Abstract
To evaluate depth of field (DOF) provided by different presbyopia-correcting intraocular lens (IOL) designs, comparing the results obtained using different criteria for defining the defocus tolerance. A total of 150 eyes undergoing cataract surgery were enrolled and divided into 6 groups depending on the IOL implanted: AT.LISA Tri (Carl Zeiss Meditec), FineVision (PhysIOL), PanOptix (Alcon Laboratories), Tecnis Symfony (Johnson & Johnson Vision), Miniwell (SIFI MedTech) and Tecnis Synergy (Johnson & Johnson Vision). Subjective DOF was obtained from defocus curves with absolute and relative criteria of tolerance of 0.1 logMAR. Aberrometry was also measured and the visual strehl optical transference function (VSOTF) with percentage of degradation of 90%, 80% and 60% was used to quantify objectively the DOF. Tecnis Symfony, Tecnis Synergy and Panoptix IOL groups showed better subjective and objective DOF compared to the rest of IOL groups, being these differences statistically significant differences (p < 0.001). Comparison between subjective and objective DOF showed that subjective measures were higher for all IOLs, being also these differences statistically significant for all groups (p < 0.001). A moderate significant correlation was found between absolute subjective criteria and VSOTF60% (r = 0.73, p < 0.05). Objective and subjective measures of DOF are not comparable due to differences in methodologies and criterions to define the level of degradation tolerance. Nevertheless, both objective and subjective measures showed a trend to a greater DOF for Tecnis Symfony and Tecnis Synergy IOLs compared to most of trifocal diffractive designs, with the exception of PanOptix.
Highlights
To evaluate depth of field (DOF) provided by different presbyopia-correcting intraocular lens (IOL) designs, comparing the results obtained using different criteria for defining the defocus tolerance
Image quality meters (IQM) derived from aberrometry have demonstrated to correlate with patient visual performance[14], and a percentage of degradation on the Visual Strehl ratio based on the optical transfer function (VSOTF) has been proposed as an objective DOF measure that is good for clinical p urposes[15,16]
Very similar DOF values were found using the relative criterion in eyes implanted with the trifocal IOL AT LISA tri (⁓2.50 D), when comparing our results with those obtained by Barisic et al.[3]
Summary
To evaluate depth of field (DOF) provided by different presbyopia-correcting intraocular lens (IOL) designs, comparing the results obtained using different criteria for defining the defocus tolerance. Subjective DOF can be obtained from the defocus curves, establishing a specific criterion of acceptable visual acuity (VA) reduction This conventional procedure is well described[4], being time consuming, but allowing to obtain in a simple way the maximum VA for each vergence with the use of trial lenses of different powers. DOF can be obtained by presenting a stimulus of a given size and asking the patient to define the range of distances for which the chart is perceived “equal” (same quality of vision) This methodology is highly dependent on what is defined as equal by each subject (detection of blur or changes on contrast)[8], and this variability on subjects’ perception made some authors to adopt different criteria. Authors such as Yi et al.[16] have analysed the relationship between subjective and objective measures of DOF, obtaining that a level of degradation of 60% on VSOTF could be the most representative of patients’ subjective p erception[16]
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