Comparison of visual performance outcomes following PanOptix and symfony ZXR00 intraocular lens implantation using the area under the distance-corrected defocus curve

Abstract

Purpose

This study aimed to compare visual performance, defined and quantified as the visual acuity reserve through the area under the distance-corrected defocus curve (AUC), along with visual acuity at discrete distances and modulation transfer function (MTF), following implantation of PanOptix TFNT00 trifocal and Symfony ZXR00 extended depth-of-focus intraocular lenses (IOLs).

Methods

This prospective study included patients, with only one eye per patient studied, who underwent cataract extraction with PanOptix or Symfony IOL implantation between May 2023 and May 2024 at Chongqing Aier Eye Hospital, China. Clinical data were collected at 3 months postoperatively. The total AUC (ST: 0.5D to -3.0D) and partial AUCs for distance (SD, + 0.5 to -0.5 D), intermediate (SI, -0.5 to -2.0 D), and near (SN, -2.0 to -3.0 D) ranges were calculated from distance-corrected defocus curves. Corrected visual acuity at discrete distance and MTF were also assessed.

Results

A total of 69 participants (69 eyes) were included, with 36 in the PanOptix group and 33 in the Symfony group. ST and SD did not differ significantly between groups. SI was greater in the Symfony group (P = 0.029), whereas SN was greater in the PanOptix group (P = 0.005). PanOptix achieved better near visual acuity (P < 0.001), while the best corrected distance visual acuity (BCDVA) and MTF values were similar. Postoperative refraction was more myopic in the Symfony group (P < 0.001).

Conclusions

Defocus curve area analysis effectively delineated the distinct performance profiles of the two IOLs, with Symfony favoring intermediate and PanOptix favoring near vision.

Trial registration

MR-50-25-076077, July 1, 2022.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-026-04663-6.

Introduction

The advent of presbyopia-correcting intraocular lenses (IOLs) in cataract surgery has yielded substantial benefits for patients with presbyopia, leading to their widespread adoption in clinical practice. Various design philosophies have facilitated the continuous emergence of an array of innovative presbyopia-correcting IOLs [1–3]. Therefore, the assessment of IOL performance against comprehensive and appropriate criteria is crucial. Traditional monofocal IOLs offer a single focal point, rendering them inadequate for near vision tasks and necessitating reading glasses, which is inconvenient. With technological advancements, multifocal IOLs now provide clear distance and near vision, reducing patients’ reliance on spectacles and increasing their acceptance [4–7]. First-generation bifocal IOLs improved near vision but had drawbacks such as suboptimal intermediate vision, discontinuous vision range, and optical interference, posing challenges to patients’ daily activities [8, 9].

Symfony ZXR00 and PanOptix TFNT00 are two novel IOLs used in clinical practice. Both utilize diffractive technology but stem from distinct design philosophies. Symfony ZXR00 employs extended depth of focus (EDOF) technology, whereas PanOptix TFNT00 is based on trifocal technology. Both IOLs have demonstrated favorable clinical outcomes and attracted substantial interest from ophthalmic communities worldwide [10–13].

Previous assessments of presbyopia-correcting IOLs have relied primarily on metrics such as distance, intermediate, and near visual acuity; MTF values; contrast sensitivity; defocus curves; and the severity of optical interference [1, 14, 15]. However, most of these metrics gauge visual acuity at single or multiple discrete points within varying visual ranges, making it difficult to capture the true continuous and dynamic shifts in visual acuity.

While defocus curves provide visual acuity at discrete dioptric intervals, comparing overall performance across a functional range remains challenging. To address this, the area under the defocus curve (AUC) has been proposed as a composite metric to quantify aggregate visual performance over a specified defocus range [16–18]. Crucially, this AUC should be distinguished from the area under the receiver operating characteristic (ROC) curve used in diagnostic model evaluation. A related and validated concept is ‘visual acuity reserve’, calculated as the AUC between the defocus curve and a defined acuity demand threshold, summarizing the surplus visual capacity for a given task across distances [17, 19]. Building upon this methodology, our study employed a modified AUC analysis of distance-corrected defocus curves to directly compare the continuous visual performance profiles of two prevalent presbyopia-correcting IOLs with different optical designs: the trifocal PanOptix and the EDOF Symfony. We hypothesized that this AUC analysis would provide a nuanced, quantifiable comparison complementing traditional point-measurement visual acuity outcomes.

