Mr. N.T is a 26-year-old male who works on computers with no previous medical history, or any known history of keratoconus in the family. He had myopic LASIK performed in another institution on 10/11/2013. The patient complained of a progressive decrease in visual acuity greater in the left eye than the right 6 months after the surgery.
His refraction before the LASIK (10/11th/2013) was : Right eye (RE) 20/20 with -3.75 (-1 x 90°) and Left eye (LE) 20/20 with -4.50 (-0.75 x 120°).
His refraction at the first visit, 1 year after the LASIK (11/18th/2014) was : Right eye (RE) 20/20 with -0.5 (-0.5 x 35°) and Left Eye (LE) 20/40 with -2.25 (-4,00 x 115 °).
Clinical examination with the slit lamp revealed the presence of circular flap edges, and a suspicion of an irregular inferior corneal bulge in the left eye .
Corneal topography revealed the presence of bilateral corneal ectasia more pronounced in the left eye.
When asked about the possibility of frequent eye rubbing, the patient admitted to rubbing his eyes frequently with his knuckles, when working in front of the computer. He is right-handed and sleeps on his left side with his head on his arm.
At work, he uses his right hand predominantly on the computer mouse, and rubs his eyes, especially the left eye, with the other free hand (the left).
We explained to the patient that since vigorous rubbing had preceded the drop in visual acuity, this habit may have caused the cornea to deform in his case. We strongly advised this patient to stop rubbing his eyes and to change his unhealthy sleeping position. We also prescribed an eye shield for sleeping.
Here are pictures of the patient rubbing his eyes and his profiles
Ectasia is a known complication of laser vision correction. When it occurs, it is mostly encountered after LASIK for myopia and compound myopic astigmatism. Ectasia, also called keratectasia or “post LASIK ectasia” is characterized by a progressive deformation of the cornea which is very similar to that of keratoconus, leading to irregular astigmatism along with progressive central thinning. Fortunately, it is very rare (incidence vary from 1/2000 to 1/5000 cases)
In the vast majority of the cases, the occurrence of ectasia can be retrospectively explained by a conglomeration or independent existence of risk factors: high myopia, patient age, reduced preoperative corneal thickness, reduced residual stromal bed thickness after laser ablation and asymmetrical corneal steepening (forme fruste keratoconus, keratoconus or pellucid marginal degeneration), and last but not least (and often forgotten)… eye rubbing!
This case is very informative and demonstrative of the direct causal effect of eye rubbing in the pathogenesis of corneal ectasia. The asymmetry is a consequence of the preferential rubbing of the left eye as well as the left sided sleeping position. Cessation of eye rubbing resulted in stabilisation of the corneal deformation.