Adjusting Intraocular Lens Power In Short Eyes Using Anterion Optical Coherence Tomography

The purpose of our study is to determine if our algorithm using Anterion AS-OCT (Heidelberg Engineering) of recommending using one step higher or lower power IOL of 0.5 D  compared to currently used formulas in select group of short eyes will achieve a better refractive outcome.

Great Lakes Eye Consultants is a private anterior segment practice with three office locations in Michigan and MUS is a consulting company in Slovakia

Anterion AS-OCT (Heidelberg Engineering), Aviso AS-UBM ultrasound biomicroscopy (Quantel) and Aladdin optical biometry (Topcon) was obtained before cataract surgery in a group of 20 short eyes. We have analyzed 36 different parameters of the anterior segment including commonly used parameters and parameters involving scleral spur, iris and ciliary body. The algorithm using scleral spur depth, lens thickness and spur-iris distance was developed for Anterion AS-OCT to predict refractive prediction errors of >0.25 D and with recommendation to change the power of the IOL calculated with currently used formulas in clinical practice. This algorithm was tested on a another group of 35 short eys using Anterion AS-OCT measurements.

The change of one step of IOL power of 0.5 D compared to currently used IOL power calculation formulas was recommended in 8 out of 35 short eyes with AL of <22.75 mm using the algorithm using scleral spur depth, lens thickness and spur-iris distance developed for Anterion AS-OCT. The refractive prediction error of these 8 eyes compared to BarretU2 formula was 0.4 diopter +/- 0.22 D (min 0.08 D and max 0.75 D) and most other currently used formulas showed similar prediction errors. The recommendation to change the IOL power by 0.5 D was correct in 7 out of 8 eyes and in one eye was not associated with prediction error.

Our study suggests that Anterion AS-OCT (Heidelberg Engineering) could be clinically used in short eyes with AL< 22.75 mm using our current algorithm with parameters of scleral spur depth, lens thickness and spur-iris distance to improve refraction prediction error of currently used formulas and change the IOL power by one step of 0.5 D in approximatelly 20-25% of patients with short eyes.