illustration actualites

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.

READ THIS ARTICLE...


Article from the magazine "Point de vue"

points de vue

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

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.

READ THIS ARTICLE...


Article from the magazine "Point de vue"

points de vue

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.

READ THIS ARTICLE...


Article from the magazine "Point de vue"

points de vue

The three pillars of myopia controle in practiceClick here to read the article

Myopia has become such an epidemic that the World Health Organization describes it as a key risk factor for ocular pathologies that can lead to blindness. As eyecare professionals and public health authorities respond to the crisis, this article offers a strategic approach with effective mechanisms for myopia control. This approach is based on three pillars of intervention: managing the environments of young people with myopia, managing their ametropia and peripheral defocus, and treating anomalies in binocular vision.

 

READ THIS ARTICLE...


Article from the magazine "Point de vue"

points de vue

Refraction : patients are sensitive to increments smaller than a quarter diopter !Click here to read the article

Traditionally, in the ophthalmic lens industry optical corrections have been offered in increments no smaller than 0.25 D. But patients are often sensitive to smaller dioptric changes. A study carried out by Essilor International at its Singapore R&D centre with a representative sample of patients showed that 95% were sensitive to dioptric changes of under 0.25 D and that 44% could distinguish between changes of less than 0.125 D. This article presents the results of the study and demonstrates how a patient’s sensitivity can influence the precision of their refraction result. It also explores the outlook offered by the new high-precision subjective-refraction techniques and the ophthalmic lenses associated with them.

 

READ THIS ARTICLE...


Article from the magazine "Point de vue"

points de vue

A new approach to subjective refractionClick here to read the article

The advent of phoropters offering continuous power changes has made new subjective refraction techniques possible. One of them consists of determining a patient’s refraction using semi-automated algorithms that simultaneously change sphere, cylinder and axis in increments of variable dimension.* This article provides an overview of this technique’s general principles and shows how it can make both determining refraction easier and achieve more accurate results.

 

READ THIS ARTICLE...


Article from the magazine "Point de vue"

points de vue

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.

 

READ THIS ARTICLE...


Article from the magazine "Point de vue"

points de vue

Page 1 of 5