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Biomedical subjects

T D Williams

Publications and source records attributed to T D Williams.

At least 145 records · Page 8Linked to original sources
PubMed1984

Adult community-acquired pneumonia in central London.

Strep. pneumoniae was diagnosed as the cause of pneumonia in 40 (50%) of 80 consecutive adults admitted to St Stephen's Hospital with community-acquired pneumonia. None of the patients had evidence of Mycoplasma pneumoniae infection, and Legionella pneumophila serology was positive on only one occasion. In 29 patients (36%) no causative organism was demonstrated. The diagnosis of pneumococcal infection was obtained in 15 cases by isolating Strep. pneumoniae from the sputum, in 13 further cases by demonstrating pneumococcal capsular antigen in sputum, and in 12 other cases by detecting pneumococcal antigen in serum only. Only 2 cases with pneumococcal pneumonia were bacteraemic and 3 patients (7%), all aged more than 75 years, died. The relatively low bacteraemic and mortality rates suggest that community-acquired pneumococcal pneumonia currently seen in patients admitted to hospital in central London may not be so severe as in some other areas.

Adult↗
PubMed1983

Speculations on the direction of the optic nerve.

A theory is proposed to explain the direction of the optic nerve on the basis of differing embryonic growth of axons on opposite sides of the nerve head. Several ophthalmoscopic indicators of the direction of the optic nerve are discussed. Some clinical implications are presented.

Choroid↗
PubMed1982

Quantification of arteriolar tortuosity in two normotensive age groups.

Arterioles of the human retinal circulation are directly visible and exhibit wide variations in their course. Not only is there marked variation in arteriolar tortuosity within a given age group, but also it has been proposed that the degree of arteriolar tortuosity is different in younger and older age groups. This paper reports on the development of a computer-assisted technique for measurement of arteriolar tortuosity and on the frequency distribution of this index in younger (mean age 22 years) and older (mean age 54.3 years) populations without hypertension.

Adult↗
PubMed1980

Annual review of section on ocular disease: diseases of the optic nerve, tracts, and visual cortex.

The ophthalmic literature dealing with diseases of the optic nerve, tracts, and visual cortex was reviewed for the period November 1977 to December 1978. Fifty-nine papers of interest to optometrists have been abstracted. Main areas of interest include: role of axoplasmic transport in production of disc edema and cotton-wool spots; ocular effects of local and systemic vascular disturbances; congenital abnormalities of the eye alone and in association with other bodily malformation; field testing, including an ingenious ophthalmoscopic method which can lead to detection of very small scotomas; a new quantitative method for assessing integrity of the optic nerve in multiple sclerosis and related conditions; stimulating questions on the development of optic atrophy and on its relation to retinal vascularity; considerations of acquired and congenital abnormalities of the cavernous sinus and their ocular manifestations; swinging-flashlight test in hemianoptic patients; a case of subacute sclerosing panecephalitis; methods to enhance magnification during opthalmoscopy; methods enabling a closer investigation of the retinal nerve fiber layer.

Adolescent↗
PubMed1980

Inferior conus: a new hypothesis for associated field defects.

A case of bilateral inferior conus is reported; relative scotomas were found to be congruent with the location of the conus. Existing theories, proposed to account for scotomas associated with inferior conus, are discussed. A new theory is proposed.

Adult↗
PubMed1979

Disc vascularity in Down's syndrome.

Ocular fundus photographs of 100 eyes were obtained from an institutionalized population of patients with Down's Syndrome (66 males, 34 females). The vascularity of the optic nerve head was assessed in each photograph by counting the number of arterioles, venules, and fine vessels crossing the disc margin. The results of this analysis were compared to similar data obtained from 100 ocular fundus photographs of normal patients and show that there are more large vessels crossing the disc margin in those with Down's Syndrome.

Adolescent↗
PubMed1979

Effect of meridional disparity on depth perception.

When a meridional-size lens is used to provide magnification in the horizonal meridan for one eye the resulting stereopsis distortion is readily accounted for in the terms of the binocular disparity caused by changed angular relations. When the same size lens is used to magnify the vertical meridian for one eye there is an opposite stereoscopic distortion for which is no ready geometric explanation. A perceptually induced mechanism operating in the vertical meridian has been suggested by Ogle. In the present experiment, apparatus was designed to introduce disparity of binocularly fused targets successively in each of several oblique meridians independent of the stereopsis measuring targets. Unlike the above-mentioned results obtained with size lenses, the induced stereoscopic distortion was in the same direction and of essentially the same magnitude for disparity in every meridian. It would follow that the perceptually induced mechanism is not exclusive to the vertical meridian.

Depth Perception↗