Stereopsis simulating small aperture corneal inlay and monovision conditions

Purpose: To analyze stereoscopic vision under a broad range of experimental conditions simulating small-aperture corneal inlay and monovision conditions. Methods: A total of 10 patients participated in the study. The anisocoria generated by corneal inlays was simulated by using a small-aperture contact lens fitted on the non-dominant eye. Visual acuity, contrast sensitivity function, visual discrimination capacity (halo perception), and stereoacuity tests were performed under natural conditions or when the non-dominant eye wore the small-aperture contact lens under two conditions: induced anisocoria and induced anisocoria combined with monovision (using two add-powers: +0.75 and +1.25 diopters [D]). Stereoscopic vision and binocular summation were analyzed under those experimental conditions and for far, intermediate, and near vision. Results: The results showed a deterioration in stereoacuity with respect to natural conditions, being significant mainly for near and intermediate distances. Results with other visual functions showed a deterioration of the binocular summation and therefore of visual performance, although not in a generalized way for all distances. Binocular visual acuity under the conditions that used the small-aperture contact lens was comparable to that of the natural eye. Conclusions: The deterioration of stereopsis and other binocular functions found in this study may be acceptable for patients who had this surgical technique because it is similar to the deterioration found in other surgical procedures of emmetropization.Ministerio de Economía y Competitividad y Fondo Regional Europeo para el Desarrollo (Grant FIS2013-42204-R)Ministerio de Educación, Cultura y Deporte (FPU15/05571

Effect of the chromaticity of stimuli on night vision disturbances

The perception of halos and other night vision disturbances is a common complaint in clinical practice. Such visual disturbances must be assessed in order to fully characterize each patient’s visual performance, which is particularly relevant when carrying out a range of daily tasks. Visual problems are usually assessed using achromatic stimuli, yet the stimuli encountered in daily life have very different chromaticities. Hence, it is important to assess the effect of the chromaticity of visual stimuli on night vision disturbances. The aim of this work is to study the influence of the chromaticity of different visual stimuli on night vision disturbances by analyzing straylight and visual discrimination under low-light conditions. For that, we assessed the monocular and binocular visual discrimination of 27 subjects under low illumination using the Halo test. The subjects’ visual discrimination was assessed after exposure to different visual stimuli: achromatic, red, green, and blue, both at the monitor’s maximum luminance and maintaining the same luminance value for the different visual stimuli. Monocular straylight was also measured for an achromatic, red, green, and blue stimuli. The blue stimulus had the greatest effect on halos in both monocular and binocular conditions. Visual discrimination was similar for the red, green, and achromatic stimuli, but worsened at lower luminance. The greatest influence of straylight was observed for the blue stimulus. In addition, visual discrimination correlated with straylight measurements for achromatic stimuli, wherein greater straylight values correlated with an increased perception of halos and other visual disturbances.- Proyecto A-FQM-532-UGR20, financiado por FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades - Proyecto PID2020-115184RB-I00, financiado por MCIN/AEI/10.13039/50110001103

Effects of Smoking Cannabis on Visual Function and Driving Performance. A Driving-Simulator Based Study

Cannabis is the most widely used illegal drug in the world. Limited information about the effects of cannabis on visual function is available, and more detail about the possible impact of visual effects on car driving is required. This study investigated the effects of smoking cannabis on vision and driving performance, and whether these effects are correlated. Twenty drivers and occasional users were included (mean (SE) age, 23.3 (1.0) years; five women). Vision and simulated driving performance were evaluated in a baseline session and after smoking cannabis. Under the influence of cannabis, certain visual functions such as visual acuity (p < 0.001), contrast sensitivity (p = 0.004) and stereoacuity (far, p < 0.001; near, p = 0.013) worsened. In addition, there was an overall deterioration of driving performance, with the task of keeping the vehicle in the lane proving more difficult (p < 0.05). A correlation analysis showed significant associations between driving performance and visual function. Thus, the strongest correlations were found between the distance driven onto the shoulder and stereoacuity, for near (ρ = 0.504; p = 0.001) and far distances (ρ = 0.408; p = 0.011). This study provides the first evidence to show that the visual e ects of cannabis could impact driving performance, compromising driving safety. The results indicate that information and awareness campaigns are essential for reducing the incidence of driving under the influence of cannabis.This research was funded by the Ministry of Economy and Competitiveness (Spain) and the European Regional Development Fund (ERDF), grant number FIS2017-85058-R and by the Ministry of Science, Innovation and Universities (Spain), grant number Grant FPU15/05571

Parental awareness of the implications of myopia control and strategies to control its progression: A survey-based study

