Abstract:
PURPOSE:In the studies of spatial integration an increase in the spatial extent of the stimulus usually results in a decrease in the spatial frequency bandwidth of the stimulus. The authors investigated separately the effects of these two factors on contrast detectability. METHODS:Efficiencies were measured for a circular grating at 4 c/deg and for bandpass-filtered point stimuli having a constant center frequency at 4 c/deg and bandwidths of 0.25, 0.5, 1, and 2 octaves. The phase range of these two-dimensional stimuli was increased from zero to 90, 180, 270, and 360 degrees by replacing the original zero phase at each spatial frequency component by a random number with zero mean. This procedure left the spatial frequency bandwidth unaffected. RESULTS:The increase in phase range and decrease in spatial frequency bandwidth caused a progressively larger proportion of the contrast energy of the point stimuli to spread into their surroundings. As a result, detection efficiency decreased with increasing bandwidth and phase range for all point stimuli. However, a change in the stimulus bandwidth affected efficiency only when it altered stimulus area. The area of the circular grating and its detection efficiency remained almost constant irrespective of the phase range. When efficiency was plotted in semi-logarithmic coordinates as a function of stimulus area expressed in terms of the spatial spread of contrast energy, the line of least squares explained 85% of the total variance. CONCLUSION:The primary determinant of detection efficiency for stimuli with constant center spatial frequency is not stimulus bandwidth but stimulus area expressed in terms of the spatial spread of contrast energy.
journal_name
Invest Ophthalmol Vis Scijournal_title
Investigative ophthalmology & visual scienceauthors
Kukkonen H,Näsänen R,Rovamo Jsubject
Has Abstractpub_date
1994-06-01 00:00:00pages
3111-8issue
7eissn
0146-0404issn
1552-5783journal_volume
35pub_type
杂志文章abstract:PURPOSE:To investigate the effects of adhesion promoting surgical adjuncts in Descemets stripping automated endothelial keratoplasty (DSAEK). The effects of air-fill pressure, duration, use of venting incisions and stromal roughening on fluid dispersion, and donor adhesion strength were examined in theoretical, optical...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.12-9593
更新日期:2012-06-20 00:00:00
abstract:PURPOSE:To investigate the topographic relationship between ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) defects in open-angle glaucoma patients with localized RNFL defects, using spectral-domain optical coherence tomography (SD-OCT). METHODS:We analyzed 140 eyes of 1...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.14-13925
更新日期:2014-05-06 00:00:00
abstract::The ability of human and rabbit ocular tissues to degrade prostaglandins (PGs) was compared by following the metabolic fate of PGF2 alpha. No metabolism was observed in vitro after 5.0 hr incubation with human cornea, iris/ciliary body, or sclera, as indicated by the absence of a decrease in [3H]-PGF2 alpha concentrat...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:1990-07-01 00:00:00
abstract:PURPOSE:The fibrotic lens disorder posterior capsule opacification (PCO) develops in millions of patients following cataract surgery. PCO characteristics are extensive extracellular matrix (ECM) production and contraction of the posterior lens capsule, resulting in light-scattering ECM modification (wrinkling). The pro...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.12-9457
更新日期:2012-06-26 00:00:00
abstract:PURPOSE:Human blood contains low levels of protoporphyrin IX (PP IX), a photoactive compound that produces reactive oxygen species when exposed to light. It has been proposed that photoactivation of PP IX and subsequent generation of potentially tissue-damaging reactive oxygen may be a mechanism of retinal injury in re...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:1993-09-01 00:00:00
abstract::Evidence for a population of acetylcholine (ACh) receptors in the human retina is presented. The authors have used the irreversible ligand 3H-propylbenzilylcholine mustard (3H-PrBCM) to label muscarinic receptors. 3H- or 125I-alpha-bungarotoxin (alpha-BTx) was used to label putative nicotinic receptors. Muscarinic rec...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:1985-11-01 00:00:00
abstract:PURPOSE:Previous studies have demonstrated that in 129alpha3Cx46-/- mice, age-related nuclear cataract is formed. In the present study, a more in vivo-relevant model was generated to test the hypothesis that the calpain 3 gene is involved in age-related nuclear cataractogenesis in alpha3Cx46 knockout mice. METHODS:To ...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.06-0926
