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At least 19 recordsLinked to original sources
PubMed1995

Disability glare: effects of temporal characteristics of the glare source and of the visual-field location of the test stimulus.

One of the main early complaints of cataract patients, even when these patients exhibit only mild glare problems as measured by standard tests, is that glare impairs their night driving. To provide a better measure of the patients' impairment, glare tests should include measurements of the glare effect in conditions more similar to those found in night driving. During night driving the ambient light is very low, and oncoming headlights present a transient temporal pattern. Furthermore, the objects of interest often appear initially in the peripheral visual field. Thus three important characteristics of glare in night driving are that the ambient illuminance is in the scotopic-mesopic range, the detection stimulus is in the periphery, and the glare source is transient. Most of the current glare testers measure glare only at photopic levels, and all the glare tests that we know of use only steady sources of glare with foveal discriminations. All these conditions are dealt with. The transient glare source raised thresholds by 0.5-0.75 log unit more than the steady glare source, and the transient glare effect was more pronounced and more long lasting in the periphery. Standard glare testers seriously underestimate disability glare effects in everyday life.

Adaptation, Ocular↗
PubMed2000

The immediate effects of glare and electrochromic glare-reducing mirrors in simulated truck driving.

In this experiment 12 experienced truck drivers drove a fixed-base driving simulator for three 8-h sessions under simulated nighttime driving conditions. Sessions included (a) no glare, (b) intermittent glare presented in the exterior rearview mirrors to simulate following vehicles, and (c) intermittent glare with electrochromic glare reduction. The driving task combined vehicle control on straight and curved road segments with detection of pedestrians appearing alongside the road and targets appearing in the rearview mirrors. The presence of glare slowed detection of pedestrians and, to a lesser extent, slowed the detection of targets appearing in mirrors. Glare was also associated with increased lane position variability, reduced speed on curves, and, most consistently, increased steering variability. We found only meager evidence that electrochromic glare reduction improved target detection performance and no evidence that glare reduction improved vehicle control, despite the fact that participants consistently voiced positive preferences for glare reduction. The results will aid decision making that requires incorporation of the benefits of electrochromic glare-reducing mirrors.

Adult↗
PubMed2003

On the cause of disability glare and its dependence on glare angle, age and ocular pigmentation.

BACKGROUND: In the 1920s and 1930s, disability glare was a topic of great interest in the Commission Internationale de l'Eclairage (CIE). The Second World War prevented agreement being reached on a standard to quantify disability glare but the Stiles-Holladay formula was widely accepted as such. In 1983, CIE started a new effort to develop a CIE standard making use of research data published in the post-war years. METHODS: A committee was formed that agreed that new data and insights justified an extension of the angular domain of a disability glare formula and allowed introduction of an age factor and allowance for ocular pigmentation. RESULTS: Three disability glare equations were formulated, each for an appropriately restricted angular domain. The most general, the CIE General Disability Glare equation, covers the full angular range between 0.1 degrees and 100 degrees but for optometrists the CIE Age-adjusted Stiles-Holladay Disability Glare equation, with validity domain between one degree and 30 degrees, will often suffice. CONCLUSIONS: Disability glare is due to intraocular scatter and obeys, in the one-degree to 30-degree angular domain, albeit with great individual spread, the Age-adjusted Stiles-Holladay equation: (L(veil) /E(glare))(Age-adjusted Stiles-Holladay) = 10 (1 + [Age/70](4)).1/theta(2). Quantitative examples are given of the manifestation of disability glare, particularly in traffic.

Aging↗
PubMed1988

The relationship between cataract type and glare disability as measured by the Miller-Nadler glare tester.

Cataract patients were tested for glare disability using the Miller-Nadler glare tester. Predicted outdoor visual acuity was then compared with the actual outdoor visual acuity. The Miller-Nadler glare test scores predicted actual outdoor visual impairment to within one Snellen line in 46.7% of the eyes, underestimated actual outdoor visual impairment by more than one Snellen line in 31.5% of the eyes, and overestimated outdoor visual impairment by more than one Snellen line in 21.7% of the eyes. Overall, 64.1% of the eyes had outdoor vision which was more closely predicted by their glare scores than by their indoor Snellen acuity. When the cataractous eyes were divided into three categories, eyes with pure nuclear sclerosis, eyes with nuclear sclerosis and posterior subcapsular opacities, and eyes with all other cataractous combinations, predictability differences were observed. Although we found that actual outdoor visual acuities were not precisely predicted by disability glare scores in a substantial proportion of our subjects, the glare scores were considerably more predictive than indoor Snellen acuity. Further development and field testing of glare testing devices as predictors of outdoor visual impairment is necessary.

