Changes In Color Perception Research Articles

Optic Neuritis and its Prevalence in Immunocompromised Patients: A Review Article

Optic neuritis is an inflammation that affects the optic nerve, causing vision loss, eye pain, and changes in color perception. The condition can be associated with autoimmune diseases such as multiple sclerosis (MS) or infections, especially in immunocompromised individuals such as HIV/AIDS patients or those undergoing chemotherapy. In these individuals, optic neuritis usually results from opportunistic infections like toxoplasmosis and syphilis, complicating diagnosis and treatment. In immunocompetent patients, optic neuritis may indicate autoimmune diseases like MS or neuromyelitis optica (NMO), with better prognoses when treated early with corticosteroids. However, in immunocompromised individuals, the prognosis tends to be worse due to underlying infections and a limited response to immunosuppressive treatment. The management of optic neuritis involves anti-inflammatory therapies and, in cases of infections, specific antimicrobials. Continuous clinical and visual follow-up is also crucial. Studies suggest that clinical outcomes vary depending on the etiology and the patient's immune status, highlighting the need for personalized therapeutic strategies. Early diagnosis is critical to improving vision and quality of life for patients.

Effect of various staining beverages on the color stability of CAD/CAM PMMA denture teeth: An in vitro study.

This study aimed to compare the color change of computer-aided design (CAD)/computer-aidedmanufacturing (CAM)polymethyl methacrylate (PMMA)denture teeth and conventional acrylic teeth after immersion in three staining beverages (coffee, red tea, and cola) for a day, 7 days, and 30 days. Group 1: Conventional acrylic teeth (n = 32). Group 2: Milled CAD/CAMteeth out of PMMA disc (n = 32). The specimens of each material were further divided into four subgroups: (1) Control group, distilled water (n = 16). (2) Red tea solution (n = 16). (3) Coffee solution (n = 16). (4) Cola (n = 16). The color change ( ) was assessed using a spectrophotometer at four time points: at the baseline (t0 ), on the 1st day (t1 ), on the 7th day (t2 ), and the 30th day (t3 ) of immersion. Kolmogorov-Smirnov test was applied, followed by performing independent samples t test, one-way analysis of variance and post-hoc Tukey tests to compare the color change values at different time points. The mean score of NBS values of the coffee solution indicates perceivable color change at the end of the 30th day in the conventional acrylic teeth group. It was 0.843 ± 0.395 at t1 , then increased to 1.017 ± 0.477 at t2 and to 2.259 ± 1.059 at t3 . There is a statistically significant difference (p < 0.05) in color change values between both tooth types at the end of the 30th day of immersion in red tea solution and a statistically significant difference at the end of the 7th day (p < 0.05) and the 30th day (p < 0.05) of immersion in coffee solution. CAD/CAMPMMA teeth are more color stable than conventional acrylic teeth after 30 days of immersion in coffee and red tea solution.

Changes in colour perception in Alzheimer's disease continuum

Aims/Purpose: The progression of Alzheimer's disease (AD) manifests from a preclinical stage, characterized by asymptomatic pathological alterations, to an advanced stage of AD accompanied by cognitive impairment. The aim of this study was to explore visual function along the entire AD continuum, from individuals with a high genetic predisposition to those in the moderate phase of the disease.Methods: All participants underwent a visual examination and had to be visually healthy to be included. The study contained five groups: controls (n = 53), individuals with a positive family history of AD (HF+) (n = 13), mild cognitive impairment (MCI) (n = 23), mild AD (n = 25) and moderate AD (n = 21). The study analysed the results of errors in colour perception.Results: A significant increase in the total number of errors was observed between the control group and the moderate AD group. And also when comparing the FH+ group with the MCI group, the mild AD group and the moderate AD group. Significant differences were found on the tritan axis between the control group and the mild AD group, as well as in the moderate AD group. Significant differences were observed between the FH+ group and the mild AD group, as well as in the moderate AD group. A significant increase in the number of errors on the deutan axis was observed between the control group and both the mild and moderate AD groups. In addition, a statistically significant increase was observed when comparing the FH+ group with the moderate AD group. The test correlated with the MMSE score and also showed good predictive value when memory impairment was present.Conclusions: Understanding the importance of changes in colour perception in AD continuum can aid in the early detection and treatment of AD, potentially improving patient outcomes and facilitating targeted interventions.

