Low Contrast Sensitivity Research Articles

Brake time is correlated with lower extremity strength, dynamic balance and low-contrast sensitivity in unpredictable driving situations in elderly drivers compared with young drivers: A cross-sectional study.

To compare physical function, driving fitness and brake time of young and elderly drivers, and to identify the association of physical function and driving fitness with brake time in elderly drivers in predictable or unpredictable situations during driving. This study included 86 participants (50 men and 36 women), comprising 52 elderly drivers (age: 72.44 years, weight: 60.39 kg, height: 158.06 cm) and 34 young drivers (age: 26.53 years, weight: 63.74 kg, height: 153.65 cm), with a valid driver's license who drive at least once a week. Physical function was measured as upper and lower body flexibility and strength, dynamic balance and aerobic endurance. Driving fitness was measured as high- and low-contrast sensitivity, route planning, visualization of missing information, visual search with divided attention and visual information processing speed using the DrivingHealth® Inventory. Brake time and braking distance was evaluated as unpredictable and predictable driving situations. Measurements of all categories, except lower extremity flexibility, endurance and high-contrast sensitivity, were significantly lower in elderly drivers than in young drivers. Brake time did not differ in predictable situations but was slower (P = 0.004) in elderly drivers in unpredictable situations. In elderly drivers, upper body strength (P = 0.036), dynamic balance (P < 0.001) and low-contrast sensitivity (P = 0.003) were associated with brake time in unpredictable driving situations. In unpredictable situations, slower brake time in elderly drivers is associated with lower limb muscle strength, agility and low-contrast sensitivity. Therefore, for safe driving, these parameters should be considered as guidelines for maintaining the driving ability of elderly drivers and aging people. Geriatr Gerontol Int 2020; ••: ••-••.

Comparing Visual Acuity, Low Contrast Acuity and Contrast Sensitivity After Trifocal Toric and Extended Depth of Focus Toric Intraocular Lens Implantation.

PurposeThe aim of this study was to compare visual acuity at various distances (far, intermediate and near), low contrast acuity and contrast sensitivity after trifocal toric and extended depth of focus (EDOF) toric intraocular lens (IOL) implantation.Patients and MethodsThis was a non-interventional two-arm comparative study of visual outcomes after uncomplicated bilateral cataract or refractive lens exchange surgery with IOL implantation between 6 months and 5 years before a single diagnostic examination visit. There was no masking and no control group. Subjects had to have uncorrected distance visual acuity (UDVA) of 20/40 (0.3 logMAR) or better measured at the time of their study visit. Clinical evaluations included the manifest refraction, visual acuity (VA) at distance, intermediate (60 cm) and near (40 cm), low contrast (10%) VA and contrast sensitivity.ResultsA total of 50 bilaterally implanted patients (25 trifocal, 25 EDOF) were examined; the two groups had similar characteristics, including corneal astigmatism. Postoperative refractive outcomes were also similar. There were no statistically significant differences in distance or intermediate VA between groups, but the trifocal group had significantly better near VA both uncorrected (p = 0.009) and distance-corrected (p = 0.014). There were no statistically significant differences in the low contrast acuity measures between IOLs at either distance or 40 cm, with or without glare. Contrast sensitivity in mesopic and photopic conditions was similar.ConclusionThe trifocal and EDOF toric IOLs performed similarly for all measures except near VA, where the trifocal toric provided significantly better acuity. For subjects interested in reducing spectacle independence at near, this may be an important consideration.

Improvement or Worsening of Human Contrast Sensitivity Due to Blue Light Attenuation at 450 nm.

