Glare Test Research Articles

Visual function improvement using photocromic and selective blue-violet light filtering spectacle lenses in patients affected by retinal diseases

BackgroundTo evaluate functional visual parameters using photocromic and selective blue-violet light filtering spectacle lenses in patients affected by central or peripheral scotoma due to retinal diseases.Sixty patients were enrolled in this study: 30 patients affected by central scotoma, group 1, and 30 affected by peripheral scotoma, group 2.Black on White Best Corrected Visual Acuity (BW-BCVA), White on Black Best Corrected Visual Acuity (WB-BCVA), Mars Contrast Sensitivity (CS) and a Glare Test (GT) were performed to all patients.Test results with blue-violet filter, a short-pass yellow filter and with no filters were compared.ResultsAll scores from test results increased significantly with blue-violet filters for all patients.The mean BW-BCVA increased from 0.30 ± 0.20 to 0.36 ± 0.21 decimals in group 1 and from 0.44 ± 0.22 to 0.51 ± 0.23 decimals in group 2 (Mean ± SD, p < 0.0001 in both cases).The mean WB-BCVA increased from 0.31 ± 0.19 to 0.38 ± 0.23 decimals in group 1 and from 0.46 ± 0.20 to 0.56 ± 0.22 decimals in group 2 (Mean ± SD, p < 0.0001 in both cases).The letter count for the CS test increased from 26.7 ± 7.9 to 30.06 ± 7.8 in group 1 (Mean ± SD, p = 0.0005) and from 31.5 ± 7.6 to 33.72 ± 7.3 in group 2 (Mean ± SD, p = 0.031).GT was significantly reduced: the letter count increased from 20.93 ± 5.42 to 22.82 ± 4.93 in group 1 (Mean ± SD, p < 0.0001) and from 24.15 ± 5.5 to 25.97 ± 4.7 in group 2 (Mean ± SD, p < 0.0001).Higher scores were recorded with the Blue filter compared to Yellow filter in all tests (p < 0.05).No significant differences in any test results could be detected between the Yellow filter and the No filter condition.ConclusionsThe use of a combination of photocromic lens with a selective blue-violet light filter showed functional benefit in all evaluated patients.

Comparative study of visual function and ocular aberrations of two different one-piece designed hydrophilic acrylic intraocular lens.

To determine whether the aspherical IOL, Tecnis ZCB00, can improve the visual quality by measuring visual acuity, wavefront aberrations, and contrast sensitivity. It was a retrospective case series. Patients who underwent phacoemulsification cataract surgery were divided into two groups. One group (Group TC) was implanted with one-piece aspherical acrylic IOL (Tecnis ZCB00, AMO); the other (Group SA) was implanted with one-piece spherical acrylic IOL (Sensar AAB00, AMO). Eighty-eight eyes were selected into this study, among them 43 eyes in 26 male cases and 45 eyes in 29 female cases. Thirty-six eyes in 23 cases were in Group TC, and 52 eyes in 32 cases were in Group SA. Threemonths postoperatively, aberrations were analyzed with i-Trace visual function analyzer (Tracy Technologies, USA). Contrast sensitivities were measured with Takaci-CGT-1000 contrast glare tester (Seiko, Japan). All the 88 eyes underwent phacoemulsification with intraocular lens implantation, without complications during or after surgery. Threemonths postoperatively, the uncorrected vision acuity in Group TC was significantly better than in Group SA (P=0.007). At the pupil size of 5.0mm, higher-order aberrations in Group TC were significantly higher than in Group SA (P=0.02), especially the spherical aberration (Z 40 ) (P<0.001); at the pupil size of 4.0mm, Z 40 in Group SA was statistically higher than in Group TC (P<0.001); at the pupil size of 3.0mm, higher-order aberrations such as coma (Z 3-1,1 ) and trefoil aberration (Z 3-3,3 ) in Group SA were obviously higher than in Group TC (P=0.01). In the low spatial frequency, the contrast sensitivity and the glare sensitivity in Group TC were significantly higher than in Group SA (P<0.05). By the short-term follow-up (3months), the aspherical acrylic IOL can reduce the higher-order aberrations (especially the spherical aberration) and increase the contrast sensitivity to improve the visual performance.

