Visual function correlates of self-reported vision-related nighttime driving difficulties / La función visual se correlaciona con las dificultades de conducción nocturna relacionadas con la visión autoinformadas

Purpose: To investigate the visual function correlates of self-reported vision-related night driving difficulties among drivers. Methods: One hundred and seven drivers (age: 46.06 ± 8.24, visual acuity [VA] of 0.2logMAR or better) were included in the study. A standard vision and night driving questionnaire (VND-Q) was administered. VA and contrast sensitivity were measured under photopic and mesopic conditions. Mesopic VA was remeasured after introducing a peripheral glare source into the participants' field of view to enable computation of disability glare index. Regression analyses were used to assess the associations between VND-Q scores, and visual function measures. Results: The mean VND-Q score was -3.96±1.95 logit (interval scale score: 2.46±1.28). Simple linear regression models for photopic contrast sensitivity, mesopic VA, mesopic contrast sensitivity, and disability index significantly predicted VND-Q score (P<0.05), with mesopic VA and disability glare index accounting for the greatest variation (21 %) in VND-Q scores followed by photopic contrast sensitivity (19 %), and mesopic contrast sensitivity (15 %). A multiple regression model to determine the association between the predictors (photopic contrast sensitivity, mesopic VA, mesopic contrast sensitivity, and disability index) and VND-Q score yielded significant results, F (4, 102) = 8.58, P < 0.001, adj. R2 = 0.2224. Seeing dark-colored cars was the most challenging vision task. Conclusion: Changes in mesopic visual acuity, photopic and mesopic contrast sensitivity, as well as disability glare index are associated with and explain night driving-related visual difficulties. It is recommended to incorporate measurement of these visual functions into assessments related to driving performance.(AU)

Visual function correlates of self-reported vision-related nighttime driving difficulties.

PURPOSE: To investigate the visual function correlates of self-reported vision-related night driving difficulties among drivers. METHODS: One hundred and seven drivers (age: 46.06 ± 8.24, visual acuity [VA] of 0.2logMAR or better) were included in the study. A standard vision and night driving questionnaire (VND-Q) was administered. VA and contrast sensitivity were measured under photopic and mesopic conditions. Mesopic VA was remeasured after introducing a peripheral glare source into the participants' field of view to enable computation of disability glare index. Regression analyses were used to assess the associations between VND-Q scores, and visual function measures. RESULTS: The mean VND-Q score was -3.96±1.95 logit (interval scale score: 2.46±1.28). Simple linear regression models for photopic contrast sensitivity, mesopic VA, mesopic contrast sensitivity, and disability index significantly predicted VND-Q score (P<0.05), with mesopic VA and disability glare index accounting for the greatest variation (21 %) in VND-Q scores followed by photopic contrast sensitivity (19 %), and mesopic contrast sensitivity (15 %). A multiple regression model to determine the association between the predictors (photopic contrast sensitivity, mesopic VA, mesopic contrast sensitivity, and disability index) and VND-Q score yielded significant results, F (4, 102) = 8.58, P < 0.001, adj. R2 = 0.2224. Seeing dark-colored cars was the most challenging vision task. CONCLUSION: Changes in mesopic visual acuity, photopic and mesopic contrast sensitivity, as well as disability glare index are associated with and explain night driving-related visual difficulties. It is recommended to incorporate measurement of these visual functions into assessments related to driving performance.

Quantitative indicators of street lighting with mood, fatigue, mental workload and sleepiness in car drivers: Using generalized structural equation modeling.