PurposeThe work was aimed at comparing contrast sensitivity performance in an indoor environment with two filters, which differ only in the presence of a band at 450±20 nm in the transmittance spectrum.Patients and MethodsThirty-nine subjects participated. The filters were the Standard (ST) and Professional (PRO) Drive lenses (Hoya, Japan), the latter showing the attenuation band at 450 nm. Photopic contrast sensitivity (CS) was measured at different spatial frequencies from 1.5 to 18 cpd through Functional Acuity Contrast Test with both lenses (LogCSST and LogCSPRO, respectively). The areas under the curves of LogCSST and LogCSPRO as a function of the spatial frequency were also considered.ResultsIn the range of the measured values of LogCSST for the thirty-nine participants, at each spatial frequency and also for the areas, the difference Δ = LogCSPRO – LogCSST was found to decrease and change sign from positive to negative as a function of LogCSST, thus allowing to deduce a threshold (LogCSthreshold) for LogCSST corresponding to Δ=0. Significant CS worsening was found with the PRO compared to the ST lens for the subjects showing LogCSST > LogCSthreshold. Vice versa, CS improvement was found when LogCSST < LogCSthreshold.ConclusionIn the choice of a blue-filtering lens, practitioners should take into consideration that the attenuation of light in the range 420–470 nm is expected to produce a CS worsening in subjects showing a relatively high initial CS (higher than a threshold CS). For these subjects, the general reduction of transmitted light intensity prevails on possible advantages. On the contrary, subjects showing a relatively low initial CS are expected to show a CS improvement because the attenuation of light in the range 420–470 nm is expected to reduce intraocular scattering and to mimic the effect as an optical filter of the human macular pigment, advantages which prevail on the reduction of the transmitted light intensity.

Visual contrast sensitivity in school-age Guadeloupean children exposed to chlordecone

Recent evidence suggests that prenatal exposure to chlordecone, a persistent organochlorine pesticide that was used intensively in the French West Indies, affects infant neurodevelopment. The aim of the present study was to evaluate the association between prenatal and postnatal chlordecone exposures on visual contrast sensitivity in 285 children aged from 7.1 to 8 years old (mean age = 7.68 ± 0.21 years; sex ratio = 54 % girls) in a Guadeloupean prospective birth cohort (TIMOUN). The Freiburg Visual Acuity and Contrast Test (FrAcT) was used to assess visual contrast sensitivity. Chlordecone concentrations were measured in blood samples at birth (cord blood) and in children at testing time to estimate pre- and postnatal exposure, respectively. Exposures were categorized into three groups and were also log-transformed and considered as continuous variables. Multiple linear regression models were performed on all children taking into account various potential confounders, including maternal characteristics (age, education, intellectual functioning, alcohol and tobacco use during pregnancy). Potential moderation effect of sex was also examined. Results showed that higher cord plasma chlordecone levels were associated with lower contrast sensitivity. Although child chlordecone levels was not associated with the FrAcT, sex-specific stratified analyses revealed significant associations in boys. Associations between postnatal exposure and FrACT scores in girls were null. This study indicates that exposure to chlordecone in utero and during childhood may impair visual contrast sensitivity at school age, particularly in boys.

Vision-related quality of life and visual function in a 70-year-old Swedish population.

To investigate vision-related quality of life (VRQoL), visual function and predictors of poor vision in a population of 70-year-olds. Self-reported ocular morbidity and responses to the National Eye Institute Visual Functioning Questionnaire-25 (NEI VFQ-25) in a cross-sectional population study (N=1203) in Gothenburg, Sweden, were compared with results from ophthalmic examination (N=560). The most common self-reported ophthalmic morbidities were cataract (23.4%), age-related macular degeneration (AMD; 4.7%), glaucoma (4.3%) and diabetic retinopathy (1.4%). Cataract was more prevalent in women (p=0.001). The composite score from NEI VFQ-25 for the entire cohort was 91.4 (standard deviation: 27.5). When comparing composite score for different eye diseases, persons with cataract or AMD exhibited lower scores (p=0.029 and 0.018, respectively). Best-corrected visual acuity (BCVA) was normal (≥0.5 decimal) in 98.9%; two individuals had low vision (<0.3). Men exhibited better BCVA (median: -0.08 logMAR) than women (-0.06; p=0.005). Visual field defects were observed in 16.3% and uncorrected refractive errors in 61.5%. Poor vision was reported by 7.4% of participants with presenting visual acuity (PVA) ≥0.5 (decimal), while 66.7% with PVA <0.5 reported good vision. Of 27 individuals with PVA <0.5, 55.6% obtained a BCVA of ≥1.0 with the right correction. Low contrast sensitivity was a significant predictor of experiencing poor vision (p=0.008), while PVA and visual field defects were not. Low contrast sensitivity is a predictor of experiencing poor vision. There is a discrepancy between subjective/objective visual function and a high prevalence of uncorrected refractive errors. Women have more cataract, and men demonstrate slightly better visual acuity.

