摘要:

Static visual acuity was measured at two contrast levels (12 and 49%) in ten subjects in a double blind experiment involving five drug conditions of alcohol and marijuana (0.5 ml and 1.0 ml/kg body weight of 95% ethanol, 8 and 15 mg Δ-9-tetrahydrocannahinol (THC), and a placebo). We found no statistically significant change in static visual acuity for any of the dose levels at any of the measurement times up to six hours following drug ingestion; this is sharply contrasted with the marked decrements in acuity which were found in the same subjects under the same drug conditions when the targets were in motion and required coordinated eye movements for their resolution.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Adverse drug reactions are potentially serious and are becoming increasingly common. Although optometrists employ only a limited spectrum of drugs they may encounter such reactions among their patients. There is always a risk that a life threatening situation will develop in a patient quite apart from the use of any drugs. An optometrist as a member of the health-care team must be competent to provide first-aid if an emergency occurs.Tables are provided listing possible reactions to topical anesthetics with the usual signs and the preferred treatment.Optometrists are reminded that many of these treatments are the responsibility of physicians. Optometrists should be prepared to provide artificial respiration and external cardiac massage and should plan in advance how they will obtain additional assistance if an emergency occurs in their office.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The critical flicker frequency and the Pulfrich stereophenomenon were both used to investigate the long term effects on temporal resolution and visual latency of wearing a timed lens in front of one eye for a period of five days. The results obtained from three subjects showed that in every case the critical flicker frequency was depressed by the tinted lens and displayed no adaptive recovery, but the Pulfrich effect displayed a reduction of apparent depth in the median plane indicating the presence of an adaptive recovery. It is postulated that the CFF indicates that the physiological trans, mission of the visual signal is unaltered over the five days and the Pulfrich adaptation occurs due to an alteration of the interpretation of the unchanged visual response. That is, the adaptation is a perceptual rather than a physiological one.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Off-axis streak retinoscopy is analyzed in terms of the velocity of the reflex motion in the meridian being scoped. A single equation which relates the velocity of the reflex motion to the optical parameters of the eye for both on and off-axis meridians is given. A graph is presented which shows how the off-axis behavior merges smoothly into the on-axis behavior.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Forty-three native American bifocal wearers grouped by yearly age levels from 9 to 15 with a mixed group of 6 to 8 year olds are matched on beginning age, sex, beginning refractive error and ending age with 83 Native American control subjects. Similarly 226 Caucasian bifocal wearers are matched on the same criteria against 192 control subjects. Although the comparisons are made on each age group, the average annual rate of progression for the bifocal Native American subjects is −0.12 and −0.10 diopters in the right and left eyes respectively against a comparable rate of progression of −0.38 and −0.36 diopters for the control subjects. These differences are significant but not as significant as those found on the Caucasian subjects of −0.02 and −0.03 diopters right and left eyes against −0.53 and −0.52 diopters for the controls.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The Drop Ball Test (DBT) has some distinct disadvantages both as a standard measurement for ophthalmic lens fracture resistance and as a research tool. The Static Test (ST) was devised to allow a load and energy analysis of the DBT and enable more rapid and accurate testing of large ophthalmic lens samples. It was found that over 50% of the energy generated in the DBT is absorbed by the lens mount instead of the test lens. This means that the standard DBT height of 50 inches is more an indication of DBT components than lens fracture resistance.Static testing of non-tempered, beat tempered and chemically tempered lenses correlated well with former DBT studies. The ST, however, allowed lens fracture resistance to be represented in pounds-load, a value better understood practically and mathematically.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Optometrists, like all health care providers, should emphasize primary or preventive care. To provide this care optometrists must be aware of the risk factors for major causes of mortality. As an example, the risk profile for a white male age 45 to 49 years is given and discussed. Suggestions for primary vision care and detection of major risk factors by optometrists are also presented.

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1975

数据来源: OVID