

Abnormalities, Multiple↗
PubMed1987

Neuraminidase deficiency: case report and review of the phenotype.

A 12 year old boy with neuraminidase deficiency (sialidosis, mucolipidosis I) is described. His clinical features included coarse facies, cherry red spot, ataxia, myoclonus, and dysotosis multiplex. The level of neuraminidase activity in cultured fibroblasts was very low and intermediate levels were observed in both parents. The clinical disorders associated with neuraminidase deficiency are reviewed.

Child↗
PubMed1986

Weill-Marchesani syndrome in mother and son.

A mother and son, each showing the characteristic features of the Weill-Marchesani syndrome, are described. It is suggested that this family provides further evidence for genetic heterogeneity in this condition.

Adult↗
PubMed1986

Temperature--a factor in ocular development?

Mean ocular temperature measured using a hand-held infrared thermometer was 36.54 degrees C and 36.38 degrees C for the right and left eyes of 51 premature babies; whilst for 54 fullterm controls the corresponding figures were 36.40 degrees C and 36.25 degrees C. As fetal temperature at about 38.0 degrees C is above maternal core temperature this means that the eye of the prematurely born infant experiences a thermal deficit of 1.0 to 2.0 degrees C which is never replaced postnatally. The possibility that this reduction in temperature could influence ocular growth is discussed, with particular regard to the development of myopia which people born prematurely are prone to develop.

Body Temperature↗
PubMed1986

Retinopathy of prematurity: age at onset.

The age at which retinopathy of prematurity was first seen was determined in 143 infants. In all, the initial ophthalmological examination was normal. Birth weights varied from 630 to 2700 g and gestational ages from 24.5 to 40.0 weeks. The median postnatal age at which acute retinopathy of prematurity was first seen was 51 and 40 days for those less than 28 and greater than or equal to 28 weeks' gestational age, respectively, and this difference is highly significant. Similar results were obtained when infants were grouped according to birth weight less than 1000 or greater than or equal to 1000 g. Using postmenstrual age as the variable, the first signs of retinopathy of prematurity were seen over a fairly narrow age range and 86% of infants developed retinopathy between 32.5 and 38.5 weeks of age. These findings suggest that the age (but not the occurrence or severity) at which retinopathy of prematurity is first seen is controlled predominantly by stage of development rather than neonatal events.

Age Factors↗
PubMed1986

Benign intracranial hypertension: visual loss and optic nerve sheath fenestration.

Five patients with serious ocular complications of benign intracranial hypertension are described. Optic nerve sheath fenestration resulted in resolution of papilloedema with, in three instances, improvement in vision. Benign intracranial hypertension may not always be benign for vision and fenestration operations may prevent or reverse visual deterioration by an effect on the optic nerve rather than by reducing intra-cranial pressure.

Adult↗
PubMed1986

Optic nerve hypoplasia in infancy.

Certain features of optic nerve hypoplasia (ONH), its systemic associations and investigation are exclusive to infancy. These include the facility to use cranial ultrasound, difficulties in assessing ocular features and visual function, and neonatal hypoglycaemia and jaundice. Six infants with ONH are presented; cerebral abnormalities were demonstrated by cranial ultrasound in five. Neonatal cholestatic jaundice and hypoglycaemia occurred in one infant. Two died and represent a group likely to remain undetected unless routine ophthalmic examination of neurologically abnormal neonates is undertaken. In infancy, both ocular and systemic aspects of ONH can be investigated simply and without sedation.

Female↗
PubMed1986

Congenital ocular motor apraxia.

Nine patients with congenital ocular motor apraxia (COMA) are presented and the natural history of this condition is considered. Two presented in early infancy, before the onset of the head thrust, and the means of establishing the diagnosis at this age are discussed. All exhibited motor delay in infancy which lessened, but did not completely resolve, with time. Conceptual delay, particularly with speech, affected all in early childhood. Three had agenesis of the corpus callosum and 2 cerebellar abnormalities. The autopsy of one infant showed cerebellar cortical dysplasia. The pathogenesis of COMA remains unknown and it is possible that agenesis of the corpus callosum and cerebellar hypoplasia are markers indicative of early CNS maldevelopment and not an integral part of the mechanism of COMA.

Agenesis of Corpus Callosum↗
PubMed1985

Thermal transition studies of a mature xanthelasma by differential scanning calorimetry.

A large xanthelasma which had been present for at least 5 years was removed surgically from a normolipaemic female age 54 years, and examined in the fresh state by differential scanning calorimetry. Thermal transitions recorded over the range 30-40 degrees C suggest that the lipid present, predominantly esterified cholesterol, is not bound to protein or other tissue components, and that the chronicity of mature xanthelasmata as with ectopic lipid deposits at other sites is enhanced by chemical modification of lipid and effects on component phase behaviour, which are significant at local skin temperature.

Calorimetry, Differential Scanning↗