IMPAIRED DARK ADAPTATION ASSOCIATED WITH A DISEASED BRUCH MEMBRANE IN PSEUDOXANTHOMA ELASTICUM.

To characterize dark adaptation in patients with pseudoxanthoma elasticum, a systemic disease leading to calcification of elastic tissue including the Bruch membrane. In this prospective case-control study, dark adaptation thresholds were measured using a Goldmann-Weekers dark adaptometer. Additional assessments included best-corrected visual acuity testing, contrast sensitivity, low luminance deficit, and vision-related quality of life. Dark adaptation thresholds were significantly higher, and adaptation periods were prolonged in patients with pseudoxanthoma elasticum (n = 35; 33 with 2 ABCC6 mutations) compared with controls (n = 35). The time to adapt 4 log units (20.6 ± 8.6 vs. 8.0 ± 1.3 minutes) and the mean dark adaptation threshold after 15 minutes (3.5 ± 1.1 vs. 1.8 ± 0.2 log units) were significantly different between patients and controls (both P < 0.001). Low luminance deficits (12.3 ± 6.4 vs. 6.1 ± 4.3 ETDRS letters), contrast sensitivity (1.4 ± 0.3 vs. 1.9 ± 0.1), and low luminance-related quality of life (LLQ score: 1,286 ± 355 vs. 2,167 ± 68) were also significantly worse in patients with pseudoxanthoma elasticum (all, P < 0.001). Two patients were treated with high-dose vitamin A which partially reversed impaired dark adaptation. Patients with pseudoxanthoma elasticum often have impaired dark adaptation. Positive effects of vitamin A supplementation may indicate restricted retinal access of vitamin A through the Bruch membrane as one possible underlying pathogenic factor.

Measurement of CIELAB spatio-chromatic contrast sensitivity in different spatial and chromatic directions

This paper presents data on CIELAB chromatic contrast sensitivity collected in a psychophysical experiment. To complement previously published data in the low-frequency range, we selected five spatial frequencies in the range from 2.4 to 19.1 cycles per degree (cpd). A Gabor stimulus was modulated along six chromatic directions in the a*-b* plane. We also investigated the impact on contrast sensitivity from spatial orientations – both vertically and diagonally oriented stimuli were used. The analysis of the collected data showed lowest contrast sensitivity in the chromatic direction of around 120° from the positive a*-axis. The contrast sensitivity in the diagonal spatial orientation is slightly lower when compared to the vertical orientation.

Spatial Frequency Tuning and Transfer of Perceptual Learning for Motion Coherence Reflects the Tuning Properties of Global Motion Processing.

Perceptual learning is typically highly specific to the stimuli and task used during training. However, recently, it has been shown that training on global motion can transfer to untrained tasks, reflecting the generalising properties of mechanisms at this level of processing. We investigated (i) if feedback was required for learning in a motion coherence task, (ii) the transfer across the spatial frequency of training on a global motion coherence task and (iii) the transfer of this training to a measure of contrast sensitivity. For our first experiment, two groups, with and without feedback, trained for ten days on a broadband motion coherence task. Results indicated that feedback was a requirement for robust learning. For the second experiment, training consisted of five days of direction discrimination using one of three motion coherence stimuli (where individual elements were comprised of either broadband Gaussian blobs or low- or high-frequency random-dot Gabor patches), with trial-by-trial auditory feedback. A pre- and post-training assessment was conducted for each of the three types of global motion coherence conditions and high and low spatial frequency contrast sensitivity (both without feedback). Our training paradigm was successful at eliciting improvement in the trained tasks over the five days. Post-training assessments found evidence of transfer for the motion coherence task exclusively for the group trained on low spatial frequency elements. For the contrast sensitivity tasks, improved performance was observed for low- and high-frequency stimuli, following motion coherence training with broadband stimuli, and for low-frequency stimuli, following low-frequency training. Our findings are consistent with perceptual learning, which depends on the global stage of motion processing in higher cortical areas, which is broadly tuned for spatial frequency, with a preference for low frequencies.

