MedWorm: Ophthalmology

The American Optometric Association And Digital Healthcare, Inc. Sign Memorandum Of Understanding

Eye Health / Optometry News From Medical News Today — Fri, 20 Nov 2009 11:00:00 +0100

The American Optometric Association (AOA) and Digital Healthcare, Inc. (DH) have joined together to assist optometrists in providing better care for patients with diabetes and other chronic diseases, and in promoting public health. Both parties recently signed a Memorandum of Understanding (MOU). (Source: Eye Health / Optometry News From Medical News Today)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Patients Win With Immediate Avastin Payment Reversal

Eye Health / Optometry News From Medical News Today — Fri, 20 Nov 2009 11:00:00 +0100

Following efforts by the American Academy of Ophthalmology with the help of the American Society of Retina Specialists, the Macula Society, the Retina Society and Congressional allies, the Center for Medicare and Medicaid Services (CMS) said that it will retract an Oct. 1 payment policy for small doses of Avastin. Avastin, a cancer drug, is used in smaller doses to treat eye diseases such as age-related macular degeneration (AMD). (Source: Eye Health / Optometry News From Medical News Today)

Monocular signals in human lateral geniculate nucleus reflect the Craik–Cornsweet–O'Brien effect

Journal of Vision Articles — Fri, 20 Nov 2009 10:10:00 +0100

The human visual system has a remarkable ability to accurately estimate the relative brightness of adjacent objects despite large variations in illumination. However, the lightness of two identical equiluminant gray regions can appear quite different when a light–dark luminance transition falls between them. This illusory brightness “filling-in” phenomenon, the Craik–Cornsweet–O'Brien (CCOB) illusion, exposes fundamental assumptions made by the visual system in estimating lightness, but its neural basis remains unclear. While the responses of high-level visual cortex can be correlated with perception of the CCOB, simple computational models suggest that the effect may originate from a much lower level, possibly subcortical. Here, we used high spatial resolution functional magneti...

Structural Changes In Brain May Help Offset Loss Of Vision And Strengthen Other Senses

Eye Health / Optometry News From Medical News Today — Thu, 19 Nov 2009 14:00:00 +0100

Visually impaired people appear to be fearless, navigating busy sidewalks and crosswalks, safely finding their way using nothing more than a cane as a guide. The reason they can do this, researchers suggest, is that in at least some circumstances, blindness can heighten other senses, helping individuals adapt. (Source: Eye Health / Optometry News From Medical News Today)

A summary-statistic representation in peripheral vision explains visual crowding

Journal of Vision Articles — Thu, 19 Nov 2009 00:00:00 +0100

Peripheral vision provides a less faithful representation of the visual input than foveal vision. Nonetheless, we can gain a lot of information about the world from our peripheral vision, for example in order to plan eye movements. The phenomenon of crowding shows that the reduction of information available in the periphery is not merely the result of reduced resolution. Crowding refers to visual phenomena in which identification of a target stimulus is significantly impaired by the presence of nearby stimuli, or flankers. What information is available in the periphery? We propose that the visual system locally represents peripheral stimuli by the joint statistics of responses of cells sensitive to different position, phase, orientation, and scale. This “textural” representation by sum...

The fate of task-irrelevant visual motion: Perceptual load versus feature-based attention

Journal of Vision Articles — Wed, 18 Nov 2009 22:57:00 +0100

We tested contrasting predictions derived from perceptual load theory and from recent feature-based selection accounts. Observers viewed moving, colored stimuli and performed low or high load tasks associated with one stimulus feature, either color or motion. The resultant motion aftereffect (MAE) was used to evaluate attentional allocation. We found that task-irrelevant visual features received less attention than co-localized task-relevant features of the same objects. Moreover, when color and motion features were co-localized yet perceived to belong to two distinct surfaces, feature-based selection was further increased at the expense of object-based co-selection. Load theory predicts that the MAE for task-irrelevant motion would be reduced with a higher load color task. However, this w...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Smoking Causes Blindness

Eye Health / Optometry News From Medical News Today — Wed, 18 Nov 2009 10:00:00 +0100

AMD Alliance International strongly urges all smokers to participate in the Great American Smokeout on November 19 to save their eyes and protect their vision from the debilitating effects of macular degeneration. Research has demonstrated that age-related macular degeneration (AMD), a progressive disease that causes the loss of central vision, is two to three times as frequent among tobacco smokers, and the risk is dose dependent(1, 2). (Source: Eye Health / Optometry News From Medical News Today)

Evaluation of antibacterial efficacy of photo-activated riboflavin using ultraviolet light (UVA)

Graefe's Archive for Clinical and Experimental Ophthalmology — Wed, 18 Nov 2009 09:23:36 +0100

Conclusion Riboflavin photo-activation using UVA (365 nm) can achieve an extensive eradication of bacteria, and the combination is more potent in reducing bacterial number than UV alone. Content Type Journal ArticleCategory Basic ScienceDOI 10.1007/s00417-009-1231-2Authors Karim Makdoumi, Örebro University Hospital Department of Ophthalmology Örebro SwedenAnders Bäckman, Örebro University Hospital Clinical Research Centre SE-701 85 Örebro SwedenJes Mortensen, Örebro University Hospital Department of Ophthalmology Örebro SwedenSven Crafoord, Örebro University Hospital Department of Ophthalmology Örebro Sweden Journal Graefe's Archive for Clinical and Experimental OphthalmologyOnline ISSN 1435-702XPrint ISSN 0721-832X (Source: Graefe's Archive for Cl...

