ESCRS - PO248 - OCULAR BIOMETRY AND IOL POWER CALCULATION FORMULAS: SOME ASPECTS.

OCULAR BIOMETRY AND IOL POWER CALCULATION FORMULAS: SOME ASPECTS.

Published 2025 - 29th ESCRS Winter Meeting

Reference: PO248 | Type: Presented Poster & Poster | DOI: 10.82333/cdx6-5d11

Authors: Bayim Babayeva* 1 , Leyla Bilandarli 2 , Gulmin Akhmadova 3

1Glaucoma,Azerbaijan National Ophthalmology Center ,Baku,Azerbaijan, 2Azerbaijan National Ophthalmology Center ,Baku,Azerbaijan;Azerbaijan National Ophthalmology Center ,Baku,Azerbaijan, 3Azerbaijan National Ophthalmology Center ,Baku,Azerbaijan

Purpose

 

There're a lot of publications about biometric characteristics of eyes in patients from different ethnic groups. Using data of ophthalmo-biometric audit of Azerbaijani residents, we comperatively analyzed results of IOL power calculations by several formulas, including those based on AI.

 

Setting

 Biometry was performed on IOL Master500 (Carl Zeiss Meditec AG, Germany). IOL power was calculated for Ray One Trifocal RA0613Z (Rayner Surgical Group Limited, UK) using Hoffer/SRK-T/Holladay and ESCRS IOL Calculator (https://iolcalculator.escrs.org) using Hill-RBF/Kane formulas.

Methods

Theoretical IOL calculation  was made in combination of minimum, medium and maximum values ​​of main parameters (axial length (AL), keratometry (K), anterior chamber depth (ACD) and corneal diameter (WTW)). Data was divided into 4 groups according to AL. Group1 – AL≤22.00mm (minimum, medium and maximum values ​​of AL, keratometry and ACD – 20.29, 21.59, 21.98mm; 41.28, 45.25, 47.68D; 2.12, 2.78, 3.67mm, respectively); Group2 - AL 22.01-24.00mm (22.01, 23.15, 24.00mm; 40.11, 44.28, 47.38D; 2.04, 3.10, 4.32mm); Group3 - 24.01-26.00mm (24.01, 24.68, 25.96mm; 39.13, 42.96, 47.91D; 2.31, 3.42, 4.19mm); Group4 ≥26.01mm (26.01, 28.71, 36.82mm; 39.05, 43.66, 47.48D; 2.04, 3.51, 4.45mm).

 

Results

 

Shift of 0.5-1D was observed in group1 within same AL using Hoffer, Holladay, Hill-RBF and Kane. Spread in IOL power for minimum, medium and maximum values ​​of AL and constant K&ACD for various formulas was 7.5D. There's agreement for 4 formulas when combining med/max ALvalues ​​and keratometry with min&med ACD ​​within this group. Calculation of IOL power in group 2 within same AL revealed shift of 0.5-1D. Spread in IOL power for min, med and max ALvalues and constant K/ACD according to different formulas was 7.5 diopters. Identical results using SRK-T/Holladay, Hill-RBF/Kane formulas were obtained with medium ACD/K values ​​in combination with all three AL values ​​included in 3rd group, also with AL=25.96mm, K =42.96D and min ACD value. Shift between results increased to 1.5D. Greatest variability was observed with following combination: max AL/minimum K/maximum ACD. In group 4, no identical values ​​of IOL power were observed. Smallest diopter fluctuation occurred with combination of medACD, minAL and all K values. When AL exceeding 35mm, IOL calculation by Hill-RBF/Kane formulas wasn't possible due to the established limit.

Conclusion

 

Similar/maximally close in value results of IOL calculation using various formulas are achieved in eyes with medium biometric indicators. Deviation of biometric parameters from statistical average and increase of “disproportionality” of eye increases spread of data in IOL power calculations.Thus, conduction of national ophthalmobiometric audit seems very important. It'll clarify the situation with “disproportionate” eyes in a particular population and possibly optimize optical component of cataract surgery.