AIM: To investigate the relationship between the thickness of choroid and the development of idiopathic macular epiretinal membrane(IMEM).

METHODS: A retrospective analysis on 48 cases(48 eyes)of idiopathic macular epiretinal membrane patients(the IMEM group)was taken in our hospital from January 2014 to December 2016, and 50 right eyes in 50 healthy persons with physical examination were selected the control group, comparison on subfoveal choroidal thickness(SFCT)levels of sicked eyes, normal eyes in IMEM group and the control group were made, postoperative SFCT level change of sicked eyes in IMEM patients and normal eyes were investigated via follow-up, and analysis on correlation between postoperative choroidal thickness and the best corrected visual acuity was taken.

RESULTS: The SFCT of sicked eyes in IMEM group 362.22±40.75μm was significantly lower than that of the contralateral eyes(410.56±38.45μm)and the right eyes of the control group(420.73±39.63μm), and data of the contralateral eyes was lower than right eyes of the control group, distinct difference was shown between groups(P<0.05). The IMEM group's SFCT of sicked eyes and normal eyes at postoperative 1wk had no significant difference with that before operation(P>0.05), and at postoperative 1mo, SFCT of sicked eyes and normal eyes evidently increased, showing sharp difference compared with that before operation(P<0.05). After that, the SFCT value stabilized, but there was no obvious difference between the sicked eyes and healthy eyes at postoperatively 1mo(P>0.05). The numbers of patients whose postoperative BCVA ≥0.5 with different preoperative SFCT values had statistically significant differences(P<0.05), and those with BCVA ≥0.5 of SFCT values> 380μm were significantly higher than those with <320μm and 320μm-380μm groups. Fisher exact probability analysis showed that the differences were significant. Pearson analysis showed that there was a positive correlation between the postoperative choroid thickness and the best corrected visual acuity of IMEM group(r=0.629, P<0.05).

CONCLUSION: Choroidal thinning may be an important cause of IMEM, and preoperative choroidal thickness also has an influential effect on postoperative visual recovery.