Inadequate lighting will be associated with some degree of perceptual error such as sleepiness. The main purpose of this study was to investigate the interactions between mood, fatigue, mental workload, and sleepiness and their relationship with quantitative indicators of street lighting in passenger car drivers. The present study was a cross-sectional study that was performed on 270 drivers of passenger cars. The quantitative indices of lighting studied were illuminance, luminance, uniformity, and disability glare which were calculated using the Hagner device (EC1-L) and according to EN 13201 standard. Alertness and mood indices, fatigue scale (SAMN-PERELLI), mental workload (NASA-TLX), positive and negative affect schedule (PANAS) were used. Generalized structural equation modeling (GSEM) was used to investigate the relationship between mood, fatigue, mental workload, and drivers' sleepiness. Data analysis was performed in version 26 of SPSS software and version 14 of Stata software There is a significant relationship between illuminance and mood (P < 0.001). There is a significant relationship between the degree of disability glare on the streets and the mood (P = 0.006). There is a significant relationship between fatigue score and mood (P < 0.001) so that with increasing one unit in fatigue scale, mood score decreases by 0.669 units (P < 0.001). Finally, it can be assured that lighting interventions can be done as an effective way to increase alertness and reduce fatigue and the mental workload of drivers with the aim of reducing night traffic accidents.

Impact of Perioperative Dry Eye Treatment with Rebamipide Versus Artificial Tears on Visual Outcomes After Cataract Surgery in Japanese Population.

INTRODUCTION: The present study aimed to compare the effects of rebamipide and artificial tears during the perioperative period of cataract surgery on the postoperative visual outcomes. METHODS: Seventy-two eyes from 36 patients with a cataract were enrolled. Rebamipide (group R) was administered in one eye and Mytear® artificial tear ophthalmic solution (group A) in the other eye from 4 weeks preoperatively to 3 months postoperatively. Tear breakup time (TBUT), high-order aberrations (HOAs), superficial punctate keratopathy in the central part of the cornea (C-SPK), and corrected distance visual acuity (CDVA) were assessed at baseline, 1 week, 1 month, and 3 months after cataract surgery with trifocal intraocular lens (IOL) implantation. Contrast sensitivity and disability glare with visual angle values compatible with spatial frequencies of 1.1, 1.8, 2.9, 4.5, 7.1, and 10.2 cycles/degree (CPD) were evaluated postoperatively. Between-group differences of all variables were analyzed. RESULTS: At baseline, no significant differences in the variables were noted between the two groups. Mean TBUT was significantly higher, while mean C-SPK and HOAs were significantly lower in group R than in group A at each assessment. Mean CDVA was significantly higher at 1 week and 1 month postoperatively in group R compared with group A; this value was not significant at 3 months. Between-group differences in contrast sensitivity and disability glare were statistically significant at all spatial frequencies, 1 week and 1 month postoperatively. At 3 months postoperatively, there were significant differences in contrast sensitivity and disability glare at most spatial frequencies. CONCLUSION: Dry eye management with rebamipide in the perioperative period of cataract surgery with trifocal IOL implantation was significantly more effective than artificial tears in improving ocular surface condition, contrast sensitivity, and disability glare postoperatively.

Photophobia and disability glare in adult patients with Marfan syndrome: a case-control study.

PURPOSE: The aim of the present study was to investigate photophobia and disability glare in adult patients with Marfan syndrome (MFS). METHODS: In this case-control study, 44 patients with MFS (87 eyes) were compared to 44 controls (88 eyes), who were matched for age and sex. The subjects were asked to grade their photophobia and glare using 10-cm visual analogue scales (VAS), which were marked with 'never' at zero and 'always' at 10 -cm. In addition, disability glare was measured with C-Quant straylight meter. RESULTS: The patients with MFS had significantly higher VAS scores than the controls in four out of seven statements related to photophobia and glare. When including cataract, spherical equivalent, iris colour, axial length and corneal curvature, three of the seven statements were still significantly different between the two groups. The mean straylight values were 1.29 ± 0.03 log(s) in the MFS group and 1.01 ± 0.03 log(s) in the control group (p < 0.001, mixed model). These differences remained significant after adjusting for cataract, spherical equivalent, iris colour, axial length and corneal curvature. CONCLUSION: Patients with MFS reported more photophobia and had a higher straylight value than the control group. Awareness of these findings of more photophobia and glare in the MFS patients is important when counselling and treating these patients.

