Ms. F.RG is a 23-year-old woman with no medical history of note, and no known family history of keratoconus. She has high myopia which has been stable for many years, and wears monthly soft contact lenses. There are no known allergies or history of atopy.
The patient complained about a decline in vision over the last 3 years. Her ophthalmologist had observed the appearance of an inter-eye asymmetric astigmatism (right > left). As the magnitude of the astigmatism was increasing with time, she was referred to us for a suspicion of keratoconus.
Her Refraction was : Right Eye 20/25 -8,25 (-3,25 x 40 °) and Left Eye 20/20 -8 (-1 x 120 °).
Clinical examination with the slit lamp revealed an irregular corneal bulge in the right cornea. Munson’s sign (the lower lid bulges when the patient looks down, due to the abnormal shape of the cornea) was positive.
She described sleeping mostly on her stomach, with her head resting on her right arm. She also acknowledged that rubbed her eyes quite regularly, especially the right eye when she awoke in the morning.
We strongly advised the patient to stop rubbing her eyes, and to change her sleeping position (in order to avoid right eye compression during night time).
Here are pictures of the patient rubbing her eyes and her profiles
Difference maps were performed at each subsequent visit. No evolution was observed between the first and last visits . The keratoconus is stable for over 2 years in both eyes.
This is because the patient stopped rubbing her eyes after the first visit when keratoconus was diagnosed, and changed her sleeping posture. The latter resulted in less irritation to the right eye through the night, less rubbing in the morning and hence stabilisation of the keratoconus.
This case reveals the importance of sleeping habits in the genesis and evolution of keratoconus.
Indeed, some sleep positions are more traumatic to the eye(s) than others. The association between such sleeping positions with keratoconus (on the eye that is compressed) is striking and underestimated. An unhealthy sleeping posture can itself cause a deformation of the curvature of the cornea (by pressure, friction or palpebral malposition during night time). It could also cause eye irritation, inducing itch and hence the need for rubbing in the morning. In the long term, weakening of the corneal biomechanics leads to corneal thinning and curvature changes, culminating in the picture of keratoconus.
At the time of diagnosis, every patient with known or suspected keratoconus should be questioned about his sleeping habits and position. It is important to sensitize the patient to the dangers of an unhealthy sleeping position, to modify his habits, so as to prevent, through the cessation of eye rubbing, the evolution of keratoconus.