Atypical sensory sensitivity as a shared feature between synaesthesia and autism

Several studies have suggested that there is a link between synaesthesia and autism but the nature of that link remains poorly characterised. The present study considers whether atypical sensory sensitivity may be a common link between the conditions. Sensory hypersensitivity (aversion to certain sounds, touch, etc., or increased ability to make sensory discriminations) and/or hyposensitivity (desire to stimulate the senses , or a reduced response to sensory stimuli are a recently introduced diagnostic feature of autism spectrum conditions (ASC). Synaesthesia is defined by unusual sensory experiences and has also been linked to a typical cortical hyper-excitability. The Glasgow Sensory Questionnaire (GSQ) was administered to synaesthetes and people with ASC. Both groups reported increased sensory sensitivity relative to controls with a large effect size. Both groups also reported a similar pattern of both increased hyper- and hypo-sensitivities across multiple senses. The AQ (Autism-Spectrum Quotient) scores were elevated in the synaesthetes, and one subscale of this measure (attention to detail) placed synaesthetes within the autistic range. A standard laboratory test of visual stress (the Pattern Glare Test), administered online, corroborated the findings of increased sensitivity to aversive visual stimuli in synaesthetes. We conclude that atypical sensory sensitivity is an important shared feature between autism and synaesthesia.

A Delphi study to develop practical diagnostic guidelines for visual stress (pattern-related visual stress)

PurposeVisual stress (VS) is characterised by symptoms of visual perceptual distortions and eyestrain when viewing text, symptoms that are alleviated by individually prescribed coloured filters. A recent review supports the existence of VS and its treatment, but noted that controversy remains, in part due to inconsistencies in the diagnosis of the condition. The present paper reviews the diagnostic criteria for VS in the literature and reports a Delphi analysis of the criteria currently used in clinical practice. MethodsTwenty-six eyecare practitioners were invited to participate in a Delphi study. They were selected because they were frequent prescribers of precision tinted lenses. In the first round they were sent a list of the indicators for which there is literature to suggest a relevance in the diagnosis of VS. The practitioners were invited to rank the indicators and add any additional criteria they use in diagnosis. In the second round a revised list was circulated, including items added from the responses in the first round. ResultsThe respondents included optometrists, orthoptists and opticians. In the first round the response rate was 85%. Ninety-one percent of those who participated in the first round also responded in the second round. Strong indicators in the second round included the symptom of words moving when reading, voluntary use of an overlay for a prolonged period, improved performance of ≥15% with an overlay on the Wilkins Rate of Reading test, and an abnormally high score on the Pattern Glare Test. ConclusionsThe strongest diagnostic criteria are combined in a diagnostic tool. This is proposed as a guide for clinical practice and further research.

Contrast Sensitivity after Pars Plana Vitrectomy: Comparison between Macula-On and Macula-Off Rhegmatogenous Retinal Detachment

Purpose: To evaluate the contrast sensitivity (CS) of eyes successfully repaired by vitrectomy for rhegmatogenous retinal detachment (RRD) with or without preoperative macular involvement. Methods: In this retrospective, consecutive, interventional case series, 109 eyes received primary vitrectomy for RRD, of which 36 with at least 12 months of follow-up and a best-corrected visual acuity (BCVA) ≥1 at 12 months postoperatively were investigated. The main outcome measurements were BCVA and CS at 12 months postoperatively. Patients with macula-on RRD preoperatively were included in the macula-on group, and patients with macula-off RRD preoperatively were included in the macula-off group. The between-group difference in CS under evening vision conditions was measured with a Takagi glare tester CGT-2000 at 6 visual angles and 13 contrast levels with and without glare. Results: CS was significantly lower in the macula-off group for targets with visual angles of 1.6, 1.0, and 0.64° with glare (p < 0.05) and for the target with a visual angle of 0.64° without glare (p < 0.05). Conclusions: CS in the higher spatial frequency range (especially with glare) is reduced in macula-off RRD patients with good postoperative BCVA compared to macula-on RRD patients with good postoperative BCVA.

