Case #70

Case #70

The patient

Patient left profile

Unilateral Asymmetric Keratoconus induced by eye rubbing

Identity : Mr Z.C
First visit : 01/16/2018
Last Visit : Coming soon

Age (years)
The crosslinking controversy

Mr. Z.C is a 39-year-old male with no family history of keratoconus. He has a history of atopy since childhood. He complained of a progressive decrease in visual acuity greater in the left eye than the right.  He had previously consulted an ophthalmologist from an institution in Dallas (USA), where he was working as an expatriate. He was diagnosed with keratoconus and was advised to have corneal collagen cross-linking. While visiting his family in Paris, he came to us for a second opinion.

His refraction at the first visit at the Rothschild Foundation (on 01/16th/2018) was: Right Eye (RE) 20/20 with +0.25 (-1 x 5 °) and Left Eye (LE) 20/32 with -0.5 (-1.75 x 115 °).

Clinical examination with the slit lamp was unremarkable in both eyes.

Corneal topography performed at our institution showed the presence of mild unilateral keratoconus in the left eye.

When asked about the possibility of frequent eye rubbing at the first visit, he admitted to rubbing his eyes but only occasionally, especially the left eye with his left hand (although he is right-handed), as demonstrated in the video of the interview below. His mother, who was present at the consultation confirmed that she had often witnessed him rubbing his eyes vigorously during childhood. With regards to his sleeping posture, she said that he has been sleeping on his stomach with his head in the pillow (pillow hugging) since he was a child, and had a tendency to bury his eyes and orbits deeply in the pillow. This was corroborated by the patient himself.

We explained to the patient that since vigorous rubbing had preceded the drop in visual acuity, this habit may have caused the cornea to thin and deform, leading to the classic clinical presentation of keratoconus in his case. We asked the patient to pay more attention to possible conscious rubbing episodes, such as in the morning, or during work at the computer. We strongly advised this patient to stop rubbing his eyes and to change his unhealthy sleeping position. An eye shield to be worn at night was prescribed in order to identify and prevent possible compression and rubbing during bedtime.

We have given him an appointment for a follow-up visit a month later. A topography difference map will be performed and the significance of rubbing re-evaluated.

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

photo of the profile of the right eye of the patientPATIENT RIGHT PROFILE
Left corneal profilePATIENT LEFT PROFILE. Note the periocular eczema.
left eye rubbing with knuckesPATIENT RUBBING HIS EYE WITH HIS KNUCKLES (LEFT EYE). The knuckles are the toughest part of the fingers. When rubbing is repeated many times a day, it can be very detrimental to the corneal structure.
left eye rubbing with the palm of the hand.PATIENT RUBBING HIS EYE WITH HIS PALM (LEFT EYE). This technique of rubbing is often ignored by patients, who do it unconsciously. In some of them, it evokes a sense of well being and relaxation.
patient showing his sleeping positionPATIENT DEMONSTRATING HIS SLEEPING POSITION (LEFT SIDE). He uses his bag as a pillow substitute. Note the proximity of the pillow and the left hand to the left eye!

A video interview of the patient and his mother. During the interview, the patient attests to sleeping with his left eye buried in the pillow, but he is unsure about his eye rubbing habits. His mother however, remembers him rubbing his eyes since childhood. The important aspects of patient counselling by the attending ophthalmologist is also featured in the video.

Here are the Pentacam maps, OPD scans and OCT epithelial maps of the first visit .

Pentacam map of a patient with keratoconus on the other eyeRIGHT EYE PENTACAM (1st VISIT). This Pentacam examination is unremarkable: the cornea of the right eye is thick, and the curvature map is regular.
pentacam map of a mild keratoconus of the left eyeLEFT EYE PENTACAM (1st VISIT). This examination shows moderate deformation with inferior steepening, evocative of keratoconus. There is a marked central thinning (bottom left) and both the anterior and posterior elevation maps (right column) are showing increased positive elevation centrally.
OPDscan III map of a normal eyeRIGHT EYE OPDscan III combined topography and aberrometry examination. This examination looks unremarkable. The corneal navigator (bottom right) classifies this anterior corneal surface as normal.
OPDscan III map of an eye with keratoconus (left eye)LEFT EYE OPDscan III combined topography and aberrométry mapping. The corneal deformation causes the ocular wavefront to be distorted (increase of coma and negative spherical aberration). These aberrations cannot be corrected by spectacles. This causes the vision to remain affected even with the "best spectacle correction".
high resolution OCT corneal map of a normal eyeRIGHT EYE high resolution OCT TOTAL CORNEAL AND EPITHELIAL MAP. The examination is unremarkable.
high resolution OCT in a keratoconus eyeLEFT EYE HIGH RESOLUTION OCT EPITHELIAL MAP. There is a reduction of the epithelial thickness near the apex of the corneal deformation. This thinning could be the consequence of eye rubbing, and/or linked to a "smoothening" mechanism to make the corneal shape more regular anteriorly.

The follow-up is in progress and we will communicate to you soon the results of his next visit .

In this case we find many triggers for eye rubbing like allergy and an unhealthy sleeping position which correlates with the side of  rubbing. The unilateral or asymmetric nature of keratoconus development may be directly related to the sleeping position (left-sided) and the habit of preferentially rubbing the left eye. In the case of dust mite allergy, chronic bedtime contamination of the left eye from pillow hugging is sufficient to explain a chronic itchy and irritated left eye, hence the subsequent chronic eye rubbing with the left hand. 

Other cases presented on this site reveal the presence of a striking association between sleep position, rubbed side, and the presence of a unilateral keratoconus on the same side: in particular the case #34 shows troubling analogy with this case (see also : case #54, case #23, and case #1).

In summary, to explain this case of unilateral keratoconus, one may propose the following sequence of events: Unilateral chronic eye irritation and contamination related to the extended compression of the left eye on the pillow induces the patient to rub his left eye during the day. The left eye is exposed to local heating and contamination by irritants (allergens from laundry products, dust mites, etc.). These repeated episodes of night time corneal weakening (heating, night time swelling) and daytime corneal rubbing, eventually cause  deformation and the thinning of the cornea (by redistribution of ground substance within the cornea) typically encountered in keratoconus eyes.

In our experience we notice that patients are not as conscious of their eye rubbing habits during the first visit. In this case however, the patient’s mother was fortunately accompanying him at the first consultation, and she could verify his eye rubbing habit which he was not fully aware of. (see the video)

This case is very informative and demonstrative of the causal effects of eye rubbing in the pathogenesis of keratoconus.

  • Date 18 janvier 2018
  • Tags Allergy, Asymmetric, Childhood rubbing, Computer screen, Cross linking, Dry eyes, Eye rubbing, Forme frustre keratoconus (FFKC), Inferior keratoconus, Knuckles rubbing, Male, Morning rubbing, Palm rubbing, Pillow hugging, Sleep position, Unilateral keratoconus, Witness, Work rubbing