Device for measuring maxwell spot centroid orientations, particularly in people with dyslexia

Abstract

The invention makes it possible to improve on the disadvantages of the prior art by proposing an electronic device which is able to measure the critical orientations of the ellipses with a precision of 2°, and respective orientations of the main axes for both eyes, which lead to reading difficulties in children in particular. The device according to the invention comprises a control unit for controlling the orientation of an elliptical profile in order to be able to measure mirror-image or translational orientations that are liable to lead to reading difficulties. Indeed, opposite or parallel orientations of two profiles having the same ellipticity may in particular lead to two types of dyslexia. The entopic image of each Maxwell spot centroid along with its orientation, observed using a viewing system with a double blue-green rotary filter, makes it possible to diagnose various types of dyslexia. Advantageously, the rotary system makes it possible to choose the rotational frequency so as to optimise contrast quality.

Description

[0001] DESCRIPTION

[0002] Title: DEVICE FOR MEASURING MAXWELL CENTROID ORIENTATIONS, PARTICULARLY IN DYSLEXIC PEOPLE

[0003] 1. Field of the invention.

[0004] The present invention relates to a device for measuring all cases of orientations between the profiles of Maxwell's centroids, including elliptical profiles, for the two foveas, in particular for a person with reading difficulties, and this for all possible orientations of the major axes of the ellipses.

[0005] 2. State of the prior art.

[0006] Dyslexia is usually defined as a complex learning deficit, particularly in reading, that appears in childhood. Despite the different approaches that have been proposed, from biology, neurology, cognitive science, and genetics, all converge towards a biological origin linked to neurology and brain connectivity. This deficit is widespread, affecting approximately 10% of a given population according to international statistics, with all countries being equally affected.

[0007] Vision, coming from the two eyes providing the two most important masses of information for the brain, but slightly different to the visual cortex has been, from the beginning of the 20 èmecentury, suspected of being involved. The visual clutter and confusion of symmetrical letters like "b" and "d," and even words and their mirrors, led Ernest Mach (The Analysis of Sensations, Chicago: Open Court 1914) to write: "To remove the confusion of the bd type, an asymmetry must be introduced somewhere in the brain." Moreover, recent results of functional magnetic resonance imaging have shown that, in dyslexic people, the brain is too weakly lateralized to perform certain functions. Reading, in particular, uses the left cerebral hemisphere for about 98% of a population. An asymmetry was detected between Maxwell's centroids, that is, between the two small regions devoid of blue cones (about 100 microns in diameter) at the center of the two foveas, for each person with no reading deficit (normal readers).A patent (Le Floch, Bourdillon, Ropars) was filed on 06 / 11 / 2012 at the INPI (FR2997618) for a device for detecting this asymmetry in normal readers. For people with ocular instabilities, a first lack of asymmetry was observed, but it was not until 2017 that the first dyslexic people were found with circular Maxwell centroids, without asymmetries, with excess mirror or double images that cause visual clutter making reading difficult (Le Floch A., Ropars G., 2017, Proc. R. Soc. B, https: / / doi.org / 10.1098 / rspb.2017.1380). However, the lack of asymmetry in dyslexic people is not limited to the case of circular contours. Indeed, it is possible to observe a lack of asymmetry between the two elliptical profiles for a dyslexic person.However, an error was made in this manuscript on page 5, which states “and there is no preferred azimuth cp (figure Id) for the elliptical outline”. Contrary to what is written in the 2017 article, it is not enough to have two circular outlines. Indeed, a dyslexic can have two elliptical outlines but then the fundamental parameter is the orientation which must be measured precisely. The purpose of this invention is to measure this orientation of the major axes for each eye, which should also allow an early diagnosis for children. Indeed, parents suspect difficulties from 4-5 years old, difficulties often highlighted by teachers from kindergarten but only confirmed by various reading tests, particularly around 8-9 years old, tests carried out by speech therapists.The aim here is therefore not to propose a device for measuring the asymmetry which fixes ocular dominance in people without problems, but on the contrary to propose a device for comparing orientations, including in the presence of ellipticities in dyslexic people.

[0008] 3. Brief description of the figures.

[0009] The invention will be better understood and other characteristics and advantages will appear on reading the description which follows, which will refer to the appended figures among which: Figure 1 is a diagram of the architecture of the device comprising a control and measurement unit UCM of the fundamental parameters of the ellipse, essentially the orientation, projected by a projector P onto a strongly illuminated screen E and the sighting system V of the observer O with a double rotating filter FB (blue filter) and FV (green filter) according to a non-limiting embodiment of the invention.

[0010] Figure 2 defines the relevant parameter to be measured, namely the angle <p donnant l'orientation des deux sommets principaux A et B par rapport à la verticale. C et D sont les sommets secondaires de l'ellipse qui permettent aussi de mesurer CD l'ellipticité définie par e = — . Si on repère l'orientation du grand axe p D for the right eye and <p G for the left eye, it's the difference <p D — <p G which is crucial.

