Comparison of two optical methods in IOL power calculation

Poster Details

First Author: Mohammad hafezNoroozizadeh IRAN

Co Author(s):    Nooshin Dadbin   Ramin Samet   Ahmad Omidvari        

Abstract Details

Purpose:

To compare three basic parameters of keratometry, axial length, and IOL power by two well-known optical biometries: Zeiss IOL Master Haag Streit LenStar

Setting:

: Negah Eye Hospital

Methods:

Numbers (patients-eyes): 62 eyes of consecutive 41 patients 3 patients were omitted: 38 patients IOL master: 1 un-responsive LenStar: 2 un-responsive 59 eyes of 38 patients Sex: Male: 15 (39.5%) Female: 23 (60.5%) Right vs. Left: OD: 32 (54%) OS: 27 (46%) Age: 51-85 yrs (mean: 68.65 ± 9.31 yrs) ……………………………………………....... Target RFN = 0.00 (plano), Regression formula: SRK/T, Two well-trained optometrists, No extra charge, Comparative study, Paired t-test.

Results:

Difference in Mean K: IOL Master > LenStar: 56 eyes (%95) [0 to - 0.5] Diopter: 25 eyes (%42) [- 0.51 to -1.0] Diopter: 27 eyes (%46) [< -1.01] Diopter: 4 eyes (%7) IOL Master < LenStar: 3 eyes (%5) Difference in Axial Length: (From +0.09 to -0.06 mm) IOL Master > LenStar: 29 eyes (%49) 0.01 to 0.09 mm IOL Master = LenStar: 8 eyes (%14) 0.00 mm IOL Master < LenStar: 22 eyes (%37) -0.01 to -0.06 mm Difference in IOL Power: IOL Master > LenStar: 39 eyes (% 66.0) 31 eyes = 0.5 D (%52) 8 eyes = 1.0 D (%14) IOL Master = LenStar: 17 eyes (% 29.0) IOL Master < LenStar: 3 eyes (% 5.0)

Conclusions:

We found statistically significant difference in “Keratometry” and “Power of IOL”. Why?? Autokeratometry feature of the IOLMaster measures a central 2.5-mm zone using 5 reference points and utilizes a computer algorithm. LenStar measures closer to the central visual axis using 32 reference points in two concentric rings of 1.65 and 2.3 mm. No statistically significant difference in measuring Axial length. FINANCIAL INTEREST: NONE