ASFH Pseudopods Abound!

As Seen From Here — Wed, 18 Nov 2009 00:12:00 +0100

Guest: John KG Dart MA DM FRCS FRCOphthConsultant Ophthalmologist, Corneal and External Disease ServiceDeputy Director of Research at MoorfieldsHonorary Reader, University College LondonMoorfields Eye Hospital London, UK (Source: As Seen From Here)

Dietary combination of omega-3 and omega-6 polyunsaturated fatty for retinal prevention: a concern

Graefe's Archive for Clinical and Experimental Ophthalmology — Wed, 18 Nov 2009 00:08:18 +0100

Content Type Journal ArticleCategory Letter to the EditorDOI 10.1007/s00417-009-1229-9Authors Viroj Wiwanitkit, Wiwanitkit House Bangkhae, Bangkok Thailand 10160 Journal Graefe's Archive for Clinical and Experimental OphthalmologyOnline ISSN 1435-702XPrint ISSN 0721-832X (Source: Graefe's Archive for Clinical and Experimental Ophthalmology)

Amlodipine effects on vasomotion in rabbit external ophthalmic artery

Graefe's Archive for Clinical and Experimental Ophthalmology — Wed, 18 Nov 2009 00:08:17 +0100

Conclusions Our study has two main conclusions: (1) amlodipine, an L-type calcium channel blocker, caused intense vasodilation and decreased both frequency and amplitude of the spontaneous oscillations observed in the rabbit external ophthalmic artery and its collaterals, and (2) when we applied amlodipine in arteries previously contracted by the administration of ET-1, vascular resistance greatly decreased and spontaneous oscillations were abolished. Since ET-1 levels are increased in several ischemic ocular diseases, amlodipine might be beneficial in these patients, allowing a protective action against vasospasm. Content Type Journal ArticleCategory Basic ScienceDOI 10.1007/s00417-009-1235-yAuthors Esmeralda Delgado, Alameda da Universidade Técnica Departamento d...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Faces and text attract gaze independent of the task: Experimental data and computer model

Journal of Vision Articles — Wed, 18 Nov 2009 00:00:00 +0100

Previous studies of eye gaze have shown that when looking at images containing human faces, observers tend to rapidly focus on the facial regions. But is this true of other high-level image features as well? We here investigate the extent to which natural scenes containing faces, text elements, and cell phones—as a suitable control—attract attention by tracking the eye movements of subjects in two types of tasks—free viewing and search. We observed that subjects in free-viewing conditions look at faces and text 16.6 and 11.1 times more than similar regions normalized for size and position of the face and text. In terms of attracting gaze, text is almost as effective as faces. Furthermore, it is difficult to avoid looking at faces and text even when doing so imposes a cost. We also fo...

The role of vertical mirror symmetry in visual shape detection

Journal of Vision Articles — Wed, 18 Nov 2009 00:00:00 +0100

The goal of our study is a better understanding of the role of vertical mirror symmetry in perceptual grouping. With a simple psychophysical task and a set of controlled stimuli, we investigated whether vertical mirror symmetry acts as a cue in figure-ground segregation. We asked participants to indicate which of two sequentially presented Gabor arrays contained a visual shape. The shape was defined by a subset of Gabor elements positioned along the outline of an unfamiliar shape. By adding orientation noise to these Gabor elements, the shape percept became less salient. Across the different noise levels, symmetric shapes were easier to detect than asymmetric ones. This finding indicates that vertical mirror symmetry is indeed used as a cue in perceptual grouping. (Source: Journal of Visio...

Spatial distributions of on- and off-responses determined with the multifocal ERG

Documenta Ophthalmologica — Tue, 17 Nov 2009 23:49:45 +0100

Abstract We studied the contribution of retinal on- and off-mechanisms in the multifocal electroretinogram (mfERG) by measuring responses to sawtooth stimuli. Six healthy subjects participated in this study. Rapid-on and rapid-off sawtooth stimuli with a period of 427 ms were presented in a multifocal pattern composed of 19 hexagons. The stimuli were interleaved with a blank field of the mean luminance and chromaticity. On- and off-responses were added to extract response asymmetries. The amplitudes of on-, off-, and added-responses were determined for different eccentricities relative to a signal baseline that was defined as the average of the electrical level recorded in two different time windows in which no responses were present. Measurements were repeated with e...

