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Displaying items by tag: vision

Subjective Refraction: A new vectorial method for determining the cylinder 3/3Click here to read the article

The refraction technique traditionally used to determine the corrective cylinder for a prescription has changed very little over the years, mainly due to the limitations imposed by subjective phoropters, which present lenses in increments usually no smaller than 0.25 D.
Today, thanks to phoropters with continuous power changes that allow to simultaneously and accurately act on sphere, cylinder and axis, it is now possible to develop new refraction techniques. This series of three articles describes the principles of a new vectorial method for determining the corrective cylinder and presents the rationale for an associated automated cylinder search algorithm.

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Article from the magazine "Point de vue"

points de vue

Published in Optometry

Subjective Refraction: A new vectorial method for determining the cylinder 2/3Click here to read the article

The refraction technique traditionally used to determine the corrective cylinder for a prescription has changed very little over the years, mainly due to the limitations imposed by subjective phoropters, which present lenses in increments usually no smaller than 0.25 D.
Today, thanks to phoropters with continuous power changes that allow to simultaneously and accurately act on sphere, cylinder and axis, it is now possible to develop new refraction techniques. This series of three articles describes the principles of a new vectorial method for determining the corrective cylinder and presents the rationale for an associated automated cylinder search algorithm.

READ THIS ARTICLE...


Article from the magazine "Point de vue"

points de vue

Published in Optometry

Subjective Refraction: A new vectorial method for determining the cylinder 1/3Click here to read the article

The refraction technique traditionally used to determine the corrective cylinder for a prescription has changed very little over the years, mainly due to the limitations imposed by subjective phoropters, which present lenses in increments usually no smaller than 0.25 D.
Today, thanks to phoropters with continuous power changes that allow to simultaneously and accurately act on sphere, cylinder and axis, it is now possible to develop new refraction techniques. This series of three articles describes the principles of a new vectorial method for determining the corrective cylinder and presents the rationale for an associated automated cylinder search algorithm.

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Article from the magazine "Point de vue"

points de vue

Published in Optometry
Tuesday, 19 January 2021

Refraction : Vertex distance matters!

Refraction : Vertex distance matters!Click here to read the article

Although the effect of vertex distance on optical correction is well known, it is rarely taken into account in practice, except in cases of very strong corrections. When ophthalmic lenses were offered only in 0.25 D increments, this had little influence on most corrections.
But today, with refraction determined in 0.01 D increments* and the lenses associated with them, knowledge and measurement of vertex distance becomes particularly important. This article reviews the optical effects of vertex distance, shows how eye-to-phoropter distance can vary and discusses how vertex distance can now be taken into account for an accurate calculation of corrective lens power.

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Article from the magazine "Point de vue"

points de vue

Published in Optometry
Tuesday, 14 January 2020

Convergence insufficiency

Convergence insufficiencyClick here to read the article

One of the most common disorders of binocular vision encountered in the eye clinic is convergence insufficiency (CI). Population studies estimate upwards of 8% of the population suffer from convergence insufficiency, with the incidence increasing with age. Convergence insufficiency results with vergence ability at near is unable to match vergence demand. When this occurs, sensory fusion may be disrupted leading to intermittent diplopia, asthenopia, and fatigue. Clinicians should be able to quickly screen for abnormalities in convergence ability of a patient and provide a thorough evaluation of binocular ability when indicated. Many patients will respond well to vergence therapy, leading to both an increase in fusional vergence ability and a subsequent decrease in symptoms.

 

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Article from the magazine "Point de vue"

points de vue

Published in Optometry
Tuesday, 22 October 2019

The hidden cost of eye injuries

The hidden cost of eye injuriesClick here to read the article

Vision is intimately linked with our ability to navigate our environment and can strongly affect our mental, physical and economic well-being.

Losing one’s vision through an eye injury can lead to substantial long-term costs, and impact on an individual and their family & community. Eye injuries occur in a range of environments, including in the workplace, during sports and at home. Young working males are at the highest risk of eye injury. Up to 90% of eye injuries are preventable, with effective interventions including; education about the hazards, policies and training on the correct use of eye protection. Eye health professionals can play an important role in promoting and prescribing eye injury prevention strategies to help reduce this avoidable cause of vision loss.

 

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Article from the magazine "Point de vue"

points de vue

Published in Optometry
Tuesday, 15 January 2019

A low vision magnification breakthrough

A low vision magnification breakthroughClick here to read the article

For people suffering from low vision today, it often takes tenacity and perseverance to find an optical solution that allows them to optimize their remaining sight. Meg Zatorski knows this only too well. Afflicted with Stargardt disease (a common form of inherited juvenile macular degeneration), she spent a decade trying to obtain powerful enough high plus lenses to enable her to regain the ability to read. Essilor’s Stanislas Poussin and Anne-Catherine Scherlen recount how her challenge was met and what needs to be done so others like her can benefit from a solution that meets their visual needs.

 

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Article from the magazine "Point de vue"

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Published in Optometry

Vision and road safety : Putting the brakes on a global public health threatClick here to read the article

Uncorrected vision continues to endanger the lives of drivers, passengers, and pedestrians around the world. Compounded by external factors such as nighttime driving, inclement weather, and adverse road conditions, uncorrected vision contributes to more than 1.25 million road accident deaths each year. Until recently, the intersection of vision and road safety has not received adequate attention. Consequently, there is a lack of awareness around the need to address the impact of vision problems on driver and road safety. While governments and policymakers can play a significant role in raising greater awareness of this public health threat, eye care professionals are also part of the solution as they are a competent authority in promoting effective assessment of vision and correcting drivers’ visual functions.

 

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Article from the magazine "Point de vue"

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Published in Optometry

Proper visual correction and safe drivingClick here to read the article

The results of optometric analyses are reported to discuss the relationship between adequate visual acuity, efficient state of binocularity, and other abilities required when driving. The results are also supported by the presence of substantial symptoms reported by drivers and associated with these visual performances. Experimental evidence found that the role of visual acuity related to the binocularity, particularly in presence of anisometropia, has consequences on the perception of distances in terms of speed of perception (stereospeed). Significant correlation was also found between visual acuity and both glare sensitivity and light vision. Both eye-hand and eye-foot reaction times were measured, and the presence of limitations of the visual field was found to influence the speed of response to a visual stimulus.

 

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Article from the magazine "Point de vue"

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Published in Optometry

Single vision lenses with additional near powerClick here to read the article

Life in modern societies is increasingly digitalized. The increase in near-point activities brought on by the widespread use of all kinds of digital devices is triggering a notable increase in the visual fatigue syndrome known as digital eye strain (DES), accommodative and vergence dysfunctions and dry eye. As practitioners, we must face this challenge – which represents nothing less than the digital Everest for our eyes – with concrete solutions for real life. Single vision lenses with additional near-power is an example of one such solution we are using to treat a number of clinical cases. In this review, we are going to share what we are busy doing to resolve this challenge.

 

 

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Article from the magazine "Point de vue"

points de vue

Published in Optometry