Ms. O.F is a 38-year-old female with no previous medical history other than atopy. She has no known family history of keratoconus. She had been seen at another institution for a refractive surgery suitability assessment and was informed that LASIK « was unsafe because of the corneas ». She came to us of a second opinion, hoping for some refractive surgical option as she preferred not to wear glasses (due to aesthetic and functional reasons) and was no longer comfortable with contact lenses.
Her refraction at the first visit (08/05th/2013) was: Right Eye (RE) 20/20 with -5 (-0,25 x 55 °) and Left Eye (LE) 20/20 with -4.5 (-0,5 x 130 °)
Clinical examination with the slit lamp was normal in both eyes.
Corneal topography revealed the presence of bilateral inferior keratoconus, with more pronounced steepening in the right eye.
When asked about the possibility of frequent eye rubbing, the patient admitted to rubbing her eyes frequently every day, especially when working in front of the computer, because she enjoyed it.
We explained to the patient that the topographic changes in her were a consequence of her eye rubbing habit, and told her to stop rubbing her eyes immediately. We also explained that we had to document topographic stability after cessation of eye rubbing before the idea of refractive surgery could be entertained. We advised her against LASIK as there was a high risk of worsening of the corneal deformation with the procedure. From our experience and from many reports in the literature, Photorefractive Keratectomy (PRK) is not contraindicated in such cases with mild myopia, especially if the topography shows stability of at least one year. We also explained in detail to her that eye rubbing after PRK could compromise the outcome of the procedure.
At her 3rd visit, 3 years after her first consultation, corneal stability using difference maps was clearly demonstrable. We then performed bilateral PRK (on 12,15th/2016).
Three months after the PRK her refraction was : RE 20/20 with -0.25 (-0.25 x 140°) and LE 20/20 with -0.25 (-0.5 x 25°) .
Here are pictures of the patient rubbing her eyes and her profiles
Difference maps were performed at each subsequent visit. No evolution was observed between the first and last visits. The keratoconus is stable, more than 4 years since the first visit and 1 month since the PRK after the patient definitively stopped rubbing her eyes .
BEFORE PRK SURGERY
2013 to 2016
AFTER PRK SURGERY
This case is both informative and intriguing. It is debatable whether it is legitimate to perform PRK on proven or suspected keratoconus cases. This is one of the grey zones of refractive surgery!
Our experience shows that performing laser surface ablation (PRK, with no flap cut) in such instances is safe for the cornea provided the patient has understood the stakes involved in eye rubbing after surgery. We also found that PRK creates a similar surgical environment to cross-linking without endothelial toxicity and much less keratocyte apoptosis (cellular death). PRK may not induce much of a stiffening effect, but the inflammation generated by the laser and by the stromo-epithelial healing response may generate a slightly different (reduced) corneal sensitivity in the long run. This surgically induced cornea desensitisation (like in cross-linking), together with post-operative pain and the fear of poor surgical outcome or failure are major deterrents to eye rubbing.
In the literature, the cases of post-PRK ectasia are very scarce, and it appears that the prevalence of ectasia in the operated population is less than the prevalence of keratoconus in the non-operated population.
Explaining the deleterious effects of chronic and vigorous eye rubbing to refractive surgery candidates is one of the most important steps in the prevent of post-surgical corneal ectasia.
Other cases :
- Date 15 août 2017
- Tags Computer screen, Enjoyed eye rubbing, Eye rubbing, Female, PRK, Work rubbing