Effects of Kilovoltage on Image Quality and Entrance Surface Dose in Lumbar Spine Digital Radiography

Introduction: Digital radiography possesses a wide dynamic range and has a major advantage in producing an acceptable image of diagnostic value even though overexposure occurs. Lumbar spine (LS) radiography is the most common examinations that gives high radiation dose to patients and accounts for the highest collective population dose of any conventional radiographic examinations. As such, this study was carried out to ascertain the impact of image quality and entrance surface dose (ESD) with different exposure settings in the anteroposterior (AP) and lateral LS. Material and Methods: The torso of the PBU-50 phantom was exposed to medium and high kilovoltage peak (kVp). A total of 14 images for LS were obtained. Relative image quality was assessed using Leeds Test Objects TOR CDR whilst the ESD was ascertained using an optically stimulated luminescence dosimeter. Results: The results of Friedman test indicated a significant difference in image quality when using medium and high kVp. Wilcoxon signed-rank test also reflected a significant difference in ESD between the use of medium and high kVp for both AP and lateral LS. Conclusion: Significant differences in image quality and ESD were obtained using medium and high kVp with medium kVp resulting in high contrast but low contrast sensitivity and vice versa. The findings of the present study indicated that the recommended kVp for AP LS was from 75kVp to 81kVp whilst for lateral LS the recommended kVp was from 85kVp to 90kVp for an average adult patient.

Prospective, Randomized, Contralateral Eye Comparison of Wavefront-Guided and Wavefront-Optimized Laser in Situ Keratomileusis

To compare outcomes in wavefront-optimized (WFO) laser insitu keratomileusis (LASIK) to high-resolution wavefront-guided (WFG) LASIK. Randomized, fellow eye controlled, clinical trial. A total of 200 eyes of 100 patients with myopia or compound myopic astigmatism undergoing bilateral LASIK between October 2015 and February 2017 underwent wavefront-optimized (WFO) LASIK in 1 eye and wavefront-guided (WFG) LASIK in the fellow eye. Each eye was evaluated for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), contrast sensitivity, refractive error, and wavefront aberrometry. Outcome measurement primarily UDVA at 12months. Secondary outcomes were safety, predictability, stability, refractive error, CDVA, contrast sensitivity, and higher-order aberrations at 12months. WFG LASIK had higher levels of supervision and better contrast sensitivity compared to WFO. Both types had excellent postoperative UDVA results, without a significant difference in either mean UDVA or frequency of achieving a specified UDVA, for example, 20/16 or better (all P > 0.05). The mean gain in lines of CDVA was significantly higher in the WFG than in the WFO group (0.80 ± 0.75 vs 0.62 ±0.72, respectively; P= 0.04). The WFG cohort had significantly better contrast sensitivity for mean and frequency of achieving >20/40 for <5% low-contrast sensitivity (37.1%; 95% confidence interval [CI], 27.5-46.7 vs 24.7%; 95% CI, 16.2-33.3, respectively; P=0.01) and >20/32 for <25% low-contrast sensitivity (10.3%; 95% CI, 4.3-16.4 vs 4%, respectively; 95% CI, 0.0-8.1, respectively; P= 0.04). The WFO group had a significantly higher frequency of <0.25 diopters (D) of refractive astigmatism at 12months (82.5%; 95% CI, 75.0-90.0; vs 72.1%, respectively; 95% CI, 63.2-81.2; P= 0.02) but not <0.50 D (95.6%; 95% CI, 91.9-99.8; vs 96.9, respectively; 95% CI, 93.5-100; P= 0.61). The WFG group was significantly closer to emmetropia for both sphere and spherical equivalents at all time points. Trefoil was significantly lower in the WFG group and was also significantly lower than preoperative measurements. Wavefront-optimized and high-resolution wavefront-guided LASIK achieve excellent visual outcomes. Nonetheless, treatments based on a high-resolution aberrometer appear to offer superior results in some regards.

