摘要:

ABSTRACTVision screening tests should include a simple, reliable, and valid test of color vision defects. In this investigation the single plate Farnsworth F-2 test and the AO H-R-R pseudoischromatic plates were compared as primary screening tests for red-green color defective vision. The tests were administered to 2827 children, kindergarten through high school grades. Both tests failed a higher percentage of children than expected in the lower grades (kindergarten through 3). In grades 4 through high school, however, 4.16% failed the F-2 test and 4.02% failed the AO H-R-R, compared to a predicted 4.2% of the general population with inherited red-green deficiencies. The failure rates of the F-2 test for 1171 high school boys and girls were 7.3 and 0.89%, respectively, very close to the expected incidence of red-green defects in males and females. Although the F-2 test passed a few pupils who failed the AO H-R-R test, their defects were categorized as mild or borderline on the AO H-R-R test and therefore not likely to be of practical significance. Less than 0.5% of the children in grades 4 through high school failed the F-2 test after passing the AO H-R-R. Some children with normal color vision, particularly very young children, may fail the F-2 test because of difficulty picking out the less obvious blue square. Nevertheless, for screening purposes the F-2 test is comparable to the AO H-R-R test and except for kindergarten and grade 1 pupils is an excellent single plate color vision screening test. The F-2 plate has the advantage over the AO H-R-R test and most other plate tests in that it tests for blue-yellow and red-green defects with a single plate.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACTUsing data collected from a retrospective study of the records of 110 patients diagnosed as having convergence insufficiency, a model has been developed which allows the classification of a patient into one of two categories of success (total or partial/none) on the basis of an initial examination. The subjects were treated with orthoptics and classified into either the total success group (no objective or subjective visual difficulties) or the partial/no success group. Stepwise discriminant analysis was used in the data reduction phase in which 6 of 14 possible variables were selected which best explained the variation in the degree of success. These six variables were: (1) the AC/A ratio; (2) the negative vergence blur value at 40 cm; (3) the recovery value of the positive vergences at 6 m; (4) the break value of the positive vergence at 6 m; (5) the amplitude of accommodation; and (6) the frequency of the deviation. Subjects were more likely to be successful when 1, 2 and 3 were high, 4 and 5 were low, and the deviation was latent. Discriminant analysis using these six variables allowed 25 of 33 (76%) of the patients to be correctly classified in terms of their success. The application of the model for classifying patients with convergence insufficiency is presented and briefly discussed.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACTA retrospective study of 110 subjects with convergence insufficency has been completed. Their mean age was 19.9 years. There were 72 females and 38 males in the group. The clinical profiles of these subjects were examined before and after a standard orthoptic treatment regimen. Over the course of treatment, the near angle of deviation, the AC/A ratio, a portion of the negative vergence values, all the positive vergence values, the near-point of convergence, and the amplitude of accommodation were found to have changed in a statistically significant manner. The importance of these findings is discussed.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACTTwenty preadapted male myopes were fitted with two series of rigid gas permeable corneal lenses made of the same material (Hyperm). All lenses had identical characteristics with the exception of center thickness (0.12 vs. 0.15 mm). The mechanical, physiological, and visual performance of the lenses were evaluated. It was found that the thicker lenses performed better.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACTPrevious research on the effects of accommodation and repeated corneal applanations on intraocular pressure (IOP) has yielded inconsistent and conflicting results. Using 30 subjects, this study compares the effects of repeated Goldmann applanation tonometry with accommodation relaxed and with accommodation stimulated. IOP's were also measured after various amounts of long- and short-term accommodation. Repeated applanations with accommodation relaxed had a negligible effect on IOP. However, there was a significant reduction in IOP with accommodation stimulated. These results indicate that the effects of accommodation should be considered in the clinical measurements of IOP.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACTSeveral experiments have shown that monocular occlusion (MO) leads to a variety of changes in the visual functioning of the non-occluded eye. An experiment was conducted to assess the effect of 24 hr of MO on the lateral phoria, a binocular phenomenon. The results demonstrated marked tendencies for increased esophoria after MO, especially for near vision. Follow-up tests revealed that normal phoria was reestablished 24 hr after the termination of MO. The results are discussed in the context of the use of MO in treatment procedures for visual dysfunctions and their implication for future investigations.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACTThe mixture diagram for a dichromat reduces to a single line connecting two points that represent the surviving fundamental colors. The intermediate colors match mixtures of the two fundamentals. The luminous efficiency curve can be split into its red and blue, or red and green, or green and blue components which represent the response curves. These response curves can be compared to the response curves of a normal trichromat. The curves derived for a trichromat depend upon the points chosen to represent the three fundamentals. The rationale involved in the choice of fundamentals is explained. The choice depends on (1) the shape of the spectrum locus, (2) adaptation data, and (3) the directions of the confusion lines for dichromats. The red curve derived for a trichromat in this way has two peaks, one at each end of the spectrum. The peak at the short wave end is missing in the case of deuteranopes. Otherwise, the curves in dichromats and trichromats are similar. No allowance has been made for effects of macular pigment and transmission of the media.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACTIn a previous paper a procedure was outlined for locating the red, green, and blue fundamental colors on a color mixture diagram. This makes it possible to derive the red, green, and blue response curves from the mixture data and the luminous efficiency curve. Curves were derived in a similar way for dichromats and compared to those for normal observers. In this paper, the study has been extended to include anomalous trichromats. In normal observers, tritanopes, and deuteranomalous subjects, the red response curve has two peaks, one at the red end and one at the blue end. The red response can be analyzed into long wave and short wave components. The short wave component is missing in deuteranopes and in the protanomalous observer investigated in this study. The data based on the one protanomal point to the possibility that the long wave component of the red response of the protanomal is similar to that of the normal but reduced in magnitude. In the deuteranomal, the green response is similar to that of a normal but reduced in magnitude.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACTComparative experiments were performed on conventionally chemtempered lenses and ones chemtempered in an ultrasonically stimulated, slowly oscillated salt bath. With ultrasonic stimulation, a substantially shorter treatment time was found to result in greater strength and greater surface enrichment of K+ions. The K+-rich surface layer was as deep or deeper than that found in conventionally chemtempered lenses. The results suggest that the ultrasonic stimulation continually enriches the salt bath with K+ions in the region of the lens surface.

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1984

数据来源: OVID