Pollinator response to yellow UV-patterned versus white UV-patternless flower dimorphism in Anemone palmata.

Flower colour polymorphisms are uncommon but widespread among angiosperms and can be maintained by a variety of balancing selection mechanisms. Anemone palmata is mostly yellow-flowered, but white-flowered plants coexist in some populations. We analysed the distribution of colour morphs of A. palmata across its range. We also characterised their colours and compared their vegetative and sexual reproductive traits, pollinator attention and fitness. The range of A. palmata is limited to the Western Mediterranean, while white-flowered plants are restricted to Portugal and SW Spain, where they occur at low proportions. Yellow flowers have a characteristic UV pattern, with a UV-absorbing centre and UV-reflecting periphery, which is absent in the white morph. Colour features of both morphs were highly delineated, making it easy for pollinators to distinguish them. Both morphs were protogynous, with the same duration of sexual stages, and the main floral traits related to pollinator attraction, apart from flower colour, were similar. Hymenoptera and Diptera were the main pollinators, showing preference for the yellow morph, clear partitioning of pollinator groups between the two colour morphs and a marked constancy to flower colour during foraging. Both morphs combined clonal propagation with sexual reproduction, but sexual reproductive potential was lower in white-flowered plants. Finally, female fitness was higher in the yellow morph. Pollinator partitioning and colour constancy could maintain this polymorphism, despite the lower visitation rate and fitness of white-flowered plants, which could facilitate their clonal propagation.

Colour Vision Changes across Lifespan: Insights from FM100 and CAD Tests.

(1) Background: in this research study, colour vision was evaluated in individuals aged 19 to 70 years with and without red-green colour vision disorders. (2) Methods: study participant colour vision was assessed with anomaloscope, HRR, FM100 hue, and CAD tests. (3) Results: No significant correlation was found between participant age and chromatic sensitivity of the red-green colour opponent channel. However, a decrease in blue-yellow colour opponent channel chromatic sensitivity was confirmed with the FM100 hue test and CAD test. Analysis of FM100 hue test error scores across age groups revealed a decline in chromatic sensitivity in the short-wave region of visible light with increasing age. Comparison of the colour-deficient individual results of the CAD and anomaloscope tests confirmed that CAD test sensitivity and specificity reaches 100%. However, some individuals with deutan-type deficits were misclassified as having protan-type deficits. This study confirmed the effectiveness of the FM100 test in identifying individuals with moderate to severe colour vision deficits, with sensitivity and specificity rates of 81.25% and 95.38%. (4) Conclusions: It was found that the FM100 hue test effectively identifies individuals with moderate and severe red-green colour vision deficiencies. On the other hand, individuals with mild colour vision deficiencies may go undetected with the FM100 hue test.

Learning to be a colour-blind doctor.

Colour-vision deficiency is common among medical students, doctors and their patients. Although it can influence choice of careers, it can also put patient safety at risk if not recognised and adapted to early in a health professional's working life. Simple recommendations to support medical students, doctors and their patients are provided to support better health outcomes.

Effect of Blue Light Filter Intraocular Lens (IOL) on Colour Vision.

Purpose The objective of this study is to know the effect of blue light filter (BF) intraocular lenses (IOL) on colour vision of Sudanese patiens as BF IOLs are relatively new in Sudan and its effect on Sudanese patients is not yet studied. Methods  This was a descriptive cross-sectional observational study. Data collection was done through interview and pretested structured questionnaire containing three sections: (i) personal data, (ii) past medical and ocular surgical history, and (iii) visual acuity (VA), the anterior and posterior segment exam result, and the D15 photopic color vision test result. Results In this study, 206 eyes of 103 patients were enrolled. Of them, 57 (55.3%) were females and 46 (44.7 %) were males. The mean age of the participants was 58.38 years±11.488 (SD). Furthermore, 81 patients (78.64%) achieved normal D15 color vision test results, while 22 patients (21.4%) had abnormal results. There was a significant effect (P=.00) on photopic color vision perception. Finally, the gender-wise performance showed an insignificant difference (P=.933) with 78.3% of the males having normal D15 color vision test and the females having slightly better results with 78.9 %.  Conclusions The results suggested that implantation of BF IOLs has a significant effect on photopic color vision perception.

