On Dependency between Wishes and Perception

Introduction. Empirical studies of recent years convincingly show that the character of sensory perception can be influenced by non-cognitive mental states of the agent, such as her desires. The aim of the paper is to analyze how this causal connection between agent's wishes and her sensations can affect the epistemological status of dependent sensations.Methodology and sources. The author examines S. Siegel's argument on this issue. S. Siegel argues that the empirically proven dependence of sensations on desires (wishful seeing) should lead to a decrease of the epistemological status of sensations to the same extent as the dependence of beliefs on desires (wishful thinking) leads to a decrease of the epistemological status of these beliefs. Thus Siegel's argument concludes that the phenomenon of wishful seeing deprives us of any reason to accept sensations as credible evidence of the states of the world. So, this is an argument in favor of skepticism.Results and discussion. The article discusses two main strategies for rejecting Siegel's argument. According to the first strategy proposed by R. Long, sensations are not so similar to beliefs that one can conclude that their epistemological status should be decreased on the basis of their dependence on desires. According to another strategy for refuting Siegel's argument, proposed by A. Raftopoulos, the influence of desires on perception does not extend to early vision. Early vision is free from the influence of higher order conscious mental states. The dependence of the results of sensory perception on other mental states is reduced to the influence of these states on the agent's attention. At the same time, attention can be volitionally controlled and can be trained. Therefore dependent perception under certain conditions can be rationally accepted.Conclusion. Thus, the article shows that, even though perception is dependent on other non-cognitive mental states, such as desires, this dependence does not necessarily lead to a decrease in the epistemological status of sensations, so sensations can be rationally accepted under certain conditions. This means that Siegel's argument for skepticism is not compelling.

Temporal vision: measures, mechanisms and meaning

ABSTRACT Time is largely a hidden variable in vision. It is the condition for seeing interesting things such as spatial forms and patterns, colours and movements in the external world, and yet is not meant to be noticed in itself. Temporal aspects of visual processing have received comparatively little attention in research. Temporal properties have been made explicit mainly in measurements of resolution and integration in simple tasks such as detection of spatially homogeneous flicker or light pulses of varying duration. Only through a mechanistic understanding of their basis in retinal photoreceptors and circuits can such measures guide modelling of natural vision in different species and illuminate functional and evolutionary trade-offs. Temporal vision research would benefit from bridging traditions that speak different languages. Towards that goal, I here review studies from the fields of human psychophysics, retinal physiology and neuroethology, with a focus on fundamental constraints set by early vision.

An Image Reconstruction Framework for Characterizing Early Vision

We developed an image-computable observer model of the early visual system that operates on fully naturalistic input, based on a framework of Bayesian image reconstruction from retinal cone mosaic excitations. Our model extends previous work on ideal observer analysis and the evaluation of performance beyond psychophysical discrimination tasks, takes into account the statistical regularities of our visual environment, and provides a unifying framework for answering a wide range of questions regarding early vision. Using the error in the reconstruction as a metric, we analyzed the variations of the number of different photoreceptor types on human retina as an optimal design problem. In addition, the reconstructions allow both visualization and quantification of information loss due to physiological optics and cone mosaic sampling, and how these vary with eccentricity. Furthermore, in simulations of color deficiencies and interferometric experiments, we found that the reconstructed images provide a reasonable proxy for directly modeling subjects' percepts. Lastly, we used the reconstruction-based observer for the analysis of psychophysical threshold, and found notable interactions between spatial frequency and chromatic direction in the resulting spatial contrast sensitivity function. Our method should be widely applicable to many experiments and practical applications in which early vision plays an important role.

