Case #48

The patient

Patient right profile

Bilateral Asymmetric Keratoconus induced by eye rubbing

Identity : Ms P.A
First visit : 03/10/2013
Last Visit : 05/22/2018

Age (years)
Follow-up (months)

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

PATIENT RUBBING HER EYES WITH FINGERS. The patient uses the finger pulps to rub with circular and lateral movements.
PATIENT SHOWING HER SLEEP POSITION (ON LEFT SIDE WITH HEAD ON THE HAND). This position results in night time compression, local heating, and contamination with germs, allergens, dust mites, etc. It could explain the chronic itch and the left eye rubbing.

This video shows how the patient compresses her left eye to relieve headaches

Here are the Orbscans quadmaps, Pentacams, OPDscan (topography and aberrometry) maps and Ocular Resonse Analyzer (ORA) results of the first visit .

RIGHT EYE ORBSCAN (1st VISIT). This map reveals the presence of a thin cornea, and subtle vertical asymmetry. But there is no frank keratoconus pattern.
LEFT EYE ORBSCAN (1st VISIT). On the left eye, the deformation is more pronounced: there is marked asymmetry on the axial map (bottom left) and both the anterior and posterior surfaces of the cornea have increased prolateness.
RIGHT EYE PENTACAM (1st VISIT). As for the Orbscan map, the cornea is thin, slightly asymmetric, but the keratoconus indices are negative.
LEFT EYE PENTACAM (1st VISIT). The keratoconus detection indices are positive, the corneal deformation is obvious.
RIGHT EYE OPDscan (1st VISIT). The wavefront analysis is unremarkable.
LEFT EYE OPDscan (1st VISIT). The wavefront analysis reveals the presence of increased amounts of negative spherical aberration, and vertical coma.
RIGHT EYE ORA. The hysteresis is low, and the height of the peaks is reduced. This reveals the presence of weakened corneal biomechanics.
LEFT EYE ORA. The signals are pathological: the peaks are low and broadened. The hysteresis value is very low.

Difference maps have been performed at each subsequent visit. No evolution has been observed between the first and last visit. The keratoconus is still stable, more than 4 years after the patient has definitely stopped to rub her eyes .

ORBSCAN DIFFERENTIAL MAPS : RIGHT EYE (between 2nd and 3rd VISITS). The slight corneal deformation (vertical asymmetry) is stable.
ORBSCAN DIFFERENTIAL MAPS : LEFT EYE (between 2nd and 3rd VISITS). This maps suggests that keratoconus in the left eye is stable, or may even have slightly improved: The flattened superior part of the cornea has steepened, and the inferior part has flattened. This stabilization was attained by cessation of eye rubbing.
PENTACAM DIFFERENTIAL MAPS : RIGHT EYE (between 3rd to 4th visit)
PENTACAM DIFFERENTIAL MAPS : LEFT EYE (between 3rd and 4th visits)
PENTACAM DIFFERENTIAL MAPS : RIGHT EYE (between 2017 to 2018). This difference map is unremarkable; there is no significant change between the two consecutive examinations; the corneal deformation did not progress.
PENTACAM DIFFERENTIAL MAPS : LEFT EYE (between 2017 to 2018). This difference map is unremarkable; there is no significant change between the two consecutive examinations; the corneal deformation did not progress.

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.