Glare Reduction Research Articles

Computer users’ risk factors for developing shoulder, elbow and back symptoms

This prospective study concentrated on determining factors of computer work that predict musculoskeletal symptoms in the shoulder, elbow, and low-back regions. A questionnaire on ergonomics, work pauses, work techniques, and psychosocial and work factors was delivered to 5033 office workers at baseline in early 1999 (response rate 69%) and to 3361 respondents at the time of the follow-up in late 2000 (response rate 77%). An increased frequency or intensity of symptoms was the outcome variable, including only nonsymptomatic respondents from the baseline questionnaire (symptom frequency below 8 days within the last 12 months or intensity score below 4 within the last 3 months). In the follow-up, 10%, 18%, and 23% had symptoms more often in the elbow, shoulder, and low back, respectively, and 14%, 20%, and 22% had more intense symptoms. Women were more likely to be afflicted than men in all regions. In the full-fit multivariate logistic regression analysis, little influence on the timing of a rest pause and being disturbed by glare or reflection were significant predictors of shoulder symptoms, screen below eye height was a significant predictor for elbow symptoms, and previous symptoms was a significant predictor for symptoms in all regions. Computer worktime and psychosocial dimensions were not significant predictors. Influence on work pauses, reduction of glare or reflection, and screen height are important factors in the design of future computer workstations. Since previous symptoms was a significant predictor of recurrent symptoms in all three regions under study, it can be concluded that musculoskeletal symptoms are persistent.

Black diaphragm intraocular lens implantation in aphakic eyes with traumatic aniridia and previous pars plana vitrectomy

Purpose: To evaluate the efficacy of secondary black diaphragm intraocular lens (IOL) implantation in aphakic eyes with traumatic aniridia and previous pars plana vitrectomy (PPV). Setting: Shandong Eye Institute and Hospital, Qingdao, China. Methods: This retrospective study comprised 15 aphakic eyes with aniridia and no vitreous that had implantation of a secondary black diaphragm IOL 6 to 72 months after PPV. The PPV was performed as a result of trauma to the posterior segment. Before implantation of the IOL, all patients had reduced visual acuity from aphakia and intolerable glare from aniridia. Eyes were aphakic as a result of previous extracapsular cataract extraction (1 eye), lens extrusion during trauma (3 eyes), or simultaneous cataract lensectomy during PPV (11 eyes). Significant iris defects were present, with 9 eyes being aniridic after the injury. The mean follow-up was 17 months (range 3 to 34 months). The postoperative visual acuity, intra- ocular pressure (IOP), endothelial cell density, IOL centration, and intraocular inflammation were monitored. Results: All 15 eyes had improved visual acuity and marked glare reduction after IOL implantation. No major IOL decentration was seen. Five patients had increased IOP 3 to 5 days after IOL implantation; 3 were known to have secondary glaucoma from trauma before surgery and their IOP was controlled preoperatively (< 21 mm Hg) with timolol 0.5% eyedrops. The other 2 patients had normal- appearing angles, and 1 was diagnosed with hemolytic glaucoma after IOL insertion. Postoperative elevated IOP was controlled by timolol eyedrops (4 eyes) or selective laser trabeculoplasty (1 eye). Hyphema was seen in 1 patient on the first day after IOL implantation, but no further bleeding was noted. Vitreous hemorrhage was seen the first day after IOL insertion in 2 patients. One resolved without sequelae; the other required vitreous washout. Retinal detachment and cystoid macular edema did not occur in any patient. Conclusions: Black diaphragm IOL implantation can be considered in eyes with coexisting aphakia and aniridia and without vitreous. Intraoperative IOP regulation is crucial in vitrectomized eyes to prevent complications such as expulsive hemorrhage. In general, visual function was better after IOL insertion as a result of better visual acuity and glare reduction. Although this IOL appears to be safe, long-term results must be assessed in studies with a longer follow-up and a larger study group.

