Ms. B.V is a 16-year-old female with no previous medical history or any known keratoconus in her family .
She has a history of atopy in childood, and complained of a progressive decrease in visual acuity greater in the left eye. The patient sleeps on her left side and stomach, with her head on the arm.
Her refraction at the first visit (09/22th/2016) was : Right Eye (RE) 20/20 with -4 (-0.75 x 70 °) and Left Eye (LE) 20/25 with -5.25 (-3,25 x 100 °).
Clinical examination with the slit lamp revealed an irregular inferior corneal bulge in the left eye. We found tarsal papillae (indicating chronic ocular allergy) which was more pronounced in the left eye.
Corneal topography revealed the presence of unilateral keratoconus in the left eye.
When asked about the possibility of frequent eye rubbing at the first visit, the patient did not immediately admit to rubbing her eyes. However, her mother, who was present at the consultation, confirmed that she often witnessed her daughter rubbing her eyes vigorously for the past 2 years, especially during spring (with seasonal allergy). Subsequent to her mother’s input, the patient acknowledged that she was rubbing her eyes, especially with the knuckles.
We explained to the patient that since vigorous rubbing had preceded the drop in visual acuity, this habit may have caused the cornea to deform in her case. We strongly advised her to stop rubbing here eye, and treated her allergy concomitantly.
Here are pictures of the patient rubbing her eyes and her profiles
In this case, many factors responsible for eye rubbing are present: allergies, and an unhealthy sleeping position. Sleeping on one side results in orbit compression, favoring the exposure of the eyelids and conjunctiva to contamination from dust mites and/or other irritants.
The association between allergy and eye rubbing is well documented. Allergy is also associated with keratoconus. In our opinion, this association between allergy and keratoconus is redundant as the pertinent link in this context is between keratoconus and eye rubbing. Atopic and allergic patients who do not rub their eyes frequently and vigorously are not susceptible to develop the corneal deformation that we call keratoconus.
Also, we observed that the laterality of the sleeping position was often related to the laterality of the keratoconus in unilateral or highly asymmetric cases. The prolonged compression may result in a local increase in temperature, and the lack of oxygenation and prolonged contact with the pillow (& allergens) during the night may be responsible for ocular discomfort and pruritus and thus a desire to rub the eyes on awakening.
All these factors were explained to the patient at the first visit. Thereafter, the patient decided to stop eye rubbing, and also tried changing her sleeping position. As a result the keratoconus in the left eye has not evolved over the last 8 months, and no keratoconus has appeared in the right eye.