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Biomedical subjects

J H Seaber

Publications and source records attributed to J H Seaber.

16 recordsLinked to original sources

Adaptation to monocular torsion after macular translocation.

PURPOSE: To document the functional outcome of two patients following successful macular translocation for the treatment of severe subretinal hemorrhage in age-related maculopathy. METHODS: The retina was surgically rotated around the optic nerve with translocation of the fovea either upward or downward to an area of healthy retinal pigment epithelium. In the postoperative period, visual function was carefully studied with emphasis on adaptation to torsion. RESULTS: Visual acuity in one patient improved from 20/200 to 20/80 and the other patient remained at 20/200. Both patients developed horizontal and vertical strabismus with torsion of up to 55 degrees. After a prolonged period of occlusion of the unoperated eye, both patients were subjectively able to adapt to monocular torsion. However, adaptation under binocular conditions did not occur. CONCLUSION: Macular translocation was successful in improving visual acuity in one patient, with no improvement in the second. Both patients had significant ocular torsion and strabismus, but under monocular conditions they were successful in perceptually adapting to the change in the visual environment. Fear of cyclotorsion should not be a deterrent to considering macular translocation as a possible treatment option for severe subretinal macular hemorrhage if the patient is willing to accept monocular vision.

Adaptation, Ocular

Long-term visual results of children after initially successful vitrectomy for stage V retinopathy of prematurity.

PURPOSE: To assess the effectiveness of vitrectomy for stage V retinopathy of prematurity (ROP) at the authors' institution, 33 patients with ROP who had initially successful total or partial anatomic retinal attachments (51 eyes) were evaluated for visual function and long-term anatomic stability. In addition, this study was an attempt to differentiate levels of visual function in children with very low vision and attendant developmental delays. METHODS: Visual function was assessed before retinal examination by an experienced pediatric vision specialist. The behavioral visual assessment was divided into seven segments with two to five tasks in each segment designed to establish a level of functional vision, ranging from light perception to form identification (and ambulation). The status of the retina was classified by the patient's retinal surgeon. RESULTS: The median follow-up was 61 months, and median age at the time of examination was 68 months. Of 51 eyes treated, form identification was achieved in 5, and all five patients had ambulatory vision. Of 51 eyes, 15 had no light perception, 11 had light perception, 6 could localize light, 10 could follow lights, and 4 were able to detect form. Only one eye in ten children with comparable ROP in each eye underwent surgery, and vision improved in six of ten of the surgical eyes. Redetachment was high, with 35 retinas totally or partially detached and only 13 retinas fully attached 61 months after surgery. CONCLUSION: The visual results are very low and disappointing. Initially successfully attached retinas can detach. There is some evidence that vitrectomized eyes function better than nonvitrectomized eyes. There is also evidence that visual function lower than form identification is useful to these children and that they are able to use their limited vision better than previously though.

Child

Management of the posterior capsule during pediatric intraocular lens implantation.

One of the major obstacles in pediatric intraocular lens implantation has been the subsequent dense opacification of the posterior capsule. We used a modification of the standard pediatric cataract surgical procedure, which involved endocapsular cataract extraction, posterior chamber intraocular lens implantation, pars plana posterior capsulotomy, and pars plana anterior vitrectomy in 20 consecutive patients with unilateral traumatic, radiation-induced, and developmental cataracts. Visual axes were rapidly restored in all patients without further intervention for posterior capsule opacification. Visual acuity returned to 20/40 or better in all patients and 75% of all patients (15 patients) reached maximum improvement by five weeks. No complications attributed to intraoperative removal of the posterior capsule occurred.

Adolescent

McCollough aftereffects in strabismus and amblyopia.

In strabismic people, the functioning of the deviating eye is impaired. This impairment is binocular in origin since it depends on stimulation of the straight eye; sensitivity and acuity of the deviating eye are usually better when the straight eye is patched than when both eyes are viewing. We investigated interactions between the eyes in strabismic people by using the McCollough color aftereffect as an exploratory procedure. Both normal and strabismic people adapted to black and colored bars and then examined black and white test bars. They reported colors in the achromatic test bars that were complementary to the adapting colors; this is the McCollough aftereffect. Both a monocular McCollough effect and a binocular McCollough effect were induced in people having normal vision. Strabismic people did not show a binocular McCollough effect. Aftereffect strengths were the same in each eye of normal people but were stronger in the impaired eye of strabismic people. A speculation is offered as to why the "non-seeing" eye of strabismic people "sees" the aftereffect better.

