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Biomedical subjects

T H Kirkham

Publications and source records attributed to T H Kirkham.

At least 37 records · Page 2Linked to original sources
PubMed1981

Improved contrast sensitivity with antireflective coated lenses in the presence of glare.

Contrast sensitivity was measured to quantify the glare-reducing effects of antireflective coatings of magnesium fluoride on spectacle lenses. Experiments were conducted on four subjects, who judged contrast thresholds while wearing corrective spectacles with noncoated and then coated lenses in both the absence and the presence of a source of glare (back-scattered reflection from the posterior surface of their lenses). Glare substantially reduced contrast sensitivity at all spatial frequencies; although the reduction was greater at higher spatial frequencies ther was no shift in peak contrast sensitivity. The coated lenses enhanced contrast sensitivity in the presence of glare between 1.5 and 5 times compared with the noncoated lenses. In the absence of glare, contrast sensitivity was greater with coated lenses than with noncoated lenses.

Adult↗
PubMed1981

Increased visual field area with antireflective coated lenses in the presence of glare.

Visual fields were charted with the Goldmann perimeter for five subjects wearing corrective spectacles with noncoated lenses and then lenses with antireflective coatings of mmagnesium fluoride in both the absence and the presence of a source of glare (back-scattered reflection from the posterior surface of their lenses). There was a greater reduction in temporal isopters than nasal isopters in the presence of glare with both types of lenses, but the coated lenses were superior to the noncoated lenses in reducing the effect of glare on the visual field area.

Adult↗
PubMed1980

Giant axonal neuropathy: visual and oculomotor deficits.

Giant axonal neuropathy, a generalised disorder or neurofilaments, presents as a chronic, progressive peripheral neuropathy in childhood. Evidence for central nervous system involvement is demonstrated in this study of four male patients with giant axonal neuropathy who had defective visual function and abnormal ocular motility. The visual system was studied by electroretinography, which showed normal retinal function, and by visual evoked potentials, which showed disease of both optic nerves and retrochiasmal visual pathways. The ocular motility disorder, studied by electrooculography, comprised defective pursuit, inability to maintain eccentric gaze with gaze paretic and rebound nystagmus, abnormal optokinetic responses and failure of suppression of the vestibulo-ocular reflex by fixation. These findings suggested involvement by giant axonal neuropathy of the cerebellar and brain stem pathways important in the control of ocular motility.

Axons↗
PubMed1980

Sialidosis: the cherry-red spot--myoclonus syndrome.

The sialidoses are a group of storage disorders of autosomal recessive inheritance in which there is a deficiency of lysosomal neuraminidase (sialidase) activity and associated sialyloligosacchariduria. Patients with one type of sialidosis may present initially to the ophthalmologist because of a cherry-red spot at the macula. In most of these patients progressive neurologic deficits ultimately develop; myoclonus is a prominent feature. A patient with the so-called cherry-red spot--myoclonus syndrome is described who had a marked deficit of the ocular smooth pursuit system, with consequent nystagmus. His visual system was normal clinically and electrophysiologically despite the obvious storage in the retinal ganglion cells.

Child↗
PubMed1979

Oculomotor abnormalities in Friedreich's ataxia.

A clinical neuro-ophthalmological and electro-oculographic study was made on fourteen patients with Friedreich's ataxia. None had evidence of optic nerve dysfunction. No patient complained of oscillopsia although all had ocular motor deficits of varying degrees, which appeared to be related to the severity of the general manifestations of the disease. The defects comprised square wave jerks, jerky pursuit with inability to maintain eccentric gaze resulting in gaze paretic nystagmus and rebound nystagmus. There was failure to suppress by fixation the vestibulo-ocular reflex. The slow phase velocity of caloric nystagmus was always of reduced velocity. There was inability to augment the slow phase velocity of optokinetic nystagmus with increasing stimulus velocity. Abnormalities of the saccadic system were manifest particularly as hypermetria. These signs in combination are suggestive of disease involving the cerebellar flocculus and vermis or their brain stem connections. No abnormalities were found in 17 parents or siblings.

Adolescent↗
PubMed1979

Periodic alternating gaze.

A 77-year-old man with autopsy-proven bilateral cerebral infarction had a periodic alternating conjugate horizontal ocular deviation for 2 days, which ceased shortly before death. There have been four previously reported patients with this disorder. The phenomenon suggests acute bilateral cerebral disease with a relatively intact brainstem.

Aged↗
PubMed1978

Traumatic central retinal vein occlusion.

A patient with the clinical picture of thrombosis of the central retinal vein following relatively minor head trauma is discussed. Only 2 reports in the literature have documented a similar event. It is suggested that the condition may have arisen as a result of an abnormality of the central retinal venous outflow system since such an abnormal pattern was discovered on orbital venography.

Adult↗
PubMed1978

Paroxysmal positional vertigo--a study of 255 cases.