Single target acuity is not higher than grating acuity in a bird, the budgerigar

We examined the capacity of budgerigars (Melopsittacus undulatus) to visually detect dark single targets against a brighter background and established their spatial resolution limit for such targets. While the sampling density of the retina limits the resolution of gratings, target detection is theoretically limited by contrast sensitivity. This allows many animals to detect single targets smaller than their visual resolution limit, but this is not the case for budgerigars. The budgerigars were able to detect a high contrast circular target with a luminance profile of a single period of a sine wave subtending 0.065 degrees of their visual field, corresponding to a spatial acuity of 7.7 cycles degree−1, a measurement in line with the previously measured grating acuity of budgerigars (7.7 and 10 cycles degree−1). This result is different from findings on the spatial acuity of humans, who can detect single targets much smaller than predicted by their acuity for gratings. The low contrast sensitivity of budgerigar vision might be one of the reasons why the single target acuity is not higher than grating acuity. Adding a bright surround to the target did not influence detection threshold significantly. However, the threshold was slightly higher for a target with a square-wave luminance profile than for a target with a sinusoidal luminance profile.

Skin Intrinsic Fluorescence and Selected Measures of Visual Function and aging in Older Adults

ABSTRACTPurpose: Functional, structural and metabolic decline in many systems and in combination contribute to biologic aging and may be manifest as increased risk of morbid events such as neuropathy, albuminuria, and coronary artery disease or mortality. A biologic marker of aging may be a useful tool in identifying persons at increased risk of morbidity or mortality. We have measured skin intrinsic fluorescence (SIF) in a group of older adults to determine whether this easily determined measure could serve as such a biomarker.Methods: Survivors of a population based study of older adults in a moderate sized Midwestern town. Of the 1181 persons participating, 939 had measures of skin intrinsic fluorescence (SIF) and at least one functional or diagnostic characteristic at the most recent examination. Characteristics such as blood pressure, forced expiratory volume, vision, time to walk a standard course and medical history and their associations with SIF measures were examined. Mortality after the last examination with respect to SIF was also investigated. There were 118 deaths among those who participated in this phase of the study. All analyses pertinent to these findings were adjusted for age.Results: SIF measures were significantly associated with low contrast sensitivity, more errors on frequency doubling technology testing (loss of peripheral vision), self-reported poor vision, slow gait, poor forced expiratory volume, and self-reported poor health. SIF was also associated with increased risk of death. All of these analyses were adjusted for age.Conclusions: Skin intrinsic fluorescence provides easily obtained markers of age-related functional outcomes, suggesting SIF measurements may be useful to identify persons who may benefit from more frequent medical scrutiny to decrease morbidity and mortality.

Comparing Three Different Contrast Sensitivity Tests in Adults and in Children with and without Amblyopia.