388 The evaluation of early regional recurrence using clinical examination and ultrasonography of the axilla after omitting axillary clearance in patients with tumour negative sentinel nodes

To measure intraocular straylight (as a measure of glare) after cataract surgery and implantation of an AcrySof ReSTOR SA60D3 multifocal or AcrySof SA60AT monofocal intraocular lens (IOL) (both Alcon Laboratories).University Hospital Maastricht, Maastricht; Isala Clinics, Zwolle; Netherlands Institute for Neurosciences, Amsterdam, The Netherlands.In a prospective open observational case series, a newly developed straylight meter was used to objectively measure straylight 6 months postoperatively in 66 eyes with a diffractive AcrySof ReSTOR SA60D3 IOL (multifocal group) and 40 eyes with a monofocal AcrySof SA60AT IOL (monofocal group). A comparison of straylight levels in an age-matched population without cataract (control group) was performed.The straylight level was 1.20 log units ± 0.16 (SD) in the multifocal group and 1.10 ± 0.19 log units in the monofocal group. When the difference in mean level of straylight was adjusted for age, mean straylight levels were 0.078 log units lower in the monofocal group than in the multifocal group (P = .026). Straylight levels in both pseudophakic groups were lower than in the control group without cataract (P<.0001).Levels of intraocular straylight log(s) were significantly lower for both types of IOL than in age-matched subjects from the normal population. The mean level of intraocular straylight 6 months postoperatively was higher in patients with an AcrySof ReSTOR SA60D3 IOL than in patients with a monofocal AcrySof SA60AT IOL. Implantation of the former IOL would therefore result in a smaller gain in contrast sensitivity and a smaller reduction in glare and halos than implantation of the latter IOL.

Impact of cataract surgery on self-reported visual difficulties: Comparison with a no-surgery reference group

Purpose To examine the impact of cataract surgery on older adults’ self-reported visual difficulties and compare them with those of patients with cataract who declined surgery over the same period. Setting Twelve area practices. Methods This was a consecutive chart review over a 6-month period. Primary inclusion criteria were 55 years or older, cataract in 1 or both eyes with 20/40 visual acuity or worse (best corrected, distance), and no previous cataract surgery in either eye. The Activities of Daily Vision Scale (ADVS) and visual acuity, contrast sensitivity, and disability glare tests were administered at baseline and at a 1-year follow-up visit. Results This study comprised 245 patients, 156 of whom elected to have cataract surgery and 89 of whom declined. Those electing surgery were more likely to be white, female, and have worse visual acuity and no ocular comorbidities. At baseline, ADVS subscale scores ranged from 53 to 76 in the surgery group and from 72 to 89 in the no-surgery group. In the surgery group, subscale scores improved by 15 to 21 points on average at the 1-year follow-up; scores were unchanged or worse in the no-surgery group over this period. This difference between the groups remained statistically significant after adjustment for group baseline differences in demographics, vision, and ADVS score. In the surgery group, visual acuity improvement in the first eye was an independent predictor of increases in the ADVS overall score and night driving and glare disability subscales; contrast sensitivity was an independent predictor of improvement in the night driving subscale. A reduction in disability glare in the second eye was independently linked to increases in the overall ADVS score and the night driving, near vision, and glare disability subscales. Conclusions Baseline findings suggest that cataract patients who have surgery have more difficulty in visual tasks than those who decline surgery. After surgery, patients reported less difficulty with visual tasks. In the no-surgery group, no change was reported. Improvements in visual acuity and contrast sensitivity and reductions in disability glare after surgery were independently linked to improvements in ADVS scores.

Prosthetic iris implantation for congenital, traumatic, or functional iris deficiencies

Purpose: To determine the efficacy and safety of surgical implantation of prosthetic iris devices in patients with anatomic or functional iris deficiencies. Setting: Cincinnati Eye Institute, Cincinnati, Ohio, USA. Methods: Twenty-five patients were enrolled in an interventional prospective noncomparative case series. Twenty-eight eyes had prosthetic iris diaphragm implantation for traumatic iris defects, congenital aniridia or iris coloboma, herpetic iris atrophy, surgical iris loss, or ocular albinism. Prosthetic iris implantation was performed with phacoemulsification and intraocular lens (IOL) implantation in 20 eyes, secondary IOL implantation in 6 eyes, and IOL exchange in 1 eye. A single pseudophakic eye with disabling glare secondary to traumatic aniridia had secondary prosthetic iris implantation alone. The surgical ease of insertion, intraoperative and postoperative complications, postoperative anatomic results, visual acuity, and subjective glare reduction were evaluated. Results: Patients were followed postoperatively for a mean of 10.2 months (range 1.4 to 25.7 months). All eyes achieved the desired anatomic result. Visual acuity was improved in 22 of 28 eyes (79%), unchanged in 5 eyes, and worsened by a single line in 1 eye. Patients were surveyed postoperatively to determine the change in glare disability. The severity of glare disability was subjectively improved in 23 of 24 patients (96%) who responded to the survey. Intraoperative complications included 3 fractured implants as well as an incomplete or torn capsulorhexis in 3 eyes. Postoperative complications included transient hypotony in 2 eyes, mild persistent inflammation in 1 eye, and macular edema followed by a retinal detachment in 1 eye with recent severe trauma. Conclusions: Implantation of prosthetic iris devices improved postoperative outcomes by reducing glare disability and, in selected cases, by correcting aphakia. Although operating on traumatized, congenitally aniridic, or uveitic eyes presents special challenges, implantation of prosthetic iris devices appears to be a safe and effective method for reducing the ubiquitous glare in patients with iris deficiency.

