Abstract：
PURPOSE:Fractal dimension of retinal vasculature is a global summary measure of retinal vascular network pattern and geometry. This study was conducted to examine the effect of variations in image color, brightness, focus, contrast, and format on the measurement of retinal vascular fractal dimension. METHODS:A set of 30 retinal images from the Blue Mountains Eye Study was used for a series of experiments by varying brightness, focus (blur), contrast, and color (color versus monochrome). The original and the modified images were graded for fractal dimension (D(f)) using dedicated retinal imaging software (IRIS-Fractal). A further set of 20 grayscale images was used to compare image format (.jpg versus .tif) with regard to the resultant D(f) and processing time. RESULTS:The mean D(f) of original images in this sample was 1.454. Compared with the original set of images, variations in brightness, focus, contrast, and color affected the measurements to a small to moderate degree (Pearson correlation coefficient, r, ranged from 0.47 to 0.97). Very dark or blurry images resulted in a substantially lower estimate of D(f). Monochrome images were also consistently associated with lower D(f) compared with that obtained from color images. Using .jpg or .tif image formats did not affect the measurement or the time needed to process and measure D(f). CONCLUSIONS:Variations in image brightness, focus, and contrast can significantly affect the measurement of retinal vascular fractals. Standardization of image parameters and consistent use of either monochrome or color images would reduce measurement noise and enhance the comparability of the results.
journal_name
Invest Ophthalmol Vis Scijournal_title
Investigative ophthalmology & visual scienceauthors
Wainwright A,Liew G,Burlutsky G,Rochtchina E,Zhang YP,Hsu W,Lee JM,Wong TY,Mitchell P,Wang JJdoi
10.1167/iovs.09-4129subject
Has Abstractpub_date
2010-11-01 00:00:00pages
5525-9issue
11eissn
0146-0404issn
1552-5783pii
iovs.09-4129journal_volume
51pub_type
杂志文章abstract：:The vestibulo-ocular reflex of normal monkeys was tested by a modified Bárány spinning test (B-test) and by sinosoidal rotation. The two tests gave concordant estimates of the time constant and corner frequency. Deviation from concordance was caused largely by modification of the reflex during the testing procedures. ...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1979-10-01 00:00:00
abstract：PURPOSE:Macrophages are thought to be the first line of defense in many infectious diseases and are present in high numbers in corneas with Acanthamoeba keratitis. Conjunctival macrophage depletion was performed in an animal model of Acanthamoeba infection to determine the importance of macrophages in this disease. ME...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1996-06-01 00:00:00
abstract：PURPOSE:Glaucoma is an optic neuropathy caused by the chronic and progressive death of retinal ganglion cells (RGCs), resulting in irreversible blindness. Ocular hypertension is a major risk factor, but RGC death often continues after ocular hypertension is normalized, and can take place with normal tension. Continuous...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.10-6691
更新日期：2011-07-15 00:00:00
abstract：PURPOSE:To assess the reproducibility of the ocular response analyzer (ORA) in nonoperated eyes and the impact of corneal biomechanical properties on intraocular pressure (IOP) measurements in normal and glaucomatous eyes. METHODS:In the reliability study, two independent examiners obtained repeated ORA measurements i...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.07-0280
更新日期：2008-03-01 00:00:00
abstract：:Collagen deposition is largely responsible for scar information, an undesirable outcome of glaucoma filtering surgery. Because interferon-gamma (IFN-gamma) has been reported to inhibit collagen synthesis in a variety of cells, the authors examined its effect on collagen synthesis by Tenon's capsule fibroblasts culture...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1991-10-01 00:00:00
abstract：Purpose:Hyaluronan (HA) overproduction by orbital fibroblasts (OFs) is a major factor in the pathogenesis of Graves' orbitopathy (GO). 4-methylumbelliferone (4-MU) is an inhibitor of HA synthesis in different cell types in vitro and has beneficial effects in animal models of autoimmune diseases. Methods:HA production ...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.61.2.27
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abstract：PURPOSE:Hypoxia and growth factors are postulated to be involved in the development of retinal neovascularization through the regulation of extracellular proteinase production. It has been shown that matrix metalloproteinases (MMPs) are elevated in the retina during the neovascularization process. However, the factors ...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：2002-01-01 00:00:00
abstract：:Cataracts in cultured rabbit lenses were produced by elevation of internal calcium. Experimental procedures were successful in increasing levels of total and bound Ca++, often without significant changes in sodium, potassium, or water content. Although the excess in calcium was predominantly associated with water-solu...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1982-02-01 00:00:00
abstract：PURPOSE:To identify if whole-body hydration plays an important role in dry eye (DE). We hypothesized that individuals classified as DE have higher plasma osmolality (Posm), indicating suboptimal hydration, compared with those classified as non-DE. METHODS:Using a hospital-based observational cross-sectional design, as...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.12-10175
更新日期：2012-09-25 00:00:00
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journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.17-23336
更新日期：2018-04-01 00:00:00
abstract：PURPOSE:When intraocular pressure (IOP) was monitored in supine healthy young adults throughout a 24-hour period, a diurnal-to-nocturnal elevation of IOP was observed. This study was undertaken to investigate whether a similar elevation of IOP can be detected when experimental subjects are in the sitting position. MET...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.03-0349
更新日期：2003-10-01 00:00:00