Cataract↗
PubMed1992

["Glare vision". II. Study of visual acuity of glare sensitive patients in increasing test field luminance].

Sensitivity to glare is an unspecific ophthalmological symptom that can be caused by different anatomical structures; it can be related to optical and to cortical structures, it also can be due to defects in the neuronal mechanisms of the retina that control adaptation processes. In many cases the exact mechanisms are still unknown. Tests of visual acuity in glare sensitive patients with increasing test field luminance reveal-depending on the underlying disease-several types of variations from the normal visual-acuity-function that was determined over a wide range of light intensity from 0.1 to 30,000 cd/m2. Marked changes in the visual acuity-luminance-function at high test field intensities were found primarily in patients with retinal diseases, particularly in disturbances of the cone system. These visual acuity losses at high test field luminances can be explained by major functional impediments of the neuronal adaptive mechanisms at the retinal level. Less apparent were the changes in visual acuity-luminance-function in cases of optic nerve diseases. According to our studies changes in the visual acuity-luminance-function accompanied with high glare sensitivity are most often due to pathological changes in neuronal circuitry of the retina, less often to the effects of stray light. This test therefore can provide an important criterion for establishing the correct diagnosis.

Adolescent↗
PubMed1995

[Glare adaptation for inhomogeneous glare distribution with respect to the dynamic components of the vision task].

Basic investigations in the field of adaptation luminance were carried out using Holladay's visual threshold criterion. The connection between adaptation luminance LA, illumination at the spot in the eye EB1 and the angle of glare theta is LA = 9.2 x EB1 x theta -2 LA in cd/m2, Eb1 in 1x, theta in degrees. In most cases the investigations of adaptation luminance were also carried out under conditions of fixed view and static visual tasks. It is however, important to take into account the dynamic visual task and the adaptation process by determining the adaptation luminance, but very few measurements have been carried out under these conditions. For the results represented here the visual threshold was replaced by the readaptation time necessary for perception of movement direction of a striped pattern (dynamic) and with the idea of also comparing the perception of the slot location in a ring in the Landolt rings (static). The method of investigations was as follows: The subject adapts to the inhomogeneous field of luminance for which the adaptation luminance must be determined. Then in a dark surrounding field for comparison, the visual task is offered, and the readaptation time necessary for the fulfillment of the visual task is measured. This procedure is repeated with a homogeneous field of luminance. The luminance of a homogeneous field is equal to the adaptation luminance. If the readaptation times are equal, the inhomogeneous distribution of luminance has the adaptation luminance LA. The important difference in comparison to previous investigations is the inclusion of dynamic components (readaptation time and dynamic visual task).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Ocular↗
PubMed2000

Contrast sensitivity and glare disability by halogen light after monofocal and multifocal lens implantation.