The effect of veiling luminance on the disability glare of car headlamps designed in Iran.

Objectives. One of the main risk factors involved in increasing driving accidents at night is due to the veiling luminance of the car's headlights reducing the contrast of images in the retina and, thus, reducing the visual performance of drivers. The aim of this study is to investigate the veiling luminance caused by the headlights of the best-selling vehicles in Iran. Methods. Using the Stiles-Holiday disability glare equation, the veiling luminance of headlights of common vehicles at distances of 10-100 m for both high-beam and low-beam modes of oncoming vehicles was measured on a road for healthy (young, middle-aged and older) drivers. Results. Under high-beam illumination, as the cars approached each other, the average illuminance of the car headlights gradually increased. Moreover, age had a significant impact on the veiling luminance. This study also showed that, in same-age groups, the Samand Souren and Peugeot Pars cars had the highest and lowest mean veiling luminance, respectively. Conclusion. The findings showed that the illuminance (at large distances between two cars) and the angle between the source of glare and the eyes of drivers (as two cars approach to each other) have a dominant influence on the disability glare.

Disability glare and nighttime driving performance among commercial drivers in Ghana.

OBJECTIVE: Glare caused by the headlights of on-coming vehicles risk safe driving at night. The study aimed to determine the relationship between glare exposure and nighttime driving performance among commercial drivers in Ghana. METHODS: This cross-sectional study involved commercial drivers with complaints of nighttime driving difficulties (N = 80; mean age = 41.5 ± 11.1 years). A questionnaire was used to investigate nighttime driving performance following glare exposure. We measured contrast sensitivity and visual acuity under photopic conditions. With an experimental setup in a mesopic setting, we measured visual acuity with and without glare exposure. The difference between the two mesopic visual acuities was quantified as disability glare index. With the same setup, photostress recovery time was also measured. Regression analyses were used to determine the relationship between nighttime driving performance score and the measures taken in both photopic and mesopic settings. RESULTS: The average nighttime driving performance score was 47.8 ± 17.5. Driving performance was negatively correlated with all variables (R = -0.87 to -0.30, all p < .01), except contrast sensitivity (R = 0.74, p < .01). A multiple linear regression showed that the model with all variables explained 83.8% of the variance, but only disability glare index was a significant predictor of nighttime driving performance following glare exposure (standardized B = -0.61, p < .01). CONCLUSION: Our results show that the change in mesopic visual acuities following glare can predict nighttime driving performance. This measure can be incorporated into the assessment of driving fitness by licensing departments to evaluate whether a person can drive safely at night amidst glare exposure.

Straylight in Different Types of Intraocular Lenses.

Purpose: To show the importance of measuring the angular distribution of straylight as an in vitro test for intraocular lenses (IOLs). Methods: The optical integration method was implemented to measure the point spread function, up to 5.1°, of IOLs immersed in a wet cell. The straylight parameter was calculated as the product of the point spread function by the squared angle. The effect of the scattered light is shown in extended images of a target surrounded by headlamps as glare sources. Three different IOLs were tested: (1) AcrySof IQ SN60WF, monofocal, (2) AcrySof IQ PanOptix, trifocal, and (3) Tecnis Symfony ZRX00, bifocal with extended depth of focus. Measurements were compared to previously reported clinical studies where the same IOL models were implanted. Results: The mean amount of scattered light, between 1.0° and 5.1°, generated by each IOLs were, in deg2sr-1 units: (1) 1.2, (2) 12.1, and (3) 33.4. Lens (3) present a high amount of straylight related to a halo of an approximate diameter of 2°. Conclusions: In vitro measurements of the angular distribution of the point spread function of different types of IOLs showed important aspects related to their manufacturing quality. These results are in line with previous clinical findings where glare sensitivity was tested in the same angular range. Translational Relevance: In vitro measurement of angular dependence of straylight in IOLs, regardless their design, provides a valuable feedback to improve their optical quality. The minimization of the amounts of straylight positively impacts the recurrence of photic phenomena.

