Keratoconus: definition, causes and risk factors
Keratoconus is an eye disease whose symptoms stem from a deformation of the cornea. This deformation is responsible for astigmatism, an onset (increase) of myopia, and various symptômes visuels some of which are not corrected by wearing glasses: splitting of bright images on a dark background (such as the outline that appears splitted or tripled from the moon in the sky), persistent visual blur, etc.
The diagnosis of keratoconus is confirmed by an examination of corneal topography (study of the shape and variations in corneal curvature). The keratoconus is a primitive mechanical, not primitive genetic condition: corneal deformation is induced by eye rubbingexcessive.
Friction acts both mechanically (disorganization of the weft of the collagen fibres of the cornea) and biomolecularly (mechanical cytotoxicity, cellular reaction with secretion of cytokines and pro-inflammatory enzymes).
The perception with an eye of a doubling, or multiple images, ghosts, around the light sources, can make search for the presence of a Keratoconus: these symptoms reflect the presence of an astigmatism said irregular. The duplication and ghosting can be mitigated with a correction of glasses but they do not disappear completely (contrary to the symptoms caused by a simple astigmatism regular, correcgible in glasses). Beware, these symptoms are not specific to Keratoconus. A beginner cataract can also cause a slight duplication of perceived images.
When it is of corneal origin, any sensation of splitting or multiple images is not necessarily the sign of a Keratoconus, but translates some degree of reduction in the optical quality of the cornea. For example, superficial keratitis can cause the same type of symptoms. The more the Keratoconus is evolved, the more the intensity of these visual anomalies is pronounced. In the majority of case of Keratoconus, the images "Drools" mainly downward or slanting downwards. More about the vision of an eye reached by Keratoconus here
Classic (but partially erroneous) definition of keratoconus
The keratoconus, from the Greek Kératos for cornea and conus for cone shape, is defined classically as a bilateral, asymmetric, non-inflammatory corneal dystrophy (unknown cause). The keratoconus is characterized by a thinning and progressive deformation of the cornea. In optical terms, this deformation induced in theregular and irregular astigmatism (optical aberrations of high degree) caused by a marked alteration of the geometry of the cornea.
Definition alternative and modern of Keratoconus
In this classic, descriptive and functional definition, the author of this site proposes to substitute a more causal definition. The keratoconus is characterized by the appearance of a deformation of the cornea. This deformation is directly related to the action of Repeated eye rubbing, responsible for a Mechanical stress of the cornea. The keratoconus would not be a primitive dystrophy, nor a genetic disease, but a Mechanical condition of origin: Without friction, without repeated mechanical stress, there is no occurrence of deformation of the corneal dome, and therefore of keratoconus (See page dedicated the role of eye rubbing repeated with respect to the incidence of Keratoconus, see article « Eye rubbing. a sine qua non for keratoconus?« , see article "No Rub, no Cone, the Keraotconus Conjecture".
A site is totally dedicated to the understanding of the origin, as well as the modern and unbiased support of the keratoconus: https://defeatkeratoconus.com/.
De nombreux case of Keratoconus are presented and illustrate the fact that the eye rubbing is an indispensable and necessary element for the genesis of the Keratoconus. The stopping of friction guarantees the absence of progression of the cornea deformation, which confirms the direct responsibility and the indispensable character of the frictions in the induction of the keratoconus.
Keratoconus is not a idiopathic dystrophy but a syndrome whose topographical expression translates the deformation of the cornea, caused by the mechanical stress represented by the repeated eye rubbing. This explanation has the merit of simplicity and is compatible with all the data published in the medical literature. It is crucial to explain to patients who are affected and at risk (allergic, night workers, on screen, etc.) not to rub their eyes. This simple prescription has the potential to eradicate this disease, and to stop its progression. This explanation of Keratoconus is not popular with some practitioners who advocate the realization of certain surgical acts, sometimes from the first consultation, during the diagnosis, because it rightly questions the merits of their interventionist attitude. It is never urgent to make a cross linking, the laying of rings or the realization of a laser photoablation.
There is only one emergency in Keratoconus: stop any unwanted eye friction
The disease (caused by friction) no longer progresses as soon as they stop, and with the correction of the sleep position (stop sleeping on the belly or the side, with the head depressed in the pillow, arm or hand in contact with the orbits etc.)