Comparison Of Calculation Error Of The 3Rd And 4Th Generation Rules For Different Types Of Intra Ocular Lenses.

Accuracy comparison of 3 generation 3 formulas (SRK/T, Holladay 1, Hoffer Q) and 3 generation 4 formulas (Haigis, Holladay 2, Barrett Universal II Formula) for different types of intraocular lenses (toric, monofocal, multifocal).

The introduction of new types of intraocular lenses and calculation formulas to cataract surgery necessitates the selection of the most accurate calculation method suited to a specific type of lens. There are few studies in the available literature that compare calculation accuracy for changing lens types. Finding the relationship between the calculation formula, the length of the eyeball and the type of intraocular lens is the subject of many studies.

A retrospective analyze was performed on the results of the calculation of intraocular lenses with postoperative acuity in 145 patients (214 eyes). The material consisted of eyes:   21 - 26 mm long. Calculation error (Predictive Error - PE) was compared for four multifocal lenses (M + Oculetnis, Fine Vision PhysIOL, Symfony Johnson & Johnson and InFo SAVIOL) and two types of toric monofocal lenses (Precizon Toric OPTHEC, Acrysof IQ Toric Alcon).                   The control group consisted of patients with the PhysIOL Micropure monofocal lens. There were perfomred all diagnotic examination like: AL Scan biometry, tompography (Sirius, TMS-5), Visual acuity and calculation formula 3th and 4rd generation.

The lowest mean SE value was obtained for the lenses Micropure -0,13 D, Fine Vision  - 0,15 D and AcrySofIQ Toric - 0,17 D. The highest mean value for SE was obtained for the Symfony 0.48 D lens. There were no statistically significant differences between the study groups. Based on the performed statistical analysis, it was shown that there are no statistically significant differences in the MAE between the 3rd and 4th generation formulas for individual types of lenses, except for Fine Vision lenses.There were several statistically significant correlations between the error generated by the 3rd and 4th generation rules and the length of the eyeball, the curvature of the cornea and the depth of the anterior chamber for all types of lenses.

Due to the small number of patients, these results should be confirmed in a larger analysis. In terms of clinical practice, the calculation accuracy of monofocal lenses is similar to that of multifocal and toric lenses (no significant differences between the MAEs for individual study groups for all rules).