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Biomedical subjects

S R Lambert

Publications and source records attributed to S R Lambert.

At least 73 records · Page 4Linked to original sources
PubMed1989

Joubert syndrome.

Joubert syndrome is an autosomal recessive condition in which there is a variable combination of central nervous system defects with a distinctive congenital retinal dystrophy, ocular motor abnormalities, and respiratory abnormalities in early infancy. The retinal dystrophy has been previously classified as a variant of Leber's congenital amaurosis. We report electrophysiologic and eye movement findings in a series of seven consecutive children with Joubert syndrome. Unlike patients with Leber's congenital amaurosis, all but one of these children had preserved flash and pattern-reversal visual evoked potentials. Six of the seven children had abnormalities of smooth pursuit, optokinetic nystagmus, and saccades. Six of the children had nystagmus: three had a pendular torsional nystagmus and three had a form of see-saw nystagmus. An alternating hyperdeviation was present in five of the patients, two of whom also had a tonic deviation of their eyes laterally. All seven patients had cerebellar vermis hypoplasia on a magnetic resonance imaging scan. Developmentally delayed children with an absent or highly attenuated electroretinogram should be investigated for Joubert syndrome.

Blindness↗
PubMed1989

Delayed visual maturation. A longitudinal clinical and electrophysiological assessment.

Delayed visual maturation is an idiopathic condition characterized by visual inattention during infancy. The authors followed longitudinally nine children with an initial diagnosis of delayed visual maturation and compared their electroretinograms (ERGs) and visual evoked potentials with those of age-matched controls. Eight of the nine patients consistently had normal visual evoked potentials to flash and to pattern stimulation. All of the children had normal ERGs. Visually mediated behavior gradually developed in all of these children when they were between 3 and 8 months of age (mean, 5.5 months). Five patients also were delayed in other spheres of development. Visual evoked potentials are helpful in formulating a visual prognosis for children with delayed visual maturation.

Age Factors↗
PubMed1989

Autosomal recessive microcephaly, mental retardation with nonpigmentary retinopathy and a distinctive electroretinogram.

The association of microcephaly and mental retardation with a non-pigmentary retinopathy is described in three siblings of consanguineous parents. The electroretinogram showed the distinctive appearance of markedly attenuated "b" wave but normal "a" wave suggestive of a retinal dystrophy primarily affecting post-receptoral elements in the inner retina. This appears to be an autosomal recessive condition which has not been previously reported.

Child↗
PubMed1988

Congenital idiopathic microcoria.

Five infants had congenital unilateral microcoria. The red reflex was absent and vision was severely reduced in all five eyes preoperatively. A pupil was created surgically in three of the eyes, resulting in a variable improvement in vision. The underlying lens was clear in all three children. The origin of the pupillary anomaly is unknown, but probably is related to remnants of the fetal pupillary membrane. Early surgical treatment and vigorous occlusion therapy can result in useful vision.

Child, Preschool↗
PubMed1987

Visual recovery from hypoxic cortical blindness during childhood. Computed tomographic and magnetic resonance imaging predictors.

We reviewed the clinical courses and computed tomographic (CT) and magnetic resonance imaging (MRI) scans of 30 infants and children with cortical blindness following hypoxic insults. The degree of injury to the striate and parastriate cortices and the area of the optic radiations were graded from 0 to 4 by a neuroradiologist. Only two children had normal scans of the posterior visual pathway and both had favorable visual outcomes. The visual recovery differed significantly with respect to the age at which the hypoxic insult occurred and CT and MRI abnormalities in the area of the optic radiations, but not with abnormalities in the striate or parastriate cortices. Our results suggest that CT and MRI scanning are helpful in prognosticating the visual potential of children with hypoxic cortical blindness.

Age Factors↗
PubMed1986

Spontaneous regression of a choroidal melanoma.

Although spontaneous regression of uveal malignant melanoma is rare, its occurrence is not uncommon in cutaneous melanomas. We report a 15-year follow-up of an enlarging posterior pigmented tumor. It initially appeared to spontaneously regress into a flat chorioretinal scar, but, ten years later, it grew markedly and the eye was enucleated. Histopathologic changes similar to those found in regressed cutaneous melanomas were located in the region of the chorioretinal scar.

Adult↗
PubMed1986

Optic nerve sheath and retinal hemorrhages associated with the shaken baby syndrome.

A 13-month-old child with the pathognomonic findings of the shaken baby syndrome died secondary to cerebellar herniation. Pathologic examination disclosed extensive intraocular, optic nerve sheath, and intracranial hemorrhages, despite a paucity of external signs of trauma. Many of the hemorrhages were old, suggesting that the child had experienced multiple episodes of trauma. Hemorrhages of the optic nerve sheaths have not been previously reported with the shaken baby syndrome but probably accompany this condition frequently. Our patient's ocular hemorrhages may have resulted from a sudden rise in intracranial pressure.

Child Abuse↗
PubMed1985

Serous retinal detachments in thrombotic thrombocytopenic purpura.

Serous retinal detachments are a rare ocular complication of thrombotic thrombocytopenic purpura (TTP), with only six previous case reports in the literature. We have recently observed two patients with relapsing TTP who developed bilateral serous retinal detachments during acute exacerbations of their disease. In contrast to all but one of the previously described patients, both of our patients survived the episode during which retinal detachments occurred. Hypertension appears to contribute to the development of retinal detachments in TTP, and vigorous efforts at blood pressure control are indicated. Serous retinal detachments may be a more frequent component of chronic relapsing TTP than has been suspected.