Tests of contrast sensitivity (CS) are not routinely performed in the clinic, although CS is reduced in many conditions, such as amblyopia or glaucoma. This may be due to perceived time constraints or unaffordability of equipment. Monocular CS functions obtained with the FACT, CSV 1000E, and Lea Symbols were compared in 19 healthy subjects aged 24 - 78 years and 24 subjects aged 5 - 16 years, 9 of whom had amblyopia. CS functions could be obtained with all three tests. The tests were equally comfortable for young and adult patients, and took less than 5 minutes to perform (one eye). All measured CSs at 3, 6, 12, and 18 cycles per degree (cpd), but the FACT included 1.5 cpd. LINEAR MIXED EFFECT MODELS: were performed. While there was no significant difference at low spatial frequencies, the Lea CS test showed a ceiling effect in that range, while the FACT showed a floor effect at high spatial frequencies. CS in amblyopic children did not differ between the contralateral and the amblyopic eye. Overall, amblyopic eyes had lower CS values than the control eyes and CS did not correlate significantly to visual acuity at distance. All three CS tests could be usefully applied in the clinic in adults as well as children over the age of 4 years. Only the CSV 1000E exhibited neither a ceiling nor a floor effect. This was also the fastest test. In children with amblyopia, CS testing offers additional information on visual function. In contrast to previous reports, we did not find that the CSV and FACT are interchangeable.

Modeling macular pigment optical density effects on photopic and scotopic vision in degraded visual environments

The macular pigment (MP) is an accumulation of the carotenoids lutein, zeaxanthin, and mesozeaxanthin in the central retina. These are derived from dietary sources. MP absorbs light in the 400- to 520-nm range. Consequently, the MP is a spectral filter over the photoreceptors, reducing the effects of internally scattered light and attenuating the short wavelength component of natural sunlight. The average MP optical density (OD) is about 0.2 to 0.6 log units depending on the sample population, whereas the range of MPOD is reportedly 0 to 1.5 log units. Some people can increase their MPOD by increasing their consumption of lutein, zeaxanthin, and mesozeaxanthin, and this may be important for vision in degraded visual environments (DVE). Specifically, nutritional interventions and dietary supplements have produced statistically significant enhancements under laboratory conditions in visual tasks, such as visibility through haze, low contrast target detection, contrast sensitivity, glare resistance and recovery, photostress recovery, dark adaptation, mesopic sensitivity, and enhanced reaction times. The question is whether these enhancements are operationally meaningful or not. The present paper begins to address the question by modeling MPOD effects on the visibility to low contrast photopic and scotopic targets seen under a range of DVE over realistic distances that incorporate atmospheric filtering. Specific model parameters include luminance, target contrast, spectral content, and distance. The model can be extended to estimate the efficacy of MPOD effects on target detection, discrimination, and standoff distances.

Efficacy and safety of vitrectomy for congenital cataract surgery: a systematic review and meta-analysis based on randomized and controlled trials.

PurposeTo explore the effectiveness and safety of vitrectomy for congenital cataract surgery.MethodsWe searched PubMed, Science Direct, The Cochrane Library, China National Knowledge Infrastructure and the Wanfang Database. Two researchers extracted data and assessed paper quality independently. Posterior capsule opacification (PCO) or visual axis opacification (VAO), reoperation rate, visual acuity, intraocular lenses (IOL) deposit, synechias, uveitis, secondary glaucoma, low‐contrast sensitivity and IOL decentration were compared.ResultsWe included 11 randomized controlled trials (RCTs) with 634 congenital cataract eyes. Cases of posterior capsule opacification in vitrectomy group were significantly less than that of control group, with risk ratio (RR) of 0.15 [95% confidence interval (CI): 0.09, 0.26], and there was no heterogeneity (I 2 = 0%, p = 0.94). Reoperation rate in vitrectomy group was lower than that of control group either (RR = 0.40, 95%CI: 0.17, 0.94), and there was no heterogeneity (I 2 = 0%, p = 0.85). Best‐corrected visual acuity (BCVA) measured in LogMAR unit of vitrectomy group was smaller, with a mean difference (MD) of −0.17 (95%CI: −0.28, −0.05), and I 2 was only 22%, indicating of a small heterogeneity. No statistical difference was found between two groups on IOL deposit (RR = 1.23, 95%CI: 0.70, 2.17), and the heterogeneity was small (I 2 = 16%, p = 0.31). No statistical difference was found between two groups on synechias (RR = 1.08, 95%CI: 0.60, 1.94), with a quite small heterogeneity (I 2 = 3%, p = 0.38). No statistical difference was found between two groups on uveitis (RR = 0.55, 95%CI: 0.15, 2.01), and there was no heterogeneity (I 2 = 0%, p = 0.94). There was no statistical difference on IOP either, with a MD of 0.25 (95%CI: −1.56, 2.07), and there was no heterogeneity (I 2 = 0%). Egger's test showed that there was no publication bias for all assessed outcomes. Low‐contrast sensitivity was better in the vitrectomy group. And no evidence indicated vitrectomy could lead to a higher risk on secondary glaucoma or IOL decentration.ConclusionVitrectomy helps lower the PCO risk and reoperation risk after congenital cataract surgery, and also, vitrectomy helps patients gain a better BCVA and achieve a better low‐contrast sensitivity, with no trade‐off on IOP control, IOL deposit, synechias, uveitis and secondary glaucoma. We recommend performing vitrectomy during congenital cataract surgery.