Reduced Contrast Sensitivity Function in Central and Peripheral Vision by Disability Glare.

Various glares can decrease visual performance and cause discomfort, thus increasing drivers' risk for traffic accidents in real life. The current study aimed to systematically investigate glare sensitivity in the central and peripheral visual fields by measuring contrast sensitivity function (CSF) under nonglare, steady glare, and transient glare conditions. Nine observers with normal visual acuity in the dominant eye were enrolled. The CSF in central and peripheral vision (the 5° upper left visual field) was measured in a mesopic environment while the stimulus was displayed under three conditions: nonglare, steady glare, and transient glare. An orientation identification task was used to obtain the CSF. After the experiment, the observers were asked to report their level of discomfort in the presence of the glare. The area under the log CSF (AULCSF) and cut-off spatial frequency served as indicators of visual performance. In agreement with previous studies, both steady and transient glare reduced the AULCSF and cut-off frequency. However, the AULCSF and cut-off frequency were reduced more for central vision than for nearly peripheral vision. In addition, the extent of the decreases in the AULCSF and cut-off frequency was greater for steady glare than for transient glare; in contrast, more discomfort was associated with transient glare than steady glare.

Validation of the driver ecological glare test.

INTRODUCTION: The present study proposes to validate the Driver Ecological Glare Test (DEGT), a test developed to measure the benefit of a headlight glare Advanced Driver Assistance System (ADAS), by comparing it to a laboratory glare test. METHOD: Twenty-four participants, aged from 55 to 70 years, were recruited to complete a visual examination, including monocular halo size measurement for both eyes using Vision Monitor device (MonCv3; Metrovision). An on-field evaluation took place at night at the UTAC CERAM test track to obtain disability glare measures using the DEGT. RESULTS: A significant correlation was found between the two glare tests and Bland-Altman analysis reveals a good agreement with a bias of 73.7 arcmin between the halo size measurements obtained from the DEGT and Vision Monitor. The results of the present study demonstrate that the DEGT is a valid method to test halo size and is adapted to evaluate the benefits of an antiglare device for drivers in an ecological situation.

Investigation of flashing and intensity characteristics for vehicle-mounted warning beacons.

Reducing the potential for crashes involving front line service workers and passing vehicles is important for increasing worker safety in work zones and similar locations. Flashing yellow warning beacons are often used to protect, delineate, and provide visual information to drivers within and approaching work zones. A nighttime field study using simulated workers, with and without reflective vests, present outside trucks was conducted to evaluate the effects of different warning beacon intensities and flash frequencies. Interactions between intensity and flash frequency were also analyzed. This study determined that intensitiesof 25/2.5 cd and 150/15 cd (peak/trough intensity) provided the farthest detection distances of the simulated worker. Mean detection distances in response to a flash frequency of 1 Hz were not statistically different from those in response to 4 Hz flashing. Simulated workers wearing reflective vests were seen the farthest distances away from the trucks for all combinations of intensity and flash frequency.

Disability glare in soft multifocal contact lenses.

