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Biomedical subjects

W L Alward

Publications and source records attributed to W L Alward.

17 recordsLinked to original sources
PubMed1992

Effects of jogging exercise on patients with the pigmentary dispersion syndrome and pigmentary glaucoma.

BACKGROUND: Exercise-induced anterior chamber pigment dispersion with intraocular pressure (IOP) elevation has been reported in patients with the pigmentary dispersion syndrome. Marked pigment dispersion with or without elevation of IOP could predispose these patients to visual field loss. The authors designed this study to evaluate the effects of jogging exercise on anterior chamber pigment and IOP in a group of patients with the pigmentary dispersion syndrome or pigmentary glaucoma. METHODS: Fourteen subjects with the pigmentary dispersion syndrome, 10 subjects with pigmentary glaucoma, and 10 control subjects underwent a 45-minute protocol of jogging exercise. Anterior chamber pigment was graded and IOP was measured before and up to 3 hours after completion of the exercise protocol. RESULTS: Eyes of experimental subjects were significantly more likely to develop exercise-induced pigment dispersion than were eyes of control subjects. In experimental subjects, eyes treated with pilocarpine at the time of the study were significantly less likely to develop exercise-induced pigment dispersion than eyes not treated with pilocarpine. In two experimental subjects, pre-exercise treatment with pilocarpine appeared to inhibit exercise-induced pigment dispersion. CONCLUSIONS: The authors do not believe that all patients with the pigmentary dispersion syndrome or pigmentary glaucoma need to avoid exercise. However, for patients with these disorders who regularly engage in jogging or more strenuous or more jarring types of exercise, they suggest an evaluation before and after the type of exercise in question. If marked exercise-induced pigment dispersion occurs, pilocarpine therapy may be an alternative to avoidance of the exercise.

Anterior Chamber↗
PubMed1992

Linkage of Rieger syndrome to the region of the epidermal growth factor gene on chromosome 4.

Rieger syndrome is an autosomal dominant disorder of morphogenesis in which previous cytogenetic arrangements have suggested chromosome 4 as a candidate chromosome. Using a group of highly polymorphic short tandem repeat polymorphisms (STRP), including a new tetranucleotide repeat for epidermal growth factor (EGF), significant linkage of Rieger syndrome to 4q markers has been identified. Tight linkage to EGF supports its role as a candidate gene, although a recombinant in an unaffected individual has been identified. This study demonstrates the utility of using polymorphic STRP markers when only a limited number of small families are available for study.

Abnormalities, Multiple↗
PubMed1991

Long-term visual function in acute posterior multifocal placoid pigment epitheliopathy.

Acute posterior multifocal placoid pigment epithellopathy is a chorioretinal inflammatory disease occurring in young, healthy adults. The long-term visual prognosis and recurrence rate is uncertain. We reexamined 28 patients (53 affected eyes) with acute posterior multifocal placoid pigment epitheliopathy (mean follow-up, 8 years) to obtain details on the long-term functional visual outcome. The final visual acuities were 20/25 or better in 48 eyes (90.6%), 20/30 to 20/100 in four eyes (7.5%), and 20/200 in one eye (1.9%). Although the final visual acuity was good, 33 eyes (62.3%) were symptomatic with blurred vision, metamorphopsia, or scotomas. Thirty-six eyes (67.9%) had significant central visual field defects on follow-up examination. There were no recurrences after the initial month of symptoms. The chorioretinal scars did not enlarge with time. Acute posterior multifocal placoid pigment epitheliopathy has a good longterm prognosis for visual acuity, although most patients have residual symptoms and paracentral scotomas.

Acute Disease↗
PubMed1991

A multilens case.

Explore the source record for details and available documents.

Contact Lenses↗
PubMed1991

Effect of cataract on automated perimetry.

Humphrey visual fields (30-2 program) were performed on 24 otherwise healthy patients before and after cataract extraction to examine the effect of cataract on automated visual fields. All patients met reliability index criteria and recovered visual acuity of 20/25 or better. The effect of learning associated with repeated testing was controlled with visual fields of the fellow eye. Although a greater absolute threshold recovery occurred in the central region of the visual field after cataract extraction, the percent of threshold recovery did not vary across the visual field except for the most peripheral testing points, which demonstrated less recovery. Thus, cataracts depress an automated visual field fairly uniformly. Clinical grading of cataracts by a single experienced clinician was generally a poor predictor of visual field loss. Only the presence of posterior subcapsular plaque in the visual axis and the preoperative visual acuity correlated significantly with postoperative central threshold recovery. Pattern standard deviation remained unchanged after cataract removal, confirming it as a useful way of estimating visual loss from cataracts.

Aged↗
PubMed1990

Use of infrared videography to detect and record iris transillumination defects.

We have developed a technique of detecting and recording iris transillumination defects using an infrared sensitive video camera. This method is useful for assessing the loss of posterior iris pigment in patients with the pigmentary dispersion syndrome and pigmentary glaucoma. Some patients with no transillumination defects on slit-lamp examination were noted to have discrete defects on infrared videography. This technique is a rapid, convenient, and reproducible method of permanently recording posterior iris pigment changes. These high-quality video images can then be followed to determine the natural course and the results of therapy in these patients.

Glaucoma, Open-Angle↗
PubMed1989

An autosomal dominant form of low-tension glaucoma.

A condition causing glaucomatous optic atrophy and visual field loss at normal or borderline intraocular pressure affected eight members of a family of consecutive generations. The disease was detectable in early adulthood and progressed slowly throughout life. The pattern of inheritance is autosomal dominant. One affected individual died of a myocardial infarction, and his eyes were obtained post mortem. Light and electron microscopic examination demonstrated glaucomatous optic atrophy with loss of ganglion cells. The trabecular meshwork, choroidal and optic nerve vasculature, retinal pigment epithelium, and photoreceptors were normal in appearance. We believe this family has an autosomal dominant genetic condition that is a distinct type of low-tension glaucoma.

