摘要:

An attempt has been made to explain how dichromatic confusion lines can be used in building a model for color vision. In the König color vision model the fundamental colors are located on the mixture diagram at the copunctal points for protanopes, deuteranopes, and tritanopes. In Fry's model the copunctal points fall on the alychne and cannot represent the fundamental colors. On a constant luminance diagram the confusion lines for the different dichromats are sets of parallel lines. This arrangment of the confusion lines can be explained in terms of a zone theory of color vision.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The visible light and ultraviolet (UV) radiation transmission was measured for four different tints from two contact lens companies. It was found that luminous transmittance ranged from 60 to 82% and mean UV transmission from 15 to 74% for the lenses under investigation. Differences in luminous transmittance between the two lenses of each tint evaluated were generally within 1%, which was also the approximate accuracy of the technique.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Under some circumstances it is advantageous to measure intraocular pressure (IOP) without removing soft contact lenses. In this study comparisons have been made between IOP measurements [using a noncontact tonometer (NCT)] with and without soft contact lenses on the eye. The influence of lenses of different water content, lens design, lens power, method of manufacture, and lens center thickness was examined. The most important parameter affecting the results was center thickness. It was shown that reliable and valid IOP findings can be obtained using a NCT with soft lenses on the eye when center thickness is less than 0.15 mm. In glaucoma screening readings obtained with lenses thicker than 0.15 mm may be convenient and useful al-though such results would be achieved with increased sensitivity and concomitant reduced specificity.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

One hundred consecutively presenting patients, fifty from each of two contact lens clinics, were questioned about the procedures encountered in care and maintenance of their contact lenses and asked to demonstrate their use of those procedures. Their clinic records were then analyzed for the occurrence of signs and symptoms that were related potentially to noncompliance with instructions and procedures, and that could not be otherwise explained. Only 26% of patients were fully compliant. Noncompliance with instructions was related strongly to the occurrence of signs and symptoms indicative of potential wearing problems. Improvements in the level of patient compliance with instructions is likely to bring about increased patient success with contact lens wearing.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

A quick and simple clinical test for detection of strabismus was evaluated for three groups of subjects. The test reliably detected the strabismic eye in the first group of strabismic subjects when observers discriminated between brightness of the right and left fundus reflex. The test reliably detected strabismus in the second group of strabismic subjects when observers decided if brightness of the fundus reflexes were equal or unequal. However, the Bruckner test yielded false positives when it indicated strabismus in the third group of non-strabismic subjects. The Brückner test is recommended only as an adjunct to testing for use by professionals, but not as a single test for strabismus detection by lay screeners.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The dot visual acuity test is used to test the acuity of children between the ages of 2 and 4 years who do not respond to the tumbling E test. Because the test involves the detection of a black dot on a white background it is appropriate to ask if the detection threshold is lowered artificially in the presence of target blur. Twenty-one children (42 eyes) were used in the study. Refractive errors were fully corrected and each subject's lag of accommodation was measured. A monotonic decrease in acuity was found with increasing amounts of optical blur. The explanation for the de-creased acuity is found in the reduced retinal image contrast of the blurred target.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The influence of 3 different lid positions on the astigmatism of 50 young heathy eyes was investigated with an autorefractor. The results showed that a significant amount of astigmatism may be induced when the palpebral aperture is voluntarily narrowed.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Stereoacuity has been measured at various luminance difference levels and also at the isoluminance point, where the target and the background have equal luminances. The results of the experiment show that acuity at isoluminance is three times worse than the value obtained when there is maximum contrast between target and background. Possible reasons for these findings were investigated. Results of control experiments show that neither chromatic aberration nor defective accomodative response could be responsible for this finding.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The purpose of this study was to investigate the feasibility of designing a simple, filter-free (“real-depth” conditions) farpoint stereotest. A two-step pilot study is described wherein (Step 1) an enlarged, somewhat modified version of the standard version of the Frisby stereotest was constructed and administered to 42 adult subjects. This was followed (Step 2) by the construction and try-out of a similar apparatus that was based on the same principles, but comprised different stimuli. Descriptions of both tests are provided along with data which suggest that designing such a test for clinical application is feasible.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

A patient with uncorrected antimetropia was found to attain motor fusion through blinking. Although this patient was also able to attain motor fusion through saccadic vergence and slow fusional vergence, he usually relied on blink vergence. In this patient, blink vergence was an efficient alternative to slow fusional vergence.

ISSN:0093-7002    

出版商:OVID    

年代:1986

数据来源: OVID