Posters

Don’t let me down: intraocular lens calculation formulae effectiveness for short 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 short 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) lesser than 22mm, excluding ocular pathology and absence of post-operative refraction, validating 72 eyes of 62 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 21.617 (+-0.083). MPE was -0.186 (+-0.199) Haigis, 0.280 (+-0.177) Barrett II, 0.294 (+-0.175) Holladay I, 0.250 (+-0.175) SRK/T and 0.216 (+-0.186) Hoffer Q, with statistical significance only in comparison to Haigis (p<0.0001). Refractions percentage within 0.25, 0.50, 0.75 and 1.00D of prediction were respectively 30.6%/52.8%/66.7%/79.2% for Haigis, 25%/43.1%/65.3%/75% for Barrett II, 29.2%/54.2%/65.3%/73.6% for Holladay I, 26.4%/52.8%/66.7%/77.8% for SRK/T and 30.6%/54.2%/59.7%/72.1% for Hoffer Q (p>0.05).

Conclusions:

When dealing with short eyes, there is difference from Haigis to any other formulae. Haigis is the only formula with myopic mean prediction error, while all the other present hyperopic mean prediction errors. When comparing refractions deviation percentages, Haigis seems to fare better than other formulae, even better than Barrett II which is surprising considering the already published comparisons between them. This difference between the literature and these results 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