BACKGROUND: Standard examination of contrast sensitivity under conditions of glare disability is performed with incandescent light. A new halogen glare test that simulates glare as seen with oncoming vehicle headlights was used to measure glare disability in patients implanted with multifocal and monofocal intraocular lenses (IOLs). METHODS: 28 patients with an average age of 69 years (SD 12 years) were implanted with a monofocal IOL (SI-40NB, Allergan) and 28 patients with an average of 66 years (12 years) were implanted with a refractive multifocal IOL (Array-SA-40N, Allergan). All patients were followed for 5 months postoperatively. Contrast sensitivity at four spatial frequencies (3, 6, 12, and 18 cycles per degree, cpd) with and without a glare source were measured using the halogen glare test (CSV-1000 HGT). Statistical analysis was performed using the two sample Wilcoxon test. The local significance level was set at 0.05. RESULTS: When tested at the lowest spatial frequency (3 cpd) without halogen glare, contrast sensitivity was lower in the multifocal group than in the monofocal group (p=0.0292). With additional glare, there was no difference between both groups. At all other spatial frequencies (6, 12, and 18 cpd), when tested without halogen glare (6 cpd, p=0.5250; 12 cpd, p=0.8483; 18 cpd, p=0.9496) and with moderate (3 cpd, p=0.7993; 6 cpd, p=0.4639; 12 cpd, p=0.7456; 18 cpd, p=1.0) and high halogen glare (3 cpd, p=0. 1513; 6 cpd, p=0.2016; 12 cpd, p=0.3069; 18 cpd, p=0.9933), there was no statistically significant difference between groups. Patients in both groups of age 70 or older had reduced contrast sensitivity without halogen glare and with moderate and strong glare. When monofocal and multifocal patients older than 70 years of age were analysed separately, there was no statistically significant difference in contrast sensitivity with and without glare. Astigmatism >1 dioptre had no significant influence on contrast sensitivity and glare disability when monofocal and multifocal eyes were compared. CONCLUSION: Reduced contrast sensitivity was found in the multifocal group only at the lowest spatial frequency without halogen glare. The monofocal and multifocal groups had no statistically significant differences in contrast sensitivity with moderate and strong glare. These results suggest no difference in glare disability induced by halogen light similar to oncoming vehicle headlights for patients implanted with monofocal and multifocal IOLs.

Adult↗
PubMed1986

Impairment of contrast sensitivity function (CSF) as a measure of disability glare.

A method for quantitative measurements of disability glare in clinical practice is presented. Glare is induced by a circular fluorescent tube which surrounds a sinusoidal grating displayed on a monitor. The threshold contrast that is needed for detection of the grating is measured with and without presence of the glare light. This is repeated for several different spatial frequencies. The discrepancy between the contrast sensitivity function (CSF) obtained with and without glare light was used to calculate the glare score (n) as a measure of disability glare. This was done for normals and cataract patients. The results show that an increasing glare score is related to an increase in turbidity of the optic media, while visual acuity had a weak correlation to the glare score. We also studied the relation glare score versus luminance and found that normals had a glare score that was almost independent of luminance level, while the cataract patients had a marked decrease in glare sensitivity when the luminance decreased. Most patients had a glare score that corresponded to their glare problems. These findings indicate a potential for using this psychophysical disability glare test method in industry, transport, and clinical ophthalmology. Some sources of methodological error inherent in the test method are evaluated and discussed.

Adult↗
PubMed1986

Radial keratotomy and glare effects on contrast sensitivity.

After radial keratotomy (RK) to correct myopia, some patients complain of 'glare'. Effects of a glare source on contrast sensitivity were measured in fifteen patients after unilateral RK. With each eye, determinations were made of the contrast required for detection of steady gratings (spatial frequencies of 0.7 and 2.9 cycles/deg), and for detection of flicker (unpatterned field flickering at rates of 8, 16, and 32 Hz). Grating or flicker was presented on a centrally fixated 4 deg test target (34 cd/m2 mean luminance), surrounded by a diffuse glare source (1700 cd/m2 mean luminance). For each stimulus, contrast thresholds were determined with glare-source off and with glare-source on. 'Glare loss' was defined as the decrement in contrast sensitivity measured with the glare source on. Significant findings were: (1) Both eyes showed glare losses for detection of gratings and for detection of flicker; (2) Spectacle lenses increased glare losses both for gratings and for flicker; (3) The RK eye showed a larger glare loss for flicker than the unoperated eye, but a smaller glare-loss for gratings; (4) For both flicker and gratings, glare loss tended to be greater in the RK eye, compared to the unoperated eye, in subjects who had larger pupil diameters in the testing situation; (5) The psychophysical measurements obtained in this study were not significantly correlated either with a questionnaire index of glare complaints or with the score obtained with the Miller-Nadler GlareTester.

Adult↗
PubMed1998

Comparison of methods to assess visual impairment from glare and light scattering with posterior capsule opacification.

