摘要:

Monochromatic-test stimuli were produced with a double monochromator with a neutral wedge linked to the mechanism for changing wavelength. Only minor adjustments of the width of the entrance slit were required to produce monochromatic stimuli of equal luminance. For any given wavelength, the radiance of the stimulus was proportional to the width of the entrance slit. These test stimuli were adjusted to equal luminance, using various criteria: (1) flicker, (2) direct comparison, (3) distimulus matching, and (4) step-by-step. For two out of three subjects, measurements made by the distimulus method agree with flicker measurements when the primaries are adjusted to be equal by flicker photometry. They provide a test for additivity. Red and green, which are equal in luminance to yellow by flicker photometry, are brighter than yellow by direct comparison and also by the step-by-step method of assessment. The step-by-step data prove that the discrepancy between flicker and direct comparison involves more than a confusion between saturation and brightness and is consistent with the notion of summation of responses in the chromatic and achromatic channels, as proposed by lves and others.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Mathematical statements are made for the various hypotheses describing the change in radius of curvature of the back surface of a flexible contact lens as it flexes. These hypotheses may now be tested for validity in predicting both optical and physiological behavior of real contact lenses in situ.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

The reproducibility of the in vivo performance of a contact lens depends on how the specifications are determined and how the lens is made. Using reproducibility of edge clearance as a criterion, the peripheral curve design of a contact lens is analyzed. Optimum values of peripheral curve width exist which minimize errors of reproducibility.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Corneal sensitivity and thickness were measured in nine subjects. Two different types of hard contact lenses were fitted to each subject; a traditional polymethylmethacrylate (PMMA) lens on one eye and a gas-permeable cellulose acetate butyrate (CAB) lens on the other eye. Corneal sensitivity did not differ significantly between the two eyes after 6 and 10 hr of wear, but PMMA lenses tended to induce slightly more corneal edema than CAB lenses. As oxygen tension behind such contact lenses is different, whereas mechanical stimulation is nearly the same, this would appear to support the view that corneal sensitivity changes are related to mechanical stimulation. However, careful scrutiny of the data does not support this view unequivocally, and other suggestions are made.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Ophthalmoscopic appearances of congenital and acquired presumed ocular toxoplasmosis are described. Four illustrative cases of presumed ocular toxoplasmosis are discussed, with some emphasis on related general health history. Some speculations are offered to account for the varied Ophthalmoscopic appearances of these lesions.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

A retrospective study of 94 soft contact lens patients was performed to determine the relationship of a number of physiological and lensfitting characteristics. Results yielded only medium to low relationships, the highest correlation being between age, Schirmer, and K readings. Persons with dry and excessively mucoid eyes were found to be older and to have flatter corneas and lower Schirmer results. Older patients also tended to have more acidic tears and a shorter tear film breakup time. The group was studied from three aspects: (1) as a whole to establish means, (2) the relationship of physiological conditions, and (3) the relationship to hydrogel lens surface coating.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Preventive health care for children can have a significant impact on detecting and treating potential health problems. The Early and Periodic Screening, Diagnosis, and Treatment Program (EPSDT) is a preventive health program under Medicaid designed to improve the health of indigent children. Since this program is the only federal Medicaid program which requires vision screening and treatment services, the opportunity exists for enormous benefits for detecting and treating an indigent child's vision problems, as well as general health problems. Even though the program has been slow in evolving, it is taking an expanding role in all phases of indigent child health care, including vision care.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Thirteen patients with suspected glaucoma were subjected to the water-provocative test for glaucoma. Intraocular pressures were measured over a 1-hr period, and characteristic rises were compared with those of four glaucomatous eyes (in two patients). Glaucoma was subsequently ruled out for the 13 patients. Criteria are suggested for confirming the presence of glaucoma.

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1979

数据来源: OVID