High resolution of colour vision, but low contrast sensitivity in a diurnal raptor.

Animals are thought to use achromatic signals to detect small (or distant) objects and chromatic signals for large (or nearby) objects. While the spatial resolution of the achromatic channel has been widely studied, the spatial resolution of the chromatic channel has rarely been estimated. Using an operant conditioning method, we determined (i) the achromatic contrast sensitivity function and (ii) the spatial resolution of the chromatic channel of a diurnal raptor, the Harris's hawk Parabuteo unicinctus The maximal spatial resolution for achromatic gratings was 62.3 c deg-1, but the contrast sensitivity was relatively low (10.8-12.7). The spatial resolution for isoluminant red-green gratings was 21.6 c deg-1-lower than that of the achromatic channel, but the highest found in the animal kingdom to date. Our study reveals that Harris's hawks have high spatial resolving power for both achromatic and chromatic vision, suggesting the importance of colour vision for foraging. By contrast, similar to other bird species, Harris's hawks have low contrast sensitivity possibly suggesting a trade-off with chromatic sensitivity. The result is interesting in the light of the recent finding that double cones-thought to mediate high-resolution vision in birds-are absent in the central fovea of raptors.

Evaluation of Preloaded IOL Delivery System and Hydrophobic Acrylic Intraocular Lens in Cataract Surgery.

Background:Advancements in cataract surgery have necessitated the availability of intraocular lens preloaded delivery systems that can safely, effectively and predictably deliver IOLs in the eye. Preloaded delivery systems simplify and reduce procedural variability during surgery preparation.Objective:The objective of this study was to evaluate clinical acceptability, delivery characteristics and clinical outcomes in patients implanted with new generation hydrophobic acrylic Intraocular Lens with Preloaded delivery system.Methods:This was a single centre retrospective study. Total 41 patients were enrolled in the study to get at least 38 patients for evaluation. All patients were assessed on day1 and 1, 3 and 6 months after surgery.Results:EYECRYL-SERT showed ‘excellent’ ease of insertion and handling in all 41(100%) patients. Corrected Distance Visual Acuity (CDVA) improved from 0.74±0.58 logMAR during screening to 0.03±0.04 logMAR 6 months after surgery. The Corrected Intermediate Visual Acuity (CIVA) and Corrected Near Visual Acuity (CNVA) were 0.10±0.04 and 0.01±0.02 logMAR post 6 months surgery, respectively. The refractive spherical equivalence was -1.94±2.51 D during screening, which improved significantly (p=0.0018) to -0.21±0.47 D post 6 months surgery. The low and high contrast sensitivity was 0.06±0.06 and -0.05±0.06 logMAR after 6 months surgery, respectively. The endothelial cell loss was 5.67%, 7.22% and 9.75% at 1, 3, and 6 months after surgery, respectively, as compared to screening. None of the subjects reported any adverse event during the study period.Conclusion:The IOL delivery system (EYECRYL_SERT) provided desired delivery characteristics during cataract surgery and was effective in improving clinical outcomes in cataract patients.

