{"title":"\"Saturation\" of the Dark-Adapted b-Wave","authors":"N. Peachey, K. Alexander, G. Fishman","doi":"10.1364/navs.1988.wa2","DOIUrl":"https://doi.org/10.1364/navs.1988.wa2","url":null,"abstract":"Luminance-response functions of the dark-adapted ERG b-wave have been previously described by the Naka-Rushton equation R/R\u0000 max\u0000 = L\u0000 n\u0000 /(L\u0000 n\u0000 + K\u0000 n\u0000 ), in which R is the response to a stimulus of luminance L, R\u0000 max\u0000 is the maximum response amplitude, K is the luminance required to achieve a response one-half the amplitude of R\u0000 max\u0000 , and n is a dimensionless slope constant (1,2). However, when recording from normal observers and from patients with retinal disorders, we have observed that the Naka-Rushton equation does not represent the entire b-wave luminance-response function. Instead, our functions are composed of two distinct limbs. One limb appears to saturate at the luminance levels reported previously (1). However, as flash luminance increases above this level, a second limb appears. In the present report, we document the non-monotonic nature of the b-wave luminance-response function and examine possible explanations for the high luminance limb by recording ERGs from selected patients.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124466093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Validation of a Predictive Model of Clinical Measures of Visual Function","authors":"A. Lang, V. Lakshminarayanan, V. Portney","doi":"10.1364/navs.1993.nsua.4","DOIUrl":"https://doi.org/10.1364/navs.1993.nsua.4","url":null,"abstract":"At the 1992 NAVS/OVO meeting1, we introduced a phenomenological model (called Expected Visual Outcome) which is intended to predict clinical function (e.g., contrast sensitivity, through-focus-acuity, etc.) base on in-vitro modulation transfer function (MTF) measurements of intraocular lens (IOL) performance2. In this paper, we discuss the validation of this model using individual patient data derived from the AMO ArrayTM multifocal IOL clinical study3.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124829147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Petrig, C. Riva, Candace K. Furubayashi, Paul S. Cunningham.
{"title":"Retinal Blood Flow Measurements Using the Blue Field Entoptic Phenomenon: Does Perceived Leukocyte Velocity Depend on Contrast and Illuminance?","authors":"B. Petrig, C. Riva, Candace K. Furubayashi, Paul S. Cunningham.","doi":"10.1364/navs.1988.thb4","DOIUrl":"https://doi.org/10.1364/navs.1988.thb4","url":null,"abstract":"Noninvasive quantification of blood flow velocity in retinal macular capillaries is possible now by using the blue field simulation technique (BFST).1 The technique is based on the blue field entoptic phenomenon, which allows the observation of one's own leukocytes (white blood cells, WBCs) moving in retinal capillaries. To measure the velocity of these WBCs, a precisely controlled computer generated replica of the phenomenon is presented on a color graphics monitor. The subject is asked to adjust the number and velocity of the simulated WBCs to match those of the entoptically perceived WBCs.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124978803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Arteriolar Tortuosity in a Hypertensive and a Normotensive Group","authors":"T. Williams, S. Cooper","doi":"10.1364/navs.1988.wc1","DOIUrl":"https://doi.org/10.1364/navs.1988.wc1","url":null,"abstract":"The arterioles of the retina are routinely assessed in ophthalmic examinations. While changes in their caliber and transparency may be evaluated during such examinations, their tortuosity is much less readily determined. Clinicians have been obliged to use subjective scales such as absent-minor-moderate-marked or the like in discussing arteriolar tortuosity.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125938268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Assessing Visual Function in Patients With Macular Edema","authors":"G. Rubin, J. Sunness","doi":"10.1364/navs.1988.tha1","DOIUrl":"https://doi.org/10.1364/navs.1988.tha1","url":null,"abstract":"Diabetic retinopathy is a major cause of blindness throughout the world and diabetic macular edema (DME) is the leading cause of visual impairment in patients with diabetes. DME is a thickening of the sensory retina resulting from leakage of fluid from capillaries or microaneurysms. The fluid has a tendency to collect in the outer plexiform layer of the retina and may be accompanied by the deposition of hard exudates. The Early Treatment Diabetic Retinopathy Study (ETDRS) demonstrated that laser photocoagulation is an effective treatment for DME.1 The ETDRS based its conclusion on the finding that 24% of untreated eyes lose at least three lines of visual acuity (a doubling of the visual angle) while only 12% of treated eyes suffer the same loss, in a three year follow-up period. Eyes with more severe DME showed a greater treatment effect than eyes with milder DME.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128986374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Katz Barrett, W. Roy, J. K. Mark, A. Patricia, E. S. Marilyn, Haegerstrom-Portnoy Gunilla