PURPOSE: The study investigated the effect of the design of multifocal contact lenses on the sensitivity to contrast and disability glare. METHODS: Contrast sensitivity was measured in 16 young adults (mean age: 25.5±2.5years) at a distance of 2m under two conditions: no-glare and glare. Two designs (Center Near and Center Distance) of the Biofinity soft contact lens were used to simulate correction for presbyopes, while a correction with single vision trial lenses and contact lenses acted as controls. RESULTS: The design of the used multifocal contact lenses had a significant influence on the log area under the curve of the contrast sensitivity function (AUC-CSF). Compared to the spectacle lens correction, the AUC-CSF was significantly reduced, in case CS was measured with the Center Near design lens, under the no-glare (p<0.001) and the glare condition (p: p<0.001). In case of the Center Distance design contact lens, the AUC-CSF was significantly smaller in case CS was tested under glare (p=0.001). Disability glare (DG) was depending on the spatial frequency and the design of the multifocal lens, while the Center Distance design produced higher amounts of DG (p<0.001), compared to the other used corrections. CONCLUSION: The optical design of a multifocal contact lenses has a significant impact on the contrast sensitivity as well as the disability glare. In order to dispense the best correction in terms of contact lenses, the sensitivity to contrast under no-glare and glare conditions should be tested a medium spatial frequencies.

Macular carotenoid supplementation improves disability glare performance and dynamics of photostress recovery.

BACKGROUND: The so-called macular carotenoids (MC) lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ) comprise the diet-derived macular pigment (MP). The purpose of this study was to determine effects of MC supplementation on the optical density of MP (MPOD), repeated-exposure photostress recovery (PSR), and disability glare (DG) thresholds. METHODS: This was a double-blind, placebo-controlled trial. Fifty-nine young (mean age = 21.7), healthy volunteers participated in this study. Subjects supplemented their daily diet with either 10 mg L + 2 mg total Z (1 mg Z + 1 mg MZ; n = 24), 20 mg L + 4 mg total Z (2 mg Z + 2 mg MZ; n = 25), or placebo (n = 10) for 12 months. The primary outcome was a composite measure of visual performance in glare, defined by change in DG and PSR. Secondary outcomes included MPOD and visual fatigue. The primary endpoint for outcomes was 12 months. MPOD was assessed with customized heterochromatic flicker photometry. PSR times for an 8 cycle /degree, 15 % contrast Gabor patch target were determined after each of five successive exposures to intense LED lights. DG threshold was defined as the intensity of a ring of lights through which subjects were able to maintain visibility of the aforementioned target. Measures of all parameters were conducted at baseline, 6 months, and 12 months. Repeated-measures ANOVA, and Pearson product-moment correlations were used to determine statistically significant correlations, and changes within and between groups. RESULTS: MPOD for subjects in both supplementation groups increased significantly versus placebo at both 6- and 12-month visits (p < 0.001 for all). Additionally, PSR times and DG thresholds improved significantly from baseline compared to placebo at 6- and 12-month visits (p < 0.001 for all). At baseline, MPOD was significantly related to both DG thresholds (r = 0.444; p = 0.0021) and PSR times (r = -0.56; p < 0.001). As a function of MPOD, the repeated-exposure PSR curves became more asymptotic, as opposed to linear. The change in subjects' DG thresholds were significantly related to changes in PSR times across the study period (r = -0.534; p < 0.001). CONCLUSIONS: Increases in MPOD lead to significant improvements in PSR times and DG thresholds. The asymptotic shape of the repeated-exposure PSR curves suggests that increases in MPOD produce more consistent steady-state visual performance in bright light conditions. The mechanism for this effect may involve both the optical filtering and biochemical (antioxidant) properties of MP. TRIAL REGISTRATION: ISRCTN trial registration number: ISRCTN54990825. Data reported in this manuscript represent secondary outcome measures from the registered trial.

Google Glass Glare: disability glare produced by a head-mounted visual display.

