1
|
Rosenfield M. Comparison of accommodative adaptation using laser and infra-red optometers. Ophthalmic Physiol Opt 1989; 9:431-6. [PMID: 2631012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Previous investigations have reported differences in the rate of decay of accommodative adaptation depending on the form of optometer used to assess dark-focus (DF). This study has used both laser and infra-red optometers to measure pre- and post-task values of DF in 10 subjects. DF was assessed before and immediately after an 8 min near-vision task performed at the subjective near-point of accommodation. Examination of the data from the two optometers revealed significant differences in both magnitude and distribution of pre-task DF. Additionally variations in the post- to pre-task shift in DF were observed between the two methods of assessment. Using the laser optometer, six subjects exhibited positive adaptation following the near-task which was not apparent with the infra-red optometer. The data suggest that both instruments may not be sampling open-loop accommodation; the laser optometer is particularly vulnerable to extraneous influences.
Collapse
Affiliation(s)
- M Rosenfield
- Schnurmacher Institute for Vision Research, SUNY/State College of Optometry, NY 10010
| |
Collapse
|
2
|
Abstract
We modified a Polaroid SE camera for use as a photoretinoscope. A total of 187 infants between 2 and 18 months of age were photographed using this device. About half of these infants (97) participated in a double blind study in which the results of photorefraction were compared with those of standard cycloplegic retinoscopy. Eighty-three infants were photographed without cycloplegia. Thirty-four infants were photographed while cyclopleged. Photographs were evaluated for significant refractive errors and other ocular abnormalities. The effectiveness of the camera system to screen for significant refractive errors without the use of cycloplegia was assessed. Infants were identified to be at risk by photorefraction if, in any photograph, a hyperopic bright crescent calculated to be greater than or equal to +1.25 D was present in the pupil. Clinically significant refractive errors were defined by the results of cycloplegic retinoscopy: "at-risk" infants had either 3.5 D or more hyperopia in either eye, or astigmatism in either eye greater than or equal to 2.5 D, or anisometropia greater than or equal to 1.5 D. With these clinical criteria and the above photographic screening criterion, the camera's sensitivity and specificity were 83% and 69%, respectively. The present system compares favorably with earlier, more sophisticated units in alerting practitioners to potentially significant refractive errors in infants. Additionally, as a screening tool, this device offers the benefits of being inexpensive and easy to use, and of providing immediate feedback.
Collapse
Affiliation(s)
- C Hsu-Winges
- Kaiser Permanente Medical Center, San Francisco, CA 94080
| | | | | | | | | |
Collapse
|
3
|
Hannush SB, Crawford SL, Waring GO, Gemmill MC, Lynn MJ, Nizam A. Accuracy and precision of keratometry, photokeratoscopy, and corneal modeling on calibrated steel balls. Arch Ophthalmol 1989; 107:1235-9. [PMID: 2757555 DOI: 10.1001/archopht.1989.01070020301043] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Surgical manipulation of corneal shape requires an accurate and precise method of measuring anterior corneal curvature from apex to limbus. We evaluated the accuracy and precision of the Bausch & Lomb Keratometer, Kera Corneascope, and Computed Anatomy Corneal Modeling System by measuring comparable locations on four calibrated steel test balls. The Keratometer and Corneal Modeling System were more accurate and precise than the Corneascope. No statistically significant difference was found between the Keratometer and Corneal Modeling System with respect to accuracy or precision. In addition, the accuracy and precision of all 31 rings of the Corneal Modeling System were studied. Rings 2 through 26 were read accurately and precisely within +/- 0.25 diopter on three of the four balls. Values on the steepest ball were within +/- 0.37 diopter.