Adaptation, Ocular

Incidence and characteristics of McCollough aftereffects following video display terminal use.

After using video display terminals (VDT), some persons notice that achromatic patterns appear faintly colored hours after terminal use. We investigated the incidence of this effect, the McCollough effect (ME), among 125 VDT users. Subjects completed a questionnaire regarding work habits and certain life-style aspects. They were shown photographs of varying spatial frequencies to identify the adapting stimulus responsible for the ME. The incidence of ME after routine use of VDTs was 19.1%. The adapting stimulus was the repeating character lines of the VDT. No aspect of life-style investigated appeared to predispose an individual to develop the ME. Those subjects who developed the ME did not differ from those who did not in age, sleep, caffeine consumption, use of medication, refractive errors, or computer usage, nor did they have a higher incidence of ocular defects or eye strain.

Computer Systems

Traumatic superior oblique palsies.

The differences in the clinical and diagnostic characteristics of 33 consecutive traumatic unilateral (21 patients, 62%) and bilateral (12 patients, 38%) superior oblique palsies were studied. The unilateral palsies had a large hypertropia in primary position, more vertical than torsional diplopia, a compensatory head tilt to obtain fusion, and a positive Bielschowsky head tilt test. In contrast, the bilateral palsies had small hypertropias in primary gaze that alternated on right and left gaze, a large V-pattern esotropia with excyclotorsion that was frequently bilateral, and a compensatory head position with fusion in upgaze. The results of the study indicate that a V-pattern in excess of 25 prism diopters, an excyclotorsion of greater than 10 degrees, or head trauma severe enough to cause loss of consciousness should also signal bilateral involvement. Torsional diplopia was present in only 20% of unilateral palsies vs 75% of bilateral palsies. The Bielschowsky head tilt test was diagnostic in 100% of the patients with unilateral palsy and 83% of the patients with bilateral palsy. It was undiagnostic in the supine position in all patients. Spontaneous resolution occurred in 65% of the unilateral palsies but in only 25% of the bilateral palsies. Surgical correction was successful in relieving persistent symptoms.

Adult

Dyskinetic strabismus as a sign of cerebral palsy.

We found dyskinetic strabismus in 66 patients with cerebral palsy. The most striking feature of dyskinetic strabismus is the fluctuation from esotropia to exotropia under the same accommodative conditions with a slow tonic deviation similar to a vergence movement. With increasing age, exodeviation becomes more prevalent. Dyskinetic strabismus is seen exclusively in cerebral palsy patients. Many of these patients have an athetoid component to their disorder. The association of dyskinetic strabismus with athetosis and upward gaze palsy suggests that the basal ganglia may be the site of the malfunction. The strabismus responds poorly to surgery and the associated athetosis is important in the diagnosis and treatment of cerebral palsy.

Adolescent

Unilateral pseudophakia in children under 4 years.

PURPOSE: We examined the efficacy of intraocular lens implantation (IOL) in children younger than 4 years of age for unilateral aphakic visual rehabilitation. METHODS: Twenty-one patients underwent unilateral cataract extraction, IOL placement, posterior capsulotomy, and anterior vitrectomy between 1990 and 1994. Postoperative vision, refractive change, and complications were monitored prospectively. Two cataract subgroups were analyzed: 12 patients with infantile (congenital and developmental) cataracts, and nine patients with posttraumatic cataracts. RESULTS: Overall age at surgery averaged 26 months (range 9 to 44 months), with follow up of 5 to 55 months. Fifty-two percent achieved 20/40 or better vision: 42% in the infantile group and 67% in the traumatic group. IOL power averaged 22.6 diopters (D). The difference between predicted and actual postoperative refraction was less than 1 D in 70%. After 6 months, the average change in refraction was 0.50 D (21 patients). An increasing myopic shift of 1.10 D at 12 months (14 patients), 1.80 D at 18 months (nine patients), and 2.90 D after 24 months (eight patients) was noted. This trend was greater in the infantile group. Amblyopia treatment was implemented in 18 patients. Half have completed occlusion successfully, one third continue therapy, 17% are treatment failures, and 11% (two patients) were lost to follow up. Six patients required strabismus surgery; five had infantile cataracts. Postoperative complications occurred in four eyes, two infantile and two traumatic; they consisted of posttraumatic temporal IOL dislocation, corectopia, partial pupillary capture of an IOL, and partial pupillary membrane. CONCLUSION: Primary IOL implantation is an effective way to rapidly achieve aphakic visual rehabilitation in preschool children. We continue to evaluate the long-term safety and effects of pediatric pseudophakia.

Aphakia