PURPOSE: Head mounted displays are a type of wearable technology - a market that is projected to expand rapidly over the coming years. Probably the most well known example is the device Google Glass (or 'Glass'). Here we investigate the extent to which the device display can interfere with normal visual function by producing monocular disability glare. METHODS: Contrast sensitivity was measured in two normally sighted participants, 32 and 52 years of age. Data were recorded for the right eye, the left eye and then again in a binocular condition. Measurements were taken both with and without the Glass in place, across a range of stimulus luminance levels using a two-alternative forced-choice methodology. RESULTS: The device produced a significant reduction in contrast sensitivity in the right eye (>0.5 log units). The level of disability glare increased as stimulus luminance was reduced in a manner consistent with intraocular light scatter, resulting in a veiling retinal illuminance. Sensitivity in the left eye was unaffected. A significant reduction in binocular contrast sensitivity occurred at lower luminance levels due to a loss of binocular summation, although binocular sensitivity was not found to fall below the sensitivity of the better monocular level (binocular inhibition). CONCLUSIONS: Head mounted displays such as Google Glass have the potential to cause significant disability glare in the eye exposed to the visual display, particularly under conditions of low luminance. They can also cause a more modest binocular reduction in sensitivity by eliminating the benefits of binocular summation.

Toward Performance Specifications for Flashing Warning Beacons.

Yellow flashing warning beacons help protect front line service workers, including those in transportation, utility and construction sectors. To safeguard these workers, beacons should be readily detected and should provide veridical information about their relative movement. Two psychophysical laboratory experiments were conducted to provide empirical foundations for two aspects of warning beacon performance, detection and judgments of relative movement. In the first experiment reaction times were measured to the onset of flashing warning beacons varying in peak intensity while observers viewed different scene conditions. Observers also judged the visibility of nearby low-contrast targets in the presence of the flashing warning beacons. Asymptotic response times to the onset of beacons occurred when their peak intensity was at least 750 cd during daytime. Visibility of low contrast targets during nighttime, when glare is most critical, did not decrease substantially when the peak intensity was below 2000 cd. In the second experiment response times were measured to warning beacons of different flash-sequence patterns as they approached the observer. Judgments of gap closure were improved, relative to fully-on/fully-off flashing, with flash sequences where the minimum beacon intensity was at least 10% of the peak intensity and with two synchronized flashing beacons rather than one. With regard to performance specifications, the minimum value for the peak intensity of warning beacons should be 750 cd, with a maximum value of 2000 cd for detection. Fully-on/fully-off flash sequences should be changed to fully-on/partial-off to enhance judgments of gap closure on moving vehicles. Moreover, two flashing warning beacons, rather than one, should be mounted on service vehicles to improve gap closure judgments.

A pilot study to determine if intraocular lens choice at the time of cataract surgery has an impact on patient-reported driving habits.

PURPOSE: To determine if intraocular lens (IOL) choice at the time of cataract surgery affects driving habits. MATERIALS AND METHODS: Pseudophakes who were 28-35 months postbilateral cataract surgery with one of two contemporary one-piece hydrophobic acrylic IOLs (SN60WF or ZCB00) were asked to complete the Driving Habits Questionnaire, a validated instrument for determining self-reported driving status, frequency, and difficulty. To determine if there were any differences in driving habits between the two groups, t-tests and χ (2) tests were used. RESULTS: Of 90 respondents, 72 (40 SN60WF and 32 ZCB00) were still active drivers. The SN60WF-implanted subjects were less likely to drive at the same speed or faster than the general flow of traffic, less likely to rate their quality of driving as average/above average, less likely to have traveled beyond their immediate neighborhood, less likely to drive at night, more likely to have moderate-to-severe difficulty driving at night, and more likely to have self-reported road traffic accidents. The differences did not reach statistical significance. CONCLUSION: Changes in patients' driving habits 2-3 years after cataract surgery may be associated with the type of IOL implanted. A larger study, powered to demonstrate statistical significance, is needed to verify the trends identified in this pilot study and discover possible contributing factors.

A double-blind, placebo-controlled study on the effects of lutein and zeaxanthin on photostress recovery, glare disability, and chromatic contrast.

