Case #18

The patient

Patient sleep position

Unilateral forme frustre keratoconus induced by eye rubbing

Identity : Ms A.M
First visit : 02/24/2017
Last Visit : No more

Age (years)

Ms. A.M is a 23-year-old law student with no previous medical history or family history of keratoconus. She consulted us initially for refractive surgery suitability. There is no known allergy or history of atopy.

She complained of mild blurring in her right eye which was not improved with a change in glasses. She mistakenly thought that refractive surgery would solve this problem and improve her vision, and so she presented to us for a consultation.

Her refraction at the first visit (02/24th/2017) was: RE 20/25 with -1,5 (-2,5 x 75 °) and LE 20/32 -4,5 with (-0,75 x 125 °).

Clinical examination with the slit lamp showed normal corneas, but the break up time with fluorescein was less than 8 seconds, indicating the presence of an unstable tear film and dry eye.

Systematic corneal topography revealed irregular astigmatism in the right eye (marked inferior steepening, associated with corneal astigmatism of oblique orientation).

When asked about her sleeping position, she described sleeping on her right side.  She is right-handed.

When asked about eye rubbing, this patient realised during the interrogation that she rubbed her eyes frequently while working in front of the computer.  She verbalised rubbing her right eye more than her left.

We explained to this patient that there was a probable association between her sleeping posture and the eye rubbing habit. We encouraged her to try to change her sleeping position, and to stop rubbing her eyes. We suggested wearing an ocular patch or shield over the right eye at night to reduce the compression and irritation responsible for the itch upon awakening.

The patient uses the pulps of the fingers of her right hand to press on the upper eyelid of the right eye, in the supero temporal area. This may have induced the oblique astigmatism over time.
The patient demonstrates how she positions her head at night while sleeping.

Here are the Orbscans maps, OPDscan (topography and aberrometry) maps and ORA (biomechanical evaluation) results of the first visit .

RIGHT EYE ORBSCAN (1st Visit) This map reveals an infero-nasal steepening. There is oblique astigmatism. The thickness map of the cornea (bottom right) is normal.
LEFT EYE ORBSCAN (1st visit). This map is unremarkable. Interestingly, the direction of the corneal astigmatism is "with the rule". There is no mirror symmetry for astigmatism between the eyes.
RIGHT EYE OPDscan. The topography and aberrometry combined map confirms the presence of irregular astigmatism of corneal origin (elevation of coma and trefoil). This irregularity can cause the perception of ghosting or spiculae around bright sources of light in dim light conditions.
LEFT EYE OPDScan. The optical quality estimated from the ocular wavefront analysis is within normal range.
RIGHT EYE ORA The hysteresis value and waveform peaks height is normal.
LEFT EYE ORA. The biomechanical indices are normal.

This case demonstrates that an unhealthy sleeping position and ocular rubbing habit may be responsible for many cases of unilateral irregular astigmatism and inferior steepening patterns observed in corneal topography maps. When encountering such cases, it is important to assess the possibility of night compression of the eye by asking the patient about his/her sleeping habit. Extended night compression of the eye and orbit can favor the contamination of the ocular surface and eyelid by irritants (laundry) or allergenic particles (dust mites). All these factors combined cause ocular discomfort and pruritus, and the need to rub the eye(s) in the morning upon awakening. Understanding this mechanism is key to managing these corneal irregularities seen in keratoconus. This disease should not be attributed to a semi-dormant genetic susceptibility to « ectasia » but rather orientated towards local risks factors for eye rubbing.

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