AIM: To evaluate the objective visual quality of patients who underwent corneal cross-linking for the keratoconus using double-pass analysis system.

METHODS: Advanced keratoconus patients who underwent UV-riboflavin corneal cross-linking from January to July 2015 were included.The outcomes of their objective scattering index(OSI), predicted visual acuity(VA), the cut-off frequency of modulation transfer function(MTF cut-off), the Strehl ratio(SR)were compared before and 6mo after corneal cross-linking.

RESULTS: A total of 13 patients(16 eyes)were included. There was no statistically significant difference between pre- and 6mo postoperative data in uncorrected visual acuity,best corrected visual acuity,refractions and mean value of Sim-k(P>0.05). Non-invasive average tear film break up time(NIAvg-BUT)detected by the Sirius system decreased after corneal cross-linking(P<0.05). Using double-pass analysis system, no statistically significant change was found in MTF cut off, Strehl Ratio, OSI before and after treatment(P>0.05). Tear Film Analysis Mean OSI increased at 6mo postoperatively(P<0.05).

CONCLUSION: The subjective visual quality isn't effected by corneal cross-linking. The tear stabilities of patients are influenced by these operations at 6mo postoperatively. More observations on long-term effect are needed to be taken in the future.