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Biomedical subjects

D W Davidson

Publications and source records attributed to D W Davidson.

30 records · Page 2Linked to original sources
PubMed1977

Reliability of visual acuity measures of amblyopic eyes.

Ten amblyopes had their visual acuity measured once a week for 6 weeks using a Snellen chart (whole chart and single line) and a newly developed E chart was designed specifically for testing the acuity of amblyopes. For each test at each trial, the subject's acuity responses were graphically plotted and were fitted by a least-squares straight line to the central-most data. The reliability (repeatability) of the 50% threshold acuity was compared for the 3 acuity tests. The new E chart was the most reliable and the Snellen single-line test was the least reliable. These results have complications for quantifying acuity improvement during and following amblyopia therapy. The slope of the fitted acuity line may have value in assessing the prognosis for treatment.

Adolescent↗
PubMed1977

Pituitary-ovarian relationships in polycystic ovary syndrome.

The spontaneous pattern of pituitary gonadotropins and ovarian steroids and their response to dynamic tests were measured in 12 women with polycystic ovarian syndrome (PCO) and the results compared to those from 6 normal women during the early follicllar phase of the cycle (controls). As judged by serial measurements of urinary total estrogen and pregnanediol over a 12-week period, in PCO patients 75% of cycles were anovulatory (anovulatory PCO) as compared to 100% ovulatory in controls. The basal concentrations of LH, androstenedione and estrone were significantly higher and the concentration os FSH significantly lower in anovulatory PCO than in the controls (P less than .05). In PCO patients the concentration of LH was lower following an ovulatory cycle than that following a period of anovulation. Negative and positive feedback responses to an estrogen provocation test (200 microgram ethinyl estradiol per day for 3 days) were normal in anovulatory PCO although the LH peak occurred 24 h earlier than in the controls. The amplitude of the pulses of LH was significantly greater in anovulatory PCO than in the controls and was suppressed in both groups after ethinyl estradiol. The peak release of LH in response to 56 microgram LRF in ovulatory PCO was similar in controls but LH responses in anovulatory PCO were significantly greater. It is suggested that the abnormalities in gonadotropin secretion in PCO are secondary to excessive and prolonged extraglandular production of estrogen from androstenedione.

Adult↗
PubMed1977

The future of vision screening.

The future of vision screening is presently receiving heated debate. Recent federal legislative activity in the area of comprehensive health planning has caused renewed interest in vision screening. Optometric recommendations supported at various governmental levels call for the development of standards for comprehensive vision screening of school children on a national scale. This paper attempts to review the philosophy and justification for school vision screening and to bring the readers up to date on related governmental activity. The question of adequate manpower to implement a nationwide vision screening program is discussed, and an argument is developed for preparing school nurse practitioners to assume an expanded role in comprehensive vision screening.

Adolescent↗