The effect of viewing distance on responses to the pattern glare test

BackgroundWe investigated whether symptoms of pattern glare were affected by viewing distance, as distinct from spatial frequency, because of an association between symptoms and anomalies of accommodation and vergence.MethodsOne hundred young adults viewed gratings with spatial frequencies of 0.3, 2.3 and 9.4-cycles per degree (cpd) at four test distances (0.4, 0.8, 1.6 and 3.2 metres). Participants were asked to grade the presence of 15 symptoms of visual perceptual distortions and discomfort, on a scale from zero (no symptoms) to 10 (maximum perceptual and somatic symptoms).ResultsThe viewing distance did not affect the nature and strength of symptoms, when viewing gratings with similar spatial frequencies. The symptoms increased with spatial frequency (p < 0.008 for all comparisons).ConclusionsThe symptoms from the Pattern Glare Test do not appear to be modulated by the changes in accommodation and vergence associated with viewing distance, at least in an unselected sample of students. The highest spatial frequency of the current Pattern Glare Test was 9.4-cpd at 0.4 metre and this is insufficiently high to measure the reduction in symptoms at high spatial frequencies. If assessing relative aversion to gratings of different spatial frequencies, it may be useful to increase the testing distance to 0.6 metre so as to increase the spatial frequency of the third grating to 14.2-cpd.

Increased Vulnerability to Pattern-Related Visual Stress in Myalgic Encephalomyelitis.

The objective of this study was to determine vulnerability to pattern-related visual stress in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). A total of 20 ME/CFS patients and 20 matched (age, gender) controls were recruited to the study. Pattern-related visual stress was determined using the Pattern Glare Test. Participants viewed three patterns, the spatial frequencies (SF) of which were 0.3 (low-SF), 2.3 (mid-SF), and 9.4 (high-SF) cycles per degree (c/deg). They reported the number of distortions they experienced when viewing each pattern. ME/CFS patients exhibited significantly higher pattern glare scores than controls for the mid-SF pattern. Mid-high SF differences were also significantly higher in patients than controls. These findings provide evidence of altered visual perception in ME/CFS. Pattern-related visual stress may represent an identifiable clinical feature of ME/CFS that will prove useful in its diagnosis. However, further research is required to establish if these symptoms reflect ME/CFS-related changes in the functioning of sensory neural pathways.

Pattern glare: the effects of contrast and color.

Aim: To test a theory of visual stress by investigating the inter-relationships between (1) the threshold contrast/saturation at which individuals first report discomfort when viewing colored gratings of progressively increasing contrast and decreasing saturation; (2) the choice of a colored overlay for reading; (3) any increase in reading speed when the overlay is used.Method: Ninety-five young adults, with normal color vision, reported illusions from square-wave gratings (Pattern Glare Test), chose any colored overlays that improved clarity (Intuitive Color Overlays) and read aloud randomly ordered common words (Wilkins Rate of Reading Test). This was followed by an automated choice of tints for text using various screen colors on a tablet, and a test of discomfort from patterns of progressively increasing contrast and decreasing saturation, using software developed for this study. All participants wore their optimal refractive correction throughout the procedure.Results: Fifty-eight participants chose a colored overlay and reported that it made text easier and more comfortable to read. On average, these individuals had a greater improvement in reading speed with their overlays (p = 0.003), a lower contrast threshold at which discomfort from achromatic gratings was first reported (p = 0.015), and a tendency to report more pattern glare (p = 0.052), compared to the other participants. Participants who chose both a most and least preferred tint for text using the automated procedure reported discomfort from colored gratings at a significantly higher contrast with their most preferred color compared to their least preferred color (p = 0.003). The choice of a colored tint was moderately consistent across tests. The most and least preferred colors tended to be complementary.Conclusion: Colored tints that improved reading speed reduced pattern glare both in terms of the illusion susceptibility and in terms of discomfort contrast threshold, supporting a theory of visual stress. An automated test that incorporates colored gratings and a choice of most and least preferred color might better identify individuals whose reading speed improves with colored overlays.