Poster Session II: Spillover effects of color discrimination training on color category boundaries and color appearance.

Perceptual learning refers to the increase in perceptual sensitivity that results from several days of training on a perceptual task. Although perceptual learning has been shown to be effective in a variety of perceptual tasks, few studies have examined perceptual learning in color perception. In this study, we investigated how color discrimination training at a base color affected various aspects of color perception for entire hues. The training consisted of five days of S color discrimination (300 trials/day) at either the negative or positive L-M base color, depending on the observer groups. Before and after the training, three types of color perception tests (color difference, unique hue, and color category boundary) were conducted for colors with various hues to examine the changes in color perception due to the training. The results showed that the color discrimination thresholds in the training decreased as expected with repeated trials. Interestingly, the training also affected the performance of the three types of tests; the perceived color difference around the training color tended to increase, and some of the unique hues and the color category boundaries shifted significantly toward the training color. These results suggest that only a few days of color discrimination training can spill over to the entire color space and induce distortion of the perceptual color space.

Influence of Cementation on the Aesthetical Appearance of Full-Ceramic Restorations.

The use of dental ceramics as restorative materials requires corresponding luting materials (cements) that, in turn, influence the visual appearance of the restoration. Due to the high light transmission through the ceramics, the cements can affect the color perception of the dental restoration. This study aims to investigate the optical effects of various cements on the visual appearance of full-ceramic restorations. Three fixing polymer resins (Bifix SE (VOCO GmbH, Cuxhafen, Germany), BreezeTM (Pentron Clinical, West Collins Orange, CA, USA), and PanaviaTM F. 2.0 (Kuraray, Noritake, Osaka, Japan)), with layer thicknesses of 50, 100, 200, and 250 µm, were applied onto a ceramic base model (0.4 mm thick), and irradiated with laser light of wavelengths 532, 632.8, and 1064 nm. Light intensities and scattering effects of light of various wavelengths were angle-dependent, analyzed using a goniophotometer with perpendicular light incidence on the sample specimen (base model plus luting material). In addition, the transmitted power of the light through the sample specimen was determined as a function of the layer thickness. With increasing layer thickness, power losses of respectively 30% for Bifix SE and BreezeTM in the visible spectral range were comparable, whereas PanaviaTM F. 2.0 showed a power loss of ca. 44% here. For the near-infrared range, the power losses for all cements were 25%. This could be confirmed by the interpretation of the line widths. Moreover, the line widths for thin cement layer thicknesses (50 and 100 µm) in the visible spectral range displayed only a redistribution of light by scattering, which does not affect color perception at all. In addition, at 200 and 250 µm, absorption occurred which causes a change in color perception. Within the scope of this study, it could be shown that for thin-layer thicknesses of the cement applied here, there is no adverse optical effect on the aesthetic visual appearance of the restoration.

Effect of laser eye protection devices on color perception.

Laser eye protection (LEP) devices may alter how colors are perceived in visual displays. This study investigates changes in color perception experienced by color-normal observers while wearing LEPs. Color perception with and without LEPs was measured using clinical color tests: City University Color Assessment and Diagnosis, Konan Medical ColorDx CCT-HD, and Farnsworth-Munsell 100-Hue. All LEPs induced a shift in color perception. The level of change in color perception significantly varied across LEPs. Consideration should be made when designing color displays where LEP devices are worn.

