| Study | Reason for exclusion |
|---|---|
| Alessio 2013 | Not an RCT |
| Caporossi 2010 | Not an RCT |
| Caporossi 2013 | Not an RCT |
| Coskunseven 2009 | Not an RCT |
| Doors 2009 | Not an RCT |
| Gkika 2012 | Not an RCT |
| Goldich 2010 | Not an RCT |
| Greenstein 2013 | Not an RCT |
| Grewal 2009 | Not an RCT |
| Hallahan 2014 | Not an RCT |
| Henriquez 2011 | Not an RCT |
| Holopainen 2011 | Not an RCT |
| ISRCTN04451470 | RCT comparing epithelium on or off |
| ISRCTN29378493 | RCT comparing use of contact lenses before surgery or not |
| Jordan 2014 | Not an RCT |
| Kilic 2012 | Not an RCT |
| Koller 2009 | Not an RCT |
| Kránitz 2014 | Not an RCT |
| Mastropasqua 2013 | RCT comparing two different cross‐linking methods |
| Mazzotta 2007 | Not an RCT |
| NCT01143389 | RCT comparing two different riboflavin regimens |
| NCT01152541 | RCT comparing two different riboflavin regimens |
| NCT01181219 | RCT comparing epithelium on or off |
| NCT01325298 | RCT comparing two different UVA dosing regimens |
| NCT01344187 | RCT comparing riboflavin versus placebo |
| NCT01459679 | RCT comparing three different treatment regimens |
| NCT01464268 | RCT comparing two different riboflavin regimens |
| NCT01643226 | RCT comparing riboflavin versus placebo |
| NCT01708538 | RCT comparing epithelium on or off |
| NCT01868620 | RCT comparing iontophoretic CXL with standard CXL |
| NCT01972854 | RCT comparing riboflavin versus placebo |
| NCT02009709 | RCT comparing two different irradiance levels |
| Poli 2013 | Not an RCT |
| Razmjoo 2014 | RCT comparing total and partial removal of the epithelium |
| Rechichi 2013 | Not an RCT |
| Salman 2013 | Not an RCT |
| Viswanathan 2013 | Not an RCT |
| Wisse 2014 | Not an RCT |
RCT: randomised controlled trial