Adolescent↗
PubMed1989

Threshold equivalence between perimeters.

To determine equivalence between perimeters, 49 eyes of 35 subjects underwent static threshold testing of the central 30 degrees twice on each of three automated perimeters and twice by manual kinetic threshold testing with the Goldmann perimeter. The Octopus-Humphrey difference was 3.3 dB (2.3 dB in the upper two rows for programs 32 and 30-2). The Dicon-Octopus difference was 3.5 dB and the Dicon-Humphrey, 6.5 dB. The I4e stimulus of the Goldmann perimeter was equivalent to 17.1 dB, 13.6 dB, and 10.8 dB on the Humphrey, Octopus, and Dicon perimeters, respectively. The III4e stimulus of the Goldmann perimeter, used for visual impairment determination, was roughly equivalent to 7 to 10 dB, 4 to 7 dB, and 0 to 6 dB on the Humphrey, Octopus, and Dicon perimeters, respectively. The prediction when converting from one instrument to another was only 10% less reliable than the ability of a perimeter to predict the values on a second examination with the same perimeter. Validity of the conversion formulas was confirmed by the age-corrected normal values available for the Octopus, Humphrey, and Goldmann perimeters.

Adult↗
PubMed1989

Dislocated lens nuclei simulating choroidal melanomas.

Three patients underwent echographic examinations for lesions suspected of being choroidal malignant melanomas. All patients were pseudophakic, and two had extensive optic nerve damage from inflammatory glaucoma. In all three patients echography demonstrated an intravitreal lens nucleus that had been lost during cataract extraction. To our knowledge, dislocated lens nuclei have not been reported previously in the differential diagnosis of choroidal melanoma. This diagnosis should be considered in the aphakic or pseudophakic patient with a fundus mass lesion. Echography is especially helpful in establishing the correct diagnosis.

Aged↗
PubMed1988

Thymoxamine reverses phenylephrine-induced mydriasis.

We performed a randomized double-masked evaluation of the alpha-adrenergic blocking agent thymoxamine (0.1%) as compared to placebo for the reversal of phenylephrine-induced mydriasis. Topically applied thymoxamine reversed the mydriasis from a single drop of 2.5% phenylephrine in 36 of 40 eyes (90%) within one hour. The mydriasis was completely reversed in 25 of 40 eyes (63%). Eyes with blue irides responded more quickly and more completely than did those with brown irides. The 40 contralateral eyes, which had also been dilated with phenylephrine, remained dilated or dilated further after receiving a placebo eyedrop. Twenty subjects (50%) reported mild transient ocular irritation upon instillation of thymoxamine. Thymoxamine was useful in individuals with narrow anterior chamber angles who were at risk of acute closed-angle glaucoma following dilation with an adrenergic agent.

Adult↗
PubMed1985

The long-term serological course of asymptomatic hepatitis B virus carriers and the development of primary hepatocellular carcinoma.

One hundred fifty asymptomatic patients who were carriers of hepatitis B surface antigen (HBsAg) were studied serologically for up to 11.3 years (mean, 6.1 years). Only 9 (6.0%) lost HBsAg during the study period, for a mean annual clearance rate of 1.0%. We found no difference in the clearance of HBsAg by age, but a higher percentage of females lost HBsAg than did males (P less than .02). Hepatitis B e antigen (HBeAg) was found in 102 (68.5%) of the 149 carriers of HBsAg who were tested. Carriers of HBsAg who were seropositive for HBeAg were younger than those who were seronegative for HBeAg (P less than .01). The prevalence of HBeAg was not affected by the patients' sex. The clearance of HBeAg was gradual; 9.6% of the HBsAg carriers lost HBeAg each year. Females were more likely to clear HBeAg than were males (P less than .01), and those who cleared HBeAg were older than those who did not (P less than .01). Three (2.0%) of the HBsAg carriers developed primary hepatocellular carcinoma during the study period.

Adolescent↗
PubMed1985

The control of hepatitis B virus infection with vaccine in Yupik Eskimos. Demonstration of safety, immunogenicity, and efficacy under field conditions.

In 1981, a hepatitis B vaccine demonstration project was initiated among Yupik Eskimos of southwest Alaska to demonstrate that, under field conditions, the vaccine was safe, immunogenic, and efficacious. Laboratory tests for serologic markers of hepatitis B virus infection (HBsAg, anti-HBs, and anti-HBc) performed on sera collected in May 1981 from 3,988 residents of 17 remote Eskimo villages revealed that 2,645 (66.3%) had no evidence of hepatitis B virus infection. Because of a limited supply of vaccine, specific criteria for selection were used so that those at highest risk of infection would be immunized first. In November 1981, the first dose of vaccine was administered to 1,693 carefully selected individuals. The second dose was administered to 1,678 (99.1%) of those who received the first dose, and the final dose was administered to 1,630 persons (96.3%). Serologic follow-up showed the vaccine to be safe (0.4% experienced minor adverse reactions) and immunogenic (97.4% developed antibody). Vaccine-induced antibody levels were significantly higher for persons less than 30 years of age (p less than 0.001) and for females (p less than 0.001). Vaccine recipients were also protected from hepatitis B virus infection (p = 0.002). This public health measure proved to be feasible and effective in this remote arctic population despite difficult conditions for delivery and administration of this temperature-sensitive vaccine. This strategy for immunization is now being applied on a larger scale in Alaska as part of a program for the primary prevention of this infection and its sequelae.

Adolescent↗