Simulated Partial Monovision Versus Bilateral Trifocal Intraocular Lens Configuration: Binocular Defocus Curve Analysis
Published 2026 - 44th Congress of the ESCRS
Reference: FP01.06 | Type: Free paper | DOI: 10.82333/zbtp-0g12
Authors: Mr Ricardo Elsner* 1 , Dr Vitus Knecht 1 , Mrs Jasmin Abu Arif 1 , Mrs Josephine Brüch 2 , Prof. Dr Eckart Bertelmann 1
1Ophthalmology,Charité University Medical Center,Berlin,Germany, 2Optometry,Berlin University of Applied Sciences and Technology,Berlin,Germany
Purpose
To compare binocular defocus curves of simulated partial monovision (PMV) using asymmetric trifocal–monofocal intraocular lens (IOL) combinations with bilateral trifocal IOL implantation, and to determine the functional impact across near, intermediate, and distance ranges.
Setting
Department of Ophthalmology, Charité University Hospital, Germany.
Methods
Thirty-six phakic subjects (age 21–30 years) were examined using the Real-Artificial-Lens-Vision (RALV) system (DEZIMAL Medical Engineering/1stQ GmbH, Mannheim, Germany). Three binocular IOL configurations were simulated in randomized order under mesopic conditions: bilateral trifocal (TT; Basis Z Trifokal, 1stQ, +3.50 D add), monofocal right/trifocal left (MT), and trifocal right/monofocal left (TM; Basis Z mono, 1stQ). Binocular defocus curves were measured from −4.00 to +1.00 D in 0.50 D steps. Non-parametric statistics (Friedman test, Wilcoxon signed-rank with Bonferroni correction; α=0.017) were applied after Shapiro-Wilk normality testing. Effect sizes were reported as Cohen’s d.
Results
TT showed significantly better near vision at −4.00 D (0.46±0.14 vs. MT 0.36±0.12; p<0.001; d=0.67) and at −3.00 to −2.00 D (all p<0.003; d=0.59–0.88). In the intermediate range (−1.50 to −1.00 D), no significant differences were found between TT, MT, and TM (all p>0.05). Distance VA in logMAR (0.0 D) was comparable across groups (TT: 1.16±0.14; MT: 1.20±0.10; TM: 1.18±0.14; p=0.225). At +0.50 and +1.00 D, PMV configurations significantly outperformed TT (all p<0.001; d=0.77–0.84). MT and TM did not differ significantly at any defocus level (all p>0.017).
Conclusions
Bilateral trifocal implantation provided superior near visual performance, while simulated partial monovision maintained equivalent intermediate and distance vision and offered better visual acuity beyond the 0.0 D focal point (+0.50/+1.00 D). These results support PMV as a viable alternative to bilateral trifocal implantation, with a trade-off limited to near visual acuity at high defocus levels while preserving the full intermediate and distance range.