ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

There is extant a population of subjects who have average or better than average interpretive reading skills as measured by standardized tests but who read slowly and inefficiently. Ten cases are presented where both Iowa Silent Reading Tests (ISRT) (Level III), and eye movement recordings were completed. Three of the subjects received training to improve reading efficiency.Reducing the cognitive level of the reading selections did not result in improved reading efficiency for subjects who have good interpretive skills. Substantial improvement in reading efficiency was measured in each of the three subjects selected for training.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The eye movements of 13 dyslexics, 10 normal, and 16 retarded readers were recorded while they sequentially fixated 7 equidistantly spaced digits from left to right (L → R) and right to left (R → L). This nonreading task simulated the sequential motor components of the reading process. Dyslexics and their controls were selected on the basis of comprehensive and quantifiable criteria. All three groups were of the same chronological age. The dyslexics and retarded readers had also the same reading difficulties, but the causes of their problems were different.Dyslexics made significantly more regressions than the normal or the retarded readers in both directions (L → R and R → L). These results were in line with the ones reported in similar studies and suggest that the dyslexics' erratic eye movements and their excessive number of regressions are present even in nonreading, nonverbal sequential tasks. It may, therefore, be possible to use the eye movement records from nonreading sequential tasks for the objective diagnosis of dyslexia. As such tasks do not depend on reading, they may even be used before reading age.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Among the patients we tested, most of those who had lost normal macular function developed extrafoveal retinal loci which resulted in strongly preferred viewing angles for steady fixation. These patients used these extrafoveal retinal loci to scan lines of characters in patterns similar to patients with normal macular function. Although the scanning speed of these patients was adversely affected by their large size scotomas, their reading accuracy was not necessarily reduced. The assessment of scanning and reading performance in this population requires careful measurement of the visual skills involved in reading.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Eye movements during reading and nonreading tasks were measured in four patients having either Friedreich's ataxia, congenital dyslexia, acquired dyslexia with quadrantanopia, or acquired dyslexia with hemianopia. Abnormalities included saccadic intrusions, abnormally large dynamic overshoots, increased fixation duration and number of fixations, and/or reduced reading rate. The results clearly demonstrate the importance of objective eye movement recording for the precise specification of the abnormal reading pattern in patients with neurological dysfunctions.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The present study was designed to determine whether classical accommodation theory or dual-innervation accommodation theory best explains the visual fatigue effects of prolonged visual work. The accommodation responses of 20 young male adults were measured, using a laser optometer, while they viewed a near target (30 cm), a far target (6 m), or in total darkness. Measurements were made before and after 1-h fatigue sessions, during which subjects either read monocularly presented slides of text at near or far distances, or remained in darkness. There were no significant changes in near or far target static accommodation as a result of any of the fatigue sessions. Dark focus accommodation shifted inward after the near target viewing task and after prolonged dark viewing. The results are discussed in terms of their implications for research in accommodative fatigue, and their relation to other current research.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

We examined the difference in refraction when using portions of the visible spectrum from 437 to 671 nm, and report on the influence of age on the chromatic aberration in one subject 20 years after previous measurements. Changes in refraction were measured with a Rodenstock refractometer which has an exit pupil of 3 mm, and nine narrow band interference filters. Eight subjects were examined under cycloplegia and with dilated pupils. Results confirm previous reports that the magnitude of chromatic aberration decreases with age.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Basic closed-form theoretical results are derived relating the stress-strain σ = σ(ε), pressure-volume p = p(V), and ocular rigidity-pressure K = K(p) functions for a spherically symmetric eye of contant thickness and material properties. The results can be used to predict the pressure-volume and ocular rigidity behavior of both hyperopic and myopic eyes, in addition to the emmetropic case. The theoretical results are compared with eight different experimental studies from the literature. Five experimentally obtained mechanical variables, the pre-exponential stress-strain constant A (Pascals), the dimensionless exponential stiffening constant α, the pressure-volume globe stiffness intercept a (mm Hg/mm3), the globe stiffness slope b (mm−3), and the ocular rigidity K(mm−3) are found on average to agree with the theoretical predictions within a factor of 3 or better. Possible clinical applications might include measuring the ocular rigidity function K = K(p, Vo) to infer the mechanical strength of the corneo-scleral shell. The results may also be useful to help understand glaucoma dynamics as a function of refraction, and also with respect to tonometer calibration.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Specular microscopy was used to measure thickness changes of stroma-endothelium preparations from rabbit corneasin vitro.The preparations were first bathed on both sides for 90 min with different bicarbonate-Ringer solutions (2 to 50 mM bicarbonate) maintained in equilibrium with 5% CO2-air (pH 6.2 to 7.9). During this equilibration, the stroma attained a stable thickness that was inversely related to the hydrostatic pressure (20 to 100 cm H2O) applied to the endothelial surface. After equilibration and at 20 cm H2O pressure, covering the anterior stromal surface with silicone oil (Dow Corning 200 dielectric fluid, 20 cs viscosity) resulted in stromal thinning. The rate of this deturgescence increased (from 5 to 75 μm/h) as the equilibration solution bicarbonate level increased from 2 to 30 mM. The net size of the thickness change was also related to the equilibration bicarbonate level. However, indirect studies on the cornea using phenol red indicator and pH electrode measurements of solutions revealed that the stromal bathing solutions became more alkaline under the silicone oil layer. CO2is soluble in silicone oil. Implications of these CO2and pH effects on mechanisms of corneal deturgescence are discussed.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

A 1-year evaluation of the feasibility of the use of gas-permeable rigid lenses for extended wear was carried out, using two different materials. Forty subjects were entered into the study. Fifteen were fitted with the Polycon II lens and another 15 with the Boston IV lens. These two groups wore the lenses on a weekly basis for the duration of the study. Two other groups, the controls, were fitted with the same types of lenses as the experimental groups, but wore the lenses on a daily basis. All lenses were made to the Syntex specifications for the Polycon lens and the groups were comparable with regard to age, sex, refractive error, corneal astigmatism, and any pre-existing ocular pathology. All subjects carried out the same care regimen for their lenses and were examined after 24 h, 1 week, 1 month, 3 months, 6 months, and 1 year. Examinations performed at the follow-up visits were to determine any clinically observable effects of lens wear in each patient in all groups. The results of the study suggest that the extended wear of gas-permeable rigid materials is a viable option. However, the results also indicate that extended wear is not without problems, and these need to be studied more fully before the use of gas-permeable rigid lenses for extended wear can be recommended.

ISSN:0093-7002    

出版商:OVID    

年代:1985

数据来源: OVID