Collapse
Affiliation(s)
- S B Hannush
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA
| | | | | | | | | | | |
Collapse
|
4
|
Abstract
The study examines to what degree the output of the Canon Auto-ref R1 infra-red (IR) optometer is affected by variations in pupil size for both static measurement of refractive error and for continuous recording of accommodation when switched to its modified mode of operation. In the normal static mode of operation the measurement of refractive state simply depends on the position of the peak photodetector output for each of three meridians: it does not depend on signal amplitude and hence pupil size. However, in continuous mode the actual output of a single photodiode is measured and the measurement is susceptible to changes in pupil size that occur within the area of the exit pupil utilized by the instrument. Using static and dynamic recording on model and human eyes the study shows that a 10% reduction in output signal relative to the maximum output level (for a constant stimulus) occurs for pupil sizes of 3.9 mm. The relatively small exit pupil has important advantages with regard to the use of mydriatic drugs and task-induced changes in pupil diameter.
Collapse
Affiliation(s)
- B Winn
- Department of Vision Sciences, Aston University, Birmingham, UK
| | | | | | | |
Collapse
|
5
|
Abstract
A study is made of the accuracy and repeatability of the Humphrey autorefractor (HAR) objective refraction for different refractive groups as measured against subjective refraction. The value of the autofogging mechanism in objective refraction for different refractive groupings is assessed.
Collapse
Affiliation(s)
- P T Yeow
- Department of Ophthalmology, National University of Malaysia, Kuala Lumpur
| | | |
Collapse
|
6
|
Abstract
The manifest refractions of 37 high myopic and 16 high hypermetropic eyes in a total of 28 patients, aged 5 to 42 years, were determined on the Nikon NR-1000F Auto Refractometer. The data obtained were compared with the final clinical prescriptions for these eyes and analysed for degree of agreement for the spherical equivalents, sphere components, and cylinder powers and axes. The Auto Refractometer recordings for all the different refractive components were observed to skew towards more minus in the high myopic eyes but more plus in the high hypermetropes. The possible significance of these skewing patterns is discussed with reference to our earlier studies.
Collapse
Affiliation(s)
- B K Nayak
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi
| | | | | |
Collapse
|
7
|
|
8
|
Kordić R, Raguz I. [Comparative study of refraction using the Canon Autoref R-1 refractometer--the effect of age factors]. Lijec Vjesn 1985; 107:82-4. [PMID: 3982199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
9
|
Maino JH, Cibis GW, Cress P, Spellman CR, Shores RE. Noncycloplegic vs cycloplegic retinoscopy in pre-school children. Ann Ophthalmol 1984; 16:880-2. [PMID: 6508104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Refractive errors in 311 children between the ages of 18 and 48 months were assessed utilizing standard cycloplegic retinoscopy and a noncycloplegic near retinoscopy technique as promulgated by Mohindra. Results from this study indicate little agreement between the two objective refraction methods.
Collapse
|
10
|
Abstract
Clinical trials in 275 eyes indicated that an automated keratometer (Canon) was equal to or better than a conventional keratometer (Bausch & Lomb). Comparisons of the values obtained with the two instruments showed agreement on the radius of curvature. The automated keratometer detected small differences in directional axis in slightly astigmatic eyes. Because this instrument is quick and simple to operate, it should be widely used, particularly for examining children.
Collapse
|
11
|
Risse JF, Villard C, Carre H. [Clinical evaluation of the Nikon NR-1000F autorefractometer (preliminary study)]. Bull Soc Ophtalmol Fr 1983; 83:719-23. [PMID: 6671284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
12
|
Abstract
Data were collected on refraction in three isolated communities in western Newfoundland. Altogether 971 persons, about 80% of the population, were refracted. Subjects were not visually selected. Females showed a greater range of refractions than males at most ages, generally had more negative refractions than males, in particular at younger ages, and showed negative age group means earlier than males. Persons under 30 had more negative mean refractions, and more formal education than persons over 30. The age distribution of refraction in this population is compared with that reported by several others, and arguments presented that exposure to formal education is associated with increased myopia.
Collapse
|
13
|
Abstract
Experimental evidence is presented that the focus of the eye tends to return passively to an individually characteristic intermediate resting position or dark-focus whenever (1) the stimulus to accommodation is degraded or (2) when the quality of the image is independent of focus. Based on measurements of the dark-focus with a laser optometer, it is possible to predict the magnitude of night, empty field, and instrument myopia on an individual basis. The role of the intermediate dark-focus as a factor in accommodation also provides an explanation for the paradoxical variation of visual acuity with observation distance. Applications to night myopia and night driving are described, and implications for clinical practice are discussed.
