Rubbing your eyes harder and harder. Routine screen use, dry environments, colds, allergies... the eye loses moisture, itching begins, and it starts to bother. And there goes the fist against the eyelid, over and over again. "Allergic and vernal conjunctivitis that present with intense eye itching are especially prone to children tending to excessively rub their eyes," points out Miguel Naveiras Torres-Quiroga, a specialist in the Ophthalmology department at the University of Navarra.
If we imagine a ball or a sphere, our hands would be exerting continuous pressure against the mesh that covers it as a shield to avoid getting pricked. The cornea of the eyes is composed of collagen fibers, which would be that mesh, and its function is the protection of the ocular surface to prevent vision failure.
Every time we compulsively rub our eyes, we exert a certain pressure that leads to the weakening of this organic shield, causing breaks that result in a progressive decrease in this corneal tissue, which ends up deforming. "Eye rubbing worsens the inflammatory cycle on the surface and is relevant if there is a pathological predisposition in the collagen structure of the cornea," adds Naveiras.
What are the warning signs of possible damage?
Eye itching can be a sign of an incipient disease, such as keratoconus. Luis Fernández-Vega Cueto-Felgueroso, from the Fernández-Vega Ophthalmological Institute, lists that among the warning signs of this inflammatory and progressive corneal disease, "there is a gradual loss of vision, blurred vision, image distortion, irritation, eye pain, and an increased sensitivity to bright light and glare."
Recent studies point to eye rubbing with keratoconus. However, the authors of one of them, from the University of Melbourne, explain that "current evidence is limited to a small number of case-control studies that are presented as heterogeneous." Therefore, they assert that more studies are needed to address this relationship between eye rubbing and its induction, continuous progression, and severity of keratoconus.
Is excessive screen time a risk factor? "It is still early to determine a direct link," clarifies Fernández-Vega. The connection to an eye that dries out from staring at a screen for hours, "requires long-term studies, because we are facing a habit recently acquired in generations where we can observe the impact in the future," he adds.
Keratoconus is inherited in 25% of cases and, as this cornea and crystalline specialist explains, "it usually appears in childhood or adolescence and is detected by the frequent need for changing lens prescriptions and compulsive eye rubbing." Naveiras emphasizes that this continued action weakens that structure significantly and "is the most important factor in the progression to keratoconus."
Although the ophthalmologist from Navarra adds that, in predisposed populations, such as the Mediterranean, "genetic and local inflammation factors can combine on the ocular surface to weaken the collagen lamellar structure of the cornea."
Once in the consultation, the specialist performs a comprehensive examination using corneal topography and microscopic examination with a slit lamp. In addition to the mentioned signs, there are clues that can be detected in optics, during a retinoscopy.
How to prevent corneal damage?
In addition to adjusting the glasses prescription, experts prescribe methods to avoid touching the eyes: antihistamine drops and artificial tears to reduce the stimulus.
Both emphasize that parents play a decisive role in young children to instruct them that it is essential to avoid rubbing their eyes. "The traditional game of our grandparents who told us that "eyes are rubbed only with elbows," remains useful at those ages," comments Naveiras.
While it is true that the prevalence of keratoconus is "fortunately rare," Naveiras points out, "it is estimated to affect 0.05% of the general population." "It is on the verge of being a rare disease," adds Fernández-Vega. Early detection helps reduce the number of patients who reach the more advanced stages, "which is usually the case," says the ophthalmologist from Oviedo.
Once keratoconus is diagnosed, it is evaluated every six months to determine if it is stable or progressive. In case of progression, specialists list a range of therapeutic options such as intracorneal segment implants, crosslinking, or in very advanced cases (fortunately now less frequent) with lamellar corneal transplantation (DALK).
"The goal is to slow down the progression of the disease," they assure. "One of the most common surgical treatments for keratoconus is the implantation of intracorneal segments, transparent rings made of polymethylmethacrylate (PMMA), a completely biocompatible inert material, which are placed in the corneal thickness using a femtosecond laser to reinforce it, change its geometry, and restore the tissue to its original shape," Fernández-Vega concludes.