Finding A Protective Mechanism For Retinal Cells Could Save Sight

Eye Health / Optometry News From Medical News Today — Tue, 17 Nov 2009 14:00:00 +0100

Determining what triggers the death of retinal cells, called photoreceptors, could hold the key to stopping blinding disorders caused by a wide range of eye diseases, Yale School of Medicine researchers report in the November journal Investigative Ophthalmology & Visual Science. Several blinding disorders are known to cause the breakdown of photoreceptors. (Source: Eye Health / Optometry News From Medical News Today)

Survey Shows That Americans Lack Significant Knowledge Of Age-Related Vision Problems

Eye Health / Optometry News From Medical News Today — Tue, 17 Nov 2009 11:00:00 +0100

It's a fact of life that eyes change with age, and baby boomers - Americans born between 1946 and 1964 - are at the stage when many are affected by vision problems. Despite the prevalence of Americans' affected by these changes, a new survey from the American Optometric Association (AOA) shows a concerning lack of public knowledge and misunderstanding regarding age-related eye diseases and conditions. (Source: Eye Health / Optometry News From Medical News Today)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Medical Groups Applaud CMS Adoption Of Long-Awaited Practice Expense Update

Eye Health / Optometry News From Medical News Today — Tue, 17 Nov 2009 10:00:00 +0100

A coalition of medical specialties today congratulated the Center for Medicare and Medicaid Services (CMS) for its careful and reasoned implementation of up-to-date practice expense rates into its physician payments. The new practice expense rates that were recently issued by CMS use accurate data from a rigorous survey supported by more than 70 medical and health care professional groups, and they begin a long-needed correction that should remain untouched by Congress. (Source: Eye Health / Optometry News From Medical News Today)

CKS topic review: Uveitis

NeLM - Ophthalmology — Tue, 17 Nov 2009 00:00:00 +0100

Source: CKS Area: Evidence > Guidelines This CKS topic covers the management of suspected uveitis in primary care. (Source: NeLM - Ophthalmology)

Origin of the fast negative ERG component from isolated aspartate-treated mouse retina

Journal of Vision Articles — Tue, 17 Nov 2009 00:00:00 +0100

The leading edge of the a-wave of the ERG is generally believed to accurately reflect the changes in the circulating current through the cGMP-gated channels in the outer segment plasma membrane of rods and cones. The aspartate-isolated mammalian electroretinogram (ERG) to a rod-saturating flash contains a fast “nose”-like wave temporally overlapping with the a-wave. We characterize the nature of this nose, investigate the membrane current mechanisms involved in the nose mechanism, and propose a model that can explain the generation of the nose component in the rod inner segment. On the basis of pharmacological treatments and perfusate ion composition alterations we rule out the possible role of most of the known rod membrane current mechanisms that might participate in the generation o...

Stereoscopic discrimination of the layout of ground surfaces

Journal of Vision Articles — Tue, 17 Nov 2009 00:00:00 +0100

Safe and effective locomotion depends critically on judgements of the surface properties of the ground to be traversed. Little is known about the role of binocular vision in surface perception at distances relevant to visually guided locomotion in humans. Programmable arrays of illuminated targets were used to present sparsely textured surfaces with real depth at distances of 4.5 and 9.0 m. Psychophysical measurements of discrimination thresholds demonstrated a clear superiority for stereoscopic over monocular judgments of relative and absolute surface slant. Judgements of surface roughness in particular demonstrated a substantial binocular advantage. Binocular vision is thus shown to directly contribute to judgements of the layout of terrain up to at least 4.5 m, and its smoothness to at ...

Infliximab and anterior optic neuropathy: case report and review of the literature

Graefe's Archive for Clinical and Experimental Ophthalmology — Mon, 16 Nov 2009 17:59:30 +0100

Conclusion It is important to consider the possibility of anterior optic neuropathy, in addition to retrobulbar optic neuritis, in patients who experience sudden-onset visual loss while being treated with infliximab. Content Type Journal ArticleCategory Case ReportDOI 10.1007/s00417-009-1227-yAuthors Jane W. Chan, University of Kentucky College of Medicine Department of Neurology and Ophthalmology KY Clinic L-445 Lexington KY 40536 USAAlberto Castellanos, Central Baptist Hospital Department of Internal Medicine Lexington KY 40503 USA Journal Graefe's Archive for Clinical and Experimental OphthalmologyOnline ISSN 1435-702XPrint ISSN 0721-832X (Source: Graefe's Archive for Clinical and Experimental Ophthalmology)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Low-fluence-rate photodynamic therapy to treat subfoveal choroidal neovascularization in pathological myopia. A study of efficacy and safety