The clinical and electronystagmographic findings of 255 patients with paroxysmal positional vertigo are presented. We believe the disorder should be diagnosed on the basis of the history and clinical findings since we did not find any characteristic electronystagmographic findings other than the recording of an actual attack. Our observations lead us to believe that there is only one type of attack. We conclude that the nystagmus which occurs during the attack is generated by stimulation of the posterior semicircular canal of the lowermost ear.

Adult↗
PubMed1977

Renal anomalies and oligohydramnios in the cerebro-oculofacio-skeletal syndrome.

We describe two infants with the cerebro-oculofacio-skeletal syndrome in whom oligohydramnios is an additional finding. The oligohydramnios could be accounted for in one by renal agenesis but cannot in the other, who had a functioning and histologically normal kidney. The diagnosis of Potter syndrome was suspected in both patients. It is important in counseling to recognize the distinctive phenotype of this autosomal-recessive syndrome.

Abnormalities, Multiple↗
PubMed1977

An electrooculographic study of internuclear ophthalmoplegia.

The eye movements of 25 patients with internuclear ophthalmoplegia were recorded by electrooculography. The velocity of adducting saccades was markedly less than normal. The velocity of abducting saccades was within the normal range, but statistically there was a wider distribution. Recordings were made in 2 patients several months after the onset of internuclear ophthalmoplegia, at which time the adducting eye velocity was greater than the abducting eye velocity. A patient with a unilateral medial fasciculus lesion showed marked overshoot of the abducting eye on contralateral saccades and overshoot of both eyes toward the side of the lesion. Optokinetic and postcaloric nystagmus were recorded, and the slow phase showed increasing velocity exponential waveform for the abducting eye. The recordings also showed decreasing velocity exponential waveform for the abducting eye. Downbeat nystagmus was as common as upbeat nystagmus in our patients. The findings appear to confirm the theoretical analysis of the eye movement disorder in internuclear ophthalmoplegia provided by Pola and Robinson as modified by recent experimental work in primates.

Brain Ischemia↗
PubMed1977

Anophthalmos. Report of two cases.

Two infants were found to have bilateral anophthalmos and other congenital anomalies. Secondary anophthalmia was diagnosed in one patient who showed malformations of the brain and an absence of ocular tissues including the optic nerves. The other patient had degenerative (consecutive) anophthalmos; fragments of ocular tissues including the optic nerves were found in the orbits.

Abnormalities, Multiple↗
PubMed1976

Bilateral renal agenesis with multiple congenital ocular anomalies.

A 920-g male infant born with features of Potter's syndrome had multiple ocular anomalies. Ocular abnormalities included absence of keratocytes in the inner central corneal stroma, cataract with retention of cell nuclei in the nucleus of the lens, hypoplasia of the ganglion cell and nerve fiber layers of the retina, and absence of nerve bundles in the optic nerve. Other ocular findings including microphthalmos, fetal chamber angle, persistent pupillary membrane , retinal avascularity, and prominent Bergmeister's papilla may have been related to the prematurity of the child.

Abnormalities, Multiple↗
PubMed1976

Aneurysmal bone cyst of the orbit with unusual angiographic features.

A 14 month old boy with sudden onset of proptosis of the left eye due to an aneurysmal bone cyst of the orbit is reported. Sequential plain films of the orbital region demonstrated changes ranging from subtle loss of bone definition of the orbital margin to the characteristic appearance of an aneurysmal bone cyst twelve months later. Arteriography at the time of the initial evaluation demonstrated prolonged retention of the contrast medium which we believe represents changes secondary to the number of giant cells present in the tumor rather than the relative vascularity of the lesion. While aneurysmal bone cyst of the orbit is extremely rare, it should be included in the differential diagnosis of proptosis in the pediatric age group.

Angiography↗
PubMed1976

Monocular elevator paresis, Argyll Robertson pupils and sarcoidosis.

A patient with sarcoidosis involving the central nervous system is described who developed monocular paralysis of elevation and Argyll Robertson pupils. A schema for the control system for vertical eye movements is presented as well as an explanation for monocular elevator palsy. The postulated lesion for monocular elevator palsy could well produce at the same time Argyll Robertson pupils and the cause of this papillary abnormality is discussed.

Eye Movements↗
PubMed1975

Ophthalmic manifestations of Aarskog (facial-digital-genital) syndrome.

Four boys with facial-digital-genital or Aarskog syndrome were whort with triangular faces, characteristic deformities of the hands and feet, and anomalies of the external genitalia. The syndrome appears to be inherited in an X-chromosomes-limked recessive manner. Previous reports emphasized the presence of hypertelorism but careful measurements of the interorbital dimensions revealed primary telecanthus in addition to hypertelorism. The palpebral fissures had a marked antimongoloid obliquity and in half the reported cases, there was unilateral or bilateral congenital blepharoptosis. Strabismus, hyperopic astigmatism, and large corneas may be additional features.

Abnormalities, Multiple↗