Direct vs. Indirect Etiology of Traumatic Optic Neuropathy

When it comes to vision, there is a rare condition which has more potential to impair the vision, and this condition is called Traumatic optic neuropathy. Direct traumatic optic neuropathy occurs when there is direct physical trauma to the optic nerve, often due to penetrating injuries or fractures involving the bones around it. On the other hand, indirect (TON) is caused by blunt force trauma that is transmitted through the tissues or bones around the eye, leading to stretching, tearing, or damage to the blood supply of the optic nerve. Common causes of indirect (TON) include motor vehicle accidents, falls, assaults, and sports-related injuries. The mechanics, blood flow, and inflammation are all sequentially organized in Traumatic optic neuropathy. Mechanical factors disrupt the integrity of the nerve fibers and blood supply, vascular factors reduce the blood flow, and inflammatory factors activate processes that cause cell death within the optic nerve. The signs of (TON) can vary in presentation. Commonly involve a decrease in visual clarity abnormalities in the pupil's reaction to light visual field issues, changes in color perception, and alterations in the appearance of the optic disc. Diagnosing and managing (TON) can be quite challenging since there are no markers or reliable predictors of prognosis. In some cases, observation may be appropriate, while corticosteroids can be employed for their inflammatory properties and potential benefits to optic nerve blood supply. Surgical decompression focuses on relieving pressure or removing obstructions that are affecting the nerve.

The Nature of Language and Cognition Interactions in Color Perception

Perception of hue has been at the center of the debates on the relation between language and thought due to the diversity of color terms in the lexicon of different languages. In this article, we review empirical evidence on the language-cognition interface in the color domain. This discussion takes two theoretical positions regarding language and thought interactions, linguistic relativity and universalism, as a basis and asks whether color terms in language affect color perception or post-perceptual decision processes rather than perception itself. Several behavioral, developmental, electrophysiological, neuroimaging and neuromodulation studies have found language-related differences in color processing. In these studies, people have an advantage in visually discriminating colors labeled by different linguistic terms compared to colors labeled by the same linguistic terms. However, the fact that these differences disappear when access to verbal codes is prevented by behavioral methods or neuromodulation strongly suggests that this advantage does not stem from deep and permanent changes in color perception due to language. Taken together, these differences seem to be best explained by momentary and temporary interactions between visual and verbal codes during post-perceptual decisions during color processing. Keywords Color perception, language-cognition interface, language and thought, visual perception

고령자의 지각색채 분석을 위한 디지털 모의수정체 - 서울지하철 표준색채의 수치화를 중심으로 -

This research suggests digital artificial lens that digitized age-related changes in color perception. In aging societies, many elders experience decline in color perception. In this regard, there has been research in medical domain with elders" lens of color perception. However, field application of elder"s color distinction on public spatial environment need to be improved. Seoul metro is a good example. Seoul metro includes a mix of commercial, residential, office and entertainment centered around or located near a transit station. Dense, walk-able, mixed-use development near transit attracts people including elders and adds to vibrant, connected communities subjectively. To adopt digitized lens to Seoul metro maps" color, standard color in short wavelength; violet, blue and green were selected for Variance Independent(V.I.) since colors in 400∼600nm visible light make elders perception difficult. Among the confusing colors of subway line has need exclusively on the artificial lens information have inputted adjusted value and examined by margin of error in CIE L*a*b* variance. Standard color V.I. and V.I. transfered to artificial lens were measured with spectrophotometer. CIE L*a*b* and RGB; Color value on virtual filter V.D. was analyzed from V.I. This digital artificial lens is developed based on artificial lens. The implications and limitations of the digital artificial lens are discussed, and so that make some future research steps; Color of yellow in vision digitization will be need for eider"s perceptive color scheme for age friendly color scheme for the elderly should be suggested. Therefore, this research finally suggests a digital artificial lens for digital public consensus.

Extending the Color Retention of an Electrochromic Device by Immobilizing Color Switching and Ion-Storage Complementary Layers

The thermal polymerization of a bis(triphenylamine)-bis(styrene) monomer on ITO coated glass gave an electroactive film that underwent two stepwise oxidations. The perceived color change of the film upon stepwise oxidation was colorless-to-yellow followed by yellow-to-blue. The anodic cyclic voltammogram of the monomer was consistent over multiple cycles. The immobilized film could be reversibly switched between its colorless and blue states with applied potential in both a half- and full-electrochromic functioning device. The devices could also reversibly switch their colors upwards of 6 h. The retention of the electrochemically induced blue color was contingent on the device architecture. Upwards of 80% of the color was maintained 30 min after the potential was turned off with the double-layer electrochromic device structure. This device was prepared from two electroactive layers: a bis(triphenylamine) and viologen-based polymers that were immobilized on the electrodes. In contrast, 50% of the color of the active electrochromic device that was prepared from a single electroactive layer bleached 7 min once the potential was no longer applied.