The modelling of flower colour: spectral purity or colour contrast as biologically relevant descriptors of flower colour signals for bees depending upon the perceptual task.

Flower colour is an important mediator of plant-pollinator interactions. While the reflectance of light from the flower surface and background are governed by physical properties, the perceptual interpretation of such information is generated by complex multilayered visual processing. Should quantitative modelling of flower signals strive for repeatable consistency enabled by parameter simplification, or should modelling reflect the dynamic way in which bees are known to process signals? We discuss why colour is an interpretation of spectral information by the brain of an animal. Different species, or individuals within a species, may respond differently to colour signals depending on sensory apparatus and/or individual experience. Humans and bees have different spectral ranges, but colour theory is strongly rooted in human colour perception and many principles of colour vision appear to be common. We discuss bee colour perception based on physiological, neuroanatomical and behavioural evidence to provide a pathway for modelling flower colours. We examine whether flower petals and floral guides as viewed against spectrally different backgrounds should be considered as a simple colour contrast problem or require a more dynamic consideration of how bees make perceptual decisions. We discuss that plants such as deceptive orchids may present signals to exploit bee perception, whilst many plants do provide honest signalling where perceived saturation indicates the probability of collecting nutritional rewards towards the centre of a flower that then facilitates effective pollination.

Investigation through Animal-Computer Interaction: A Proof-of-Concept Study for the Behavioural Experimentation of Colour Vision in Zoo-Housed Primates.

Zoos are an important repository of animals, which have a wide range of visual systems, providing excellent opportunities to investigate many comparative questions in sensory ecology. However, behavioural testing must be carried out in an animal welfare-friendly manner, which is practical for zoo staff. Here, we present a proof-of-concept study to facilitate behavioural research on the sensory ecology of captive primates. A system consisting of a tablet computer and an automated feeder connected wirelessly was developed and presented to captive primate species to evaluate interactions with and without previous training. A colour stimulus, analogous to the Ishihara test, was used to check the level of interaction with the device, supporting future studies on sensory ecology with zoo animals. Animals were able to use the system successfully and displayed signs of learning to discriminate between the visual stimuli presented. We identified no risk for small primates in their interactions with the experimental setup without the presence of keepers. The use of electronic devices should be approached with caution to prevent accidents, as a standard practice for environmental enrichment for larger animals (e.g., spider monkeys). In the long term, the system developed here will allow us to address complex comparative questions about the functions of different visual systems in captive animals (i.e., dichromatic, trichromatic, etc.).

Impact of blur on clinical and occupational colour vision test results.

PURPOSE: To evaluate whether colour vision normal (CVN) adults pass two Fletcher-Evans (CAM) lantern tests and to investigate the impact of imposed blur on Ishihara, CAM lantern and computerised colour discrimination test (colour assessment and diagnosis test [CAD] and Cambridge colour test [CCT]) results. METHODS: In a pilot experiment, 20 (16 CVN and 4 colour vision deficient [CVD]) participants with normal VA were tested with the CAM lantern. In the main experiment, the impact of imposed dioptric blur (up to +8.00 D) on visual acuity and the Ishihara test, CAM lantern, CAD and CCT was assessed for 15 CVN participants. RESULTS: CVN participants can fail the CAM lantern, with specificity of 81.25% (aviation mode) and 75% (clinical mode), despite following the test requirements of participants having at least 0.18 logMAR (6/9) in the better eye. With blur, test accuracy was affected. As expected, significant detrimental effects of blur on test results were found for logMAR VA and CAM lantern (aviation) with +1.00 D or higher. Ishihara, CAD and CCT results were not detrimentally affected until +8.00 D. Yellow-blue discrimination was more affected by blur for the CAD than the CCT, which was not explained by the different colour spaces used or vectors tested. CONCLUSION: False-positive findings on lantern colour vision tests with small apertures are likely to be increased in patients with blur due to uncorrected refractive error or ocular and visual pathway disease. Other colour vision tests with larger stimuli are more robust to blur.

