Changes in visual function and optical and tear film quality in computer users

Purpose: To assess changes in visual function and optical and tear film quality in computer users.Methods: Forty computer workers and 40 controls were evaluated at the beginning and end of a working day. Symptoms were assessed using the Quality of Vision questionnaire (QoV), 5-item Dry Eye Questionnaire (DEQ--5) and Symptom Assessment in Dry Eye version II (SANDE II). Tear film quality was evaluated using the Medmont E300 dynamic corneal topography tool to measure the tear film surface quality (TFSQ), TFSQ area and auto tear break- -up time (TBUT). Optical quality was assessed by measuring high, low and total ocular aberrations with a Hartmann-Shack wavefront sensor. Visual performance was assessed by measuring photopic and mesopic visual acuity, photopic and mesopic contrast sensitivity and light disturbance.Results: Poorer DEQ-5, QoV and SANDE II scores were obtained in computer workers at the end of the working day compared with controls ( p = 0.19) or ocular aberrations were observed (p >= 0.09). Additionally, both light disturbance ( p = 0.07). In contrast, control subjects exhibited no decrease in any variable during the day.Conclusions: While visual acuity remained unchanged, several aspects of visual function and quality of vision decreased over a day of computer use. These changes were accompanied by greater dry eye symptoms and tear film changes, which are likely to have played a fundamental role. The present study provides insight into new metrics to assess digital eye strain.Conselleria d'Educacio, Investigacio, Cultura i Esport de la Generalitat Valenciana, Grant/Award Number: GV/2018/059; Spanish Ministry of Universities, Grant/Award Number: FPU17/0366

Impact of egg production and stock structure on MSY reference points and its management implications for southern hake (Merluccius merluccius)

Spawning stock biomass (SSB) is one of the most common measures of stock status. However recent research on reproductive potential has shown that alternative variables may be an improvement over SSB. In the case of European hake (Merluccius merluccius), it is known that large individuals produce more eggs by unit of body weight, and their quality is better than those of small individuals. Under these circumstances, application of reproductive potential may be pertinent in the implementation of the Johannesburg agreement, since it is not only the spawning biomass but also its age or length structure that defines stock productivity and its ability to achieve maximum sustainable yield (MSY). In this contribution we used an age-length structured population model to assess the impact of different reproductive indices (total spawning biomass, female spawning biomass and egg production) on MSY reference points. First, we analyzed how these different indices alter our perception about per recruit productivity. Second, we analyzed the quality of these alternative reproductive indices to explain and predict recruitment using different model structures (Ricker and Beverton-Holt) and Bayesian inference. Third, we combined per recruit models and stochastic stock-recruitment relationships to estimate the probability distributions of MSY biological reference points (MSY, 'F-msy, Stock(msy), and F ash). Our results show that, for hake stocks where larger fish have a strong contribution to stock reproductive potential, use of alternative reproductive indices will affect estimations of stock sustainability. The change in perception of relative contribution of each length class is exhibited in two opposite ways: reproductive potential per recruit and the shape of the stock-recruitment relationship defined with steepness. In our case, the change from SSB to egg production, resulted in an increase in steepness which counteracted the depletion per recruit resulting in a larger F-msy

Light distortion of soft multifocal contact lenses with different pupil size and shape

Purpose: To study the light distortion effects of soft multifocal contact lenses and the influence of different pupil size and shape.Methods: A total of 14 eyes of 7 healthy contact lens users (mean age 28.6 +/- 8.5 years) were recruited. The "Light Disturbance Analyser" device was employed for light characterization. The selected lenses were the monthly disposable "Biofinity multifocal" (CooperVision, CA, USA), both centre-distance and centre-near designs (addition power + 2.50 D). Two circular pupils of 3 mm and 5 mm of diameter, and an elliptical shape (3 horizontal and 5 vertical mm) were used. Metrics such as the light distortion index (LDI), best-fit circle radius and its irregularity were analysed, among others.Results: The LDI was generally higher with multifocal lenses, varying from 3.7 +/- 0.3 % of the single vision lens to 6.1 +/- 3.3 % of the multifocal centre-distance design and the 5-mm pupil. Larger pupils gave higher LDI values, changing from 4.5 +/- 2.0 % (3 mm) to 6.1 +/- 3.3 % (5 mm) with the centre-distance design. The elliptical pupil produced the largest discrepancy in the distortion size between the vertical and horizontal directions. The centre-distance and centre-near designs behaved similarly in terms of light distortion.Conclusions: The multifocal contact lenses of the study increased light distortion effects under low light conditions, especially with larger pupils. The shape of the distortion pattern is associated with the shape of the pupil. It seems that not all, but a big percentage of light distortion would be produced by the presence of the out-offocus images given by a multifocal lens.This research was supported in part by a "Formacion de Profesorado Universitario" Grant (FPU13/05332, Ministerio de Educacion, Cultura y Deporte) awarded to Daniel Monsalvez-Romin, and by the research project GV/2015/043, from "Conselleria d'Educacio, Investigacio, Cultura i Esport de la Generalitat Valenciana", awarded to Alejandro Cervino. Work performed at University of Minho has been partially supported by projects PTDC/SAU-BEB/098391/2008, PTDC/FIS-OPT/0677/2014 and UID/FIS/04650/2019