Predicting the long-term use of overlays in children: the Pattern Glare Test

Aim: To determine whether the Institute of Optome- try Pattern Glare Test (PGT) could be used as a sensitive tool to predict the continued use of coloured overlays for reading in schoolchildren aged 7 to 12 years and to compare its sensitivity with that of the Wilkins Rate of Reading Test (WRRT) and the Developmental Eye Movement (DEM) test. Methods : Twenty-six children referred for a coloured overlay assessment in relation to difficulties with literacy skills were recruited to the study. An assessment took place which included orthoptic examination, coloured overlay assessment, PGT, WRRT and DEM test. The overlay chosen was provided for use at home and at school and follow- up took place 13–15 weeks later. Overlay usage was then analysed in relation to the scores recorded at the initial visit for PGT, WRRT and DEM test. Results: Nineteen children were still consistently using their overlays at the follow-up visit. No statistically significant difference was found in the PGT score of those children who consistently used overlays (group 1) compared with those who did not (group 2) (unpaired t -test, p = 0.62). The PGT was found to have 53% sensitivity in predicting those children who would consistently use overlays, com- pared with 79% for the WRRT and 77% for the DEM test. Conclusion : This study did not find the PGT to be a sensitive tool for predicting those children who would consistently use overlays in comparison with the WRRT and the DEM test.

Aspheric versus wavefront-guided photorefractive keratectomy: Contralateral eye study

To compare the refractive, visual, and aberrometric outcomes between wavefront-guided photorefractive keratectomy (PRK) and aspheric PRK in myopic patients. Khatam-al-Anbia Eye Hospital, Mashhad, Iran. Prospective randomized clinical trial. One eye of each patient was randomly assigned to excimer laser wavefront-guided PRK (Zyoptix) and the other eye to excimer laser aspheric PRK (Technolas 217z). The preoperative and 3-month and 6-month postoperative refractive errors, visual acuity, contrast sensitivity, and higher-order aberrations (HOAs) were compared between the groups. Ninety-six eyes (48 patients) were enrolled. At the last postoperative visit, there were no between-group differences in uncorrected distance visual acuity (UDVA) (P = .987) or corrected distance visual acuity (P = .416). The mean spherical equivalent was -0.076 diopter (D) ± 0.029 (SD) in the wavefront-guided group and -0.077 ± 0.075 D in the aspheric PRK group (P = .684). Postoperatively, the mean area under the log of contrast sensitivity function (AULCSF) with and without glare testing improved over preoperative values (both P < .001). There was no statistically significant between-group difference in the AULCSF with glare (P = .903) or without glare (P = .978). Total HOAs increased after PRK in both groups, although aspheric PRK induced fewer HOAs than wavefront-guided PRK (P = .04). Both PRK methods equally improved postoperative UDVA and contrast sensitivity. The HOAs increased after treatment with both methods; however, aspheric ablation induced statistically fewer HOAs than wavefront-guided ablation. No author has a financial or proprietary interest in any material or method mentioned.

Quantitative evaluation of visual function 12 months after bilateral implantation of a diffractive trifocal IOL.

