Case #100

Case #100

The patient

Patient right profile

Unilateral Asymmetric Keratoconus induced by eye rubbing

Identity : Mr E.M
First visit : 06/06/2018
Last Visit : 10/09/2018

15
Age (years)
4
Follow-up (months)
The crosslinking controversy

Mr. E.M is a 15-year-old male with no previous medical history or any known family history of keratoconus. He is an only child. He complained of a progressive decrease in visual acuity greater in the right eye than the left. The diagnosis of keratoconus was made 3 months ago in another institution, where it was proposed to perform a corneal cross-linking procedure urgently.

His refraction at the first visit at the Rothschild Foundation (on 06/12th/2018) was : Right Eye (RE) 20/60 with -2.0 (-3.5 x 45 °) and Left Eye (LE) 20/20 with -0.75 (-1.25 x 175 °).

Clinical examination with the slit lamp suggested thin and irregular corneas with Fleischer rings in both eyes. Fleischer rings are pigmented rings in the peripheral cornea, resulting from iron deposition in basal epithelial cells, in the form of hemosiderin.

Corneal topography performed at our institution showed the presence of bilateral keratoconus, more pronounced in the right eye.

At the first visit, when asked about the possibility of eye rubbing, the patient admitted to rubbing his eyes frequently after moving to the countryside in France, where he developed an allergy to pollen. 

His parents who accompanied him to the consultation informed us that he started rubbing his eyes at the age of 10 and had the habit of rubbing vigorously, especially during episodes of acute allergy (usually from March).

He is right handed and he used to preferentially rub his right eye with his right hand. He sleeps on his right side, with the head buried in the pillow (pillow hugging)

We explained to the patient that since vigorous eye rubbing had preceded the drop in visual acuity, this habit may have caused the cornea to deform, leading to the classic clinical presentation of keratoconus in his case.

We strongly advised this patient to stop rubbing his eyes and to change his unhealthy sleeping position.

Here are pictures of the patient rubbing his eyes and his profiles

PATIENT RIGHT PROFILE
PATIENT LEFT PROFILE
PATIENT RUBBING HIS EYES WITH HIS KNUCKLES

A video of patient rubbing his eyes

Here are the Orbscan quadmaps, OPD scans and Ocular Response Analyzer (ORA) results of the first visit .

RIGHT EYE ORBSCAN (1st VISIT). The topographic pattern is evocative of advanced keratoconus: increased negative asphericity, irregular and marked inferior steepening and central thinning. The keratoconus is more pronounced in this eye.
LEFT EYE ORBSCAN (1st VISIT). The topographic pattern is evocative of mild keratoconus: increased negative asphericity, irregular and inferior steepening, central thinning.
RIGHT EYE OPDscan map: The higher order wavefront aberrations are increased by the major corneal deformation. Coma-like aberration are markedly elevated, and explain the visual degradation which cannot be fully corrected by spectacles.
LEFT EYE OPD. Topographic and aberrometric examinations of the right eye reveals an increase in higher order aberrations. These are caused by the corneal irregularity.
RIGHT EYE ORA (Ocular Response Analyzer) The height of the applanation peaks is reduced. This suggests an increased susceptibility to corneal deformation.
LEFT EYE ORA (Ocular Response Analyzer). The ORA measurement of the left eye is unremarkable, despite a slight reduction in the height of the peaks.

Difference maps were performed at each subsequent visit. No evolution has been observed between the first and last visits. The keratoconus is stable, more than 4 months after the patient definitively stopped rubbing his eyes .

PENTACAM DIFFERENTIAL MAPS : RIGHT EYE. (between 1st and 2nd visits). This difference map demonstrates the absence of keratoconus progression, coincident with the time the patient stopped rubbing his eyes.
PENTACAM DIFFERENTIAL MAPS : LEFT EYE. (between 1st and 2nd visits). This difference map demonstrates the absence of keratoconus progression, coincident with the time the patient stopped rubbing his eyes.
PENTACAM DIFFERENTIAL MAPS : RIGHT EYE. (between 1st and 3rd visits). This difference map demonstrates the absence of keratoconus progression, coincident with the time the patient stopped rubbing his eyes.
PENTACAM DIFFERENTIAL MAPS : LEFT EYE. (between 1st and 3rd visits). This difference map demonstrates the absence of keratoconus progression, coincident with the time the patient stopped rubbing his eyes.

This case is a typical illustration of how chronic incessant eye rubbing can induce a focal deformation of the cornea during childhood. Very often, like many other cases described in this site, eye rubbing that begins in childhood is related to allergy. The cornea in children is softer and more deformable and the friction applied during eye rubbing is often more intense. Patients typically notice a decline in vision about 5 years after the onset of intense rubbing.

Allergy is triggered by the presence of allergens in the environment. It may be exacerbated during seasonal variations in the weather, or by unknown factors. Itch can be severe, and rubbing triggers a non-stop « itch-rub-itch » cycle. Rubbing stimulates the release of histamine, which in turn causes redness, itch and the desire to rub. 

Patients who sleep on their stomachs or with their eyes buried in the pillow (« pillow hugging »), are often exposed throughout the night to allergens in the bed, pillow or linen, resulting in an allergic conjunctivitis and the need to rub the eyes incessantly upon awakening in the morning.

In this patient, the differential technique used to rub the right eye more than the left can explain the asymmetric nature of keratoconus. The force exerted on each cornea is often not the same, and the cornea subjected to the stronger forces is often the more distorted. 

In summary, this case is very informative and demonstrative of the causal effects of eye rubbing and allergy on the pathogenesis of keratoconus. Performing cross-linking on an urgent basis was unnecessary, as stabilization of the corneal deformation was achieved through the simple act of cessation of eye rubbing. Longer follow-up is of course required, and the result of further examinations will be reported here.

The key in the fight against keratoconus is PREVENTION through education of patients (and parents) on the DANGERS OF EYE RUBBING. 

  • Date 23 octobre 2018
  • Tags Allergy, Bilateral keratoconus, Cross linking, Enjoyed eye rubbing, Eye rubbing, Inferior keratoconus, Knuckles rubbing, Male, Sleep position, Stabilization, Witness