PURPOSE: To compare 2 glare tests to determine their relative usefulness in the assessment of posterior capsule opacification (PCO) and to evaluate the potential benefits of combined visual, acuity, contrast sensitivity, and glare testing. SETTING: Teaching hospital ophthalmology department. METHODS: Sixteen patients had glare, visual acuity, and contrast sensitivity testing before and after neodymium:YAG (Nd:YAG) capsulotomy. Results with the Brightness Acuity Tester (BAT, Mentor), which measures disability glare, and the Straylightmeter (Foundation for Eye Research, The Netherlands), which quantifies forward scatter by direct compensation techniques, were compared. The correlation between glare, ETDRS visual acuity, and Pelli-Robson contrast sensitivity was determined. RESULTS: Pretreatment visual acuity was significantly correlated with contrast sensitivity (P < .01). However, visual acuity and contrast sensitivity were poorly correlated with both the BAT and Straylightmeter (P > .05), indicating that visual acuity is predictive of contrast sensitivity but a poor predictor of glare. Glare was significantly improved (Straylightmeter, P < .0001; BAT, P < .05) following capsulotomy. While the Straylightmeter consistently measured precapsulotomy forward scatter that improved with treatment, corresponding BAT disability glare was unmeasurable in 18.8% of patients with PCO, as their visual acuities improved rather than deteriorated with glare testing. CONCLUSIONS: Glare testing provided more information than contrast sensitivity when combined with visual acuity in the evaluation of PCO. Glare related to PCO is better assessed using the Straylightmeter because the BAT may yield aberrant disability glare results.

Aged↗
PubMed2004

Mesopic contrast sensitivity in the presence or absence of glare in a large driver population.

BACKGROUND: To evaluate mesopic contrast sensitivity in conditions of glare and no glare in a vehicle driver population, and to explore the effects of age, habitual spectacle correction, photopic visual acuity and driving exposure. METHODS: A cross-sectional study was performed on 297 drivers stratified by age into six groups. The mesopic contrast sensitivity was measured in the absence or presence of glare using the Mesotest II (Oculus, Germany) in each subject both with habitual and best spectacle correction. A questionnaire on the subject's driving habits was completed. RESULTS: There were no significant differences between contrast sensitivity measured with habitual or best spectacle correction. In conditions of no glare, the mesopic contrast sensitivity gradually got worse from 51 to 60 years onwards, and from 41 to 50 years onwards in the presence of glare. In both conditions, the total decrease in contrast sensitivity was 0.3 log units. The with-glare and without-glare mesopic contrast sensitivity improved as photopic visual acuity increased. Forty-five per cent of drivers who reported difficulties in driving at night were unable to perform any of the tests with glare, compared to 20% without glare. However, the effect of driving habits on contrast sensitivity was only significant in the oldest age group. CONCLUSIONS: The mesopic contrast sensitivity and glare sensitivity seem to be stable until the age of 50 years, from which point they start to decline at a rate of 0.1 log contrast sensitivity loss per decade. Drivers with poor visual acuity and/or older drivers who avoided night driving presented worse mesopic contrast sensitivity and greater glare sensitivity.

Adult↗
PubMedDate not supplied

Glare disability in patients with hydrophilic and hydrophobic acrylic intraocular lens implants.

PURPOSE: To compare glare disability test results in patients with hydrophilic and hydrophobic acrylic intraocular lenses (IOL). METHODS: Sixty eyes of 60 patients were studied in three groups of 20. Each eye in Group 1 had a single-piece hydrophilic acrylic (Bioacryl, Biotech, France) IOL implant, and each eye in Group 2 had a three-piece hydrophobic acrylic (AcrySof, Alcon, USA) IOL implant. Group 3 was the control group, and consisted of eyes without cataracts. Glare disability was tested using the Ophthimus glare sensitivity test (Ophthimus, Sweden). For each eye, we determined log contrast sensitivity values without exposure to glare source and with exposure to glare source. The difference between these values was recorded as the threshold contrast increase. An infrared camera was used to measure pupil diameter during glare disability testing, and pupil diameter greater than 4 mm was used as an exclusion criterion to eliminate edge design as a potential contributor to glare disability. RESULTS: The respective mean log contrast sensitivity scores for Groups 1, 2, and 3 in the absence of the glare source were 0.80 +/- 0.03, 0.81 +/- 0.04, and 0.79 +/- 0.08. The corresponding findings with glare source were 0.84 +/- 0.07, 0.89 +/- 0.07, and 0.84 +/- 0.03. The threshold contrast increase in Group 2 (0.070 +/- 0.035) was significantly higher than that in both Group 1 (0.043 +/- 0.040) and the control group (0.045 +/- 0.026) (p < 0.05 for both comparisons). There were no significant differences between Group 1 and the control group regarding log contrast sensitivity values with glare source and threshold contrast increase (p > 0.05 for both comparisons). CONCLUSIONS: The eyes with hydrophilic acrylic IOL showed better glare disability results than those with hydrophobic acrylic IOL. The superior performance of the hydrophilic acrylic IOL could be related to their lower refractive index and equi-convex design.

