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Biomedical subjects

C S Hoyt

Publications and source records attributed to C S Hoyt.

At least 19 recordsLinked to original sources
PubMed1992

Optic neuritis in children with poor recovery of vision.

We reviewed the records of 10 children with optic neuritis in whom recovery of vision was poor or incomplete. Our cases were otherwise similar to those described in previous studies in that they were always bilateral, often accompanied by a viral prodrome (seven of 10), and usually associated with disc oedema (seven of 10). Seven of twenty eyes had a final visual acuity of 6/60 or worse and only one patient regained 6/6 vision in either eye. In three patients the best vision in either eye was 6/60 or worse. Recovery of vision was often slow, taking up to six years. Five of 10 patients have developed multiple sclerosis (MS), and one child had acute disseminated encephalomyelitis (ADEM) with optic neuritis. Optic neuritis in children does not always carry a good prognosis for recovery of vision; however, the failure of vision recovery in a short period of time does not necessarily indicate a poor outcome. Some children with optic neuritis develop MS, which can develop even when optic neuritis follows a viral illness.

Adolescent↗
PubMed1979

Visual loss in osteopetrosis.

We present the clinical and electrophysiological findings in three cases of osteopetrosis with visual loss. In all cases the findings on electroretinography suggested diffuse retinal degeneration, despite normal ophthalmoscopic appearance of the retinas. We suggest that retinal degeneration may be a common finding in osteopetrosis and a major cause of visual loss. Patients with osteopetrosis and poor vision should be examined using electrophysiological techniques to detect unsuspected retinal dysfunction.

Blindness↗
PubMed1979

The ocular findings in infantile spasms.

The results of this study suggest that a careful ophthalmoscopic examination of children with infantile spasms will help to establish an etiologic diagnosis in at least 20% of cases. The two clinical entities identifiable by this examination are tuberous sclerosis and Aicardi's syndrome. It is emphasized that the retinal hamartomas of tuberous sclerosis seen in infancy are flat, semitransparent, and small. The mulberry-like lesion is distinctly unusual in this age group. The essential ocular feature of Aicardi's syndrome is a chorioretinopathy of the posterior pole. This may be accompanied by microphthalmus, persistent pupillary remnant, and colobomas of the optic nerve and choroid. Diagnosis of either of these two entities is helpful in establishing the prognosis for a child with infantile spasms since both of these disorders usually lead to severe neurologic handicap and premature death. Moreover, genetic counseling is essential for the family suffering with this tragic disorder. Tuberous sclerosis is inherited as an irregular dominant trait. The genetic interpretation of sporadic cases, which are in the majority, is difficult due to the presence of unrecognized incomplete or "fruste" forms within families. On the other hand, Aicardi's syndrome has never been reported to be familial and future pregnancies can be undertaken without fear of producing another child with infantile spasms.

Child, Preschool↗
PubMed1979

Optic neuropathy in ketogenic diet.

A symmetrical, bilateral optic neuropathy is reported in 2 patients being treated with ketogenic diets for seizure control. Laboratory tests suggested a thiamine deficiency, and both patients recovered normal visual function after several weeks of treatment with thiamine. The risk of optic nerve dysfunction occurring during the treatment with a ketogenic diet can be minimised if routine vitamin B supplements are given and periodic evaluation of optic nerve function undertaken.

Child↗
PubMed1978

Ocular features of Aicardi's syndrome.

Four cases of Aicardi's syndrome are reported. The constant features of this syndrome are infantile spasms, chorioretinopathy, and agenesis of the corpus callosum. The chorioretinopathy appears to be a defect of the pigment epithelium and choroid without significant retinal involvement. Additional ocular features include microphthalmia, colobomas of the optic nerve and choroid, persistent pupillary membrane, and glial tissue extending from the disc. The cause of the syndrome is uncertain. It occurs only in females and is nonfamilial. A male lethal syndrome resulting from a gene on the X chromosome occurring as a spontaneous mutation has been suggested. The possible role of intrauterine infection needs further investigation.

Abnormalities, Multiple↗
PubMed1978

Trauma to the lacrimal system in children.

We repaired damage to the lacrimal drainage system in a series of 393 children who had lacrimal obstruction caused by congenital obstruction or facial injuries. Delayed surgery for traumatic obstruction of the nasolacrimal duct in children, including infants, was successful in all cases.

Dacryocystorhinostomy↗
PubMed1978

Maternal anticonvulsants and optic nerve hypoplasia.