Polarized task lighting to reduce reflective glare in open-plan office cubicles

This ergonomic study deals with the common situation where a glossy document is placed between a viewer and an under-shelf task light source in a common open-plan office cubicle workstation. With a task lamp in front, when looking at a document a viewer sees two images, the document itself and specular glare, which is the reflected image of the light source. Specular glare or veiling reflection causes eye discomfort, makes it difficult to read a document and has been thought to contribute to eyestrain. This paper analyzes the application of polarized lighting for this specific situation. The use of a linear polarized light source helps to minimize specular glare by darkening the reflected image of the light source on the document. The performance and predictive optimization of the use of polarized lighting in this situation is investigated according to female and male viewer height demographics. Theoretical predictions and light measurement analysis of specular glare reduction are compared with empirical results from testing on a panel of humans on semi-gloss finish and matte finish papers. This study shows that with the right alteration of a polarized light source position, specular glare may be significantly reduced, and correlations exist between the theory, empirical measurements and the human response to specular glare reduction.

Sun Shades and Eye Size in Birds

Visual field width above the head is significantly correlated (r_s = 0.92, n = 11, p < 0.001) with eye size in a sample of terrestrial birds that differ in their phylogeny and ecology. These species can be divided into two groups. Smaller-eyed sun-observers (axial length <18 mm) have comprehensive or near comprehensive visual coverage of the celestial hemisphere and are thus unable to avoid viewing the sun. Larger-eyed sun-avoiders (axial length >18 mm) have restricted visual fields and various types of optical adnexa (enlarged brows, hair like feathers on the eye lids and around the eye) which can prevent solar illumination of the cornea. We suggest that these differences relate to visual rather than pathological problems and argue that the reduction of disability glare, produced by sunlight falling directly upon the eye, becomes increasingly significant as eye size increases. We propose that the reduced visual fields and optical adnexa of the larger-eyed birds are primarily concerned with the maintenance of high spatial resolution.

Light polarization experiments with a diode laser pointer

Polarized light has many uses: glare reduction, stress analysis, microscope image enhancement, thin-film characterization, astronomy, saccharimetry, and atomic spectroscopy. Here we discuss introductory polarized light measurements in which a diode laser pointer replaces the more frequently used polarized He-Ne laser. A diode laser has been used in introductory optics experiments, and in a more advanced polarization-reflection experiment. Its strong collimated beam is completely polarized and, being free of infrared radiation, it permits Polaroid sheets to be used successfully with semiconductor detectors.

Cycling and at-rest stabilities of a complementary electrochromic device based on tungsten oxide and Prussian blue thin films

Complementary tungsten oxide (WO 3)–Prussian blue (PB) electrochromic devices (ECDs), in combination with Li +, K + or H +-based electrolytes, have been proposed by many researchers for solar attenuation and glare reduction applications. In this study, cycling and at-rest stabilities of a solid-state ECD comprised of a WO 3 and PB thin film couple with a proton-conducting solid polymer electrolyte are discussed. The transmittance of the device varied from 71.5% to 6.0% at 550 nm. The device was darkened or bleached by the application of +1.2 V or −0.6 V, respectively. Repeated switching or cycling of the ECD over 20,000 cycles has been demonstrated, indicating a large number of switchings without great degradation or irreversible side reactions. Nevertheless, at-rest stability in the absence of cycling, at room temperature over months, has not been achieved. The cause of at-rest instability during darkened-state or bleached-state storage will be discussed. Issues related to the scale-up are also discussed.