Collinear search impairment is luminance contrast invariant

Collinear search impairment (CSI) is a phenomenon where a task-irrelevant collinear structure impairs a target search in a visual display. It has been suggested that CSI is monocular, occurs without the participants’ access to consciousness and is possibly processed at an early visual site (e.g. V1). This effect has frequently been compared with a well-documented opposite effect called attentional capture (AC), in which salient and task-irrelevant basic features (e.g. color, orientation) enhance target detection. However, whether this phenomenon can be attributed to non-attentional factors such as collinear facilitation (CF) has not yet been formally tested. Here we used one well-established property of CF, i.e. that target contrast modulates its effect direction (facilitation vs suppression), to examine whether CSI shared similar signature profiles along different contrast levels. In other words, we tested whether CSI previously observed at the supra-threshold level was reduced or reversed at near-threshold contrast levels. Our results showed that, regardless of the luminance contrast levels, participants spent a longer time searching for targets displayed on the salient singleton collinear structure than those displayed off the structure. Contrast invariance suggests that it is unlikely that CSI is exclusively sub-served by an early vision mechanism (e.g. CF).

An Effective Method for Detecting and Classifying Diabetic Retinopathy Lesions Based on Deep Learning

Diabetic retinopathy occurs as a result of the harmful effects of diabetes on the eyes. Diabetic retinopathy is also a disease that should be diagnosed early. If not treated early, vision loss may occur. It is estimated that one third of more than half a million diabetic patients will have diabetic retinopathy by the 22nd century. Many effective methods have been proposed for disease detection with deep learning. In this study, unlike other studies, a deep learning-based method has been proposed in which diabetic retinopathy lesions are detected automatically and independently of datasets, and the detected lesions are classified. In the first stage of the proposed method, a data pool is created by collecting diabetic retinopathy data from different datasets. With Faster RCNN, lesions are detected, and the region of interests are marked. The images obtained in the second stage are classified using the transfer learning and attention mechanism. The method tested in Kaggle and MESSIDOR datasets reached 99.1% and 100% ACC and 99.9% and 100% AUC, respectively. When the obtained results are compared with other results in the literature, it is seen that more successful results are obtained.

A comparative study on early vision quality after implantation of refractive segmental and diffractive multifocal intraocular lens

Objectives: To compare early subjective and objective vision quality of postoperative patients undergoing phacoemulsification cataract surgery combined with implantation of refractive segmental multifocal intraocular lens (MIOL) SBL-3 and apodized diffractive MIOL SN6AD1. Methods: As a prospective study, it enrolled 53 patients (53 eyes) to undergo phacoemulsification cataract surgery combined with MIOL implantation. According to differences in MIOL implanted, patients were divided into a SBL-3 group (25 eyes) and a SN6AD1 group (28 eyes). Ophthalmological evaluation included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, uncorrected intermediate (UIVA) and near (UNVA) visual acuities, distance-corrected intermediate (DCIVA) and near (DCNVA)visual acuities and corrected near(CNVA) visual acuity, contrast sensitivity, modulation transfer function (MTF) and high order aberration (4 mm pupil diameter) at three months postoperatively. Moreover, a questionnaire survey was carried out to assess near spectacle independence, patient satisfaction and symptoms of visual disturbance. Results: At three months after surgery, UIVA and UNVA in the SBL-3 group are statistically significantly superior to those of the SN6AD1 group (P<0.05). There was statistical difference in contrast sensitivity at four spatial frequencies (3, 6, 12, 18cycles/degree) under mesopic conditions and mesopic conditions with glare (P<0.05). The total ocular high order aberration, coma and trefoil were statistically significantly larger in the SBL-3 group than in the SN6AD1 group with 4.0 mm pupil diameters (P<0.05). Statistical differences were found in the MTF at spatial frequencies of 5, 10 and 15 cycles/degree between the groups. There were no significant differences in spectacle independence, patient satisfaction and visual disturbance between the groups (P>0.05). Conclusions: Both the two multifocal intraocular lens provided an excellent level of quality of vision three months postoperatively. However, the application effect of SBL-3 MIOL is superior to that of SN6AD1 MIOL as far as intermediate vision, near vision and contrast sensitivity are concerned. doi: https://doi.org/10.12669/pjms.36.7.3364 How to cite this:Lian H, Ma W, Wei Q, Yuan X. A comparative study on early vision quality after implantation of refractive segmental and diffractive multifocal intraocular lens. Pak J Med Sci. 2020;36(7):---------. doi: https://doi.org/10.12669/pjms.36.7.3364 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.