AIM: To investigate the effects of par plana vitrectomy(PPV)+ inner limiting membrane(ILM)flat covering + vitreous cavity disinfected air filling and PPV + ILM stripping + vitreous cavity disinfected air filling on giant idiopathic macular hole(IMH)and high myopia macular hole(MH).

METHODS: The clinical data of giant IMH 40 eyes and giant high myopia MH 40 eyes were compared. Twenty patients with giant IMH underwent traditional ILM removal(Group A1), the remaining 20 underwent ILM flat transplantation(Group A2); 20 underwent traditional ILM removal(Group B1)for giant high myopic MH, and the remaining 20 underwent ILM flat transplantation(Group B2). The closure rate of MH and the improvement of best corrected visual acuity(BCVA)before and after operation were compared and analyzed.

RESULTS: There were significant differences in BCVA before and after operation in Group A(F=96.193, P<0.001), between A1 and A2(F=4.971, P=0.03), and the interaction between different time points and groups after operation(F=18.772, P<0.001). The results showed that there were significant differences of the two groups between any two time point(P<0.05). The t-test results between the two groups at different time showed that there was no difference in preoperative vision between A1 and A2(P>0.05). There were significant differences in preoperative visual acuity between the two groups at 1, 3 and 6mo after operation(P<0.05). There were significant differences in different time points before and after BCVA in Group B(F=136.150, P<0.001), B1 and B2(F=5.179, P=0.029), and the interaction between different time points and groups after BCVA(F=7.079, P=0.001). The results showed that there were significant differences of the two groups between any two time point(P<0.05). The results of t-test between the two groups at different time showed that there was no difference in preoperative visual acuity between B1 and B2(P>0.05), but there was significant difference in 1, 3 and 6mo after operation(P<0.05). After 6-month follow-up, the closure rate of Group A1 was 80%, attached rate was 20%, closure rate of Group A2 was 100%. There was no significant difference in closure rate between Group A1 and Group A2(P=0.053). The closure rate of Group B1 was 70%, attached rate was 30%, closure rate of Group B2 was 90%, attached rate was 10%. There was no significant difference in closure rate between Group B1 and Group B2(P=0.118). There was significant difference in closure rate between retinal initial membrane stripping group and plaster group(75% vs 95%, χ²=4.057, P<0.05).

CONCLUSION: For giant IMH and giant high myopia MH, there was significant difference in closure rate and BCVA improvement between ILM stripping group and covering group, on which the former is better.