PURPOSE: Past studies have shown that higher macular pigment optical density (MPOD) and lutein (L) and zeaxanthin (Z) supplementation are related to improvements in glare disability, photostress recovery, and chromatic contrast. This study assessed those links using a randomized, double-blind, placebo-controlled design. METHODS: The visual effects of 1 year of supplementing L (10 mg/d) and Z (2 mg/d) were investigated. One hundred fifteen young, healthy subjects were recruited and randomized into the study (58 received placebo, 57 L+Z). Several dependent measures were collected at baseline and then once every 3 months: serum L and Z measured by HPLC chromatography; MPOD measured using customized heterochromatic flicker photometry; photostress recovery assessed by measuring the time needed to recover visual acquisition of a grating target after 30 seconds of an intense xenon white flash exposure; glare disability evaluated as the energy in a surrounding annulus necessary to veil a central grating target; and chromatic contrast assessed by measuring thresholds for a yellow grating target superposed on a 460-nm background. RESULTS: Macular pigment optical density increased significantly versus placebo at all eccentricities (10, 30, 60, and 105 minutes from the center of the macula). Serum L and Z also increased significantly by the first follow-up visit (at 3 months), and remained elevated throughout the intervention period of 1 year. Chromatic contrast and photostress recovery time improved significantly versus placebo. Glare disability was correlated with macular pigment density throughout the study period but did not increase significantly in the treated group. CONCLUSIONS: Daily supplementation with L+Z resulted in significant increase in serum levels and MPOD and improvements in chromatic contrast and recovery from photostress. These results are consistent with past studies showing that increasing MPOD leads to improved visual performance. (ClinicalTrials.gov number, NCT00909090.).

Macular pigment levels do not influence C-Quant retinal straylight estimates in young Caucasians.

BACKGROUND: Individuals with higher than normal levels of macular pigment optical density (MPOD) are less affected by disability glare, when using glare source lights with a strong short-wavelength component. The aim of this study was to investigate whether estimates of retinal straylight from the Oculus Cataract Quantifier (C-Quant), which corresponds to disability glare, are associated with estimates of macular pigment levels in young Caucasian eyes. METHODS: Thirty-seven Caucasian individuals (aged 19 to 40 years) with good visual acuity, free from ocular disease and with clear ocular media participated. Macular pigment optical density was measured at 0.5 degrees eccentricity from the foveal centre using a heterochromatic flicker photometry-based densitometer instrument from MacularMetrics. Retinal straylight was estimated using the C-Quant, a commercially available device, which uses a psychophysical compensation comparison method. RESULTS: Mean MPOD was 0.39 ± 0.18 log units (range zero to 0.80) and was not significantly related to age (r = -0.07, p = 0.66). Mean straylight parameter (s) was 1.01 ± 0.09 log units (range 0.86 to 1.21) and was not significantly related to age (r = -0.03, p = 0.86). Although there was a small tendency for straylight measurements to be reduced in individuals with higher levels of MPOD, there was no statistically significant relationship between retinal straylight and MPOD (r = -0.17, p = 0.30). CONCLUSION: Ocular straylight, estimated by the Oculus C-Quant, is little influenced by macular pigment optical density. As the C-Quant uses balanced (white) lights, it is suggested that the previous findings on the effect of macular pigment critically depend on the use of blue-dominant glare sources.

Consensus and new improvements of disability glare / 国际眼科杂志(Guoji Yanke Zazhi)

Patients with early cataract may have normal visual acuity ( VA ) but complain that they have problems in driving at night, like seeing things through a veil. This phenomenon is defined as disability glare which maybe caused by growing stray light. Patients with intraocular lens following cataract surgery may complain about glare, halos and shadows in visual field, which are also resulted from dysphotopia. Disability glare is the VA loss due to disturbing luminance in visual field. ln other words, it's the retinal contrast sensitivity reduction because of the straylight. This article contains the consensus and new progress of disability glare. lt provides solutions according to its effect factors and offers clues for further study.

N-Acetylcarnosine sustained drug delivery eye drops to control the signs of ageless vision: glare sensitivity, cataract amelioration and quality of vision currently available treatment for the challenging 50,000-patient population.