Graefe's Archive for Clinical and Experimental Ophthalmology — Mon, 16 Nov 2009 17:59:29 +0100

Conclusions LFPDT is effective and safe for CNV secondary to PM treatment, stabilizing visual acuity and lesion size and determining only mild RPE changes. Further controlled studies are needed to demonstrate the long-term efficacy and safety of this treatment option. Content Type Journal ArticleCategory Retinal DisordersDOI 10.1007/s00417-009-1232-1Authors Gianluca Besozzi, University of Bari Department of Ophthalmology and ENT Piazza Giulio Cesare 11-70124 Bari ItalyLuigi Sborgia, University of Bari Department of Ophthalmology and ENT Piazza Giulio Cesare 11-70124 Bari ItalyClaudio Furino, University of Bari Department of Ophthalmology and ENT Piazza Giulio Cesare 11-70124 Bari ItalyNicola Cardascia, University of Bari Department of Ophthalmology and ENT Piazza Giul...

Pycnogenol® Improves Microcirculation, Retinal Edema and Visual Acuity in Early Diabetic Retinopathy

Journal of Ocular Pharmacology and Therapeutics — Mon, 16 Nov 2009 17:24:14 +0100

Journal of Ocular Pharmacology and Therapeutics , Vol. 0, No. 0. (Source: Journal of Ocular Pharmacology and Therapeutics)

Carl Zeiss Meditec Introduces New Applications For The ATLAS Corneal Topographer At AAO-Opto

Eye Health / Optometry News From Medical News Today — Sun, 15 Nov 2009 09:00:00 +0100

AAO-Opto Booth # 605 -- New software advances for the ATLAS® Corneal Topography System were released today by Carl Zeiss Meditec during the American Academy of Optometry meeting in Orlando, Florida. Review Software and MasterFit II™ Contact Lens Software for the ATLAS corneal topography system are designed to make clinical data and images more accessible for eye care providers, while facilitating improved eye care diagnosis and treatment solutions for patients. (Source: Eye Health / Optometry News From Medical News Today)

Many People With Hemianopia Have Difficulty Detecting Pedestrians While Driving, Study Advocates For Individual Testing

Eye Health / Optometry News From Medical News Today — Fri, 13 Nov 2009 11:00:00 +0100

Schepens Eye Research Institute scientists have found that--when tested in a driving simulator--patients with hemianopia (blindness in one half of the visual field in both eyes) have significantly more difficulty detecting pedestrians (on their blind side) than normally sighted people. (Source: Eye Health / Optometry News From Medical News Today)

Clinical Studies Show B&L's Lo-Torque Design Delivers Better Rotational Recovery

Eye Health / Optometry News From Medical News Today — Fri, 13 Nov 2009 08:00:00 +0100

Bausch & Lomb announced that the company's Lo-Torque® lens design demonstrates significantly better rotational recovery, which can lead to more consistent vision, compared with Acuvue's accelerated stabilization design. These findings from two clinical studies were presented at Academy 2009, the American Academy of Optometry annual meeting in Orlando, Fla. (Source: Eye Health / Optometry News From Medical News Today)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

A dietary combination of omega-3 and omega-6 polyunsaturated fatty acids is more efficient than single supplementations in the prevention of retinal damage induced by elevation of intraocular pressure in rats

Graefe's Archive for Clinical and Experimental Ophthalmology — Fri, 13 Nov 2009 07:50:59 +0100

Content Type Journal ArticleCategory Letter to the EditorDOI 10.1007/s00417-009-1228-xAuthors Coralie Schnebelen, INRA, UMR1129 FLAVIC, Eye and Nutrition Research Group F-21000 17 rue Sully BP 86510 21065 Dijon Cedex FranceBruno Pasquis, INRA, UMR1129 FLAVIC, Eye and Nutrition Research Group F-21000 17 rue Sully BP 86510 21065 Dijon Cedex FranceManuel Salinas-Navarro, University of Murcia Department of Ophthalmology F-30100 Murcia SpainCorinne Joffre, INRA, UMR1129 FLAVIC, Eye and Nutrition Research Group F-21000 17 rue Sully BP 86510 21065 Dijon Cedex FranceCatherine P. Creuzot-Garcher, INRA, UMR1129 FLAVIC, Eye and Nutrition Research Group F-21000 17 rue Sully BP 86510 21065 Dijon Cedex FranceManuel Vidal-Sanz, University of Murcia Department of Ophthalmology F-30100 Murcia SpainAlai...

Cystatin C in macular and neuronal degenerations: Implications for mechanism(s) of Age-related Macular Degeneration.