The construction of genetics teaching resources related to colour blindness and their application in genetics teaching.

Red-green colour blindness is a classic example for the teaching of X-linked recessive inheritance in genetics course. However, there are lots of types of color vision deficiencies besides red-green colour blindness. Different color vision deficiencies caused by different genes may have different modes of inheritance. In recent years, many research achievements on colour blindness have been made. These achievements could be used as teaching resources in genetics course. Here, we summarize the construction of genetics teaching resources related to colour blindness and their application in genetics teaching in several chapters such as introduction, cellular and molecular basis of genetics, sex-linked inheritance, chromosomal aberration, gene mutation and advances in genetics. Teacher could use the resources in class or after class with different teaching methods such as questioning teaching method and task method. It may expand students' academic horizons and inspire students' interest in genetics besides grasping basic genetic knowledge.

Ultraviolet vision in anemonefish improves colour discrimination.

In many animals, ultraviolet (UV) vision guides navigation, foraging, and communication, but few studies have addressed the contribution of UV signals to colour vision, or measured UV discrimination thresholds using behavioural experiments. Here, we tested UV colour vision in an anemonefish (Amphiprion ocellaris) using a five-channel (RGB-V-UV) LED display. We first determined that the maximal sensitivity of the A. ocellaris UV cone was ∼386 nm using microspectrophotometry. Three additional cone spectral sensitivities had maxima at ∼497, 515 and ∼535 nm. We then behaviourally measured colour discrimination thresholds by training anemonefish to distinguish a coloured target pixel from grey distractor pixels of varying intensity. Thresholds were calculated for nine sets of colours with and without UV signals. Using a tetrachromatic vision model, we found that anemonefish were better (i.e. discrimination thresholds were lower) at discriminating colours when target pixels had higher UV chromatic contrast. These colours caused a greater stimulation of the UV cone relative to other cone types. These findings imply that a UV component of colour signals and cues improves their detectability, which likely increases the prominence of anemonefish body patterns for communication and the silhouette of zooplankton prey.

Evaluating the level of visual acuity to minimise false-positives in different colour vision tests.

CLINICAL RELEVANCE: Accurate colour vision assessment is important in clinical settings to minimise false-positive errors and enhance the reliability of diagnoses outcomes. BACKGROUND: Colour vision testing is valuable in assessing the visual system, particularly given the high proportion of individuals with poor vision. This study aimed to determine the minimum visual acuity level required to perform a colour-vision test without errors. METHODS: After fogging the right eyes of 52 healthy participants using plus lenses to 1.60 logMAR, vision was evaluated using Ishihara, Hardy - Rand - Rittler Standard Isochromatic, Waggoner Pseudo-isochromatic, City University, Waggoner Computerised, and Farnsworth D-15 tests. Participants then completed these tests at lower fogging degrees (in 0.1-logMAR intervals). The acuity at which 5% of the tested population was considered abnormal was determined. RESULTS: Significant differences were found in the average visual acuity required to perform colour vision tests without errors (p < 0.05). The Waggoner Computerized test required the highest average visual acuity among the tests utilised. The Farnsworth D-15 test yielded the highest logMAR values. No significant differences were observed between the Waggoner Pseudo-isochromatic test and Hardy - Rand - Rittler Standard Isochromatic, Ishihara, and Farnsworth D-15 tests (p > 0.05). Additionally, no significant differences were found between the Ishihara and Hardy - Rand - Rittler tests (p > 0.1) or between the Waggoner Computerized and City University tests (p = 0.11). Colour vision testing maintained an accuracy ≤ 1.0 logMAR with the Ishihara and Hardy - Rand - Rittler tests, 1.1 logMAR with the Waggoner Pseudo-isochromatic and Farnsworth D-15 tests, and 0.9 logMAR with the Waggoner Computerized and City University tests. CONCLUSIONS: Insights are provided into the visual acuity thresholds required for accurate colour vision testing, which can serve as a basis for future research and provide a reference for clinical practice in this field.