The Influence Of Anterior Chamber Depth On The Calculation Of Piggyback Intraocular Lenses
Published 2025 - 43rd Congress of the ESCRS
Reference: PO457 | Type: Free paper | DOI: 10.82333/dsrg-nw16
Authors: Pedro Manuel Moreira Martins* 1 , Ricardo Machado Soares 1 , José Salgado-Borges 2 , Miguel Faria-Ribeiro 3
1Ophthalmology,ULSGE,Gaia,Portugal, 2Ophthalmology,Clinisborges,Porto,Portugal, 3Universidade do Minho,Braga,Portugal
Purpose
Demonstrate the variability of the spherical and toric ratios between the refraction at the intraocular lens (IOL) plane and the refraction at the spectacle
plane when the sphere and the cylinder power of toric piggyback IOLs are calculated. Also, a comparison of the results of piggyback IOL power calculation with variable
ratios, to the IOL power calculation performed by a major manufacturer (Rayner Sulcoflex) online calculator using a fixed ratio.
Setting
Private practice, Buenos Aires Argentina
Methods
Schematic eyes with different values of pseudophakic anterior chamber depth (ACD), refractive cylinder and spherewereused tocalculate theexact toric and spherical power of the IOL needed to achieve emmetropia
Results
The toric ratio could range between 0.88 and1.6,while the spherical ratio between 1.01 and 1.61. Therefore, using fixed ratios can lead to errors in IOL power calculation up to 1 diopter. The most likely errors are undercorrection in eyes with deep ACD and low amounts of sphere and astigmatism and overcorrections in eyes with shallow ACD and high preoperative sphere and/or cylinder.
Conclusions
Manufacturers that calculate the power of piggyback IOLs with a fixed ratio of toricity and sphere should develop calculators that change this ratio according to the preoperatively measured variables.