{"title":"Abnormalities of the Fellow Eye in Acute Unilateral Optic Neuritis","authors":"Katz Barrett, W. Roy, J. K. Mark, A. Patricia, E. S. Marilyn, Haegerstrom-Portnoy Gunilla","doi":"10.1364/navs.1993.ntub.1","DOIUrl":"https://doi.org/10.1364/navs.1993.ntub.1","url":null,"abstract":"The pathogenesis of optic neuritis typically involves demyelination, whether or not clinically apparent multiple sclerosis is present. In adults, the overwhelming majority of acute attacks are symptomatic in one eye only. Abnormal visual function in asymptomatic fellow eyes has been reported, though testing has not generally been performed until after resolution of the acute attack,1,2,3,4,5 or only done in patients with clinically evident multiple sclerosis.6,7 Visual function in the fellow eye at the onset of acute unilateral garden variety optic neuritis has not been systematically evaluated. We have previously described the unaffected eyes in 11 patients with acute unilateral optic neuritis.8 Their evaluation revealed deficits on several parameters, despite normal high contrast and low contrast visual acuities. Pelli-Robson contrast sensitivity, S-cone increment thresholds, M-cone increment thresholds and color vision (assessed with the Adams desaturated D-15) were often reduced. Performance on the SKILL card, a low-contrast, low luminance acuity measure, was also abnormal in most of these eyes (73%). We therefore sought to prospectively determine the prevalence of abnormalities in the fellow eyes of the 448 patients enrolled into the Optic Neuritis Treatment Trial (ONTT), a multi-center study which investigated the value of corticosteroids as treatment for optic neuritis. All patients underwent extensive visual function testing in both the affected and unaffected (fellow) eyes.9,10 Data collected on those fellow eyes form the basis for this report.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129280697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Measurement of Local Refractive Error","authors":"R. Webb, C. Penney, K. Thompson","doi":"10.1364/navs.1991.wc3","DOIUrl":"https://doi.org/10.1364/navs.1991.wc3","url":null,"abstract":"We have measured refractive error through a succession of small regions of the cornea. In these initial measurements approximately twenty regions of 1 mm diameter are selected for each measured eye. For experimental convenience, the regions are chosen along vertical horizontal and 45 degree oblique meridia through a central point near the comeal apex. Refractive error at each locus is determined by a variant of the Scheiner principle.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125125635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Howarth, I. Bailey, S. Berman, G. Heron, D. Greenhouse
{"title":"Non-linear Processes In The Pupillary System","authors":"P. Howarth, I. Bailey, S. Berman, G. Heron, D. Greenhouse","doi":"10.1364/navs.1990.thb2","DOIUrl":"https://doi.org/10.1364/navs.1990.thb2","url":null,"abstract":"The early stages of the visual and pupillary systems are thought to share common pathways. Observation of pupillary behaviour is therefore potentially a convenient, non-invasive, way to assess objectively those parts of the visual system which are shared. The pupil is readily visible, its size is easily recorded by (infra-red) photography and it is easily stimulated using everyday equipment.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123844683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Retinal Laser Doppler Velocimetry with a Near-Infrared Diode Laser","authors":"C. Riva, B. Petrig, J. Grunwald","doi":"10.1364/navs.1988.thb2","DOIUrl":"https://doi.org/10.1364/navs.1988.thb2","url":null,"abstract":"Laser Doppler velocimetry (LDV) provides noninvasive absolute measurements of the maximum (centerline) velocity, Vmax, of red blood cells (RBCs) moving in individual retinal vessels1.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"65 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120907664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Clinical Application of Temporal Modulation Sensitivity: Age Norms From Childhood to Maturity","authors":"C. Tyler, M.B. Clarke, Nina Hawker","doi":"10.1364/navs.1988.tuc1","DOIUrl":"https://doi.org/10.1364/navs.1988.tuc1","url":null,"abstract":"Sensitivity to sinusoidal temporal modulation (flicker sensitivity) of a uniform stimulus field is proving to be a useful technique for application to ophthalmological diagnosis. When measured by varying the amplitude of the light modulation at a series of fixed frequencies, flicker thresholds provide measures of contrast sensitivity for the stimulus, as well as of the temporal response characteristic of the visual system. More than just another index of visual loss, flicker sensitivity has been shown in a variety of diseases to provide earlier detection than previous tests, to measure a reversible component of the visual susceptibility to disease, to provide differential diagnosis of otherwise similar conditions, to characterize the nature of the sensory deficit, and to provide information as to which retinal mechanisms are affected by the disease.","PeriodicalId":148775,"journal":{"name":"Noninvasive Assessment of the Visual System","volume":"34 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116488584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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