Vision Research — Fri, 13 Nov 2009 00:00:00 +0100

Authors: Paraoan L, Hiscott P, Gosden C, Grierson I Cystatin C is a strong inhibitor of cysteine proteinases expressed by diverse cells. Variant B cystatin C, which was associated with increased risk of developing age-related macular degeneration, differs from the wild type protein by a single amino acid (A25T) in the signal sequence responsible for its targeting to the secretory pathway. The same variant conveys susceptibility to Alzheimer disease. Our investigations of the trafficking and processing of variant B cystatin C in living RPE cells highlight impaired secretion of extracellular modulators and inappropriate protein retention in RPE cells as potential molecular mechanisms underpinning macular, and possibly neuronal, degeneration. PMID: 19917302 [PubMed - as supplied by pu...

Recalibration of multisensory simultaneity: Cross-modal transfer coincides with a change in perceptual latency

Journal of Vision Articles — Fri, 13 Nov 2009 00:00:00 +0100

After exposure to asynchronous sound and light stimuli, perceived audio-visual synchrony changes to compensate for the asynchrony. Here we investigate to what extent this audio-visual recalibration effect transfers to visual-tactile and audio-tactile simultaneity perception in order to infer the mechanisms responsible for temporal recalibration. Results indicate that audio-visual recalibration of simultaneity can transfer to audio-tactile and visual-tactile stimuli depending on the way in which the multisensory stimuli are presented. With presentation of co-located multisensory stimuli, we found a change in the perceptual latency of the visual stimuli. Presenting auditory stimuli through headphones, on the other hand, induced a change in the perceptual latency of the auditory stimuli. We a...

Identification of independent risk factors for the development of diabetic retinopathy requiring treatment

Acta Ophthalmologica — Fri, 13 Nov 2009 00:00:00 +0100

Conclusions: Only a subset of known risk factors for development and progression of diabetic retinopathy should be used to construct a decision model for optimizing screening intervals for diabetic retinopathy. (Source: Acta Ophthalmologica)

Progressive addition lens design and the short of stature

Clinical and Experimental Optometry — Fri, 13 Nov 2009 00:00:00 +0100

(Source: Clinical and Experimental Optometry)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Retinal function in patients treated with tamoxifen

Documenta Ophthalmologica — Thu, 12 Nov 2009 18:40:50 +0100

Abstract Tamoxifen, an effective treatment of breast cancer, has been shown to cause ocular toxic effects. The purpose of this study was to determine retinal toxicity by full-field and focal electroretinograms (ERGs) in patients treated with tamoxifen. Full-field and focal ERGs were obtained from three groups: Tamoxifen—14 females (47–72 years, mean 58.3 ± 9.1) with normal fundus, treated with tamoxifen from 2 to 37 months; No Treatment—10 females (39–65 years, mean 50.1 ± 8.7) with previous breast cancer diagnosis and before tamoxifen treatment; Control—13 normal female volunteers (41–81 years, mean 52.7 ± 12.1). Peak-to-peak amplitude and b-wave implicit time were measured and statistically analyzed. Mean peak...

Laser Ablation Not Harmful to Corneal Endothelium (CME/CE)

MedPage Today Ophthalmology — Thu, 12 Nov 2009 13:53:49 +0100

Laser surgery to correct refractive errors had no long-term detrimental effects on the corneal endothelium, a small study found. (Source: MedPage Today Ophthalmology)

What Is Dry Eye Syndrome? What Causes Dry Eye Syndrome?

Eye Health / Optometry News From Medical News Today — Thu, 12 Nov 2009 11:00:00 +0100

Dry eye syndrome, also known as keratoconjunctivitis sicca (KCS), keratitis sicca, sicca syndrome, xerophthalmia, or simply dry eyes, is an eye disease in which tear film evaporation is high or tear production is low. Dry eye syndrome is commonly found in humans and some animals. The patient's eyes dry out and become inflamed. (Source: Eye Health / Optometry News From Medical News Today)

What Is A Detached Retina? What Causes A Detached Retina?

Eye Health / Optometry News From Medical News Today — Thu, 12 Nov 2009 08:00:00 +0100

The retina is a thin layer of nerve cells lining the inside back wall of the eye. The retina is essential to see properly. It turns the light that enters the eye into an image by sending a message along the optic nerve to the brain. When this layer becomes separated from the inner wall of the eye, it is called retinal detachment. The retina peels away from its underlying layer of support tissue. If this is not treated, it usually leads to blindness in the affected eye. (Source: Eye Health / Optometry News From Medical News Today)

Binocular Coordination during Scanning of Simple Dot Stimuli.

