Ms. P.A is a 40-year-old female teacher, with no previous medical history or any known keratoconus in her family .
She has known allergy to dust mites and has atopic skin (eczema). When she first consulted us, she complained of a progressive decrease in visual acuity more pronounced in the left eye.
Her refraction at the first visit (03/10th/2013) was : Right Eye (RE) 20/25 with -3 (-1.75 x 170 °) and Left Eye (LE) 20/40 with -5.5 (-2.5 x 165 °).
Clinical examination with the slit lamp revealed increased corneal nerve visibility, and obviously thin corneas.
We also observed Vogt’s striae (fine whitish lines in the posterior stroma) and Fleischer ring (Fleischer rings are pigmented rings in the peripheral cornea, resulting from iron deposition in basal epithelial cells, in the form of hemosiderin) in left eye.
She had visited another center where crosslinking had been proposed right away, and she wanted a second opinion.
Corneal topograhy performed at our institution confirmed the presence of a keratoconus pattern in the left eye. The right cornea is thin, and exhibited subtle vertical asymmetry.
When first asked about the possibility of frequent eye rubbing, the patient admitted that she would rub her eyes with her fingers when working or reading at home in front of the computer screen. She worked late at night (on night shifts) and prayed five times a day, and would rinse her eyes with tap water rigorously before and after the prayers. She believed that her vision had deteriorated over the last 10 years. This patient is right-handed and she preferentially sleeps on the left side side, with the head in the pillow (pillow hugging).
During subsequent visits, the patient acknowledged that she had come to realize that she rubbed her left eye more than the right one, especially when working in front of the computer screen, because her eye felt uncomfortable, and the prolonged sessions at the computer gave her significant headaches, for which she had to compress her left eye with her hand for long periods several times a day to relieve it. As soon as she realized this, she ceased to rub her eyes.
We explained to the patient that since chronic eye rubbing had preceded the drop in visual acuity, this habit may have caused the cornea to deform. We strongly advised her to stop the eye rubbing, and we also treated her underlying allergy. We warned her against her unhealthy sleeping position (on the left side, with the left hand compressing the left orbit and eye) and to avoid compressing her left eye to relieve her headaches . We referred the patient to an allergy specialist to determine the possible allergens responsible for her symptoms, in particular, the ocular pruritus.
Here are pictures of patient rubbing her eyes and profiles
This video shows how the patient compresses her left eye to relieve headaches
In this case, the asymmetry between the deformation in the right and left eyes is striking. We find many instances of ocular friction and compression here, like eye rubbing triggered by allergy and extended computer work and an unhealthy sleeping position. There are also particular habits linked to her daily prayer routine: the repeated wiping of the eyes and ritual preparations with tap water all played a role in the weakening of the corneas. Lastly, the habit of compressing her left eye several times a day to relieve her headache had a direct role in the genesis and asymmetry of the keratoconus.
Another interesting aspect of this case is the patient’s thin corneas. For the same rubbing intensity, a thin cornea may not absorb and dissipate the incident energy as well as a thicker cornea.
It is very important to spend time with the patient to elucidate the need for eye rubbing. Often the answers are not apparent at the first consultation, because the patient is not always conscious of the habit. Hence the importance of re-interrogating the patient at each consultation to make him aware of his rubbing habits.
This case is very informative and demonstrative of the direct involvement of eye rubbing and compression in the pathogenesis of keratoconus. Allergy is a classic risk factor associated with the disease (as in many cases on this site), but it might just be because allergic patients do rub their itchy eyes way more often and firmly than non allergic patients.
The cessation of eye rubbing and proper allergy therapy along with the correction of the sleeping position are the best tools in the prevention of the genesis and/or evolution of keratoconus.