To quantitatively evaluate visual function 12 months after bilateral implantation of the Physiol FineVision® trifocal intraocular lens (IOL) and to compare these results with those obtained in the first postoperative month. In this prospective case series, 20 eyes of 10 consecutive patients were included. Monocular and binocular, uncorrected and corrected visual acuities (distance, near, and intermediate) were measured. Metrovision® was used to test contrast sensitivity under static and dynamic conditions, both in photopic and low-mesopic settings. The same software was used for pupillometry and glare evaluation. Motion, achromatic, and chromatic contrast discrimination were tested using 2 innovative psychophysical tests. A complete ophthalmologic examination was performed preoperatively and at 1, 3, 6, and 12 months postoperatively. Psychophysical tests were performed 1 month after surgery and repeated 12 months postoperatively. Final distance uncorrected visual acuity (VA) was 0.00 ± 0.08 and distance corrected VA was 0.00 ± 0.05 logMAR. Distance corrected near VA was 0.00 ± 0.09 and distance corrected intermediate VA was 0.00 ± 0.06 logMAR. Glare testing, pupillometry, contrast sensitivity, motion, and chromatic and achromatic contrast discrimination did not differ significantly between the first and last visit (p&gt;0.05) or when compared to an age-matched control group (p&gt;0.05). The Physiol FineVision® trifocal IOL provided satisfactory full range of vision and quality of vision parameters 12 months after surgery. Visual acuity and psychophysical tests did not vary significantly between the first and last visit.

Computer Measurement of Central Visual Acuity under Mesopic and Glare Conditions in Eyes with Nuclear Cataract

Purpose: The CVA is an interactive, automated computer device that rapidly thresholds central acuity under conditions mimicking customary photopic and mesopic activities. In sequence, the CVA may test up to 6 environments, in this series under 3 mesopic environments (98%, 50% MC against 1.6 cd/m2 background, 25% MC against 5 cd/m2), then 3 glare environments (98%, 10% and 8% MC, against 200 cd/m2). This report compares the CVA thresholded acuity with that measured with letter charts, as well as with C-Quant derived glare testing and patient responses to the Activities of Daily Vision Scale (ADVS) in eyes with nuclear cataract. Methods: In 33 eyes with nuclear cataract compared with 69 emmetropic eyes without lens opacity, best refracted acuity was measured under CVA modules and with ETDRS charts presenting similar contrast and luminance. Both groups were also tested with 15% MC charts placed outdoors with sun overhead and with sun at 15° off-axis and compared with the CVA acuty at 10% MC and 8% MC thresholded in a darkened room. In 22 of the eyes with nuclear cataract, C-Quant analysis of straylight glare was also performed along with the ADVS. Results: Acuities thresholded with CVA modules demonstrated high Pearson correlation coefficients, and Bland and Altman statistical similarity with the acuities measured from similar contrast charts. The acuities measured with CVA glare modules correlated significantly with charts placed in sun glare and with C-Quant measurements of straylight. Significant correlations were noted between CVA acuities and near vision as well as distance driving tasks. Conclusions: The CVA demonstrates the ability to accurately threshold the acuity of eyes with nuclear cataract compared with chart acuity under conditions of contrast, luminance and fixation times simulating normal photopic and mesopic activities and to provide the physician with glare evaluation and ability to function under multiple types of activities.

Differences in Vision Between Clinic and Home and the Effect of Lighting in Older Adults With and Without Glaucoma

