Corneal Opacity After Crosslinking For Keratoconus

the crosslinking technique (corneal collagen crosslinking) is proposed to the patient to increase corneal rigidity in cases of progressive keratoconus.
complications
following CXL are rare. They are essentially infectious complications. Stromal scarring complications of the pseudo-haze type, although frequent, are usually regressive.

we report the case of a 17-year-old girl, who was admitted for a progressive decrease in visual acuity
 for 1 year, mainly in the right eye. A family history of atopy was found, with mention of allergic conjunctivitis since childhood and frequent eye rubbing. After clinical and topographical examination, the diagnosis of keratoconus was accepted, and the patient was treated with cross linking. 

initially, the clinical examination showed visual acuity with optical correction at 3/10 (right) and 5/10 (left), thinning and bulging of the cornea inferiorly, clear cornea, the rest of the examination was unremarkable. corneal topogaphy confirmed the diagnosis of progressive keratoconus. the patient underwent epi off cross linking in the right eye initially. 
post-op: corneal re-epithelialization in progress, except in the central part, which became opacified with inferior KPS, AV at 1/10. OCT of the SA showed stromal thinning with hyperreflectivity. after surface treatment and scleral lens adaptation, visual acuity improved to 5/10 in right eye. 

In the literature, it has been noted that complications after CXL are rare. These are essentially infectious complications. Stromal scarring complications of the pseudo-haze type, although frequent, are usually regressive.
In this case, the question is: was the patient's corneal fragility to be expected?
Preoperative pachymetry was performed and there was no contreindication to conventional CXL.
The intraoperative protocol was followed and the patient stopped rubbing her eyes postoperatively.
Could the use of an Epi on transepithelial CXL have alleviated the appearance of postoperative central keratolysis? In retrospect, it is
difficult to say, as the corneal reaction was so surprising.

Although adaptation to post-CXL lenses was made difficult by the significant change in corneal geometry and especially in the apical zone, by corneal embrittlement, which delayed adaptation and visual the result is satisfactory in terms of wearing comfort and visual comfort. Follow-up
must, however, be rigorous in order to maintain the results obtained.