Electrochromic selective filtering of chronodisruptive visible wavelengths.

We present evidence of pupil response modification, as well as differential theoretical melatonin suppression through selective and dynamic electrochromic filtering of visible light in the 400–500 nm range to minimize chronodisruptive nocturnal blue light exposure. A lower activation of intrinsically photosensitive retinal ganglion cells (ipRGCs), the first step for light to reach a human’s internal clock, is related to melatonin secretion therefore avoiding detrimental effects of excessive blue light exposure. Pupillary Light Reflex and Color Naming were experimentally assessed under light filtered by two different coloration states (transmissive and absorptive) of these novel dynamic filters, plus an uncoated test device, in 16 volunteers. Also, different commercial light sources at illuminances ranging from 1 to 1000 lux were differentially filtered and compared in terms of theoretical melatonin suppression. Representative parameters of the pupil responses reflected lower pupil constriction when the electrochromic filters (ECFs) were switched on (absorptive state, blue light is absorbed by the filter) compared to uncoated filters (control sample), but failed to do so under transmissive state (blue light passes through the filter) indicating less activation of ipRGCs under absorptive state (although no significant differences between states was found). Out of eight colors tested, just one showed significant differences in naming between both filter states. Thus, the ECF would have some protecting effect on ipRGC activation with very limited changes in color perception. While there are some limitations of the theoretical model used, the absorptive state yielded significantly lower theoretical melatonin suppression in all those light sources containing blue wavelengths across the illuminance range tested. This would open the way for further research on biological applications of electrochromic devices.

치매 예방을 위한 교구재 디자인 색상 적용 연구 -노인의 색 지각 변화 특성에 기반하여-

우리나라는 저출산 및 인구의 고령화로 인하여 노인인구 수가 점차 증가하는 추세이며, 노인인구 수 만큼 치매 환자 수 또한 증가할 것으로 예상되며 2024년에는 그 수가 100만 명에 이를 것으로 추산되고 있다. 기억력, 문제 해결력, 지남력이 악화되고 감정의 변화가 잦아지는 치매 초기에는 비약물적 치료를 통하여 인지능력의 저하를 늦출 수가 있다. 이러한 비약물 치료의 보편화된 방법이 치매 예방 교구를 사용하는 것이다. 교구란 특정한 학습 목표를 이루기 위하여 사용되는 것을 말하는데, 노인치매 예방 교구는 그 대상과 교구를 활용해 달성하고자 하는 목표가 확실하기 때문에 노인의 특징을 고려하여 교구 디자인이 이루어져야 하지만 국내의 치매 예방 교구는 치매 환자만을 고려한 것이 아니라, 인지 능력 개발이 필요한 다수를 대상으로 하므로 치매 환자가 사용하기에 어려움이 있다. 본 연구는 노인의 시각 능력 특징을 분석하여 치매 초기 비약물 치료의 한 종류인 치매 예방 교구에 사용된 색상의 사례 분석을 통하여 현재 치매 예방 교구의 한계점을 확인하고 향후 치매 예방 교구 색채디자인의 방향성을 제시하는 데 그 목적이 있다. 이를 위한 연구 방법으로는 첫 번째, 문헌 및 인터넷 조사를 통하여 치매 환자의 특징과 국내 치매 환자의 일반적 특징을 조사하였고, 둘째, 비약물 치료에 대해 알아보았다. 세 번째로는 노인의 일반적 특징을 심리, 신체, 지각 능력으로 구분하여 그 특징을 알아보았다. 네 번째로 교구는 시각 정보를 바탕으로 학습자를 사고하게 하여 학습 목표에 맞는 행동을 끌어내기 때문에 시각 정보 중 중요한 색상에 관하여 노인의 특징 중 시각 능력의 특징을 문헌 연구를 통하여 정리하였다. 다섯 번째로 국내 치매 환자 요양원에서 실제 사용하고 있는 치매 예방 교구를 유선 조사하여 제품에 사용된 색상을 조사, 분석하였다. 그리고 마지막으로는 치매 환자의 시각적 능력을 바탕으로 색상 선정 시 고려해야 할 요소를 정리하여 색상 선정과 제품에 적용하는 과정을 정리하였다. 본 연구는 국내 치매 환자의 실정을 바탕으로 국내 치매 환자 요양원에서 사용하는 제품을 사례 조사하였기 때문에 제품의 적용을 국내에 판매중인 제품으로 한정하였으며, 노인의 색 지각 능력 또한 황변화 증상을 가진 노인으로 한정하여 연구의 결과를 도출하였다. 노인의 시각 능력의 특징은 황변화로 인하여 파란색, 보라색과 같은 단파장의 색상이 검은색과 구별이 어려우며, 심한 경우 명도 차이를 통해 색상을 구분한다는 것이었다. 이에 따라, 가시광선의 7가지 색상이 각각 배경색으로 사용되었을 때를 앞의 2가지 노인의 시각 특징을 바탕으로 하여 치매 환자를 위한 교구에 색채 적용을 위한 고려 요소를 정리하였고, 이를 바탕으로 현재 국내에 시판 중인 치매 예방 교구 3가지를 대상으로 하여 제품에 사용된 색상을 분석하였는데, 3가지 제품 모두 노인의 시각 능력을 고려하지 않은 것으로 분석되었다. 앞서 정리한 고려 요소를 바탕으로 치매 환자를 위한 제품의 색상 선정 과정을 정리하여 2가지, 3가지 색상을 선정하는 과정을 예시로 정리하였다. 비록 이렇게 선정된 색상이 실제 노인 치매 환자를 통한 사용성 평가를 하지 못했다는 한계점이 있지만 본 연구가 치매를 예방하려는 노인 혹은 치매 환자에게 필요한 제품 디자인 제안을 위한 기초자료로 활용될 수 있을 것으로 기대한다.

