Case #76

Case #76

The patient

Patient right profile

Bilateral Asymmetric Keratoconus induced by eye rubbing

Identity : Mr B.P
First visit : 10/17/2017
Last Visit : 02/12/2018

18
Age (years)
4
Follow-up (months)
How to avoid eye rubbing

Mr. BP is an 18-year-old male with no known family history of keratoconus. He complained of a progressive decrease in visual acuity greater in the right eye than the left, which started more than a year prior to presentation.

He was diagnosed to have keratoconus by an ophthalmologist at another institution, and was advised to have corneal cross-linking performed on an urgent basis. He consulted us for a second opinion.

His refraction at the first visit at the Rothschild Foundation (on 10/17th/2017) was: Right Eye (RE) 20/32 with -6.0 (-5.5 x 5 °) and Left Eye (LE) 20/25 with -5 (-4.25 x 165 °).

Clinical examination with the slit lamp suggested a remarkable bilateral inferior corneal distortion with thinning, Fleischer rings and Vogt’s striae. His eye were also clinically dry, with Tear Film Break up Time (TFBUT)  < 8 secs.

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

At the first visit, when asked about the possibility of eye rubbing, he admitted to rubbing his eyes incessantly while at work. He worked for long hours at the computer at night (during his night shifts), and had to rub his eyes frequently to relieve eye strain.

He is right handed and rubs his right eye with his right hand using the knuckles.

The patient sleeps on either side, but he reported that he used to sleep on the desk at work, using his arm as a pillow, supporting the head directly on the eyes and forehead. He also mentioned that when in bed, he would sometimes contort his body such that one of the eyes was in constant contact with either the pillow or his arm. He preferred putting his head on his right arm, applying direct pressure on the right eye, which would then be systematically in direct contact with the arm.  He often found that he would awaken with bilateral red eyes

At the subsequent visit, his father iterated that his son would often rub his right eye with his right hand (see picture below).

We strongly advised the patient to stop rubbing his eyes and to change his unhealthy sleeping position. We also explained to him that since vigorous 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.

After his first visit, he became more conscious of his eye rubbing habit and the importance of the role played by eye rubbing and an unhealthy sleeping position on his cornea, and thus modified his habits accordingly. An eye shield for his right eye and lubricant eye drops for both eyes successfully curbed his desire to rub his eyes. 

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

right profile of an eye with keratoconusPATIENT RIGHT PROFILE.
Profile of the left cornea of an eye with keratoconusPATIENT LEFT PROFILE.
patient showing how he rubs his eye which has keratoconusThe patient rubbed his right eye more often and more vigorously than his left, as it was itchier and felt more uncomfortable. Rubbing with the knuckles is particularly detrimental to the corneal biomechanics.
spleeping position of a patient with keratooconusThis sleeping position played a key role in the genesis of keratoconus in this case. Chronic night-time ocular compression and irritation often results in chronic inflammation and itch. While sleeping in this position, the patient admitted that he could feel the pressure being exerted on his right eye and orbit.
father of the patient showing how his son rubs his eyeThe patient's father demonstrating the son's technique of rubbing his right eye

Here is a video of the patient rubbing his right eye (with the knuckles)

Here is a video of the patient rubbing his left eye (with the finger pulps)

Here are the Orbscan quadmaps, Pentacams maps, OPD scans, Ocular Response Analyzer (ORA) and Corneal OCT epithelial map results of the first visit.

orbscan map of the right eye of a patient with keratoconusRIGHT EYE ORBSCAN (1st VISIT). The corneal deformation is obvious: it is characterized by an irregular central steepening, with with the rule astigmatism. The corneal surfaces are hyerprolate, and there is marked central thinning.
orbscan topography of an eye with keratoconusLEFT EYE ORBSCAN (1st VISIT). The corneal deformation is obvious: it is characterized by an irregular central steepening. The corneal surfaces are hyerprolate and there is marked central thinning.
Pentacam topography of an eye with keratoconusRIGHT EYE PENTACAM (1st VISIT). The topographic features of the Pentacam examination mirror the abnormalities seen on the Orbscan,: central steepening and thinning.
Pentacam corneal topgraphy of a left eye with keratoconusLEFT EYE PENTACAM (1st VISIT). The topographic features of the Pentacam examination mirror the abnormalities seen on the Orbscan,: central steepening and thinning.
opdscan map of an eye with keratoconusRIGHT EYE OPDscan corneal topography and aberrometry examination. There is an important increase in higher order aberrations, caused by the corneal distortion. These aberrations are responsible for the reduction of the optical quality of the eye with keratoconus.
opdscan map of the left eyeLEFT EYE OPD. There is an important increase in higher order aberrations, caused by the corneal distortion. The hyperprolate corneal surface results in an increase in negative spherical aberration.
ocular response analysis examination of an eye with keratoconusRIGHT EYE ORA (Ocular Response Analyzer). The height of the peaks is slightly reduced, and the hysteresis value is low
ocular response analyzer examination of an eye with keratoconusLEFT EYE ORA (Ocular Response Analyzer). The height of the peaks is markedly reduced, as the biomechanics of the rubbed cornea are altered.
OCT of the corneaCORNEAL Optical Coherence Tomography with total and EPITHELIAL thickness map : RIGHT EYE. There is a reduction of the epithelial thickness near the apex of the corneal deformation.
OCT of the cornea in an eye with keratoconusCORNEAL Optical Coherence Tomography total and EPITHELIAL MAP : LEFT EYE. There is a marked reduction of the epithelial thickness near the apex of the corneal deformation.