Purpose Myopia has emerged as a significant public health concern. Effective methods have now been developed to delay its onset and progression. However, this information may not be reaching parents, and they are key players in terms of implementing the necessary preventive measures. This study investigated parental awareness of myopia, its implications and the strategies available for controlling it. Methods A self-administered online survey was distributed to parents of children 6–16 years of age. To be eligible to respond, their child had to be myopic or at risk of developing myopia due to family history. Results A total of 330 parents completed the survey, of which 321 were included for analysis. Sixty-seven percent of respondents had at least one myopic son/daughter, and most were between −1.00 and −1.75 D. Among parents of myopic children, 20.9% thought that their child's myopia progressed moderately. Sixty-seven percent of parents had a significant level of concern about the progression of the myopia and felt that it was caused mainly by the use of electronic devices and genetics. A generalised linear model showed that parental concern was significantly predicted by the perception of evolution (p < 0.001) and the number of known health-related consequences (p < 0.001). Almost 40% of parents were unaware of the existence of myopia control strategies. Relatives and eye care practitioners are the main sources of information. The most well-known myopia control strategy was myopia control soft contact lenses (29.2%), although the option that most parents would opt for was spectacles with peripheral defocus lenses (47.1%). The selection of a contact-lens-based myopia control method correlated significantly with the age of the children (p < 0.001). Conclusions Society in general and parents in particular need more information about myopia, its consequences and the options available for its control. Eye care practitioners play an important role in this issue.FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades (A-FQM-532-UGR20)MCIN/ AEI/10.13039/501100011033 (PID2020-115184RB-I00

Effect of interocular differences on binocular visual performance after inducing forward scattering

Research Projects PID2020-115184RB-I00, funded by MCIN/AEI/10.13039/501100011033, and A-FQM-532-UGR20, funded by FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades.Purpose: To assess binocular visual performance by means of binocular summation on visual function after inducing monocular forward scattering, and to study the influence of interocular differences on ocular parameters. Methods: Seven young healthy subjects were recruited. Four Bangerter foils and five fog filters were used to induce monocular forward scattering. To analyse the impact of the scatter, visual acuity, contrast sensitivity, visual discrimination capacity and distance stereoacuity were measured binocularly with the filter placed over the dominant eye. Additionally, interocular differences were calculated for four ocular parameters: the Objective Scatter Index (OSI), Strehl ratio (SR), modulation transfer function cut-off (MTF cut off) and straylight (log[s]). Binocular summation was determined for these visual functions. Results: A statistically significant deterioration in visual acuity, contrast sensitivity and stereoacuity was seen for all of the filter conditions with respect to the natural state (baseline), with the largest change being recorded for the Bangerter foils. Similarly, the interocular difference for the three retinal image quality parameters (OSI, SR and MTF cut-off) and log(s) increased significantly for the Bangerter foil condition, but not for the fog filters (except log(s)). Binocular summation declined gradually with the Bangerter foils, but not for the fog filters. Statistically significant correlations were found, that is, the greater the interocular differences, the lower the binocular summation of the visual functions and the greater the distance stereoacuity. Conclusion: Increased forward scattering in the dominant eye resulted in interocular differences, which reduced the overall binocular visual performance, including the binocular summation of several visual functions and distance stereoacuity. The results suggest that marked interocular differences in ocular parameters should be avoided in cases of ocular pathology, amblyopia and emmetropisation procedures (such as refractive surgery) or a monovision correction for presbyopia.FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades PID2020-115184RB-I00 MCIN/AEI/10.13039/501100011033 A-FQM-532-UGR2

Synthesis, conformational analysis and <i>in vivo</i> assays of an anti-cancer vaccine that features an unnatural antigen based on an sp²-iminosugar fragment.

The Tn antigen (GalNAc-α-1-O-Thr/Ser) is a well-known tumor-associated carbohydrate determinant. The use of glycopeptides that incorporate this structure has become a significant and promising niche of research owing to their potential use as anticancer vaccines. Herein, the conformational preferences of a glycopeptide with an unnatural Tn antigen, characterized by a threonine decorated with an sp2-iminosugar-type α-GalNAc mimic, have been studied both in solution, by combining NMR spectroscopy and molecular dynamics simulations, and in the solid state bound to an anti-mucin-1 (MUC1) antibody, by X-ray crystallography. The Tn surrogate can mimic the main conformer sampled by the natural antigen in solution and exhibits high affinity towards anti-MUC1 antibodies. Encouraged by these data, a cancer vaccine candidate based on this unnatural glycopeptide and conjugated to the carrier protein Keyhole Limpet Hemocyanin (KLH) has been prepared and tested in mice. Significantly, the experiments in vivo have proved that this vaccine elicits higher levels of specific anti-MUC1 IgG antibodies than the analog that bears the natural Tn antigen and that the elicited antibodies recognize human breast cancer cells with high selectivity. Altogether, we compile evidence to confirm that the presentation of the antigen, both in solution and in the bound state, plays a critical role in the efficacy of the designed cancer vaccines. Moreover, the outcomes derived from this vaccine prove that there is room for exploring further adjustments at the carbohydrate level that could contribute to designing more efficient cancer vaccines