ESCRS - PP13.16 - Importance Of Change In Axial Length, Related To Lens Refraction Index, In Intraocular Lens Power Calculation By Barrett Universal Il Formula

Importance Of Change In Axial Length, Related To Lens Refraction Index, In Intraocular Lens Power Calculation By Barrett Universal Il Formula

Published 2022 - 40th Congress of the ESCRS

Reference: PP13.16 | Type: ESCRS 2022 - Posters | DOI: 10.82333/km7k-f077

Authors: Salvatore Giugno* 1 , William Ticli 1

1ASP CL - UOSD CAL,Mussomeli,Italy

Purpose

To evaluate the impact of ocular axial lenght’s estimate, measured by biometer, and demostrate the accuracy of intraocular lens power calculation with Barrett Universal II (BUII) formula. 

Setting

We use Optical biometer with partially coherent infrared laser light source, at short wave length (780 nm), to obtain various measurements like: K, AL, ACD, WTW etc. Today we know that the new generation formulas, allow to optimize IOL’s power calculation thanks to all these values. Autorefractomer was used for the objective determination of the post operative spherical equivalent (SE). 

Methods

The pre operative and post operative data of 102 eyes (60 patients) were assessed. The middle age was 72 years. Only eyes not previously subjected to another type of eye surgery were selected and which have not developed macular edema in the post operative period (6 months). All eyes have been subjected to the same surgical technique with standard monofocal IOL’s implant. 

Results

From the comparison between “AL pre-op.” (average value 23,43 mm) and “AL post-op.” (average value 23,31 mm) we could find that axial lenght in cataract was always overestimated , decreased on average by 0,12 mm (DS +/- 0,06 mm) after surgery. Post operative SE obtained was:

<=0,5 D in 72,5 %;

<=1,00 D in 92,1 %;

<= 2,00 D in 100% of eyes.

Further analysis of the measurements revealed that, medium absolut error (MAE),estimated whit BUII formula, was:

<= 0,50 D in 63,7 % of cases (60,8 % with AL post-op.); 

<= 1,00 D in 90,2 % of cases (92,2 % with AL post-op);

<= 2, 00 D in 100 % of cases (results invaried with AL post-op).

Conclusions

Evidence confirms that biometer increases ocular axial lenght, in presence of cataract, in medium-long eyes. Also, spherical equivalent proves, in most cases, satisfactory results. Optimization of axial lenght is already integrated within BUII formula.