Acrylic Resins↗
PubMed2006

Using a human visual system model to optimize soft-copy mammography display: influence of veiling glare.

RATIONALE AND OBJECTIVES: This project evaluated human observer performance and that of a human visual system model (JNDmetrix) to assess whether the veiling glare of a digital display influences observer performance during soft-copy interpretation of mammographic images for the detection of masses. MATERIALS AND METHODS: A set of 160 mammographic images, half containing a single mass, was processed to simulate four levels of veiling glare: none, comparable to a medical grade monochrome curved-screen cathode ray tube (CRT) display, double that of the CRT and quadruple that of the CRT. The images were shown to six observers in a randomized presentation order on a liquid crystal display (LCD) that had essentially no veiling glare. The images were also analyzed using the JNDmetrix human visual system model. RESULTS: Observer performance as measured using receiver operating characteristic techniques declined with increasing veiling glare (F = 6.884, P = .0035), with quadruple veiling glare yielding significantly lower performance than the lower veiling glare levels. The JNDmetrix model did not show a large reduction in performance as a function of veiling glare, and correlation with the human observer data was modest (0.588). CONCLUSIONS: Soft-copy display veiling glare can influence observer performance, but only at extreme levels. The impact of veiling glare on performance may be more pronounced for less experienced readers.

Glare↗
PubMed1992

Quantification of the reduction of glare disability after standard extracapsular cataract surgery.

Glare disability is often cited as an indication for cataract extraction, but very little objective data exist showing improvement of glare disability following standard extracapsular cataract extraction with posterior chamber intraocular lens implantation. In a series of 25 patients we determined glare disability by the reduction in visual acuity with dim room lighting (baseline) and with full room lights; with the brightness acuity tester (BAT) on low, medium, and high; with the true vision analyzer (TVA) glare light. Glare disability was quantified by the difference between the log VA postoperatively and the log VA preoperatively. Glare disability with BAT medium was no different than that with bright room lights (P greater than .05). Glare disability with BAT high was greater than that with BAT medium (P less than .01) but did not differ from that with TVA (P greater than .05). Glare disability was significantly reduced (P less than .01) six weeks postoperatively as measured by all tests except BAT low. Cataract surgery can be expected to reduce glare disability as measured by these tests.

Adult↗
PubMed1990

A new glare test based on low contrast letters--evaluation in cataract patients.

A new simple glare test was designed and evaluated regarding clinical usefulness and reproducibility. The ability to recognize letters of equal size and varying contrast was determined with the absence and presence of glare sources above and below the letters. Ten patients with cataract, visual acuity of at least 0.3 and glare problems, and three age matched controls were tested, as well as one patient with glare complaints and exophoria, one with lens subluxation and one with cataract and no glare problem. The test was found to be cheap and simple to produce and useful for clinical testing. Normal eyes had no detectable reduction of letter contrast sensibility with glare. All cataractous eyes had a letter contrast sensitivity without glare that was well below that of the controls and under glare conditions they all had a drop in visual function that was unrelated to their visual acuity. The reproducibility was of a magnitude similar to that of other low contrast letter tests. Our conclusion is that this test will be a valuable tool in the evaluation of cataract patients providing information not only about glare-induced visual loss but also about contrast sensitivity, separating eyes with increased intraocular light scattering from normal eyes.

Adult↗