Vision Research — Thu, 12 Nov 2009 00:00:00 +0100

We examined the influence of a variety of visual factors on binocular coordination during saccadic orienting. Some experimental conditions placed similar demands on the oculomotor system as those that occur during reading, but in the absence of linguistic processing. We examined whether saccade target extent, preceding saccade magnitude, preceding saccade direction, and parafoveal availability of saccade target influenced fixation disparity. Disparities similar in magnitude and frequency to those obtained in previous binocular reading experiments occurred. Saccade magnitude had a robust influence upon fixation disparities. The results are very similar to those obtained in investigations of binocular coordination during reading, and indicate that similar patterns occur during reading-like e...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Categorical color constancy for simulated surfaces

Journal of Vision Articles — Thu, 12 Nov 2009 00:00:00 +0100

Color constancy is the ability to perceive constant surface colors under varying lighting conditions. Color constancy has traditionally been investigated with asymmetric matching, where stimuli are matched over two different contexts, or with achromatic settings, where a stimulus is made to appear gray. These methods deliver accurate information on the transformations of single points of color space under illuminant changes, but can be cumbersome and unintuitive for observers. Color naming is a fast and intuitive alternative to matching, allowing data collection from a large portion of color space. We asked observers to name the colors of 469 Munsell surfaces with known reflectance spectra simulated under five different illuminants. Observers were generally as consistent in naming the colo...

Latency characteristics of the short-wavelength-sensitive cones and their associated pathways

Journal of Vision Articles — Thu, 12 Nov 2009 00:00:00 +0100

There are many distinct types of retinal ganglion and LGN cells that have opponent cone inputs and which may carry chromatic information. Of interest are the asymmetries in those LGN cells that carry S-cone signals: in S-ON cells, S+ signals are opposed by (L + M) whereas, in many S-OFF cells, L+ signals are opposed by (S + M), giving −S + L − M (C. Tailby, S. G. Solomon, & P. Lennie, 2008). However, the S-opponent pathway is traditionally modeled as ±[S − (L + M)]. A phase lag of the S-cone signal has been inferred from psychophysical thresholds for discriminating combinations of simultaneous sinusoidal modulations along ±[L − M] and ±[S − (L + M)] directions (C. F. Stromeyer, R. T. Eskew, R. E. Kronauer, & L. Spillmann, 1991). We extend this experiment, measuring discriminat...

Correction of astigmatism after penetrating keratoplasty using the Acri.Comfort toric intraocular lens

Clinical and Experimental Optometry — Thu, 12 Nov 2009 00:00:00 +0100

(Source: Clinical and Experimental Optometry)

Complex Picture Emerges for Fat's Impact on the Eye (CME/CE)

MedPage Today Ophthalmology — Wed, 11 Nov 2009 19:25:41 +0100

A fat-filled diet may put younger women at risk for future age-related macular degeneration, although the effect varies by type of fat, researchers found. (Source: MedPage Today Ophthalmology)

What Is Double Vision? What Is Diplopia? What Causes Double Vision?

Eye Health / Optometry News From Medical News Today — Wed, 11 Nov 2009 14:00:00 +0100

Double vision, also known as Diplopia, is the simultaneous perception of two images of a single object - the patient sees two images of a single thing either all the time, or some of the time. The displacement may be horizontally, vertically or diagonally. Diagonal double displacement (double vision) means both the horizontal lines and vertical lines are being perceived as doubled - also known as oblique separation. (Source: Eye Health / Optometry News From Medical News Today)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Health Tip: Signs That You Have Cataracts

MedicineNet Eyesight General — Wed, 11 Nov 2009 07:00:00 +0100

Title: Health Tip: Signs That You Have CataractsCategory: Health NewsCreated: 11/11/2009 8:10:00 AMLast Editorial Review: 11/11/2009 (Source: MedicineNet Eyesight General)

Laser Eye Surgery Safe Long-Term: Study

MedicineNet Eyesight General — Wed, 11 Nov 2009 07:00:00 +0100

Title: Laser Eye Surgery Safe Long-Term: StudyCategory: Health NewsCreated: 11/10/2009 2:10:00 PMLast Editorial Review: 11/11/2009 (Source: MedicineNet Eyesight General)

Orientation tuning of curvature adaptation reveals both curvature-polarity-selective and non-selective mechanisms

Journal of Vision Articles — Wed, 11 Nov 2009 05:10:00 +0100

We have used a curvature after-effect, or CAE, to explore whether curvature detectors are tuned for the overall orientation of a curve. CAEs were measured for half-cycle cosine-shaped contours as a function of adaptor contour orientation for a fixed test contour orientation. CAEs (i) were greatest when the adaptor and test contours had the same orientation, (ii) decreased rapidly as the orientation of the adapting contours rotated away from the test, the data being well fit by a Gaussian function with a standard deviation of 16°, (iii) increased again to a secondary peak when the adapting contours were rotated 180° relative to the test. Control experiments showed that the shape of the curvature-orientation tuning function could not be explained by local orientation adaptation, and that i...

Emerging Treatment Paradigms of Ocular Surface Disease: Proceedings of the Ocular Surface Workshop.

