Search PubMed⌕ Search

Biomedical subjects

D G Pitts

Publications and source records attributed to D G Pitts.

At least 37 records · Page 2Linked to original sources
PubMed1982

Dark adaptation and aging.

The literature relating aging and dark adaptation is discussed. The final threshold shows a significant rise in the increase in age which is more marked above the age of 60. The effects of stimulus hue (color), miosis, and the changes in the transmittance of the ocular media are explored as causes of the threshold rise. When the data are corrected for all of these effects, a threshold rise of about 0.5 log units remains which may be due to the interference in metabolism and to changes in the neural system.

Adolescent↗
PubMed1982

Visual acuity as a function of age.

The literature relating visual acuity and the aging process is reviewed. The Snellen fraction, parameters affecting visual acuity and difficulties in comparing different studies in visual acuity are discussed. Visual acuity was found to be a poor 20/1,000 to 20/800 at birth but improved to an almost normal acuity of 20/20 during the first year of life and remained relatively constant from 40 to 50 years of age. There was a moderate but steady decline in acuity as a person ages above 60 and on to the age of 80. The disease and physiological etiologies for this loss in acuity are provided. Methods which may be used to maintain or improve visual performance with age are suggested.

Adolescent↗
PubMed1981

Determination of infrared radiation levels for acute ocular cataractogenesis.

One hundred pigmented rabbit eyes and ten primate eyes were exposed to infrared (IR) radiation in the 715 to 1,400 nm wavelength range and to the full spectrum output from a 5,000 W Xenon high-pressure source. The ocular exposures were evaluated independently with a slitlamp by two researchers and classified for ocular damage. The primary ocular lesions resulting from exposure to IR radiation were corneal, iritic, and lenticular. Corneal damage varied from epithelial haze to epithelial erosion but no endothelial damage was found. The iris showed stromal haze and swelling. Lenticular changes showed small white dots that, occur at the level of the anterior cortex. All lens damage depended on iris involvement. Ocular damage was related to the rate of delivery of the IR radiation since the data show that as the irradiance level increases, the radiant exposure threshold decreases. Exposures for the full spectrum were found to be additive for irradiance levels at 4 W.cm-2 and above. The threshold radiant exposures for the full spectrum of 750 J.cm-2 for the cornea, 1,000 J.cm-2 for the iris, and 2,000 J.cm-2 for the lens were essentially identical to the IR exposure thresholds for the same irradiance levels. The primate threshold radiant exposure was a factor of six above the respective rabbit thresholds.

Animals↗
PubMed1981

Threat of ultraviolet radiation to the eye--how to protect against it.

The purpose of this paper is to discuss the effects of exposure of the eye to ultraviolet (UV) radiation and to provide information from which protective criteria and standards may be established. To accomplish this purpose, the article discusses ultraviolet radiation, absorption of UV radiation by the eye, the effects of ocular exposure to ultraviolet radiation, and how to protect the eye against exposure to UV radiation.

Animals↗
PubMed1978

Glenn A. Fry Award Lecture--1977. The ocular effects of ultraviolet radiation.

The author reviews the previous known effects of UV radiation on the eye together with results obtained on human and animal eyes in his laboratory during the past 11 years. Damage to the cornea and lens is assessed, classified, and discussed. Methods of calculating safe UV exposures and establishing characteristics of protective devices are presented.

Animals↗
PubMed1977

Ocular effects of near ultraviolet radiation: literature review.

The literature related to the effects on the eye of ultraviolet radiation in the wavelength range 300 to 400 nm is reviewed. Insufficient data are available to establish criteria for ocular protection. Exposure of the eye to sufficient quantities of near ultraviolet radiation can interfere with synthesis of crystalline lens protein, catalyze lens proteins, produce chromatic changes in the lens, and enhance formation of cataract.

Adolescent↗
PubMed1977

Ocular effects of ultraviolet radiation from 295 to 365 nm.

A 5,000 watt Xe-Hg source and a double monochromator were used to produce 6.6 nm. full band-pass ultraviolet (UV) radiation. Pigmented rabbit eyes were exposed to the 6.6 nm. band-pass UV radiant energy in 5 nm. steps from 295 to 320 nm. and at random intervals above 320 nm. Corneal and lenticular damage was assessed and classified with a biomicroscope. Corneal threshold radiant exposure (Hc) rose very rapidly from 0.022 Jcm.-2 at 300 nm. to 10.99 Jcm.-2 at 335 nm. Radiant exposures exceeding 2 x Hc resulted in irreversible corneal damage. Lenticular damage was limited to wavebands above 295 nm. The action spectrum for the lens began at 295 nm. and extended to about 315 nm. Permanent lenticular damage occurred at radiant exposure levels approximately twice the threshold for lenticular radiant exposure. The importance in establishing both corneal and lenticular damage criteria is emphasized.

Animals↗
PubMed1977

Education for the optometric educator.

Optometric education is faced with the need for new thinking in developing and training educators and new methods of financing their education. Establishing of research faculty and the instituting of research in present schools of optometry must be given a high priority in the future of optometric education.

Faculty↗
PubMed1976

Scleral contact lens electrodes for electroretinography in domesticated animals.

Contact lens electrodes are necessary to produce a high quality electroretinogram. Comparison of the electroretinogram recorded with the contact lens electrode and a needle electrode showed a great difference. Contact lens electrodes showed a 50 percent or greater amplitude and less artifacts. This report details the procedure for construction of the contact lens electrodes for domestic animals.

Animals↗