Therefore, this study employed AUC analysis of defocus curves to compare the postoperative visual performance of the PanOptix and Symfony IOLs. Visual performance was evaluated multidimensionally, including visual acuity reserve (AUC), alongside traditional metrics of discrete distance visual acuity and optical quality (MTF). The objective was to deliver a quantifiable and clinically relevant comparison to guide IOL selection.

Methods

Study design and participants

This prospective study consecutively enrolled patients who underwent cataract extraction with subsequent implantation of either ALCON PanOptix trifocal or TECNIS Symfony extended depth-of-focus intraocular lenses between May 2023 and May 2024 at Chongqing Aier Eye Hospital, China. Data from only one eye per patient were analyzed. Uniform inclusion and exclusion criteria were applied to both groups. The inclusion criteria were as follows: (1) patients with age-related cataracts; (2) patients expressing a desire for spectacle independence; (3) axial length 22.0–28.0 mm; and (4) lens nuclear hardness classified as grade I–IV according to Emery grading. The exclusion criteria were as follows: (1) corneal astigmatism exceeding 1.0 D; (2) coexisting corneal disease, retinal disease, or preoperative tear film instability impacting vision; (3) pupil diameter smaller than 2 mm under natural light or larger than 6 mm under dim light; (4) previous eye surgery; (5) impaired zonular function or posterior capsule rupture during surgery; (6) inability to cooperate with examination or adhere to the follow-up schedule; and (7) patients with incomplete data. Ocular parameters were measured using the IOL Master 700 (Carl Zeiss, Germany). IOL power was calculated using the Barrett Universal II formula with a target of emmetropia. Ultrasound phacoemulsification with IOL implantation was performed on all patients by the same experienced surgeon. All surgeries were completed successfully without complications such as anterior capsule tears or posterior capsule rupture. No cases of posterior capsule opacification were reported within 3 months postoperatively.

Intraocular lenses

TECNIS Symfony (Johnson & Johnson, New Brunswick, New Jersey, USA) is an EDOF IOL that employs Echelette diffraction grating and chromatic aberration correction technologies [20]. These features help maintain superior average vision within a 1.5 D defocus range, enhancing the depth of focus across the entire defocus curve by approximately 1.0 D. Its design facilitates high luminous transmittance, with about 92% of light reaching the retina, supporting overall retinal image quality.

The AcrySof IQ PanOptix Trifocal IOL (model TFNT00; Alcon Laboratories, Inc.) is a hydrophobic, aspheric, single-piece lens with a blue light filter. Its core optical design features a 4.5-mm diffractive zone that creates dedicated focal points for intermediate and near vision, with additive powers of + 2.17 D (for 60 cm) and + 3.25 D (for 40 cm) at the IOL plane, respectively [1]. With a 3.0-mm pupil, it distributes approximately 50%, 25%, and 25% of light to the distance, intermediate, and near foci, respectively, achieving a total light transmission of 88% [21].

Data collection and definitions

Postoperative outcomes were compared between the two groups. Corrected and uncorrected visual acuity at distance (5 m), intermediate (60 cm), and near (40 cm) ranges, along with MTF values, were assessed at the 3-month postoperative visit. MTF values were measured under photopic conditions with a 3.0-mm analysis aperture diameter using the iTrace (Tracey Technologies Corp., TX, USA). Measurements were taken across multiple spatial frequencies (5, 10, 15, 20, 25, and 30 cycles/degree), and the mean MTF value across this range was calculated for analysis. Intraocular pressure and postoperative inflammation were monitored at 1 day, 1 week, 1 month, and 3 months after surgery. A Visual Quality Questionnaire was distributed to assess subjective visual outcomes, focusing on the frequency and severity of postoperative visual symptoms (e.g., glare, halos), with additional items evaluating overall satisfaction with visual quality across different distances at 1month, and 3months after surgery. Defocus curves under distance-corrected conditions were generated by starting with the patient’s distance-corrected visual acuity, beginning with + 0.50 D and incrementally adding negative lens power in 0.50 D steps up to − 3.0 D (equivalent to 33 cm).

The AUC was computed by drawing line segments between adjacent points on the curve and perpendiculars to the x-axis to form trapezoids [17]. The area of each trapezoid represents the AUC between two points. The sum of these areas yielded the total AUC (Fig. 1). The AUC was calculated as: AUC = 1/2 (y₀ + y₁) Δx + 1/2 (y₁ + y₂) Δx +., where y = 0.3 - visual acuity (logMAR), and Δx = 0.5.

Fig. 1.

