AIM: To compare the accuracy of intraocular lens(IOL)power calculations by using five formulas(Haigis, SRK-T, Hoffer Q, Holladay-1, SRK-Ⅱ)in eyes with long axial lengths in order to improve the accuracy of predicating IOL powers.

METHODS: Fifty-one eyes of 51 cases of age-related cataract and with mild long axial(24.5mm27mm)were collected who's optical biometry were performed by the Zeiss IOL Master500 before operation. They underwent regular phacoemulsification and posterior chamber IOL implantation. The actual postoperative refraction was measured with the methods of phoropter and subjective optometry 3mo after surgery. Then we compared the differences of the predicted and actual postoperative refraction of the five formulas in each group.

RESULTS: In the mild axial lengths cases, the differences between SRK Ⅱ formula and the other four formulas were statistically significant(P<0.05), and the difference between Hoffer Q and SRK-T formula was statistically significant(P<0.05); there was no difference among the other formulas(P>0.05). In the moderate and severe long axial lengths cases, the differences between SRK Ⅱ formula and the other four formulas were statistically significant(P<0.05), and the difference between Hoffer Q and SRK-T formula, Hoffer Q and Haigis formula were statistically significant(P<0.05); there was no difference among the other formulas(P>0.05). The differences of all the five formulas between the two groups were statistically significant(P<0.05).

CONCLUSION: In the mild axial lengths cases, Haigis, SRK-T, Hoffer Q, Holladay-1 performed well. In the moderate and severe long axial lengths cases, Haigis, SRK-T and Holladay-1 performed better than other formulas. The accuracy of all the five formulas decreases as the axial length getting longer.