Assessing staining resistance of a CAD/CAM interpenetrating network composite material

BackgroundColor change of dental materials over time because of staining agents has important effects on the long-term prognosis of dental esthetic treatments. In the present study, staining resistance of an interpenetrating network composite material with different translucency levels (translucent and high translucent) and various surface procedures for finishing were investigated.MethodsSame shade CAD/CAM interpenetrating network composite specimens having two different translucency levels were prepared using by a water cooling cutting saw. Specimens were grouped and different finishing procedures were performed. Then, specimens were kept in distilled water, red wine and coffee for different periods. Color was evaluated before and after exposure to staining liquids using a clinical spectrophotometer.ResultsIn the 7 days Glaze group (ΔE00 > 2.2), color difference was only perceivable in the specimens kept in red wine. In the 28 days red wine high translucent groups, only the high translucent Clinical group showed a clinically acceptable (ΔE00 < 2.2) color change. In the translucent groups kept in red wine, only the translucent Glaze group showed a clinically perceivable color change (ΔE00 > 2.2). In the 28 day measurements, all the translucent groups showed a clinically perceivable color change (ΔE00 > 2.2). Of the translucent groups kept in coffee for 28 days, it was observed that only the translucent Clinical group demonstrated a clinically non-perceivable color change (ΔE00 < 2.2).ConclusionsAll the translucent groups kept in red wine showed a clinically perceivable color change after 28 days. Only the high translucent Clinical Kit group showed a clinically acceptable color change. Among high translucent and translucent specimens kept in coffee only the translucent Clinical group showed a clinically acceptable color change after 28 days.

Fluorescent ZnII Chemosensor Mediated by a 1,8-Naphthyridine Derivative and It's Photophysical Properties.