更新日期:2007-06-01 00:00:00
abstract:PURPOSE:To examine the prognostic relevance of expression of the chemokine receptors CCR7 and CXCR4 and its ligand CXCL12 in uveal melanoma in nonmetastatic and metastatic patients with correlation to liver metastasis and overall survival. METHODS:Primary uveal melanoma specimens from 19 patients with correlating live...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.13-12407
更新日期:2013-11-08 00:00:00
abstract:PURPOSE:We investigated the progressive degeneration of retinal and superior collicular functions in a mouse model of sustained ocular hypertension. METHODS:Focal laser illumination and injection of polystyrene microbeads were used to induce chronic ocular hypertension. Retinal ganglion cell (RGC) loss was characteriz...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.14-15691
更新日期:2015-02-26 00:00:00
abstract:PURPOSE:The purpose of this study was to investigate tumor control efficacy of paclitaxel in the treatment of retinal tumors harbored by the LH beta-Tag murine transgenic model of retinoblastoma. METHODS:LH beta-Tag-positive mice (n = 5) 10 weeks of age received two 20-microL subconjunctival injections delivered with ...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.06-0796
更新日期:2007-08-01 00:00:00
abstract:PURPOSE:Sensory imbalances in humans with amblyopia have been well documented using luminance-modulated (first-order) stimuli. However, little is known regarding whether there is a deficient binocular combination in amblyopes for stimuli defined by modulations in contrast (second-order stimuli). To address this, we ask...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.15-18253
更新日期:2016-04-01 00:00:00
abstract:PURPOSE:There are two human 15-lipoxygenases (LOX), 15-LOX-1 and -2, which convert arachidonic acid to 15S-hydroxyeicosatetraenoic acid (15S-HETE). The presence of both 15-LOXs in the human cornea prompted this study to delineate their roles in the human corneal epithelium. METHODS:Human corneal epithelia from donor c...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.04-1166
更新日期:2005-03-01 00:00:00
abstract:PURPOSE:To evaluate interictal visual dysfunction in persons with migraine in terms of spatiotemporal selectivity and location within the visual pathways. METHODS:The vision of a group of 15 persons who had experienced migraine with aura was compared with that of 15 normal age-matched control subjects. A range of thre...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:2001-03-01 00:00:00
abstract:PURPOSE:Age and advanced disease in the fellow eye are the two most important risk factors for age-related macular degeneration (AMD). In this study, the authors investigated the relationship between these variables and the optical density of macular pigment (MP) in a group of subjects from a northern European populati...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:2001-02-01 00:00:00
abstract::The visual effects of carbon disulfide exposure were studied in macaque monkeys with measurements of visual thresholds, fluorescein angiography and fundus photography. Five monkeys were exposed by inhalation for 6 hr a day, 5 days a week to 256 ppm carbon disulfide (CS2). The motor dysfunction observed in these monkey...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:1988-04-01 00:00:00
abstract:PURPOSE:Interphotoreceptor retinoid-binding protein (IRBP) binds and transports retinoids and fatty acids in the interphotoreceptor space (IPS). To understand the relationship between the protein structure and its functions requires bulk quantities of human IRBP. The authors sought to produce recombinant human IRBP (rh...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:1994-09-01 00:00:00
abstract:PURPOSE:To study the antineoplastic effect of vitamin D analogues in a xenograft model of human retinoblastoma. METHODS:Athymic mice were injected subcutaneously with Y79 cells and treated 5 days a week with either mineral oil (control group) or the vitamin D analogues calcitriol or 1,25-dihydroxy-16-ene-23-yne vitami...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.02-1198
更新日期:2003-10-01 00:00:00
abstract:PURPOSE:Peripheral and limbal corneal stromal cells (PLCSCs), which contain keratocytes, have a complex phenotype. Knowledge of keratocyte cell properties, function, and origin is limited. Evidence available thus far has suggested both mesenchymal stromal and hematopoietic characteristics. Multipotent mesenchymal strom...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
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更新日期:2012-08-03 00:00:00
