PubMed Health⌕ Search

Biomedical subjects

W Cadera

Publications and source records attributed to W Cadera.

35 records · Page 2Linked to original sources
PubMed1988

Monocular adaptation of the saccadic system and vestibulo-ocular reflex.

This study asks whether or not adaptation of saccades and the VOR is constrained to be conjugate by Hering's Law. Changes in saccades and the VOR produced by surgically weakening one of the horizontal recti by recession or tenotomy were examined in monkeys with the affected eye patched. After the restoration of vision a rapid monocular recalibration of both saccades and the VOR was observed in preparations with a small or moderate muscle weakening. Preparations with a severe weakening exhibited little monocular adaptation but when the normal eye was patched exhibited a strong conjugate adaptation. Thus the results indicate that saccades and the VOR have the capacity for monocular recalibration but that this capacity is more limited than that for conjugate changes.

Adaptation, Physiological↗
PubMed1987

Cyclopia and congenital cytomegalovirus infection.

We describe the first documented association of congenital cytomegalovirus (CMV) infection and cyclopia. A previous report has suggested that any infant with congenital ocular defects should be investigated for CMV infection [Frenkel et al, 1980]. Our case underlines this suggestion and questions a teratogenic role for CMV in cyclopiaholoprosencephaly. More documented cases may help clarify the relationship of transplacental CMV infection to the holoprosencephaly developmental field defect, including cyclopia.

Abnormalities, Multiple↗
PubMed1987

The pattern of changes produced in the saccadic system and vestibuloocular reflex by visually patching one eye.

The purpose of the present study was to determine whether, in the absence of visual input to one eye, saccades remained equal in the two eyes. The same question was addressed for the VOR gain of the two eyes. After 1 wk during which one eye was continuously patched, the saccadic properties of only the unseeing eye showed changes consisting of a change, usually a decrease, in saccadic step magnitude, postsaccadic drift with an exponentially decaying component in the temporal direction, and the appearance of a vertical component as well as vertical postsaccadic drift during horizontally directed saccades. Effects were also observed in the VOR consisting of a change in gain and a vertical component during horizontal head rotation. As with saccades, the vertical component in the patched eye was upward when the eye was deviated nasally. When the patch was removed, normal function was restored within 1 day to the previously patched eye without impairing the function of the unpatched eye. These results suggest that the conjugate nature of saccades and the VOR is in part the consequence of a selective, visually driven, calibration mechanism, which can alter commands to motoneurons of one muscle of a conjugate muscle pair without affecting commands to the other. The similarity of changes observed in the VOR and saccades after patching suggests that elements common to both are altered in the absence of vision.

Animals↗
PubMed1985

Congenital glaucoma with corneal cloudiness treated by thermal sclerostomy.

Thermal sclerostomy (the Scheie procedure) was performed on nine eyes with congenital glaucoma and corneal cloudiness. The intraocular pressure was controlled and the cornea cleared in six eyes, though two required a second sclerostomy for success. In two of the remaining three eyes the intraocular pressure did not fall to normal levels, but the cornea cleared sufficiently to permit goniotomy, which was successful in each case. The remaining eye failed to respond to two sclerostomies. Thermal sclerostomy is recommended as a primary form of treatment in cases of congenital glaucoma in which corneal opacification makes goniotomy unsafe. While trabeculotomy is useful in these circumstances and may be the procedure of choice in many cases, thermal sclerostomy is recommended for the surgeon who is more familiar with this technique and for cases in which distortion of the anterior chamber angle is expected to preclude trabeculotomy or goniotomy.

Cataract↗
PubMed1984

Ocular lesions caused by caterpillar hairs (ophthalmia nodosa).

The ocular reactions to caterpillar hairs are diverse in nature and location, ranging from a toxic reaction to the external foreign bodies, keratoconjunctivitis or the formation of conjunctival nodules, to intense iritis, vitritis or papillitis. Four cases are presented in this paper to illustrate the various degrees of ocular involvement. Included are clinical photographs of intravitreal and subretinal hairs. A classification of these reactions is suggested to facilitate the choice of treatment.

Adolescent↗
PubMed1984

Botulinum toxin injection into rabbit vitreous.

Botulinum A toxin in a dose of 5.0 X 10(-4) micrograms was injected into the vitreous of eight rabbit eyes. An equal volume of normal saline was injected into the fellow eye as a control. External examination, intraocular pressure, ophthalmoscopy, electroretinography, and light microscopy showed no significant difference between toxin injected and control eyes over a two-month period.

Animals↗
PubMed1984

Filtering surgery in childhood glaucoma.

A review of 38 eyes of 24 patients receiving filtration surgery for childhood glaucoma is presented. A total of 54 procedures were performed, including both thermal sclerostomies and trabeculectomies. Successful control of intraocular pressure was obtained in 20 eyes (52%). Average follow-up time was four years, two months. Filtration surgery is seen as a useful technique in the treatment of childhood glaucoma when goniotomy fails. It also is useful in those conditions where the success rate of goniotomy is expected to be low.

Adolescent↗
PubMed1983

Depth of strabismic amblyopia determined with neutral density filters.