[0011] Figure 3 measures the case of a person with indeterminate orientations and differential ellipticity (As = 0).

[0012] Figure 4 measures the case, also with zero differential ellipticity, but with equal “mirror” orientations, i.e. with opposite orientations (example: (pc = - 40°, <po = + 40°).

[0013] Figure 5 measures the case with identical orientations and also with zero differential ellipticity, but with equal "translation" orientations, i.e. with parallel orientations (example: <p G = + 40° , <p D = + 40°).

[0014] 4. Detailed description of the invention.

[0015] In Figure 1, the modules represented are functional units which may or may not correspond to physically distinguishable units. For example, these modules or some of them are grouped into a single component. Conversely, according to other embodiments, certain modules are composed of physically separate entities. E denotes a screen illuminated with white light; P denotes a projector; UCM denotes a unit for controlling and measuring the orientation, ellipticity and elliptical surface of Maxwell's centroids; V denotes the viewing system of the observer O; FB and FV denote a blue filter and a green filter respectively.

[0016] Figure 2 introduces all the parameters used in the invention: the main vertices A and B fixing the major axis, and defining the orientation <p pour chaque œil des contours elliptiques, cruciale ici. l'affichage sur le dispositif relève alors toutes les orientations ç>D and Ç>G the respective orientations of the two major axes for the right eye and the left eye, as well as the difference.

[0017] Advantageously, the parameter controller shown in Figure 1 allows the orientation of the major axis to be adjusted in turn, for each eye, by means of an electronic card, to within 2°. The projector is adjusted to illuminate the screen in white light evenly with an illumination of around 2000 to 4000 lumens.

[0018] Advantageously, the light beam is produced from one or more LED-type elements, from the English acronym "Light Emitting Diode". Of course, the light beam can be produced from other light elements ensuring stable and sufficient illumination to visualize Maxwell's centroids with good contrast, in particular with LEDs of different colors, such as blue and green.

[0019] Advantageously, the sighting system comprising a double rotating blue-green filter uses a small electric motor allowing the rotation frequency to be varied between 0.1 Hz and 1 Hz, at the convenience of the observer. The sighting system-screen distance of the order of 3 m makes it possible to create at the screen a Maxwell centroid of approximately 3 cm in average diameter, which allows for a suitable superposition with the projected elliptical profiles.

[0020] In the case of Figure 3, the device allows the observation and recording of parameters for the most widespread situation, where in particular the dyslexic person sees two contours of the quasi-circular Maxwell centroids where <p D , <p G and the difference A <p = <p D — <p G are undetermined and where E D - E G — 1 .

[0021] Advantageously, the device makes it possible to identify the distribution of figure 4 which certainly corresponds to a zero differential ellipticity (Ae — 0 with e D - E G 1), but orientations <p D And <p G opposite (mirrored) major axes relative to a vertical axis ( <po = - <PG).

[0022] Advantageously, the device also makes it possible to qualify and measure splitting situations by non-symmetrical interhemispherical projections by translation, as shown in Figure 5. Here again, the ellipticities are certainly equal (e D - E G but 1) but the device of the invention makes it possible to measure the orientations and parallelism of the main axes (<po = Ç> G), for any value of the orientation of the two profiles.

[0023] The invention is not limited to the embodiments described above, but applies to any device making it possible to measure the orientations of Maxwell's centroids including quasi-circular profiles, profiles with differential ellipticity which are nevertheless zero but with opposite or parallel orientations of the major axes leading to reading deficits, in particular for dyslexic people.

Claims

AMENDED CLAIMS received by the International Bureau on October 12, 2023 (12.10.2023) Device for measuring the orientations related to the possible ellipticities of Maxwell centroids lacking blue cones in each eye in dyslexic individuals, characterized in that it comprises: An electronic UCM control and measurement system creating an ellipse with major axis orientation adjustable to within 2°, projected onto a screen. A lighting system of approximately 2000 to 4000 lumens illuminates a screen onto which the outline of an ellipse is simultaneously projected, with the orientations of the major axes for both eyes and their angular difference being identified and displayed. A device according to claim 1, characterized in that it comprises means for measuring and displaying the orientations of the major axes of the two ellipses and their difference between the two Maxwell centroids, so as to define the type of dyslexia. A device according to claims 1 and 2, in that it allows the difference between the orientations, to within 2°, of two ellipses of the same ellipticity for the left and right eyes, but with opposite orientations of the principal axes, leading to the first type of dyslexia.A device according to claims 1, 2, and 3, in that it allows the measurement of profiles of the same ellipticity but with parallel orientations of the principal axes, leading to the second type of dyslexia corresponding to letter and word doubling, particularly in some dyslexic individuals experiencing reading difficulties due to doubling. A device according to any one of the preceding claims, including systems optionally comprising colored LEDs for visualizing the centroids. AMENDED SHEET (ARTICLE 19) of Maxwell and to characterize the different lacks of asymmetry mentioned above, particularly in people with reading difficulties. AMENDED SHEET (ARTICLE 19)

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