Posters

Don’t let me down: intraocular lens calculation formulae effectiveness in long eyes in day-to-day practice

Poster Details

First Author: T.Morais Sarmento PORTUGAL

Co Author(s):    R. Figueiredo   J. Garrido   A. Rebelo   O. Berens   A. Candeias        

Abstract Details

Purpose:

To assess the effectiveness of intraocular lens calculation formulae in long eyes in a secondary care centre day-to-day practice

Setting:

Hospital do Espírito Santo de Évora, Ophthalmology Secondary Care Centre, Évora, Portugal

Methods:

Retrospective analysis of uneventful phacoemulsification procedures refractive outcomes from 01/01/2018 to 31/12/2018 in eyes with axial length (AL) superior to 25mm, excluding ocular pathology and absence of post-operative refraction, validating 62 eyes of 52 patients. IOLMaster500 (CarlZeiss) was used to measure axial length, keratometry and anterior chamber depth. 5 formulae (SRK/T, Hoffer Q, Holladay I, Haigis and Barrett II universal) were calculated based on User Group Laser Interference Biometry (ULIB) constants for 2 intraocular lens (IOL) used and compared based on mean prediction error (MPE) and on percentage of patients subjective refractions within 0.25, 0.50, 0.75 and 1.00D of prediction.

Results:

Mean AL was 26.778 (+-0.482). MPE was -0.337 (+-0.125) for Barrett II, +0.486 (+-0.199) for Haigis, +1.069 (+-0.197) for Holladay I, +0.916 (+-0.175) for SRK/T and 1.183 (+-0.206) for Hoffer Q, with statistical significance in comparison to Barrett II and to Haigis (p<0.001). Refractions percentage within 0.25, 0.50, 0.75 and 1.00D of prediction were respectively 43.5%/74.1%/87%/90.2% for Barrett II (p=1.00), 24.2%/46.8%/58.1%/71% for Haigis (p=0.006), 12.9%/24.2%/40.3%/50% for Holladay I (p<0.001), 14.5%/24.2%/43.5%/62.9% for SRK/T (p<0.001) and 9.7%/19.4%/29%/51.6% for Hoffer Q (p<0.001).

Conclusions:

When dealing with long eyes, there is difference from Barrett II to any other formulae. Barrett II is the only formula with myopic mean prediction error, while all the other present hyperopic mean prediction errors. When comparing refractions deviation percentages, Barrett II seems to fare fairly better than other formulae, which was expected as one of the most recent formulae. The difference between the literature and these results values may arise mainly from the use of IOLs other than Acrysof SN60WF and from the use of ULIB optimised constants (compared to sample optimisation of the constants).

Financial Disclosure:

None