We used a neutral density filter to assess motor responses in the fixation patterns of 25 patients, ranging in age from 5 to 54 years, with strabismic amblyopia. Shifts of fixation back to the preferred eye occurred when the visual acuity of the preferred eye through the filter was marginally better than that of the amblyopic eye. Thus, we were able to correlate the level of the filter at which this shift occurred with the level of amblyopia. This technique may be particularly helpful in the examination of preliterate children and in monitoring the progress in the treatment of amblyopia.

Adolescent↗
PubMed1983

Juvenile xanthogranuloma.

Three infants with juvenile xanthogranuloma are described. Of the two with ocular involvement, one responded to topical corticosteroid and mydriatic therapy and the other to irradiation. The third had skin lesions alone. In the first case new histologic findings were made: lipid vacuoles were observed, by light and electron microscopy, in smooth muscle cells of erector pili and in Schwann cells of small nerves. These findings, along with the detection of lipid vacuoles in mast cells, support the concept that the condition results from local tissue injury that evokes a histioxanthomatous response. Treatment of juvenile xanthogranuloma should be tailored to the individual case and ranges from no active intervention (when there are skin lesions alone or ocular involvement limited to the eyelid or the epibulbar tissue) to a combination of corticosteroid therapy, irradiation and surgery (when there are iris lesions, which rarely resolve spontaneously and may have serious complications). A trial of topical corticosteroid therapy alone in uncomplicated cases is suggested since it was curative in one of the cases presented here.

Conjunctiva↗
PubMed1982

Sodium hyaluronate for postoperative aphakic choroidal detachment.

Collapse of the anterior chamber, choroidal and ciliary body detachments and ocular hypotony developed without explanation 2 weeks after uneventful intracapsular cataract extraction in a 60-year-old woman. Following an unsuccessful attempt to maintain an adequate chamber depth with air, sodium hyaluronate was injected into the chamber after surgical drainage of suprachoroidal fluid, allowing for spontaneous recovery of aqueous production while protecting the anterior segment from the ravages of chamber collapse.

Aphakia, Postcataract↗
PubMedDate not supplied

Tay-Sachs disease: B1 variant.

This first child of non-Jewish parents had nystagmus at 4 months of age, bilateral cherry-red macular spots at 7 months of age, and hyperacusis at 8 months of age; the patient has deteriorated progressively following a clinical course typical of Tay-Sachs disease B variant. Total beta-N-acetylhexosaminidase assayed with 4-methylumbelliferyl-beta-glucosamine (4 MU GlcNAc) as substrate was within the normal range in plasma and cultured dermal fibroblasts and 2/3 the normal mean in leukocytes. The hexosaminidase A activity, assayed with the same substrate in plasma and cultured fibroblasts, approximated Tay-Sachs disease heterozygote levels; however, the activity of hexosaminidase A assayed with 4 MU Glc NAc-6-sulfate in the plasma, leukocytes, and cultured fibroblasts was less than 8, 2, and 1%, respectively of the control mean. This female infant with the B1 variant of Tay-Sachs disease demonstrated an earlier onset and more rapidly progressive course than was observed in 4 of the 5 previously reported patients with this Tay-Sachs disease variant.

Female↗
PubMedDate not supplied

Changes in astigmatism after surgery for congenital ptosis.

To determine the effect of ptosis surgery on the astigmatic refractive error in pediatric patients, we assessed 88 eyes postoperatively at 3, 6, and 12 months. Thirty-six eyes of unilateral cases were used as controls. There was an overall increase in average astigmatic refractive error of the study group by 0.30 diopters, while the control group decreased 0.15 D. Thirty-six percent of study eyes changed by more than 0.75 D. Results were similar for both fascia lata slings and levator resections. Those patients older than 4 years showed an increase in average cylinder (0.50 D), while those younger than 4 years decreased their average cylinder (0.20 D). Careful monitoring with postoperative refractions is required in pediatric ptosis patients.

Astigmatism↗
PubMedDate not supplied

Cine magnetic resonance imaging of ocular motility.

We describe a technique of generation of a cine motion picture of ocular movements in a patient with Duane Type II exotropia. With the magnetic resonance scanning unit, multiple scans can be sequenced to give a graphic animation to the eyes as targets are fixated across the visual field. With this technique, we were able to clearly view the contractility of the extraocular muscles and note the changes in pulling directions of the muscles in this patient. The restriction of movement due to the cocontraction of the horizontal rectus muscles was readily apparent.

Adult↗
PubMedDate not supplied

A magnetic resonance imaging study of horizontal rectus muscle palsies.

The assessment of extraocular muscle function is usually performed indirectly by an examination of ocular motility. We have utilized magnetic resonance imaging, in both cine and static modes, to directly observe the contractility behavior of the extraocular muscles. This noninvasive technique was applied to the study of patients with horizontal rectus muscle palsies. In all cases, the palsied muscle was of a smaller diameter than its normal counterpart. This size differential was noted in all fields of gaze. Additional studies are required to determine the relative contributions of denervation atrophy and loss of tonus to this diminution of muscle size.

Abducens Nerve↗
PubMedDate not supplied

Ocular pursuit movement assessment by magnetic resonance imaging.

We describe a new technique for generating cinematic magnetic resonance images. This method produces more physiological imaging of extraocular muscles than our previous method. In addition, this technique provides more comfort for the study subject and results in less head movement artifact.

Humans↗