Oldie still goldie: IOLMaster 400 with SRK/T vs Hill RBF Formula

Session Details

Session Title: Presented Poster Session: Equipment, Instrumentation & Surgical Devices

Venue: Poster Village: Pod 1

First Author: : M.Garibotto GERMANY

Co Author(s): :    S. Labjuhn   M. Segura   M. Arzdorf                 

Abstract Details

Purpose:

Refractive outcome is, if not the only, the greatest predictor of patient satisfaction. Lens power calculation is at continuous evolution, not only with new measuring techniques, but also with new or improve formulas for lens power calculations. Nevertheless newer is not always better. Our goal with this Study is to compare for three different lenses the actual gold standard technique (IOLMaster ®) with a vergence formula (SRK/T) against, among others, a new artificial intelligence formula (Hill-RBF).We also want to underline the importance of validating IOL Power calculation formulas on site.

Setting:

Augen OP Zentrum Husum, Germany. Ambulatory cataract surgery patients operated between 19.01.2017 and 29.06.2017.

Methods:

We reviewed all the patients who received Alsafit, Alsiol und Micro123+ monofocal IOLs measured with Iolmaster 400 (Zeiss) and Aladdin (Topcon) and calculated with the SRK/T formula. We used the Aladdin axial and keratometry measures to calculate lens power using the Hill-RBF formula and the Universal II formula and extracted, as described, the calculated postoperative SE. We averaged the SE of every available refraction starting 2 weeks after cataract extraction and calculated the difference between real and predicted postoperative SE for each of the used methods.

Results:

62 Eyes which received 3 different IOLs with mean Power of 21,72 Diopters, mean axial length: 23,76 mm, mean postoperative SE of -0,46 D. The Median difference of the predicted SE was: -0,20 D for the IOLMaster; -0,25 for the Aladdin; -0,47 D for the Hill-RBF and -0,37 for the Barrett-Universal II formula for the Alsanza lenses. For the Micro123+ lens the difference in SE was 0,05; 0,04; 0,00 and 0,03D respectively. Patients within +/-0,5D were 61% IOLMaster; 58% Aladdin; 52% Hill-RBF and 61% Barrett-Universal II.

Conclusions:

Newer IOL Power prediction formulas (Hill-RBF) and older techniques (IOLMaster 400 with SRK/T) do not differ enough to justify selecting another IOL Power. The accuracy of the formulas is highly dependant on the implanted IOL. By enlarging our database, including another IOL, mean predicted SE improved not only for the Hill-RBF formula but for all formulas significantly. Still the amount of patients between +/-0,5 Diopters SE is lower than reported elsewhere. It is important to re-validate formulas for every used lens and every setting to achieve satisfactory outcomes. Further studies with more patients should confirm our findings.

Financial Disclosure:

None