Phototherapeutic keratectomy (PTK) after epidemic keratoconjunctivitis

Persistent and recurrent nummuli after epidemic keratokonjunktivitis (EKC) often lead to reduced visual acuity and increased glare. In spite of long-term topical steroid therapy nummuli often recur. We tried to treat persistent nummuli with phototherapeutic keratectomy (PTK). PTK with an excimer laser (193 nm) was performed in 13 eyes of 9 patients with nummuli. The nummuli were observed over 3-72 months (mean: 36 months). Preoperatively, the visual acuity was 0.1-0.9 (mean: 0.39 +/- 0.22) and the brightness acuity test (BAT) was 0.05-0.5 (mean: 0.25 +/- 0.15). Prior to PTK all eyes had been treated with local steroids several times for recurrent nummuli. During the follow-up from 15 to 56 months (mean: 33 +/- 11.5 ms), 11 eyes had an increase in visual acuity: 0.3-1.0 (mean: 0.63 +/- 0.26). The reduction of glare was especially beneficial for the patients: 0.3-0.9 (mean: 0.55 +/- 0.21). One patient had a recurrence of nummuli in both eyes 6 weeks after PTK. The subjective-induced spheric refractive change was -2.5 D to +2.0 D. The astigmatic error changed between -2.0 D to +1.5 D. PTK seems to be an effective method of treating persistent, recurrent nummuli after EKC. The low rate of recurrence of nummuli after PTK is remarkable.

Cosmetic contact lens fit for traumatic aniridia

Traumatic aniridia is an absence of the iris tissue secondary to an ocular injury. Chief complaints may include photophobia, decreased visual acuity, impaired cosmesis, and traumatic cataracts. Opaque hydrogel lenses improve cosmesis while providing confort from photophobia. Visual acuity may also be aided by glare reduction and increased depth of focus. This case report describes a 37-year-old African-American woman with traumatic aniridia who was fitted with both a tinted annulus lens and Wesley-Jessen opaques. Although this case report focuses on cosmetic/prosthetic contact lens options for aniridia, this treatment applies to a variety of cornea, iris, and lens abnormalities.

Applying Human Factors to Classroom Visual Aids

Transparencies, slides, and computer based displays are common visual aids used in classroom presentations. This paper will outline the use of principles which improve the effectiveness of these visual aidsGeneral principles discussed include: Organizing material, clarifying material and enhancing encoding. Gestalt principles such as simplicity, similarity, proximity, and continuation, appropriate text size and font, effective use of color and other attention getting cues, and appropriate contrast and glare reduction are considered.

The x‐ray fovea, a device for reducing x‐ray dose in fluoroscopy

The x-ray fovea (U.S. patents pending) is a device for reducing x-ray dose to patients and operations during x-ray fluoroscopy. It consists of a semitransparent collimator with an open, circular, central hole. The fovea collimator is placed at the exit of the x-ray tube, and the attenuation of the peripheral x-ray beam reduces x-ray exposure to patients and operators. The shadow caused by the x-ray fovea can be compensated using real-time image processing hardware. Accurate compensation is demonstrated for both linearly and logarithmically acquired images using a model that accounts for beam hardening in the fovea collimator. The central fovea region has improved image quality due to reduced scatter and veiling glare from the periphery. From beam-stop measurements, a 40% reduction in scatter plus veiling glare is measured using the fovea. A contrast improvement ratio of 1.5 is measured throughout the central region. In the compensated periphery, noise is increased by a factor of 1.66 because fewer photons are detected, but a small amount of temporal filtering compensates this degradation. The Roentgen area product (RAP) exposure to patients is reduced by approximately 70%, while scattered exposure to operators is reduced by approximately 60%.

Treatment of band keratopathy by excimer laser phototherapeutic keratectomy: surgical techniques and long term follow up.

A series of 122 eyes with band keratopathy was treated by excimer laser phototherapeutic keratectomy (PTK), with a mean follow up of over 12.3 months (range 3 to 60 months). A single photoablation zone was used to remove the opacity over the visual axis in smooth surfaced band deposition. In eyes with reduced vision, an improvement was reported in 88% and in a series of 66 eyes mean Snellen visual acuity increased significantly (p < 0.05, t = 2.27). A reduction in glare was reported in 88% and in a series of 17 patients, visual contrast sensitivity (p < 0.01) and measurements of disability glare (p < 0.01) improved postoperatively. The mean hyperopic shift in 32 eyes at 6 months was 1.4 D (range 0-4.25 D). Multiple overlapping ablation zones, with mechanical debulking of large calcium plaques, were used to smooth the irregular corneal surface in eyes with rough bands. Ocular discomfort was improved in 95%. Band keratopathy recurred in nine eyes (8%) within 2 to 30 months (mean 12 months) of surgery, with silicone oil responsible in five eyes. Reablation was necessary in three eyes and performed successfully in all cases. Excimer laser PTK is a safe and effective outpatient treatment for band keratopathy.