Tear film stability over a myopia control contact lens compared to a monofocal design

Background: To compare the short-term effect of two contact lenses on pre-lens tear film stability and comfort: dual-focus contact lens (MiSight) and a monofocal contact lens (Proclear 1-day).Methods: This randomised, double-masked, crossover study was performed in twenty-eight healthy, myopic volunteers aged between 18 and 32 years (23.5 +/- 4.1 years). Only one randomly chosen eye was assessed. Distance vision and refraction were evaluated at baseline. Each contact lens type (monofocal and dual-focus) was randomly fitted, always in both eyes. A visual analogue scale between 0 and 10 was used to assess general comfort, physical comfort, and visual comfort. Tear Film Surface Quality (TFSQ) index, TFSQ_area and auto Tear Break-Up Time were obtained using Medmont E-300 at baseline (naked eye condition) and 25 minutes after each contact lens insertion.Results: Refractive sphere and cylinder were, respectively, -1.36 +/- 1.04 D (ranging from -6.00 to -0.25 D) and -0.23 +/- 0.30 D (ranging from -0.75 to 0.00 D). TFSQ and TFSQ area were lower (meaning more stable tear film) at baseline when compared with both contact lens types (p < 0.025). Higher pre-lens tear instability (larger TFSQ and_TFSQ area values) was found with the dual-focus than the monofocal lens. Auto Tear Break-Up Time was higher at baseline than with each of the contact lenses, without statistically significant differences between both contact lens types. Visual analogue scales revealed statistically significant better scores in the monofocal contact lens than in dual-focus contact lens for general (0.77 +/- 1.14 vs 3.12 +/- 2.79), physical (0.96 +/- 1.46 vs 2.19 +/- 2.45) and visual comfort (1.27 +/- 1.66 vs 3.92 +/- 2.04).Conclusion: A slight reduction in short-term pre-lens tear film stability was found in the dual-focus design in comparison with the monofocal lens, potentially contributing to the deterioration of visual performance and comfort during dual-focus contact lens wear.This study was supported by the University of Valencia through the 'Atraccio de Talent' scholarship [UV-INV_PREDOC18F2-886420] awarded to Jose V Garcia-Marques; the Portuguese Foundation for Science and Technology (FCT) in the framework of projects [PTDC/SAU-BEB/098391/2008, PTDC/FIS-OPT/0677/2014]; and the FCT Strategic Funding [UID/FIS/04650/2013]

Comparison of short-term light disturbance, optical and visual performance outcomes between a myopia control contact lens and a single-vision contact lens

Purpose To compare the optical and visual performance of a dual-focus (DF) contact lens used for myopia control with a single-vision (SV) contact lens of the same material. Methods A randomised, double-masked crossover study. Twenty-eight healthy, myopic volunteers between 18 and 32 years of age (23.49 +/- 4.07 years) participated in this study. The sensory dominant eye for distance vision was determined. Refraction, best-corrected visual acuity (VA) and aberrations for 3 mm and 5 mm pupil diameters were quantified without a contact lens in situ. Subjects were fitted with two contact lens designs: DF and SV, both made of omafilcon A material. The Quality of Vision (QoV) questionnaire, over-refraction, best-corrected VA, stereopsis at 40 cm, best-corrected photopic and mesopic contrast sensitivity, light disturbance and aberrations were assessed 25 min after contact lens insertion. Results There were no statistically significant differences in best-corrected VA and stereopsis between the baseline, DF and SV conditions. Photopic and mesopic contrast sensitivity were lower for the DF contact lens at all frequencies, with the exception of the mesopic contrast sensitivity at 18 cycles per degree (p = 0.23). Higher order aberrations and light disturbance size and irregularity were higher for the DF contact lens (p < 0.001). No differences were found in higher order aberrations between baseline and the SV contact lens condition for each pupil diameter. QoV scores also revealed lower frequency, severity and bothersome scores with the SV contact lens than with the DF contact lens (p < 0.001). Conclusions The DF contact lens design decreased the psychophysical and psychometric visual quality scores in the short-term under dim-light conditions when compared with a single-vision contact lens design of the same material. VA and stereopsis were unaffected by the lens design.- This work was supported by "Atraccio de Talent" scholarship UV-INV_PREDOC18F2-886420 awarded to Jose V Garcia-Marques and by the Portuguese Foundation for Science and Technology (FCT) in the framework of projects PTDC/SAU-BEB/098391/2008, PTDC/FIS-OPT/0677/2014 and the FCT Strategic Funding UID/FIS/04650/2013

Actas del IV congreso nacional de acuicultura

Available from Centro de Informacion y Documentacion Cientifica CINDOC. Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

4. congreso nacional de acuicultura

ProceedingsCentro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai