ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The performance of 11 static stereo-deficient subjects and 11 static stereo-normal subjects was compared on two types of dynamic stereo displays-one where disparities were constant during motion and one where disparities changed continuously. Computer-generated displays simulating horizontal motion of figures at different depths or rotation of figures about a vertical axis were viewed through a Brewster stereoscope. About one-half of the subjects in our static stereo-deficient sample were able to make depth judgments on the basis of disparity in both types of dynamic displays. The clinical feature which appeared to distinguish those static stereo-deficient subjects who could use disparity information in dynamic displays from those who could not was early onset constant strabismus. These results indicate that a complete evaluation of stereo ability should include tests with dynamic displays, possibly including both constant and changing disparities.

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The purpose of this study was to determine which of four tests, the Acuity Cards, the Dot Visual Acuity test, the Broken Wheel test, or the American Optical (AO) pictures, might be most useful for clinical assessment of visual acuity in 2- and 3-year-olds. Data related to clinical utility including success rates, required test times, reliability, and acuity norms were collected. High success rates and short test times support use of the Acuity Cards for 2-year-olds. For testing 3-year-olds a measure of recognition acuity, the Broken Wheel test, may be most useful

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We have conducted two experiments to investigate the effect of monovision and other contact lens corrections for presbyopia upon peripheral visual acuity. In the first study, we measured binocular peripheral visual acuity using Landolt rings with seven subjects wearing a monovision correction. The Landolt rings were presented at eccentricities of 10, 20, 40, and 70° on each side of the subject, with near additions of +1.50 D, +2.50 D, and no addition. We found no significant effect of monovision correction on peripheral visual acuity. In the second experiment we measured the peripheral visual acuity of 11 presbyopic subjects wearing distance contact lenses with lookover spectacles, soft progressive bifocal contact lenses, soft concentric bifocal contact lenses, monovision contact lenses, modified monovision contact lenses, and hard bifocal contact lenses using Koenig bar targets. There were no significant differences in peripheral visual acuity between any of the contact lens corrections for presbyopia.

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Maximum base-in (Bl) and base-out (BO) fusional vergence ranges were measured in 38 normal subjects using 3 different clinical procedures. These procedures used different instruments, instructions, and vergence stimuli (Risley prisms, vectograms, and video-displayed contour and random dot stereograms) presented at 50.8 cm. Test-retest measures, which were taken on each test for each subject, indicated high positive correlations between test and retest measures for most vergence tests. Paired inter-test correlations among five different tests varied as a function of the pairing as well as type of measure taken (Bl, BO, break, recovery). It was concluded that different methods of measuring vergence provide different kinds of information and such tests may not be used interchangeably

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

An instrument has been designed and constructed that facilitates the measurement ofin vivotear film topology, thickness, and wetting, using the principles of thin film interferometry. The use of this tear film interferometer (TFI) allows objective evaluation of the breakup characteristics of the tear film on contact lens surfaces and provides a means for examining the dynamic changes in thickness, thickness distribution, and wetting properties during sequential interblink periods. The effects of contact lens material, wetting solutions, and cleaning regimens can be compared objectively. The instrument is easy to use, no additives to the natural tear fluid are required.

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

NASA, Johnson Space Center is developing an electronic image remapper which will warp an image from one coordinate system onto another with great flexibility and speed. The Programmable Remapper will transform images at conventional video frame rate. The Remapper was designed to be used in conjunction with an optical correlator to enhance object recognition through “real time” Fourier analysis. We are investigating an additional potential application for the Remapper as a low-vision aid. In diseases which result in obvious field defects such as age-related maculopathy (ARM) or retinitis pigmentosa (RP), the Remapper can be used to redistribute onto the still-functioning retina the image information that would otherwise be lost due to the associated field defect. Compared with eccentric viewing, this process makes use of the acuity of a larger area of the retina. We envision the future aid to consist of a portable spectacle-mounted display with miniaturized camera input and the Remapper. The patient will view the remapped world on this display. Patients may require training with feedback as to eye and scotoma position in order to use the Remapper most effectively. The Remapper might be reduced in cost, weight, and size to the point of being a feasible low-vision prosthesis as a result of development required by military, space, and industrial utilization. In order to demonstrate how such an aid may work, we have generated static images on an image processor which have undergone radial-only remapping; i.e., image points are slid along radii, with their azimuths unchanged. The remapping process and the application to low vision along with static images are presented in this paper.

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Alport's syndrome is a rare disorder characterized by neurosensory hearing impairment and progressive kidney dysfunction. The syndrome affects both males and females but males manifest more serious kidney problems and have a higher mortality rate. Ocular manifestations occur in approximately 15% of these patients with anterior lenticonus being the most common. It is believed that this is the first reported case of a patient with Alport's syndrome and anterior lenticonus who underwent lensectomy and lens implant to improve visual function.

ISSN:1040-5488    

出版商:OVID    

年代:1989

数据来源: OVID