Contrast sensitivity and visual acuity under low light conditions in macular telangiectasia type 2

Background/AimMacular pigment optical density (MPOD) is centrally depleted early on in macular telangiectasia type 2 (MacTel). Contrast sensitivity (CS) might be related to MPOD, and thus impaired in early MacTel....

Driver distraction by smartphone use (WhatsApp) in different age groups

This paper investigates the effect that texting with WhatsApp, one of the most common applications for instant messaging, exerts on driving performance. Because distracted driving also affects older drivers, who can have seriously compromised vision, we also analysed the associations between visual-function parameters and driving performance. A total of 75 drivers, experienced in sending WhatsApp messages (≥10WhatsApp messages/week), participated in this study and were divided into four age categories. Visual-function tests included contrast sensitivity with and without glare, retinal straylight and objective assessment of optical quality. Simulated driving performance was assessed under a baseline driving condition (without distraction) as well as a texting condition (WhatsApp messages) while driving. The participants used their own mobile phone. Lastly, objective results of driving performance were compared with subjective self-report data from the Driver Behaviour Questionnaire (DBQ). The analysis indicated that functional changes occurring with age, such as a lower contrast sensitivity and greater retinal straylight, were correlated with a higher number of collisions, longer distances driven outside the lane, and greater standard deviation of lateral position (SDLP). The results showed a significant main effect of age for the driving-performance parameters. Also, compared to the baseline, texting WhatsApp messages while driving worsens driving performance for all age groups, most notably among older participants. Thus, the older drivers' SDLP was ∼14% higher than that for the baseline average of all the other drivers and rose to 29% under distraction, reflecting the impact of secondary tasks. The negative effect of the use of the smartphone during driving was also reflected in the number of collisions, with a greater risk of accidents in all the groups of drivers (by 8.3% for young adults, 25.0% for adults, 80.5% for middle-aged adults, and 134.5% for older drivers). Lastly, participants' subjective responses indicated that younger drivers (18–24 years) had a higher risk of deliberately violating safe driving practices (p < 0.05). The present study demonstrates that texting WhatsApp messages while driving significantly impairs the ability to drive safely, with older drivers being the group most adversely affected. It would be recommendable to include other nonstandard vision tests, which have shown associations with driving performance, in the examination for driver licensing. This would help raise the awareness of older drivers concerning their visual limitations, permitting them to adopt compensatory measures to improve their driving safety. Nevertheless, it is also necessary to raise awareness among the younger drivers of the risks involved in behaviour behind the wheel.

Molecular Imaging of Cancer Using X-ray Computed Tomography with Protease Targeted Iodinated Activity-Based Probes.

X-ray computed tomography (CT) is a robust, precise, fast, and reliable imaging method that enables excellent spatial resolution and quantification of contrast agents throughout the body. However, CT is largely inadequate for molecular imaging applications due mainly to its low contrast sensitivity that forces the use of large concentrations of contrast agents for detection. To overcome this limitation, we generated a new class of iodinated nanoscale activity-based probes (IN-ABPs) that sufficiently accumulates at the target site by covalently binding cysteine cathepsins that are exceptionally highly expressed in cancer. The IN-ABPs are comprised of a short targeting peptide selective to specific cathepsins, an electrophilic moiety that allows activity-dependent covalent binding, and tags containing dendrimers with up to 48 iodine atoms. IN-ABPs selectively bind and inhibit activity of recombinant and intracellular cathepsin B, L, and S. We compared the in vivo kinetics, biodistribution, and tumor accumulation of IN-ABPs bearing 18 and 48 iodine atoms each, and their control counterparts lacking the targeting moiety. Here we show that although both IN-ABPs bind specifically to cathepsins within the tumor and produce detectable CT contrast, the 48-iodine bearing IN-ABP was found to be optimal with signals over 2.1-fold higher than its nontargeted counterpart. In conclusion, this study shows the synthetic feasibility and potential utility of IN-ABPs as potent contrast agents that enable molecular imaging of tumors using CT.