Collapse
|
14
|
Abstract
We obtained steel test balls for keratometer calibration at nominal cost by using a selected set of steel ball bearings, readily available for nonoptical purposes. The set of keratometer tests balls each have an accuracy of greater than one part in 1,000.
Collapse
|
15
|
Abstract
Using the method of refractometry to measure protein concentration in tears, a simple model was developed to evaluate the allergic response in humans. Timothy grass pollen was instilled into the cul de sac of a human subject, and the protein content of the subject's tears was sampled every 15 minutes for three hours. Once the time course of this experiment was predictable, various eye medications were instilled into the subject's eye 30 minutes after allergic challenge. It was noted that 1.0% and 0.1% prednisolone, each combined with 0.12% phenylephrine hydrochloride, as well as 1% epinephryl borate eye drops, produced an almost immediate return to normal of tear protein levels, whereas 1.0% medrysone, 0.1% fluorometholone, 1.0% prednisolone, and 0.12% prednisolone had less pronounced effects on reduction of elevated tear protein concentration.
Collapse
|
16
|
Guyton DL. Editorial: Automated refraction. Invest Ophthalmol 1974; 13:814-8. [PMID: 4431483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
17
|
Otto J, Safra D. [Objective determination of accommodative changes of refraction (author's transl)]. Albrecht Von Graefes Arch Klin Exp Ophthalmol 1974; 191:67-76. [PMID: 4547060 DOI: 10.1007/bf00414684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
18
|
Regan D. Rapid objective refraction using evoked brain potentials. Invest Ophthalmol 1973; 12:669-79. [PMID: 4742063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
19
|
|
20
|
Burian HM. New clip-on lens holder. Am J Ophthalmol 1972; 74:347-8. [PMID: 5054250 DOI: 10.1016/0002-9394(72)90561-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
21
|
Chapman WE. Medical applications of space science research, 1. Postgrad Med 1971; 50:37-8. [PMID: 5566202 DOI: 10.1080/00325481.1971.11696710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
22
|
|
23
|
|
24
|
|
25
|
|
26
|
Bannon RE, Neumueller J, Boeder P, Burian HM. Aniseikonia and space perception--after 50 years. Am J Optom Arch Am Acad Optom 1970; 47:423-41. [PMID: 4912937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
27
|
|
28
|
|
29
|
Asher H. New means for assessment of astigmatism. J Physiol 1968; 194:72-3P. [PMID: 5639380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
|
30
|
Oshima S, Shinoda S. [An apparatus measuring changes in the refractive power of the eye]. Nippon Ganka Gakkai Zasshi 1967; 71:112-5. [PMID: 6070862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
31
|
Staflová J. [Eye polytest, an instrument for mass examination of eye functions]. Cesk Oftalmol 1965; 21:422-4. [PMID: 5294408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
32
|
Wekstein C. [Trial of a new objective optometric apparatus]. Bull Soc Ophtalmol Fr 1965; 65:284-90. [PMID: 5830985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
33
|
Hayashi H. [Binocular refractometry with an apparatus of "Polatest Berlin"]. Nihon Ganka Kiyo 1965; 16:100-18. [PMID: 5894291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
34
|
BOTVIN M. Illumination for lensometer. Trans Am Acad Ophthalmol Otolaryngol 1956; 60:606. [PMID: 13360829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
|
35
|
SAVELL AL. Acuity, fixation and test projection charts and their use in the refracting room. Am J Optom Arch Am Acad Optom 1956; 33:325-31. [PMID: 13372734 DOI: 10.1097/00006324-195606000-00007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
36
|
MORRISON JD. An aid to refracting the eyes of the deaf patient. Trans Am Acad Ophthalmol Otolaryngol 1956; 60:490. [PMID: 13360811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
|