One of the greatest challenges in using fluorescent chemosensors for highly selective and sensitive transition‐metal ions is finding an efficient and simple method for its synthesis. In this study, a highly efficient fluorescence chemosensor for ZnII was developed from N‐Boc‐L‐proline modified 1,8‐naphthyridine. The fluorescence intensity of the chemosensor was increased significantly only in the presence of ZnII ion which provided a perceived color change for rapid visual sensing, while other metal ions showed fluorescence quenching or little changes. It was worth noting that the chemosensor L distinguished ZnII from CdII commonly having similar properties. The solvent effect and possible bonding mode for fluorescence enhancement have been also discussed. Results of this study indicated that the Boc‐group in l‐proline significantly improved the sensitivity and selectivity for ZnII detection performance, as confirmed by comparison experiments and time dependent‐density functional theory (TD‐DFT) calculations.

The effect of acceleration on color vision

Background/Aim. Over 80% of all information a pilot receives during the flight is visual with color perception being one of the most important visual functions for managing an aircraft. The reception of color is of high significance in aviation due to the importance of signal tracking on instrument panels as well as the importance of visual stimulus and environment signs. There is no sufficient number of papers and studies that deal with this issue, although recent studies have shown that the connection between acceleration and color perception exists. The aim of this study was to demonstrate the correlation between pilot exposure to +Gz acceleration in human centrifuge and color perception before and after acceleration exposure. Methods. Subjects of the study were 40 military pilots, aged 35?45, with 10 and 20 years of flying experience. Pilots were exposed to +Gz acceleration (inertial force acts from head to feet) in the human centrifuge for pilot training with accelerations of +2Gz, +5.5Gz up to +7Gz. The tests focused on color perception before and after the exposure to the acceleration. Results. Out of 40 pilots examined for color vision, in 35 (87.50%) had normal results in color identification before and after +Gz; 5.00% (2 subjects) had two mistakes ? reading number 5 instead of number 3, which falls within the normal trichomes, and reading number 16 instead of number 26. Three subjects (7.50%) gave their answers slower than the accepted response time. After the +7Gz exposure, 34 (85%) persons had normal results in color identification, 2 (5%) subjects made three mistakes ? at numbers 5, 74 and 26; one (2.50%) pilot made four mistakes on numbers 5, 7, 74 and 26; 7.50% (3 pilots) of the subjects identified colors slower. Conclusion. Color perception in pilots is unstable on high +Gz accelerations. Exposure to +5.5Gz acceleration does not lead to significant changes in color perception, while exposure to +7Gz acceleration showed a significant percentage of reversible disturbance in color perception which lasted for 10 minutes.

Dynamic plasticity in phototransduction regulates seasonal changes in color perception

To cope with seasonal changes in the environment, organisms adapt their physiology and behavior. Although color perception varies among seasons, the underlying molecular basis and its physiological significance remain unclear. Here we show that dynamic plasticity in phototransduction regulates seasonal changes in color perception in medaka fish. Medaka are active and exhibit clear phototaxis in conditions simulating summer, but remain at the bottom of the tank and fail to exhibit phototaxis in conditions simulating winter. Mate preference tests using virtual fish created with computer graphics demonstrate that medaka are more attracted to orange-red-colored model fish in summer than in winter. Transcriptome analysis of the eye reveals dynamic seasonal changes in the expression of genes encoding photopigments and their downstream pathways. Behavioral analysis of photopigment-null fish shows significant differences from wild type, suggesting that plasticity in color perception is crucial for the emergence of seasonally regulated behaviors.

Discoloration of different esthetic restorative materials: A spectrophotometric evaluation.

Objective:A crucial property of esthetic restorative materials is their long-term color stability. The aim of this in vitro study was to evaluate the color stability of esthetic restorative materials (one microfilled flowable composite, one nanofilled composite, one nanoybrid composite, one microfilled composite, and one nanoybrid ormocer-based composite) after surface roughening with cola and exposure to different staining solutions (coffee and red wine).Materials and Methods:All materials were polymerized into silicone rubber rings (2 mm × 6 mm × 8 mm) to obtain 150 specimens identical in size. Seventy-five specimens of Group A were first exposed to cola for 24 h, and then samples were immersed in coffee or red wine over a 28-day test period. A colorimetric evaluation, according to the CIE L*a*b* system, was performed at 7, 14, 21, 28 days. Shapiro–Wilk test and Kruskal–Wallis analysis of variance were applied to assess significant differences among restorative materials. Means were compared with Scheffe's multiple comparison test at the 0.05 level of significance.Results:Specimens of Group A showed higher variations when compared with Group B's specimens (P < 0.05). After 28 days, the immersion protocols caused a clinically perceivable color change for all materials tested (P < 0.05). CeramX Universal and Admira Fusion showed the lowest ΔE variations (P < 0.05).Conclusions:Staining beverages caused significant discolorations for all the materials tested. The first exposure to cola enhanced the subsequent staining with coffee or red wine. Nanohybrid composites reported the lowest color variations.

