Preliminary Characterization Of Predictive Factors Of The Visual Change After Epi-On And Epi-Off Corneal Collagen Crosslinking Techniques

To investigate potential predictive factors of the visual change achieved with accelerated epi-on and epi-off corneal collagen crosslinking (CXL) in keratoconus

Department of Ophthalmology, Torrecárdenas Hospital Complex, Almería, Spain; Department of Ophthalmology (Qvision), Vithas Virgen del Mar Hospital, Almería, Spain; Department of Ophthalmology, Vithas Medimar International Hospital, Alicante, Spain 

This retrospective comparative study analyzed 67 eyes who were treated with accelerated epithelium-on (epi-on group) and epithelium-off (epi-off group) CXL. Clinical outcomes were evaluated and compared during a 1-year follow-up. Likewise, the relationship of the change achieved with both CXL techniques in corrected distance visual acuity (CDVA) with different preoperative data was investigated

Mean CDVA change at 3 months post-CXL was -0.04±0.19 and -0.07±0.25 in the epi-on and epi-off groups, respectively. In the epi-on group, this change was significantly correlated with preoperative apical and central corneal thickness and in the epi-off group, this change was also significantly correlated with preoperative apical and central corneal thickness,but also with some topometric and aberrometric indices.The change in CDVA in the epi-on group could be predicted from age, preoperative refractive astigmatism J₄₅ component, anterior corneal asphericity and posterior corneal high order aberration and in the epi-off group,this change could be predicted from preoperative minimum corneal thickness and vertical anterior corneal primary coma 

Clearly different predictive factors of the visual change induced with accelerated epi-on and epi-off CXL techniques are present, suggesting a different mechanism of action for stiffening the cornea and inducing changes in this structure