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Biomedical subjects

E M Helveston

Publications and source records attributed to E M Helveston.

At least 19 recordsLinked to original sources
PubMed1992

Ophthalmology. The resident's perspective.

To determine how and why current residents in ophthalmology chose their medical specialty, we formulated and distributed a questionnaire to all ophthalmology residents in accredited programs. The results of the survey gave insight into not only their decision-making processes in choosing ophthalmology, but also their backgrounds, the factors that were important in choosing their residency program, and their future plans in ophthalmology. A wide variety of factors was involved in the decision to pursue a career in ophthalmology. In addition, we found current residents to be well qualified academically and generally satisfied with their decision to enter ophthalmology.

Career Choice↗
PubMed1992

A new classification of superior oblique palsy based on congenital variations in the tendon.

BACKGROUND: Superior oblique palsy is the most frequent isolated cranial nerve palsy seen in strabismus practice. It is traditionally diagnosed according to etiology as acquired, congenital, or idiopathic, but surgical treatment is based on deviation not etiology. Observations at surgery led to speculation that the superior oblique tendon is different in congenital compared with acquired superior oblique palsy and that this difference should be considered in surgical treatment. METHODS: The authors reviewed the charts of 82 patients (89 eyes) undergoing surgery on the superior oblique tendon for superior oblique palsy. In each case, the palsy had been diagnosed preoperatively as acquired, congenital, or idiopathic, and, at surgery, characteristics of the tendon anatomy were described. RESULTS: Thirty-eight superior oblique tendons (36 patients), diagnosed as congenital superior oblique palsy, included 33 abnormal tendons and 5 normal tendons. Twenty-four tendons (21 patients), diagnosed as traumatic superior oblique palsy, included 22 normal and 2 abnormal tendons. Twenty-seven tendons (25 patients), diagnosed as idiopathic, included 19 normal and 8 abnormal tendons. Abnormal tendons were divided into 4 categories: (1) redundant, (2) misdirected, (3) inserted in posterior Tenon's capsule, and (4) absent. CONCLUSIONS: The authors conclude that congenital superior oblique palsy is usually associated with a structural abnormality of the superior oblique tendon (87%). Whereas acquired superior oblique palsy usually has a normal tendon (92%). Superior oblique underaction in acquired superior oblique palsy results from a neural deficit. Potential variance in anatomy of the superior oblique tendon should be considered when undertaking surgery for superior oblique palsy.

Adolescent↗
PubMed1992

Surgical treatment of subluxated lenses in children.

BACKGROUND: Surgical removal of subluxated lenses had traditionally been discouraged because of concerns about poor surgical results and unacceptably high complication rates. METHODS: The authors reviewed the surgical results of 29 eyes in 15 consecutive patients who were operated on for subluxated lenses. RESULTS: Best-corrected visual acuity improved in all 29 eyes and was limited only by amblyopia. There were no significant complications in follow-up ranging from 5 months to 12 years. CONCLUSION: Modern surgical techniques using vitrectomy instruments allow the vitreous to be handled more effectively and have led to improved results and lower complication rates. Surgery for subluxated lenses can be done effectively and safely when indicated.

Child↗
PubMed1991

Measurement of low vision in children and infants.

The authors evaluated a preferential looking technique (Teller acuity cards) and a set of gross behavioral indicators (visual function battery) for the ability to rank visually impaired children and infants on the basis of their visual function. Fourteen older children with a diagnosis of cicatricial retinopathy of prematurity who were capable of giving Snellen acuities and a group of 31 preverbal infants with decreased vision due to a variety of causes were tested. Teller acuity card and visual function battery findings were highly correlated with each other (and with Snellen acuities in the older group); however, the Teller acuity cards provided better discrimination in the moderately visually impaired range, whereas the visual function battery was better in the severely impaired range. It is concluded that, in children and infants, visual function over the entire spectrum of low vision can be characterized by using a combination of the Teller acuity cards and the visual function battery.

Adolescent↗
PubMed1991

Large recession of the horizontal recti for treatment of nystagmus.

Ten patients had large recession of four horizontal recti at one procedure for treatment of nystagmus. Six patients had congenital motor nystagmus, two had oculocutaneous albinism, and two had optic nerve hypoplasia. Anomalous head posture with null point was also present in five patients. The rectus muscles were placed at or behind the equator in all but one case. Three patients with both esotropia and nystagmus had the medial recti placed 1 mm behind the equator and the lateral recti or at 1 mm anterior to the equator. Visual acuity improved an average of 1 line at distance and/or near in 8 patients who cooperated for testing. Although nystagmus was not eliminated in any patient, its its amplitude decreased in eight of ten patients, and anomalous head posture improved in three of five patients. In all patients, near vision was better than distance vision both preoperatively and postoperatively. Ductions were diminished minimally after the large recession and there were no other complications from surgery.

Adolescent↗
PubMed1990

The value of strabismus surgery.