Patients often report greater visual difficulties at home than expected from vision testing in the clinic. Such discordance may be owing to worse vision in the home than measured in clinic. To compare vision measured between the clinic and home and evaluate factors, including lighting, associated with these differences. This cross-sectional study conducted from 2005-2009 involved 126 patients with glaucoma and 49 without glaucoma recruited from the Glaucoma and Comprehensive Eye Clinics at Washington University, St Louis, Missouri. Patients underwent clinic and home visits, were aged 55 to 90 years, were consecutively recruited, and met inclusion criteria for this study. A total of 166 eligible patients refused participation. Participants underwent clinic and home visits randomized to order of completion. At each visit, masked and certified examiners measured binocular distance visual acuity (DVA) with a nonbacklit chart, near visual acuity (NVA), contrast sensitivity (CS), CS with glare, and lighting. Differences in vision between the clinic and home. The mean scores for all vision tests were significantly better in the clinic than home for participants with and without glaucoma (P < .05, matched-pair t tests). For DVA, 29% of participants with glaucoma read 2 or more lines better in the clinic than home and 39% with advanced glaucoma read 3 or more lines better. For the entire sample, 21% of participants read 2 or more lines better in the clinic than home for NVA and 49% read 2 or more triplets better in the clinic for CS with glare. Lighting was the most significant factor associated with differences in vision between the clinic and home for DVA, NVA, and CS with glare testing (P < .05, multiple regression model). Median home lighting was 4.3 times and 2.8 times lower than clinic lighting in areas tested for DVA and NVA, respectively. Home lighting was below that recommended in 85% or greater of participants. Vision measured in the clinic is generally better than vision measured at home, with differences mainly owing to poor home lighting. Knowledge that vision discrepancies between patient report and clinical testing may be owing to home lighting may initiate clinician-patient discussions to optimize home lighting and improve the vision of older adults in their homes.

Sunglasses with Thick Temples and Frame Constrict Temporal Visual Field

Our aim was to compare the impact of two types of sunglasses on visual field and glare: one ("thick sunglasses") with a thick plastic frame and wide temples and one ("thin sunglasses") with a thin metal frame and thin temples. Using the Goldmann perimeter, visual field surface areas (cm²) were calculated as projections on a 30-cm virtual cupola. A V4 test object was used, from seen to unseen, in 15 healthy volunteers in the primary position of gaze ("base visual field"), then allowing eye motion ("eye motion visual field") without glasses, then with "thin sunglasses," followed by "thick sunglasses." Visual field surface area differences greater than the 14% reproducibility error of the method and having a p < 0.05 were considered significant. A glare test was done using a surgical lighting system pointed at the eye(s) at different incidence angles. No significant "base visual field" or "eye motion visual field" surface area variations were noted when comparing tests done without glasses and with the "thin sunglasses." In contrast, a 22% "eye motion visual field" surface area decrease (p < 0.001) was noted when comparing tests done without glasses and with "thick sunglasses." This decrease was most severe in the temporal quadrant (-33%; p < 0.001). All subjects reported less lateral glare with the "thick sunglasses" than with the "thin sunglasses" (p < 0.001). The better protection from lateral glare offered by "thick sunglasses" is offset by the much poorer ability to use lateral space exploration; this results in a loss of most, if not all, of the additional visual field gained through eye motion.

Relationship between absorptive lenses and contrast sensitivity in healthy young subjects with glare under photopic- and mesopic-vision conditions

We investigated the effect of absorptive lenses on contrast sensitivity under photopic- and mesopic-visions with glare, from the viewpoint of luminous transmittance (LT) and spectral transmittance. The subjects were 24 healthy volunteers. Log contrast sensitivity (logCS) under two luminance conditions with glare was measured with a contrast glare test device. Binocular logCSs with absorptive lenses were compared with those without absorptive lenses (control condition). Furthermore, to investigate the effect of spectral transmittance, we calculated the ratio of stimulus quantity and the correlation between this ratio and logCS. Compared with that in the control, logCS was hardly affected in the case of high-luminous-transmittance absorptive lenses under binocular visions with glare. Middle- and long-wavelength lights effectively contribute to contrast sensitivity under photopic-vision and lights at each wavelength showed almost the same coefficients of correlation under mesopic-vision. Previous studies suggested that absorptive lenses provide users with protection against harmful radiation and glare. Our present results suggested that short-wavelength and high-LT absorptive lenses are particularly useful in daylight.

