Posters

Trifocal IOLs: the complexity of the calculation

Poster Details

First Author: B.Babayeva AZERBAIJAN

Co Author(s):    L. Bilandarly              

Abstract Details

Purpose:

Cataract surgery now - is the returning of quality vision for people, who lead socially active lifestyle. The requirements for postoperative results becoming more higher. In this context it is important to use trifocal intraocular lenses. The high cost and expectation of excellent post-operative results make the optical power calculation for trifocal IOLs even more important. Number of publications dedicated to disproportionate eyes with unusual geometry, because there are many patients with non-standard biometric relationship between structures of anterior segment of the eyeball. We set out to determine the influence of the anterior chamber depth to IOL power calculation.

Setting:

Studies were performed in Azerbaijan National Centre of Ophthalmology named after acad. Z.A.Aliyeva. The authors have no any financial interests.

Methods:

To determine the effect of anterior chamber depth on the calculation of IOL, we conducted a theoretical study in which the AL and average keratometry were taken as a constant (respectively, 23, 5mm and 43, 5D). Anterior chamber depth varied from 2.0 to 5.0 mm with 0.1 mm step (31 cases). Calculation of IOL was performed on IOL Master 500 using 4 formulas: Holladay, SRK-T, Haigis and Hoffer for trifocal lenses Acriva Reviol BB MFM 611 and Zeiss AT LISA 839 MP.

Results:

Studies have shown that the calculations, according to the formulas Holladay, SRK-T and Hoffer, changes in anterior chamber depth in the range from 2.0 to 5.0 mm was not performed in all 31 cases and were 20,5D for Acriva Reviol BB MFM 611 and 21.0 D for Zeiss AT LISA 839 MP. The calculation by Haigis showed the increasing of IOL optical power by 0,5D at ACD = 2.3, 2.9, 3.6, 4.2 and 4.8 for both lenses and ranged 19,0D - 21, 5D for Acriva Reviol BB MFM 611 and 20,0D - 22,5D for Zeiss AT LISA 839 MP.

Conclusions:

1. From the IOL power calculation formulas used in IOL master 500 only Haigis formula is sensitive for the changes of ACD. 2. Holladay, SRK-T and Hoffer formulas is not sensitive to changes of the anterior chamber depth and perceive ACD as a value, that depends only from the curvature of the cornea. 3. In connection with the above, we recommend to calculate the optical power of trifocal IOLs by last generation formulas and don’t use Holladay, SRK-T and Hoffer. 4. To take into account the necessity of updating IOL Master’s 500 database and adding to the database the last generation formulas. FINANCIAL DISCLOUSRE: NONE