Seven patients with optic nerve hypoplasia, born of epileptic mothers, are presented. All the mothers took anticonvulsants during pregnancy. The possibility that maternal anticonvulsant therapy may play a role in the genesis of optic nerve hypoplasia is discussed in the light of what is known about the teratogenicity of these agents.

Abnormalities, Drug-Induced↗
PubMed1978

Physiology factors that influence blood pressure alterations.

In summary, hypertension is a disproportion between vascular capacity and blood volume. Only a small number of cases are secondary to specific diseases. The vast majority of patients have so-called "essential hypertension". In many cases the causative agent seems to be aldosterone, renin. Angiotensin II or other pressor agents. Psychosocial elements probably play important roles in the etiology of essential hypertension. Hypertension together with other factors are etiological of both tensive and atherosclerotic, cerebro, reno, and cardiovascular complications. Finally, industries and their workers are heavy losers to this disease, through lost wages, lost productivity and prodigious medical expenses.

Blood Volume↗
PubMed1978

The supranuclear disturbances of gaze in kernicterus.

Five patients with kernicterus and ocular motility disturbances are reported. All of the patients showed some defect in vertical gaze but not always upgaze. The most severely affected patient exhibited slowness of horizontal saccades in addition to a total vertical gaze palsy. In general, the severity of the ocular motility disturbance paralleled the severity of hearing loss. It is suggested that damage to the periaqueductal area accounts for disturbances in vertical gaze and the infrequent horizontal saccadic disturbances results from interruption of the descending centrifugal fibers. It is emphasized that kernicterus must be included in the differential diagnosis of any supranuclear vertical gaze disturbance.

Athetosis↗
PubMed1977

Retinoblastoma in Victoria.

This paper reports all cases of retinoblastoma occurring in Victoria over a 20-year period between 1956 and 1976. It suggests that the natural history of treated retinoblastoma in an Australian community, is characterized by low mortality (8.3%), but significant morbidity. The most common problem in management of unilateral cases was one of diagnosis in contrast to bilateral cases, in which the problem was one of maintaining useful vision whilst at the same time eradicating a life-threatening tumour. Suggestions are made as to how management of retinoblastoma may be further improved, and the need for an active national register is discussed.

Australia↗
PubMed1977

Low-carbohydrate diet optic neuropathy.

Visual loss occurring in two patients taking prolonged carbohydrate-restrictive diets is reported. The clinical data in these patients point to a specific diet deficiency of thiamine, causing a bilateral optic neuropathy. A discussion of current concepts of thiamine deficiency in neuroophthalmic disorders is presented. It is recommended that patients on low-carbohydrate diets for prolonged periods of time should receive thiamine supplements.

Adult↗
PubMedDate not supplied

Vitamin metabolism and therapy in ophthalmology.

Vitamin deficiency states are important in the genesis of many ocular disorders. Deficiencies may be due to poor dietary intake, or to alterations in metabolism produced by some commonly prescribed medications or by certain diseases. Furthermore, some vitamins may exert important pharmacologic effects on the normal eye. The ocular effects of deficiencies and excesses of specific vitamins, and the therapeutic uses of each vitamin, are reviewed.

Animals↗
PubMedDate not supplied

Megalocornea in nonketotic hyperglycinemia.

A nine-month-old girl with nonketotic hyperglycinemia and bilateral enlargement of the corneas is reported. There was no evidence of elevated intraocular pressure or iridocorneal angle anomalies. The corneas have remained clear and lusterous without tears in Descemet's membrane. The possibility that the elevated glycine level may play a part in the buphthalmia of this patient is discussed in light of what is known about the effect or excessive dietary glycine on the developing chick eye. Further ophthalmologic study of patients with various forms of glycinemia might provide further understanding of the ways in which the developing eye may enlarge.

Animals↗
PubMedDate not supplied

Acquired "double elevator" palsy and polycythemia vera.

A 67-year-old woman had the acute onset of vertical diplopia. Examination revealed that she had a "double elevator" palsy of the fixing left eye which resulted in a right hypertropia. During the medical evaluation of the patient it was established that she had polycythemia vera. It is suggested that the ocular movement disorder seen in this patient resulted from a small lesion adjacent to and including the right superior rectus subnucleus. The increased blood viscosity resulting from the patient's polycythemic state may have been a significant predisposition in the development of an occlusive vascular episode involving this area of the midbrain.

Aged↗