abstract:PURPOSE:People with limited literacy are at increased risks of chronic systemic conditions. The authors therefore investigated the independent contribution of limited literacy on visual impairment and visual function in a large eye survey in Singapore. METHODS:The authors undertook a population-based, cross-sectional ...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.11-7725
更新日期:2011-09-29 00:00:00
abstract:PURPOSE:To identify proteins secreted by the retinal pigment epithelium (RPE) and to analyze their cellular distribution in normal and pathologic rat retinas at various stages of eye development. METHODS:A cDNA library was constructed with RNA isolated from porcine RPE sheets and screened by using the yeast signal seq...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.03-1048
更新日期:2004-05-01 00:00:00
abstract:PURPOSE:Orbital eye position and vestibular sensitivity have both been postulated to influence vestibulo-ocular reflex (VOR) axis direction. The interaction of these factors in unilateral vestibular deafferentation (UVD) was examined. METHODS:Initial VOR direction and magnitude were examined in six normal human subjec...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.07-0784
更新日期:2007-12-01 00:00:00
abstract:PURPOSE:To delineate morphometric and quantitative features of the capillary image derived from high-resolution fundus fluorescein angiography (FFA) and consequently determine the diagnostic value of FFA for studying the retinal capillary circulation. METHODS:Retinal capillary images obtained from healthy young subjec...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.10-5333
更新日期:2010-11-01 00:00:00
abstract::Visual acuity of infants and young children with ophthalmologic disorders was assessed by adapting a transformed up-down staircase to preferential looking (PL) procedures. Eighty-five percent of pediatric patients between 11 days and 5 years of age were tested successfully. Acuity of infants and young children with no...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:1982-10-01 00:00:00
abstract::The retinal blood vessels serve for nutrition of the retinal ganglion cells and their axons. This study was undertaken to evaluate the vessel diameter in normal and glaucoma eyes. The calibers of the superior temporal and inferior temporal retinal artery and vein were measured at the optic disc border and at a distanc...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:1989-07-01 00:00:00
abstract:PURPOSE:Retinal ganglion cells are known to express ionotropic P2X(7) receptors for ATP. Stimulation of these receptors in other cells can elevate Ca(2+) and sometimes lead to cell death. This study asked whether P2X(7) receptor stimulation alters the Ca(2+) levels and viability of retinal ganglion cells. METHODS:P2X(...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.05-0052
更新日期:2005-06-01 00:00:00
abstract:PURPOSE:To investigate whether myopia is present in a breed of domestic dog, the Labrador retriever, and how the ocular components are related to refractive error in this breed. METHODS:Cycloplegic refractive error was measured in 75 Labrador retrievers by retinoscopy. Corneal and crystalline lens radii of curvature w...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:
更新日期:1999-06-01 00:00:00
abstract:PURPOSE:To investigate the role of leukotriene B4 (LTB4) and its receptor BLT1 in the pathogenesis of mouse uveitis. METHODS:Experimental autoimmune uveitis (EAU) was induced in B10RIII mice by immunization of interphotoreceptor retinoid binding protein (IRBP; peptide sequence 161-180) or in C57BL/6 (B6) mice by trans...
journal_title:Investigative ophthalmology & visual science
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更新日期:2006-04-01 00:00:00
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journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
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更新日期:2011-01-05 00:00:00
abstract:PURPOSE:To evaluate the effects of 5-fluorouracil (5-FU) on ocular cells in vitro and the effects of degradable 5-FU-loaded poly(DL-lactide-co-glycolide; PDLGA) 50:50 implant in the rabbit eye in vivo. METHODS:Cytotoxicity was assessed with a tetrazolium salt WST-1 cell proliferation/viability test and a lactate dehyd...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.08-3016
更新日期:2009-05-01 00:00:00
abstract::PURPOSE. To investigate the characteristics of a spectral-domain optical coherence tomography (SD-OCT) image phenomenon known as the mirror artifact, calculate its prevalence, analyze potential risk factors, measure severity, and correlate it to spherical equivalent and central visual acuity (VA). METHODS. OCT macular...
journal_title:Investigative ophthalmology & visual science
pub_type: 杂志文章
doi:10.1167/iovs.09-4057
更新日期:2010-07-01 00:00:00