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 .

RIGHT EYE ORBSCAN (2nd VISIT). Stable since first visit.
LEFT EYE ORBSCAN (2nd VISIT). Stable since first visit.
RIGHT EYE PENTACAM (2nd VISIT). Stable since first visit.
LEFT EYE PENTACAM (2nd VISIT). Stable since first visit.
pentacam difference map showing no progressionPENTACAM DIFFERENTIAL MAPS : RIGHT. The third column (difference between the two exams obtained at different time points) demonstrates the perfect stability of the corneal deformation. There is no progression of the keratoconus.
absence of progression of the keratoconusPENTACAM DIFFERENTIAL MAPS : LEFT EYE. The third column (difference between the two exams obtained at different time points) demonstrates the perfect stability of the corneal deformation. There is no progression of the keratoconus.
RIGHT EYE ORBSCAN (3rd VISIT). The pattern is not significantly different from the first visit at our institution
LEFT EYE ORBSCAN (3rd VISIT). The pattern is not significantly different from the first visit at our institution
RIGHT EYE PENTACAM (3rd VISIT). The pattern is not significantly different from the first visit at our institution
LEFT EYE PENTACAM (3rd VISIT). The pattern is not significantly different from the first visit at our institution
Difference map with the pentacam showing the absence of progression of the keratoconusPENTACAM DIFFERENTIAL MAPS : RIGHT EYE. (between first and third visits). This difference map demonstrates the absence of keratoconus progression, coincident with the time the patient stopped rubbing his eyes.
difference map with the pentacamPENTACAM DIFFERENTIAL MAPS : LEFT EYE. (between first and third visits). This difference map demonstrates the absence of keratoconus progression, coincident with the time the patient stopped rubbing his eyes.

This case reveals that eye rubbing is often triggered by long hours spent in front of the computer, which causes visual fatigue associated with dry eye (reduced blinking) and an unhealthy sleeping position. These sensations are often relieved (transiently) by eye rubbing, which as described by patients, can be pleasurable and relaxing in such circumstances. 

This case also shows the importance of the testimony of relatives to help raise awareness of the frequency and intensity of the patients’ eye rubbing habits. Other cases present on this site (Case 70, Case 66, Case 47, Case 28, Case 24, Case 23, Case 21, Case 15, Case 4 and Case 1) are also testament to the crucial role relatives play in highlighting eye rubbing behaviours. It is often useful to interview them during the consultation, especially in younger patients who may be less in tune with their habits.

The corneal dome can be likened to a shell whose equilibrium geometry depends on the difference between the intraocular pressure (exerted on its posterior surface) and the atmospheric pressure. Beyond a certain threshold, the mechanical stresses (compression, shear) conveyed by eye rubbing results in a biomechanical embrittlement, due to the rupture of the harmonious arrangement of collagen fibers, which causes an irreversible deformation of the cornea (This mechanism is analogous to the « buckling » in resistance of materials).

These repeated and sustained frictions over the long-term are responsible for a permanent warpage of the cornea, culminating in the condition called « keratoconus ». Rubbing with the knuckles is particularly detrimental to the corneas, because the knuckles are the hardest part of the hands.
Since the cessation of rubbing, there has been no aggravation of the keratoconus in this patient

As demonstrated again in this clinical example, the cessation of eye rubbing and patient education are the best tools in the prevention of the genesis and/or evolution of keratoconus

  • Date 15 février 2018
  • Tags Asymmetric, Bilateral keratoconus, Central keratoconus, Computer screen, Cross linking, Dry eyes, Enjoyed eye rubbing, Eye rubbing, Fleischer ring, Knuckles rubbing, Male, Sleep position, Stabilization, Witness, Work rubbing