abstract：:It is possible to record a pattern electroretinogram (PERG) of near normal amplitude in a situation when the eye containing the active electrode is occluded. Because PERG recording requires high amplification and sensitive signal retrieval techniques, the electrode in the occluded eye records a distant potential from ...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1983-06-01 00:00:00
abstract：:Nineteen hundred and seventy-six immature human cataracts extracted intracapsularly were classified according to the Cooperative Cataract Research Group (CCRG) method of cataract classification. Data on cataract location and extent, nuclear color, preoperative visual acuity, age, and sex were organized and stored in t...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1984-02-01 00:00:00
abstract：:This study used primary cultures of conjunctival and corneal epithelial cells from rabbit, monkey and humans to investigate the infection process and host interactions of chlamydia. The epithelial cells were isolated from bulbar and palpebral conjunctivae and the cornea following incubation with EDTA or dispase and mi...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1988-07-01 00:00:00
abstract：:Moiré fringes generated by two equal gratings in contact, looked at in Maxwellian view, are well suited for the assessment of retinal visual acuity. High-contrast fringes practically free from spatial harmonics (higher Fourier components) are obtained if, instead of the zero diffraction order, one first-order diffract...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1980-04-01 00:00:00
abstract：:The purpose of the current study was to investigate the relationship between systemic blood pressure (BP) and long posterior ciliary arterial (LPCA) blood flow (BF) in response to autonomic drugs, and to determine the types of receptors involved. LPCA BF was measured in anesthetized rabbits at the retrobulbar region u...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1990-05-01 00:00:00
abstract：:The acute effect of topical epinephrine HCl 2% on macular capillary blood flow was studied in 18 healthy human volunteers using the blue-field simulation technique. This technique provides a method for quantifying the velocity of leukocytes flowing in macular capillaries. Subjects adjusted the velocity of simulated le...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1992-01-01 00:00:00
abstract：PURPOSE:Retinal blood vessel diameter and arteriovenous ratio (AVR) are commonly used diagnostic parameters. Because vascular walls are typically not visible in funduscopy, clinical AVR estimation is based on the lumen rather than the entire vessel diameter. Here the authors used a transgenic mouse model to quantify AV...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.09-5139
更新日期：2010-10-01 00:00:00
abstract：PURPOSE:To determine the efficacy of the M1-selective muscarinic antagonist, pirenzepine, in preventing experimentally induced myopia in a mammalian model, the tree shrew. METHODS:Tree shrews were monocularly deprived (MD) using translucent goggles or negative lenses for a period of 12 days. In two of the MD groups, t...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1996-06-01 00:00:00
abstract：PURPOSE:Transgenic mice were developed that express tetracycline-controlled transactivator 1 (tTA1) specifically in photoreceptor cells. In these mice the transcription of the gene of interest can be easily inactivated in the retina in a short time frame. METHODS:A construct was prepared containing tTA1 under control ...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.02-0340
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journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1983-04-01 00:00:00
abstract：:Mucins, which play important roles on the ocular surface in wettability, lubrication, and barrier function, are classified into two categories: secreted mucins and membrane-associated mucins. The most important secreted mucin on the ocular surface is MUC5AC, which is secreted by the conjunctival goblet cells. In the h...
journal_title：Investigative ophthalmology & visual science
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更新日期：2018-11-01 00:00:00
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journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.61.8.45
更新日期：2020-07-01 00:00:00
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journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1981-06-01 00:00:00
abstract：PURPOSE:Müller glia play crucial roles in retinal homeostasis and function. Genetic modification of Müller cells by viral gene delivery would be valuable for studies of their normal physiology and roles in retinal disease states. However, stable and efficient transgene expression in Müller cells after delivery of gene ...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.05-1570
更新日期：2007-04-01 00:00:00
abstract：PURPOSE:Human leukocyte antigen (HLA) polymorphisms have been associated with the development of autoimmune diseases. In uveal melanoma, a high expression of HLA classes I and II, and infiltration with lymphocytes and macrophages are associated with a bad prognosis. Inflammation has an important role in this malignancy...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.11-8901
更新日期：2012-05-04 00:00:00
abstract：:In order to induce stereoscopic depth, retinal images in the right and left eyes must differ. Our experiments demonstrate that these uniocular differences for simple three-line configurations at stereo-threshold cannot usually be distinguished one from the other. We confirm that depth values are associated with indivi...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1979-06-01 00:00:00
abstract：Purpose:Ocular neovascularization (NV) is a pathologic process characterized by the proliferation and infiltration of various types of cells such as RPE, glial, and endothelial cells, which interact with proangiogenic factors and inflammatory cytokines. Endocan is known to be enriched in retinal endothelial tip cells u...
journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.17-22945
更新日期：2018-02-01 00:00:00
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journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：
更新日期：1989-07-01 00:00:00
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journal_title：Investigative ophthalmology & visual science
pub_type： 杂志文章
doi：10.1167/iovs.13-12376
更新日期：2013-09-09 00:00:00