Method of calculating the area under the curve

A threshold of 0.3 logMAR was used to define the “range of clear vision”, which also serves as the visual criterion for obtaining a motor vehicle driver’s license in most European and American states [22, 23]. The total AUC (ST, + 0.5 to -3.0 D) and partial AUCs for distance (SD, + 0.5 to -0.5 D), intermediate (SI, -0.5 to -2.0 D), and near (SN, -2.0 to -3.0 D) ranges were calculated and compared. AUCs within the clear vision range were recorded for both IOL types.

Statistical analysis

SPSS 19.0 statistical software (IBM Corp., Armonk, NY, USA) was used. Data normality was tested using the Shapiro–Wilk test. Two independent-sample t-tests were used for normally distributed data, and the Mann–Whitney U-test for non-normally distributed data. A P value < 0.05 indicated statistical significance.

Results

A total of 69 participants (69 eyes, 33 right eyes [OD] and 36 left eyes [OS]) were included, with 36 in the PanOptix group and 33 in the Symfony group. All postoperative data were collected from one eye per participant. The cohort comprised 36 men and 33 women, with a mean age of 65.71 ± 9.71 years. The mean axial length was 24.30 ± 1.67 mm, with corneal curvature values of K1 44.15 ± 1.70 D and K2 44.84 ± 1.74 D, and a mean corneal astigmatism of 0.66 ± 0.27 D. The anterior chamber depth averaged 3.23 ± 0.39 mm. The mean pupil diameter was 2.74 ± 0.34 mm under photopic conditions and 4.82 ± 0.71 mm under scotopic conditions. Among the eyes included in the analysis, 38 were dominant eyes and 31 were non-dominant eyes, with the distribution being similar between the two IOL groups (Table 1).

Table 1.

Basic characteristics of the participants

Parameter	Total (n = 69)
Eye
OD	33
OS	36
Sex
Male	36
Female	33
Age (year)	65.71 ± 9.71
Axial length (mm)	24.30 ± 1.67
K1 (D)	44.15 ± 1.70
K2 (D)	44.84 ± 1.74
Corneal astigmatism (D)	0.66 ± 0.27
Anterior chamber depth (ACD, mm)	3.23 ± 0.39
Pupil diameter (light, mm)	2.74 ± 0.34
Pupil diameter (dark, mm)	4.82 ± 0.71
Dominant eyes	38
Non-dominant eyes	31

Abbreviations: ACD, anterior chamber depth; K1, flat keratometry; K2, steep keratometry; OD, oculus dexter (right eye); OS, oculus sinister (left eye)

The postoperative distance-corrected defocus curves showed that PanOptix presented a bifocal curve, whereas the Symfony curve gradually declined at -1.5 D. The defocus range achieving 0.3 logMAR visual acuity was from + 0.5 D to -3.0 D for PanOptix and from + 0.5 D to -1.75D for Symfony. ST did not differ significantly between groups (0.584 ± 0.250 vs. 0.549 ± 0.160, P = 0.480), nor did SD (0.243 ± 0.100 vs. 0.243 ± 0.050, P = 0.979). SI was significantly greater in the Symfony group (0.279 ± 0.090 vs. 0.223 ± 0.120, P = 0.029), whereas SN was significantly greater in the PanOptix group (0.143 ± 0.090 vs. 0.088 ± 0.060, P = 0.005) (Figs. 2 and 3; Table 2).

Fig. 2.

Defocus curves for the PanOptix (TFNT00) group and the symfony (ZXR00) group 3 months after surgery

Fig. 3.

AUC for the PanOptix (TFNT00) group and the symfony (ZXR00) group 3 months after surgery

Table 2.

Comparison of the area under the defocus curve of patients with distant vision correction in the two groups 3 months after surgery

	PanOptix (n = 36)	Symfony (n = 33)	P value
ST	0.584 ± 0.250	0.549 ± 0.160	0.480
SD	0.243 ± 0.100	0.243 ± 0.050	0.979
SI	0.223 ± 0.120	0.279 ± 0.090	0.029
SN	0.143 ± 0.090	0.088 ± 0.060	0.005

Abbreviations: ST (+ 0.5D to -3.0D), total area under the defocus curve; SD (+ 0.5D to -0.5D), distance range area; SI (-0.5D to -2.0D), intermediate range area; SN (-2.0D to -3.0D), near range area

Monocular BCDVA at 5 m did not differ significantly between groups at 3 months (logMAR,0.039 ± 0.053 vs. 0.040 ± 0.071, P = 0.922). Distance-corrected intermediate visual acuity (DCIVA) at 60 cm was significantly better in the Symfony group (logMAR,0.005 ± 0.073 vs. 0.072 ± 0.062, P < 0.001). However, distance-corrected near visual acuity (DCNVA) at 40 cm was better in the PanOptix group (logMAR,0.220 ± 0.085 vs. 0.111 ± 0.089, P < 0.001) (Table 3).

