AIM: To compare the differences of corneal diameter measured with wavelight anterior segment analyzer(Wavelight),IOL-master optical bio-measurement(LS900), anterior segment OCT(AS-OCT)and gauge.

METHODS: Totally 89 patients(177 eyes)with myopia who want to accept ICL were examined before operation with more than five kinds of instruments respectively, white to white(WTW)were examined with Wavelight, IOL-master, LS900 and gauge, angle to angle(ATA)with AS-OCT. Then the size of ICL was calculated based on the value of gauge. The vault of ICL was examined with OCT 3mo after operation.

RESULTS: WTW was(12.45±0.73, 11.96±0.39, 11.92±0.36, 11.49±0.30)mm measured by Wavelight, IOL-Master, LS900 and gauge respectively, ATA was(11.80±0.44)mm with AS-OCT. The value of gauge was the smallest one among them(all P<0.01). Among four instruments, there was no statistical difference between LS900 and AS-OCT(P=0.098), they can instead of each other; there were differences among other instruments(P<0.01). The size of ICL based on gauge was(12.77±0.37)mm. The vault of ICL is(537.41±181.22)μm 3mo after implantation obtained by OCT.

CONCLUSION: Gauge is ideal tool for measuring corneal diameter, it cannot be instead. Wavelight, IOL Master, LS900 and AS-OCT can be taken as reference.