The British Journal of Ophthalmology — Wed, 11 Nov 2009 00:00:00 +0100

The objective of the Ocular Surface Workshop in Rome, Italy, on 6 February 2009, was to enhance the understanding of ocular surface disease (OSD) through exploration of the nature of its complexities and current treatment paradigms across Europe. It was hoped that the peer-to-peer discussions and updates regarding common knowledge, clinical practices, and shared experiences at this workshop would subsequently shape future treatment approaches to OSD in Europe. PMID: 19910284 [PubMed - as supplied by publisher] (Source: The British Journal of Ophthalmology)

Elevated serum IL-23 correlates with intraocular inflammation after cataract surgery in patients with Vogt-Koyanagi-Harada disease.

The British Journal of Ophthalmology — Wed, 11 Nov 2009 00:00:00 +0100

CONCLUSIONS: Our data indicate that serum IL-23 levels are significantly elevated in VKH vs. control patients and strongly associated with postoperative intraocular inflammation. PMID: 19910285 [PubMed - as supplied by publisher] (Source: The British Journal of Ophthalmology)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

[Postoperative complications and management of filtration surgery.]

Der Ophthalmologe — Wed, 11 Nov 2009 00:00:00 +0100

Authors: Jonescu-Cuypers CP, Seitz B Of the filtering procedures employed, trabeculectomy is the one most frequently used for surgical therapy in primary open angle glaucoma patients. Intra- and postoperative complications must be detected promptly and treated adequately. Many complications arise within the first weeks, such as bleb scaring, decreased flow beneath the scleral flap, extensive filtration with choroidal detachment and anterior chamber narrowing. Fibrin reaction, corneal dellen, iris prolapse, conjunctival leakage and ciliary body detachment are seen more rarely. With prophylactic pre- and perioperative application of antibiotics, wound infections are rare and the risk of endophthalmitis following trabeculectomy remains small. Careful surgical planning requires special con...

Scleral buckling versus primary vitrectomy in rhegmatogenous retinal detachment study (SPR Study): Multiple-event analysis of risk factors for reoperations. SPR Study report no. 4

Acta Ophthalmologica — Wed, 11 Nov 2009 00:00:00 +0100

Conclusion: Reoperations are used as an indicator for the quality and efficacy of surgical techniques. Using a refined multivariate survival model, distinct factors were identified and associated with one or more reoperations after PV or SB in RRD surgery. This information should be useful in the decision process regarding the surgical approach. (Source: Acta Ophthalmologica)

Neural contrast sensitivity calculated from measured total contrast sensitivity and modulation transfer function

Acta Ophthalmologica — Wed, 11 Nov 2009 00:00:00 +0100

Conclusion: It is possible to calculate a meaningful neural CSF from measured total CSF and MTF data. The neural CSF represents a CSF adjusted for optical aberrations. This would allow comparison of the neural component of visual function in eyes with different optical aberrations. (Source: Acta Ophthalmologica)

Allergy skin testing in predicting adverse reactions to fluorescein: a prospective clinical study

Acta Ophthalmologica — Wed, 11 Nov 2009 00:00:00 +0100

Conclusion: The vast majority of adverse reactions to fluorescein are mild and not attributed to immunological mechanisms. Allergy skin tests cannot predict non-immunological reactions but their utility remains substantial in predicting anaphylaxis during SFAs and must be performed in patients reporting risk factors in their past medical history. (Source: Acta Ophthalmologica)

New Questions -- New Answers

Ophthalmic Research — Tue, 10 Nov 2009 23:00:00 +0100

Ophthalmic Res 2009;42:175 (DOI:10.1159/000256686) (Source: Ophthalmic Research)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Laser Surgery Not Linked to Long-Term Corneal Cell Loss

Medscape Ophthalmology Headlines — Tue, 10 Nov 2009 18:24:34 +0100

No significant loss of corneal endothelial cells is apparent 9 years after laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK), according to study findings in the Archives of Ophthalmology for November. Reuters Health Information (Source: Medscape Ophthalmology Headlines)

No Increase in Macular Degeneration after Cataract Surgery (CME/CE)

MedPage Today Ophthalmology — Tue, 10 Nov 2009 17:45:47 +0100

Cataract surgery does not increase the risk of progression of age-related macular degeneration, a prospective study found. Previous observational and case-control studies had suggested an acceleration in degeneration after surgery. (Source: MedPage Today Ophthalmology)

The World's Most Common Operation

Eye Health / Optometry News From Medical News Today — Tue, 10 Nov 2009 10:00:00 +0100

As many as 10 million people around the world suffer from cataracts. Thomas Kohnen of the Goethe University in Frankfurt and his coauthors discuss cataract surgery with the implantation of an artificial lens in the current issue of Deutsches Arzteblatt International (Dtsch Arztebl Int 2009; 106[43]: 695 - 702). Blindness is usually due to opacification of the lens. In Germany alone, more than 600,000 cataract operations are performed each year. (Source: Eye Health / Optometry News From Medical News Today)

The initial torsional Ocular Following Response (tOFR) in humans: A response to the total motion energy in the stimulus?