Electrochromic characteristics of a complementary tungsten trioxide/Prussian blue cell

Optically switchable electrochromic materials are of importance in the automobile industry for the control of solar heat load, glare reduction, and privacy applications. A complementary electrochromic cell consisting of a cathodically colouring tungsten trioxide (WO3) film, an anodically colouring Prussian blue (PB) film, and a Li+ conducting polymer electrolyte was made. Cycling characteristics and colouration efficiency of the cell at various stages of cycling were evaluated. It was shown that the complementary cell requires less energy for operation compared to cells with a single film. The WO3/PB was cycled up to 1300 times. A gradual decrease in the contrast between the coloured and the bleached states upon cycling was observed during the first 400 cycles. The colouration efficiency of 102 cm2C−1 at the first cycle decreased to 67 cm2C−1 after 387 cycles. The cause of degradation is attributed to the lack of K+ ions available to PB film.

Comparison of Glare Sensation from the Light Sources in the Central Vision and the Peripheral Vision.

Reduction of discomfort glare from a lighting installation is one of important factors for comfortable lighting. In a practical room, there are several light sources located at various positions. If an occupant look around room, he will see the light sources in both central and peripheral vision. Therefore it is important to establish criteria of discomfort glare effect for two or more sources in both central and peripheral positions. For the discussion on the criteria, the difference of the glare effects between central and peripheral visions needs to be clarified. However, the experiments in former studies are not sufficient for this purpose. Authours conducted an experimental study of subjective appraisal regarding the comparison of glare sensation from the light sources in the central vision and peripheral vision. Authours compared glare of light source in the central vision with each light source in the peripheral vision of upper side, right side and lower side location.The results are as follows:(1) Both source positions have similar slope in the equal-glare curve showing the relationship between source and background luminance.(2) As far as the glare effects from solid angle of a source, peripheral vision of right side and lower side source positions is similar to central vision, but peripheral vision of upper side source position is not similar.(3) The results regarding the peripheral vision of upper side source position, show some similarities to the study by Hopkinson and Bodmann.

Vision at the workplace: Part I — Guidelines for the practitioner

Visual problems at the workplace are unlikely to affect the worker's health although they may cause unnecessary stress on the visual system, sometimes resulting in headache and fatigue. Visual performance may be affected, resulting in increased errors and time/unit. Visual problems can be due to deficiencies in the individual, the lighting, or the task. In most cases, visual deficiencies can be corrected with corrective lenses, either spectacles or contact lenses. Lighting deficiencies will be divided into quantity and quality. There are two basic approaches to lighting workstations—uniform lighting and nonuniform (task) lighting. In addition to light color and light orientation and variability, glare also affects the quality of light. Glare reduction techniques include (1) reducing brightness of the glare source and (2) reducing size of the glare source. Indirect (reflected) glare reduction techniques include (1) reducing amount of light from the source and (2) reorientation of the reflecting surface.

Excimer laser treatment of corneal surface pathology: a laboratory and clinical study.

The argon fluoride excimer laser emits radiation in the far ultraviolet part of the electromagnetic spectrum (193 nm). Each photon has high individual energy. Exposure of materials or tissues with peak absorption around 193 nm results in removal of surface layers (photoablation) with extremely high precision and minimal damage to non-irradiated areas. This precision is confirmed in a series of experiments on cadaver eyes and the treatment of 25 eyes with anterior corneal disease (follow-up 6 to 30 months). Multiple zone excimer laser superficial keratectomy is considered the treatment of choice for rough, painful corneal surfaces. All patients in this group were pain-free postoperatively. Where good visual potential exists, ablation of a single axial zone is recommended and results in improved visual acuity and reduction of glare. A hyperopic shift was noted in this group.

The use of tinted contact lenses in a case of congenital rod monochromatism

The use of red tinted soft contact lenses in a case of rod monochromatism was found to provide greatly improved visual function. The main advantages were better glare reduction than spectacles, improved perception of objects and patterns, and better cosmetic appearance than spectacles, resulting in greater self confidence.

Aging and Visual Impairment

The incidence of visual impairment greatly increases with age. Diabetic retinopathy, senile cataracts, senile macular degeneration and glaucoma are the leading causes of blindness in elderly persons. Environmental modifications, such as levels of illumination and reduction of glare, can enhance an individual's ability to function in society. The nursing home population needs to pay attention to environmental factors as well as standardization of procedures for vision assessment. Much work is needed to develop programs to properly screen and treat the visual problems in elderly persons.