Adult↗
PubMed1984

Downregulation occurs normally in cultured Epstein-Barr virus-transformed lymphocytes from patients with extreme insulin resistance. Discrepancy between downregulation in vivo and in vitro.

Levels of fasting plasma insulin are generally inversely correlated with 125I-insulin binding to circulating blood cells. In disease states associated with hyperinsulinemia (e.g., obesity and non-insulin-dependent diabetes mellitus), 125I-insulin binding is usually low. In contrast, 125I-insulin binding to circulating cells may be normal in patients with certain forms of extreme insulin resistance despite marked hyperinsulinemia. To explain this paradox, it has been proposed that postbinding defects in insulin action may give rise to defects in downregulation. We have employed cultured Epstein-Barr virus (EBV)-transformed lymphocytes from eight patients with extreme insulin resistance to address the question of whether there is a defect in the downregulation process in vitro. In this cell type, insulin leads to a decrease in the number of insulin receptors on the cell surface by accelerating the rate of degradation of insulin receptors. We could not detect any abnormality in in vitro down-regulation with cultured EBV-transformed lymphocytes from insulin-resistant patients. The apparent discrepancy between the in vivo and in vitro studies raises the possibility that some factor in the patient's internal milieu may prevent insulin-induced downregulation. An alternative possible explanation might be that the mechanism of downregulation in vitro differs from the mechanism whereby receptor number is regulated in vivo in insulin's target cells.

Adolescent↗
PubMed1981

The origins of Sattler's veil.

The symptoms of Sattler's veil accompany prolonged wear of thick contact lenses and are thought to be the result of epithelial hypoxia. We studied light scattering in the isolated rabbit cornea after hypoxia with optical techniques. We found that hypoxia produced a polygonal mesh of light scattering, outlining cells in the intermediate and basal epithelium. An optical transform of this mesh produced a halo of the same dimensions observed in Sattler's veil. Additionally, prolonged hypoxia produced an increase in stromal light scattering that may add to increased glare sensitivity. Consistent changes in epithelial thickness were not observed, raising the probability of radial swelling or compensatory epithelial volume regulation.

Animals↗
PubMedDate not supplied

Optic nerve hypoplasia.

Optic nerve hypoplasia is an easily overlooked, nonprogressive developmental anomaly which results in a wide range of visual deficits. It is frequently associated with clinically significant central nervous system and endocrine abnormalities. Maternal substance abuse is increasingly recognized in many cases. A supranormal regression of optic nerve axons in utero, rather than a primary failure of differentiation, is proposed as the pathogenesis.

Humans↗
PubMedDate not supplied

The infant with nystagmus, normal appearing fundi, but an abnormal ERG.

Many retinal disorders present during infancy with nystagmus, decreased vision, and normal-appearing fundi, but an abnormal ERG. The most common of these disorders are Leber's congenital amaurosis, achromatopsia, and congenital stationary night-blindness. Other disorders with similar ocular manifestations may be associated with a variety of life-threatening systemic abnormalities. This review describes the clinical, electrophysiological, and laboratory findings that can be used to distinguish among these conditions.

Blindness↗
PubMedDate not supplied

Infantile cataracts.

Cataracts are one of the most treatable causes of visual impairment during infancy. Recent epidemiological studies have shown that they have a prevalence of 1.2 to 6.0 cases per 10,000 infants. The morphology of infantile cataracts can be helpful in establishing their etiology and prognosis. Early surgery and optical correction have resulted in an improved outcome for infants with either unilateral or bilateral cataracts. While contact lenses continue to be the standard means of optically correcting an infant's eyes after cataract surgery, intraocular lenses are gaining in popularity as an alternative means of optically correcting these eyes. Post-operative complications occur more commonly after infantile than adult cataract surgery and many of these complications do not develop until years later. As a result, it is critical that children be followed closely on a long term basis after infantile cataract surgery.

Animals↗
PubMedDate not supplied

Rigid gas permeable contact lens correction of aphakia following congenital cataract removal during infancy.

Rigid gas permeable (RGP) contact lenses were prescribed and worn with little difficulty by 10 consecutive aphakic infants. Fluoroperm 92 lenses were used instead of silicone lenses (Bausch & Lomb) because of their lower cost, ease in handling, flexibility in design, and better neutralization of astigmatism. Lenses were worn on a daily wear basis (with occasional overnight wear) to reduce the risk of keratitis. Keratometry readings were taken at the time of surgery with the patient in a supine position. Trial lens fitting was performed 1 to 7 days later using a Burton Lamp. None of the patients developed keratitis, corneal neovascularization, or the sucked-on-lens syndrome. The lenses were well tolerated and the parents soon became adept at handling them. We now use RGP lenses as our lens of choice when treating aphakic infants.

Aphakia, Postcataract↗
PubMedDate not supplied

The optic disc in Leber congenital amaurosis.

The typical fundus appearance in Leber congenital amaurosis (LCA) in infancy is normal. Later in childhood, clinical heterogeneity develops and a variety of fundal abnormalities may be seen. These commonly include optic atrophy, retinal arteriolar attenuation, and a variety of pigmentary changes. We retrospectively reviewed the optic disc findings of 77 patients with LCA whom we had examined to confirm our clinical impression that the optic discs are frequently normal. Age at examination ranged from infancy to the fourth decade. The optic discs were normal in 53 (69%) of the 77 patients examined; 18 (23%) had varying degrees of optic atrophy; 2 (3%), pseudopapilledema; and 1 (1%), grey discs. The optic discs could not be seen in 3 (4%) patients. We conclude that the optic discs are frequently normal in appearance, even in older patients with LCA.

Adolescent↗