摘要:

ABSTRACTOxygen consumption of the frog cornea was measured electrochemically with a non-membrane oxygen sensor bathed with physiological solution. The aerobic metabolism, recorded as current flow within the fluid-filled reservoir between the cornea and oxygen sensor, was dependent on the metabolic rate of the anterior corneal cells. After the cornea had been exposed to ultraviolet light, there was an increase in the metabolic oxygen uptake indicating an absorption of ultraviolet radiation.

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

ABSTRACTImpact performance by the ballistic technique was determined for 720 test ophthalmic lenses including non-treated, beat-treated and chemical-treated glass lenses and plastic lenses. Half of the lenses were abraded on the front surface. Plastic lenses had the greatest impact resistance, while non-treated glass lenses had the least. Chemical-treated and heat-tempered glass lenses offer similar impact protection. All four types lost impact strength after being scratched on the front surface.

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

ABSTRACTThe effect of frame shape on prismatic power of eye-protectors has been shown by computation. The calculated values have been compared, for seven eye-protectors, with the value measurements by a testing method reproducing the normal conditions under which they will be worn by users. The prismatic power is, besides, measured for several points of the visual field, and for varying interpupillary distance of the users.

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

ABSTRACTMany eye practitioners unknowingly employ a method for visual acuity determination of low vision patients which is totally inaccurate when the standard test distance or room size is less than 20 feet and a projector target of Snellen optotypes is used for the measurement.aThis paper presents a mathematical derivation of an expression for accurately determining visual acuity for any standard test distance.

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

ABSTRACTEffects of different cornea to instrument distances were assessed by making paired measurements on significantly astigmatic corneas. Differences in pressure noted for the differences in corneal radii were small (less than 0.5 mm of Hg) and none proved statistically significant. The small differences observed were consistent with a hypothesis that a parabolic relationship exists between working distance and NCT pressure reading. That relationship predicts that an error as large as 1.0 mm of Hg would occur only for a few eyes with very flat corneas.

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

ABSTRACTThe oxygen-dependent enzyme, succinic dehydrogenase (SDH) was studied in the corneal epithelium of rabbits exposed to selected oxygen environments for specific periods of time. Oxygen atmospheres of 3% or less for a period of five hours caused greater than normal SDH reactivity, as did oxygen deprivation for five hours. Decreased SDH reactivity could be provoked as well by selected conditions. The histochemical procedure used here has application in studying new contact lens materials and the toxic effects of drugs and irritants on the corneal epithelium as well.

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

ABSTRACTThe initial lens/cornea relationship of steeply fitted corneal contact lenses on 40 eyes was compared with the lens/cornea relationship after wearing the lenses for periods up to six years. The corneal curvature became steeper in 24 eyes, became flatter in 12 eyes and remained the same for four eyes.

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

ABSTRACTWhen proper precautions are taken, the use of minus Fresnel Press-onTMlenses can help solve one of the most difficult patient problems - that of the moderate or highly myopic patient who is concerned with cosmetic appearance but wants large stylish wire frames.

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1974

数据来源: OVID