BACKGROUND: Innovative Vision Products, Inc. (IVP)'s scientists developed the lubricant eye drops (Can-C) designed as 1% N-acetylcarnosine (NAC) prodrug of L-carnosine containing a mucoadhesive cellulose-based compound combined with corneal absorption promoters in a sustained drug delivery system. Only the natural L-isomeric form of NAC raw material was specifically synthesized at the cGMP facility and employed for the manufacturing of Can-C eye drops. OBJECTIVE AND STUDY DESIGN: In the present clinical study the authors assessed vision before and after 9 month term of topical ocular administration of NAC lubricant eye drops or placebo in 75 symptomatic patients with age-related uncomplicated cataracts in one or both eyes, with acuity in one eye of 20/40 or worse (best-corrected distance), and no previous cataract surgery in either eye and no other ocular abnormality and 72 noncataract subjects ranged in age from 54 to 78 years. SETTING: Subjects in these subsample groups have reported complaints of glare and wanted to administer eye drops to get quick eye relief and quality of vision for their daily activities including driving and computer works. Following 9 months of treatment with NAC lubricant eye drops, most patients' glare scores were improved or returned to normal in disability glare tests with Halometer DG. Improvement in disability glare was accompanied with independent improvement in acuity. Furthermore, patients with the poorest pretreatment vision were as likely to regain certain better visual function after 9 months of treatment with N-acetylcarnosine lubricant eye drops as those with the worth pretreatment vision. PATIENTS OR OTHER PARTICIPANTS: The authors made a reference to electronic records of the product sales to patients who have been made the repurchase of the Can-C eye drops since December 2001. INTERVENTION: Based on this analysis of recorded adjustments to inventory, various parameters were analyzed during the continued repurchase behavior program, including testimonials from buyers. With these figures, researchers judged on the patients' compliance rate to self-administer NAC eye-drops. MAIN OUTCOME MEASURE AND RESULTS: The ophthalmic drug showed potential for the non-surgical treatment of age-related cataracts for participants after controlling for age, gender and daily activities and on a combined basis of repurchases behavior reports in more than 50,000 various cohort survivors, has been demonstrated to have a high efficacy and good tolerability for prevention and treatment of visual impairment determined for the older population with relative stable pattern of causes for blindness and visual impairment. The mechanisms of prevention and reversal of cataracts with NAC ophthalmic drug are considered which include prevention by the intraocular released carnosine of free-radical-induced inactivation of proprietary lens antioxidant enzymes (superoxide dismutase); prevention of carbohydrate and metal-catalyzed autooxidation of ascorbic acid-induced cross-linking glycation reactions to the lens proteins; transglycation properties of carnosine, allowing it to compete for the glycating agent, protecting proteins (lens crystallins) against modification; universal antioxidant and scavenging activity towards lipid hydroperoxides, aldehydes and oxygen radicals; activation with l-carnosine ingredient of proteasome activity in the lens; chaperone-like disaggregating to lens crystallins activity of NAC and of its bioactivated principal carnosine. Blindness incidence increased with advancing age, such as cataract and glaucoma, which are by far the commonest causes of blindness in our sample and in all age groups, glaucomatous neurodegeneration can be treated with developed NAC autoinduction prodrug eye drops equipped with corneal absorption promoters. The common blinding affections presenting in developed countries such as, senile macular degeneration, hereditary chorioretinal dystrophies, diabetic retinopathy are poorly represented in our current summary of vital-statistics and will be reported inherent in next N-acetylcarnosine ophthalmic drug studies. CONCLUSION: The authors present evidence, about why only a certain kind of NAC is safe, and why only certain formulas designed by IVP for drug discovery are efficacious in the prevention and treatment of senile cataract for long-term use. Overall cumulated studies demonstrate that the designed by IVP new vision-saving drug NAC eye drops help the aging eye to recover by improving its clarity, glare sensitivity, color perception and overall vision.