Sunglasses with wide temples and thick frame severely constrict temporal visual field extent

AbstractPurpose To compare the impact of two types of sunglasses on visual field and glare: one (“thick sunglasses”) with a thick plastic frame and wide temples, and one (“thin sunglasses”) with a thin metal frame and thin temples.Methods Using the Goldmann perimeter, visual field surfaces (cm2) were calculated as projections on a 30 cm virtual cupola. A V4 test object was used, from seen to unseen, in 15 healthy volunteers in the primary position of gaze (“base visual field”), then allowing eye motion (“eye motion visual field”) without glasses, then with “thin sunglasses”, followed by “thick sunglasses”. Visual field surface area differences superior to the 14% reproducibility error of the method and having a p‐value inferior to 5% were considered significant. A glare test was done using a surgical lighting system pointed at the eye(s) at different incidence angles.Results No significant “base visual field” nor “eye motion visual field” surface area variation were noted comparing tests done without glasses and with the “thin sunglasses”. In contrast, a 22% “eye motion visual field” surface area decrease (p‐value = 2.7.10‐13) was noted comparing tests done without glasses and with “thick sunglasses”. This decrease was most severe in the temporal quadrant (‐33%; p‐value = 6.3.10‐20). All subjects reported less lateral glare with the “thick sunglasses” than with the “thin sunglasses” (p‐value = 6.10‐5).Conclusion The better protection from lateral glare offered by “thick sunglasses” is offset by a severe temporal “eye motion visual field” surface area constriction.

Can scattered light improve visual performance?

AbstractPurpose Light scattered by the media within the eye reduces object contrast and can also cause visual discomfort, in the presence of bright light sources. The addition of uniform veiling light over the retina can, however, change retinal sensitivity by increasing retinal illuminance. The extent to which reduction of target contrast and changes in retinal sensitivity caused by the presence of a glare source affect contrast acuity (CA) thresholds remains to be established. We investigate how CA is affected by glare source intensity, surround luminance and test target location on the retina. The aim is to determine the range of glare source intensity and background adaptation level that can improve visual performance.Methods 45 subjects with normal vision were investigated. A psychophysical flicker‐cancellation test (Ophthalmic &amp; Physiological Optics, 17, 171, 1997) was used to measure the amount and angular distribution of scattered light in the eye. CA thresholds were measured using the Contrast Acuity Assessment test (ASEM, 74, 551‐559, 2003). Three glare source intensities (i.e., 0, 1.35 and 19.21 lm/m^2 in the pupil plane), three eccentricities (5, 10 and 15 degrees), and three background luminances (1, 2.6 and 26 cd/m^2) were investigated.Results CA thresholds were measured for the test target / glare source parameters listed above. In addition, the scatter function of the eye was assessed for each subject and the measured parameters were used to predict the effect of veiling glare on CA thresholds.Conclusion Low intensity glare can improve CA in the high mesopic range. High intensity glare yields increased thresholds, but this loss of contrast sensitivity is, in general, smaller than predictions based on veiling glare luminance caused by forward light scatter in the eye.

Susceptibility to pattern glare following stroke

The aim of this work was to measure susceptibility to pattern glare within a stroke group, employing a direct method of assessment. Twenty stroke subjects, aged 38–85 years, were recruited, along with an age-matched control group (n = 20). Assessment of pattern glare susceptibility was undertaken using the pattern glare test. An abnormal degree of pattern glare is present when individuals score >1 on the mid-high spatial frequency difference variable, a relative score that allows for normalization of the subject, or >3 when viewing the mid spatial frequency grating. Stroke subjects demonstrate elevated levels of pattern glare compared to normative data values and a control population, as determined using the pattern glare test. This was most notable when considering the output measure for the mid-high difference variable. The mean score for the mid-high difference variable was 2.15 SD 1.27 for the stroke subjects versus 0.10 SD 1.12 for the control subjects. When considering the mid-high difference variable, 75% of the stroke group recorded an abnormal level of pattern glare compared to 5% in the control group. This study demonstrates an association between stroke subjects and elevated levels of pattern glare. Cortical hyperexcitability has been shown to present following stroke, and this has been proposed as a plausible explanation for the perceptual distortions experienced by individuals susceptible to pattern glare. Further work to assess the benefits of spectral filters in reducing perceptual distortions in stroke patients is currently underway.