Strabismus surgery is indicated for a variety of conditions stemming from misalignment of the eyes, abnormal head posture, and nystagmus. Although part of the value of such surgery lies in the fact that it improves appearance, it differs from cosmetic surgery, because, unlike the latter, it is designed to restore only normal configuration for ocular alignment--straight and/or aligned with the object of regard. A wide array of diagnostic tests are used to determine the precise treatment required, the goal of which is to provide comfortable vision, normal head position, and normal human appearance. In some cases nonsurgical techniques can be used to treat strabismus, but there is no evidence that visual training is an effective means of straightening eyes in those cases where surgery is considered the treatment of choice. For the most common strabismus, essential infantile or "congenital" esotropia, 80+% of infants have "straight" eyes after the initial operation, and 90% after a second operation, most of these with "straight eyes" have residual deviation of 5 prism diopters of esotropia or less. More than 50% of surgically treated patients have stable, long-term satisfactory results. Considering the effort required on the part of the ophthalmologist, together with the physical and psychological benefit to the patient, the cost of strabismus surgery should be equal to that of any major ophthalmic surgical procedure. That strabismus surgery is compensated at a lower rate, than for example, cataract surgery, suggests that strabismus surgery is an excellent value.

Cost-Benefit Analysis↗
PubMed1989

Strabismus in infancy.

In order to prospectively study the development of strabismus in infancy, the ocular alignment of a large population of normal neonates was studied and follow-up examinations were obtained in a subset of these infants. The characteristic findings of congenital esotropia subsequently developed in three infants who were either orthotropic or exotropic at birth. Pathologic exotropia developed in two infants; both were exotropic at birth, but no more so than most normal neonates. In infants with congenital esotropia or pathologic exotropia, the characteristic deviation appears to develop between 2 and 4 months of age, a period during which normal infants are becoming increasingly orthotropic.

Abducens Nerve↗
PubMed1988

Treatment of acquired nystagmus with botulinum A toxin.

We injected botulinum A toxin into the retrobulbar space of one eye each in two patients who had acquired nystagmus with oscillopsia and decreased vision. After injection of 25 units of botulinum A toxin, visual acuity improved from 20/80 to 20/30 in one patient, and both patients were able to read and watch television. Improved vision lasted from five to 13 weeks. No adverse side effects were observed after a total of five injections in each patient.

Botulinum Toxins↗
PubMed1988

Inferior oblique inclusion after lateral rectus surgery.

A retrospective and prospective study evaluated the clinical characteristics of patients with inadvertent incorporation of the inferior oblique muscle to the lateral rectus muscle after lateral rectus surgery. Nineteen cases were included in the study (12 retrospectively in the preceding 18 months and 7 during the prospective 5-month period). Thirteen cases with the inferior oblique inclusion occurred after a lateral rectus resection and 6 occurred after a lateral rectus recession. Most patients demonstrated a vertical deviation in the affected eye preoperatively. Nine had hypotropia and 8 had hypertropia. Deficient elevation in adduction in all patients was found on motility testing. After reoperation, despite freeing the inferior oblique from the lateral rectus, most patients had a persistent vertical deviation. Inadvertent inferior oblique inclusion can be avoided by inspecting the under surface of the lateral rectus and freeing any inferior oblique attachment before reattaching the lateral rectus to the globe during either resection or recession.

Humans↗
PubMed1988

Esotropia.

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Age Factors↗
PubMed1987

Hibiclens keratitis.

Presumed accidental corneal exposure to Hibiclens (chlorhexidine 4% and detergent) in two patients resulted in severe and permanent corneal opacification. We investigated the corneal toxicity of Hibiclens by gross, biomicroscopic, and histopathologic studies of rabbit eyes exposed to Hibiclens for varying time intervals ranging from five to 15 minutes. Severe, irreversible, and progressive corneal damage resulted in all eyes studied.

Aged↗
PubMed1987

Persistent binocular diplopia after cataract surgery.

We reviewed the records of 38 consecutive patients who had persistent binocular diplopia after cataract surgery. The patients were divided into ten categories based on the suspected conditions underlying the diplopia. Of 16 patients who underwent strabismus surgery, five achieved the therapeutic goal of single binocular vision in the primary and reading position, and four attained this with prismatic or botulinum toxin therapy in addition to surgery. Seven patients continued to have diplopia despite strabismus surgery and adjunctive therapy. Even small residual deviations were often intolerable, because of highly diminished fusional amplitudes.

Adult↗
PubMed1987

Stereoscopic contours and optokinetic nystagmus in normal and stereoblind subjects.

Moving stereoscopic contours in a dynamic random-dot stereogram have been previously shown to induce optokinetic nystagmus in subjects with normal stereopsis. For this to be validated as an objective test of stereopsis, stereoblind subjects must also be shown not to develop OKN, especially since it has been shown that the optomotor system of stereoblind individuals retains sensitivity to some cyclopean stimuli. In this report we verify that stereoblind subjects do not have an optomotor response to stereoscopic contours--regardless of the alignment angle at which the stereo image pair is presented.

Depth Perception↗
PubMed1987

The effect of intravitreal botulinum toxin on rabbit visual evoked potential.

Intravitreal injections of botulinum A toxin in two doses, 1.25 and 25 units, were performed in two rabbit eyes. The fellow eyes were injected with an equal volume of saline to serve as controls. The visual evoked potential was unchanged at one and two weeks post-injection when compared to pre-injection recordings in both botulinum and saline injected eyes.

Animals↗
PubMed1987

Evaluation of an absorbable muscle sleeve to limit postoperative adhesions in strabismus surgery.

A muscle sleeve fashioned from polyglactin 910 Vicryl mesh was used in a rabbit animal model to evaluate its efficacy in decreasing postoperative adhesions encountered in extraocular muscle surgery. Clinical observations, as well as gross and histological comparison of the experimental and control groups, revealed a significant reduction in postoperative adhesions under conditions of normal surgical trauma. Where there was extensive trauma, however, no significant reduction was observed. No evidence of toxicity of the material to ocular tissues was found.

Animals↗