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Biomedical subjects

C L McKay

Publications and source records attributed to C L McKay.

13 recordsLinked to original sources
PubMed1979

Effects of aspirin and dimenhydrinate (Dramamine) on visual processes.

1. The effect of three doses of either aspirin (1280 mg each) or dimenhydrinate (Dramamine) (100 mg each) in an 8 h period on visual processes was investigated double-blind on sixteen volunteer subjects. 2. Tests included night-vision, colour-discrimination, stereoacuity and stereopsis, reaction-time, pupil size, eye-movements, visual evoked cortical potentials, electroencephalographs, a dial-reading task, and a test of texture discrimination. 3. Both drugs affected colour discrimination, and dimenhydrinate degraded night-vision, reaction-time, and stereopsis. 4. The effect of aspirin was minor, but the impairments produced by dimenhydrinate appear to be of practical importance.

Adult↗
PubMed1979

Vision of submariners.

A variety of vision tests have been administered to submariners over the years. The results show that the average submariner, though maintaining a normal, healthy visual system, has distant acuity somewhat below normal and manifests more myopia, esophoria, and less accommodative power than men of comparable age, as documented in the literature. The reasons for these changes are unknown but probably involve confinement; whether confinement peculiar to the submarine of the "confinement" of urban living is the more important for these changes is discussed.

Accommodation, Ocular↗
PubMed1977

The use of fluorescein angiography to study oxygen toxicity.

This study was designed to test whether oxygen toxicity results in retinal damage that could be documented by the technique of fluorescein angiography. Three squirrel monkeys lived in 100% oxygen environments for periods ranging from 50 to 117 hours. Two of the monkeys incurred damage as evidenced by early multifocal leakage and subsequent accumulation of dye in the retina. All monkeys survived the exposures and were followed for several weeks thereafter. The pathology appeared to be reversible since later angiograms were either normal, or approaching normality, when the animals were sacrificed. Subsequent histopathologic examination revealed no abnormalities.

Animals↗
PubMed1977

Visual evoked responses and EEG's of 16 divers breathing air at 7 ATA.

This study is an assessment of individual differences in electrophysiological response under diving conditions normally conducive to nitrogen narcosis. A group of 16 men made two dives each to approximately 200 ft in a pressure chamber while breathing air. The visual evoked response of the men at depth revealed several decrements; in the response to a slow rate of stimulation, there was a highly significant reduction in a component around 160 ms, and in the response to a rapid rate of stimulation, marked losses in amplitude and increases in variability were found. The latter changes were related to diving experience while the former were not. No significant changes were found in alpha or theta activity in the EEG.

Adult↗
PubMedDate not supplied

Effects of low levels of carbon monoxide on visions of smokers and nonsmokers.

The scotopic sensitivity, reaction time, eye movements, and visually evoked cortical potentials of 12 nonsmokers and 6 smokers were measured during the course of 3 hr of exposure both to air and to 200 ppm CO in air. No significant degradation in performance was observed for any of these measures in either group during the course of the exposure.

Adult↗
PubMedDate not supplied

Visual processes of smokers and nonsmokers at different ages.

Forty smokers and forty nonsmokers were matched for age over the range from 21 to 76 yr. The battery of tests included: optometric refraction for near vision, scotopic sensitivity, simple and choice reaction time, visually evoked cortical potentials to targets flashing at 1 and 16 times/sec, EEG, and a perimetric test of color detection. Roughly the same number of smokers and nonsmokers required spectacle corrections, but smokers tended to require more plus correction. The mean scotopic sensitivity of the smokers was significantly worse than that of the nonsmokers. Reaction time tended to be poorer for the smokers. There were no differences on the perimetry test and in the EEGs of the smokers and nonsmokers, and no significant changes in the visually evoked responses to either 1 or 16 flashes/sec. There was virtually no evidence of an increasing difference between the smokers and nonsmokers with increasing age.

Adult↗