Journal of Vision Articles — Tue, 10 Nov 2009 07:30:00 +0100

We recorded the initial torsional ocular following responses (tOFRs) elicited at short latency by visual images that occupied the frontal plane and rotated about the lines of sight. Using 1-D radial gratings, the local spatio-temporal characteristics of these tOFRs closely resembled those we previously reported for the hOFRs to horizontal motion with 1-D vertical gratings. When the 1-D radial grating was subdivided into a number of concentric annuli, each with the same radial thickness, tOFRs were less than predicted from the sum of the responses to the individual annuli: spatial normalization. However, the normalization was much weaker than that which we previously reported for the hOFRs. Further, when the number, thickness and contrast of these concentric annuli were varied systematicall...

Cataract Surgery Doesn't Worsen Macular Degeneration: Study

MedicineNet Eyesight General — Tue, 10 Nov 2009 07:00:00 +0100

Title: Cataract Surgery Doesn't Worsen Macular Degeneration: StudyCategory: Health NewsCreated: 11/9/2009 4:10:00 PMLast Editorial Review: 11/10/2009 (Source: MedicineNet Eyesight General)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Surface Boundary Contour Strengthens Image Dominance in Binocular Competition.

Vision Research — Tue, 10 Nov 2009 00:00:00 +0100

Authors: Xu JP, He ZJ, Ooi TL We used a binocular rivalry stimulus with one half-image having a vertical grating disc surrounded by horizontal grating, and the other half-image having a horizontal grating disc with a variable spatial phase relative to the surrounding horizontal grating. We found that increasing the phase-shift of the horizontal grating disc, which strengthens the boundary contour, progressively increases its predominance. But the predominance is little affected when a constant gray ring (boundary contour) is added onto the rim of the incrementally phase-shifted horizontal grating. This suggests the influence of boundary contour supersede that of the center-surround-interaction caused by the phase-shift. PMID: 19913047 [PubMed - as supplied by publisher] (Source: Vi...

The sliding window of audio–visual simultaneity

Journal of Vision Articles — Tue, 10 Nov 2009 00:00:00 +0100

Humans exist in an environment wherein many unrelated events occur in close spatial and temporal proximity. Audio–visual timing experiments, however, have often examined only isolated pairs of sensory events. We therefore decided to assess how audio–visual timing perception would be shaped by the presence of an additional audio or visual event. We found that the point of subjective synchrony for a sensory event can be shifted away from the presence of other temporally proximate events. These interactions made audio–visual pairs seem unrelated, or asynchronous, at timings at which they had seemed synchronous when presented in isolation. This shows that the interval across which humans are insensitive to audio–visual asynchrony is not fixed, but dynamic, shaped by interactions betwee...

Fundus autofluorescence in patients with blunt ocular trauma

Acta Ophthalmologica — Tue, 10 Nov 2009 00:00:00 +0100

Conclusion: Damaged RPE area was more evident and better delineated by FAF imaging compared with fundus examination and fundus photography alone. Autofluorescence imaging might be a useful exam to show the length and severity of post-traumatic retinal lesions and it may add relevant information in the global evaluation of blunt ocular trauma complications. Moreover, OCT added valuable information to the diagnosis and progression of choroidal rupture. Further studies to determine the predictive value of FAF in ocular blunt trauma are warranted. (Source: Acta Ophthalmologica)

Macular changes detected by Fourier-domain optical coherence tomography in patients with hypotony without clinical maculopathy

Acta Ophthalmologica — Tue, 10 Nov 2009 00:00:00 +0100

Conclusion: FD-OCT identified subclinical macular abnormalities in over half of the eyes with postoperative hypotony. These findings were accompanied by visual disturbances and central macular thickening. FD-OCT can be an important diagnostic tool for this disorder when clinical features are absent. (Source: Acta Ophthalmologica)

Follow-up of suspected ocular adverse drug reactions

Acta Ophthalmologica — Tue, 10 Nov 2009 00:00:00 +0100

(Source: Acta Ophthalmologica)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Single intravitreal injection of triamcinolone combined with bevacizumab for the treatment of diffuse diabetic macular oedema refractory to grid photocoagulation

Acta Ophthalmologica — Tue, 10 Nov 2009 00:00:00 +0100

(Source: Acta Ophthalmologica)

Cataract Surgery Does Not Worsen Age-Related Macular Degeneration

Medscape Ophthalmology Headlines — Mon, 09 Nov 2009 21:31:18 +0100

Results from a new study do not support the hypothesis that cataract surgery increases the risk for age-related macular degeneration progression. Medscape Medical News (Source: Medscape Ophthalmology Headlines)

Evolution: Theory, Not Fact--Reply [Letters]