고령자용 자동차 전조등의 눈부심 및 시인성 평가

The elder population with 65 years old or more in Korea has been entered into an aging society as 9.1[%] in 2005 to 14.3[%] in 2018. The elder population in 2026 will be expected to 20.8[%] with the rapid aging society. In this study, there has been conducted a study on development of headlamp for elder friendly vehicle in order to from two different groups, one group for elder with over 65 ages, the other group for compared ages(20 ages, 30～50 ages). Glare test and forward visibility test were performed on wet and dry road conditions. As the result of these tests, it showed to prefer headlamp installed partially yellow coated bulb, which gives warm feeling on dry road condition. Forward visibility of headlamp which developed to fit on wet road condition is similar to existing HID headlamp. Glare was evaluated less than halogen and HID headlamp. However, it need to more improve glare and forward visibility performance of headlamp for old drivers.

Bioactivation antioxidant and transglycating properties of N‐acetylcarnosine autoinduction prodrug of a dipeptide L‐carnosine in mucoadhesive drug delivery eye‐drop formulation: powerful eye health application technique and therapeutic platform

A considerable interest in N-acetylcarnosine ocular drug design for eye health is based on clinical strategies to improve ocular drug delivery through metabolic enzymatic activation. Human biology aspects of ocular N-acetylcarnosine deacetylation during its pass through the cornea to the aqueous humor and dipeptide hydrolyzing enzymes are characterized. Novel approaches to ocular drug delivery increasing intraocular bioavailability of N-acetylcarnosine biologically activated metabolite carnosine become an integral development ensuring prolonged retention of the medication in the mucoadhesive precorneal area and facilitating transcorneal penetration of the natural dipeptide with the corneal promoters. A comprehensive list of techniques for peptide drug design, synthesis, purification, and biological analyses was considered: liquid chromatography (LC), high performance liquid chromatography (HPLC), (1) H and (13) C nuclear magnetic resonance (NMR), electrospray ionization (ESI) mass spectroscopy, and spectrophotometry. The antioxidant activity of therapeutics-targeted molecules was studied in aqueous solution and in a lipid membrane environment. A deglycation therapeutic system was developed involving removal, by transglycation of sugar or aldehyde moieties from Schiff bases by histidyl-hydrazide compounds or aldehyde scavenger L-carnosine. Clinical studies included ophthalmoscopy, visual acuity (VA), halometer disability glare tests, slit-image, and retro-illumination photography. N-acetylcarnosine 1% lubricant eye drops are considered as an auto-induction prodrug and natural ocular redox state balance therapies with implications in prevention and treatment of serious eye diseases that involve pathways of continuous oxidative damage to ocular tissues(cataracts, primary open-angle glaucoma, age-related macular degeneration) and sight-threatening glycosylation processes (diabetic retinopathy and consequent visual impairment) important for public health. The results of the study document that the therapeutic benefit in clinical trials is associated with the bioactivation universal antioxidant and transglycating properties of N-acetylcarnosine acting as the ophthalmic prodrug of L-carnosine, and depends on the nature of the specific drug delivery lubricant eye-drop formulation applied as the topical solution. The research highlights findings in N-acetylcarnosine prodrug activation, transport mechanisms, drug-to-drug interactions, and formulations in order to unlock the optimization of complicated ocular pharmacology of N-acetylcarnosine. Patented N-acetylcarnosine lubricant eye-drop formula was marketed as numerous human biological brands reaching important distribution networks on over 550 000 bottles sold. Nature Does Nothing Uselessly. -Aristotle