Visualization of IOL Material-Induced Changes in Retinal Color Stimulus.

Purpose. Different IOL materials, particularly blue-light filtering materials, have different spectral transmittance characteristics. The color stimuli, which influence retinal receptors objectively, have consequently implications for color perception. We report on the quantitative determination of IOL-specific transmittance characteristics and present a method visualizing the resultant changes in color stimulus. Methods. A setup was realized to quantify IOL-absorption in a range of 390–780 nm. To visualize the influence of the different spectral transmittance characteristics an algorithm was developed, which converts RGB-pixel values of images into spectra, which performs the corresponding transmittance correction, reconverts to RGB, and reconstructs the image. IOLs of hydrophobic acrylate and hydrophilic acrylate with a hydrophobic surface in each case with/without blue-light filter were examined. Results. Assessment of the reference images verifies the suitability of the pipeline. Evaluation of the transmittance spectra reveals differences of material- and manufacturer-specifics, which are capable of inducing considerable changes in color perception, particularly in the blue color range and mixed colors involving blue. Conclusions. The developed technique provides an approach for determining IOL-specific transmittance behavior and subsequently its influence on the retinal color stimulus. Problems of altered color perception are occasionally reported after cataract surgery and these become obvious with the visualization procedure developed here.

Ratiometric optical oxygen sensor based on phosphorescence quenching

Molecular oxygen plays a pivotal role in various biological, chemical and environmental reactions, thus detection of oxygen has attracted much attention. Traditional methods of sensing oxygen including classical Winkler titration, electroanalysis, chemiluminescence and thermoluminescence suffer from limitations such as relatively long response time, oxygen consumption during the sensing process and poor selectivity. The ground state of oxygen is a triplet state, so oxygen can quench the long-lived triplet phosphorescence of luminophores. Optical sensors to detect oxygen through phosphorescence have become a very active research field because of their good sensitivity and selectivity, full reversibility, simplicity, suitability for real-time measurements and minimal consumption of oxygen during measurements. Common detection modalities in optical oxygen sensing include phosphorescence intensity, ratiometric and lifetime measurements. Ratiometric intensity measurements at two different wavelengths allow more reliable detection than at a single wavelength because oxygen responses depend on the ratio of the oxygen sensor and reference luminescent signals. In addition, most ratiometric optical oxygen sensors exhibit a perceivable color change, which is useful for rapid visual sensing. This review focuses on the mechanism of oxygen sensing, material designs for ratiometric sensors and cell imaging. The future development of oxygen sensors is also discussed.

Retinal drug toxicity in the absence of visible fundus changes

AbstractA variety of systemic medications cause retinal drug toxicity associated with characteristic ophthalmoscopic changes e.g. pigmentary retinopathies, crystalline retinopathies, retinal vasculopathies, or retinopathies associated with macula edema. However, altered retinal function can occur in the absence of visible fundus changes. For example, the cardiac glycosides, digoxin and digitoxin, are frequently associated with disturbances of colour vision mediated through the inhibition of sodium‐potassium ATPase. Similarly, phosphodiesterase inhibitors such as sildenafil can also act on the photoreceptor transduction cascade to cause reversible changes in colour perception, blurred vision and increased glare sensitivity. Exposure to antiepileptic drugs that modulate GABA, can also lead to altered visual function. The most significant adverse reaction occurs with vigabatrin which can cause irreversible concentric visual field loss in susceptible individuals. It is important for eye care professionals to be aware of the potential for adverse reactions associated with systemic drugs and consider the use of functional vision tests for their detection and monitoring.