ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The role of the peripheral curve of a soft lens in the supply of oxygen to the cornea via the tear pump mechanism is considered. A group of 18 patients was optimally fitted with spherical DuraSoft lenses with and without peripheral curves; the absence of the peripheral curve was not found to affect adversely the physiological response of the cornea as determined by pachometric changes in central corneal thickness.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The toxic potential of three major components of soft contact lenses was assessed in white mice. Accepted procedures for toxicological studies were used to evaluate the effects of 2-hydroxyethyl methacrylate, ethylene glycol, and methacrylic acid. No observable signs of gross toxicity were detected in any of the mice injected with the original doses. Larger doses of methacrylic acid produced ataxia, irregular breathing, convulsions, and death. From the concentrations of these chemicals normally occurring in contact lenses, no systemic toxic effects would be expected.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Subjects wore hydrogel lenses of two different thicknesses (0.07 mm and 0.18 mm) on one eye and no lens on the other eye during 3-hour periods of eye closure. They developed more corneal edema (12.7%) with the thicker lenses than with the thinner lenses (7.9%) and more corneal edema with the thinner lenses than with no lens (0.9%). The results suggest that hydrogel lens thickness would have to be less than 20 nm to reduce corneal edema to levels that develop when the eyes are closed without a contact lens.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Relationships among statistical quantities used in the analysis of refractive error are derived from geometrical optics principles. The accuracy of these results are verified using the data of Sorsby et al. As an application of these results, it is shown that there is difficulty in accounting for leptokurtosis of refractive error in terms of correlation among the optical parameters of the eye. Also, it is shown that the distribution of the optical parameters of the eye cannot be a jointnormal distribution.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Contrast thresholds for different spatial frequencies were measured for four individuals with optimum optical correction and with 2 D of astigmatismm induced at various meridians. Sensitivity for sine waves of low spatial frequencies was unaffected by the astigmatism; however, gross changes were found at high spatial frequencies when the astigmatism was induced with the power meridian perpendicular to the orientation of the stripes. For square waves, the results were comparable at high spatial frequencies, but astimgatism also produced a decrement at 0.2 cycles/degree. This latter effect can be predicted by assuming that astigmatism results in a loss of higher order harmonics in the response to square waves.

ISSN:0093-7002    

出版商:OVID    

年代:1980

数据来源: OVID