Table 3.

Comparison of postoperative corrected visual acuity between the two groups 3 months after surgery

	Symfony (n = 33)	PanOptix (n = 36)	P value
BCDVA (5 m)	0.039 ± 0.053	0.040 ± 0.071	0.922
DCIVA (60 cm)	0.005 ± 0.073	0.072 ± 0.0619	< 0.001
DCNVA (40 cm)	0.220 ± 0.085	0.111 ± 0.089	< 0.001

Abbreviations: BCDVA, best corrected distance visual acuity (5 m); DCIVA, distance-corrected intermediate visual acuity (60 cm); DCNVA, distance-corrected near visual acuity (40 cm)

MTF values were not significantly different between groups (PanOptix: 0.491 ± 0.140 vs. Symfony: 0.519 ± 0.110, P = 0.343). Postoperative refraction differed significantly, with the Symfony group being more myopic (Symfony: − 0.490 ± 0.490 D vs. PanOptix: 0.110 ± 0.350 D, P < 0.001) (Table 4).

Table 4.

Comparison of postoperative MTF and refractive outcomes between symfony and PanOptix TFNT00 IOLs 3 months after surgery

	Symfony (n = 33)	PanOptix (n = 36)	P value
MTF	0.519 ± 0.11	0.491 ± 0.140	0.343
Postoperative refraction (Equivalent spherical)	-0.490 ± 0.490 D	0.110 ± 0.350 D	< 0.001

Abbreviations: modulation transfer function, MTF

Based on the postoperative satisfaction questionnaire, approximately 20% of patients in both groups reported experiencing glare and halos(Fig. 4), but none indicated that these symptoms significantly impaired night driving. No statistically significant difference was observed in visual adverse symptoms between the two IOL groups (Table 5). And no marked intergroup difference was observed in satisfaction with distance or intermediate vision; however, patients in the PanOptix group reported significantly higher satisfaction with near vision than those in the Symfony group (Table 6).

Fig. 4.

glare and halos for the PanOptix (TFNT00) group and the Symfony (ZXR00) group 3 months after surgery

Table 5.

The results of questionnaire regarding visual adverse symptoms (For unilateral or bilateral implantation study Eyes) 3 months after surgery

		Symfony (n = 33)	PanOptix (n = 36)	P
Frequency
Glare	None	24	28	0.986
	Mild	6	6
	Moderate	1	2
	Severe	0	0
	Very severe	0	0
Halos	None	23	29	0.550
	Mild	6	5
	Moderate	2	2
	Severe	0	0
	Very severe	0	0
Ghosting	None	31	36	1.0
	Mild	0	0
	Moderate	0	0
	Severe	0	0
	Very severe	0	0
Diplopia	None	31	36	1.0
	Mild	0	0
	Moderate	0	0
	Severe	0	0
	Very severe	0	0
Hazy vision	None	30	25	0.408
	Mild	0	9
	Moderate	1	0
	Severe	0	0
	Very severe	0	0
Visual Distortion	None	30	36	0.281
	Mild	1	0
	Moderate	0	0
	Severe	0	0
	Very severe	0	0
Impaired Color/ Depth Perception	None	30	36	0.281
	Mild	1	0
	Moderate	0	0
	Severe	0	0
	Very severe	0	0
Difficulty with Night Vision	None	31	34	0.186
	Mild	0	1
	Moderate	0	1
	Severe	0	0
	Very severe	0	0

Table 6.

The results of questionnaire regarding satisfaction, spectacle dependence (For unilateral or bilateral implantation study Eyes) 3 months after surgery

		Symfony (n = 33)	PanOptix (n = 36)	P
Frequency
Distance	Very satisfied	30	36	0.281
	Satisfied	1	0
	Neutral	0	0
	Dissatisfied	0	0
	Very dissatisfied	0	0
Intermediate	Very satisfied	30	36	0.281
	Satisfied	1	0
	Neutral	0	0
	Dissatisfied	0	0
	Very dissatisfied	0	0
Near	Very satisfied	16	28	0.017
	Satisfied	12	8
	Neutral	2	0
	Dissatisfied	0	0
	Very dissatisfied	1	0
Watching TV	Never	33	36	1.00
	Occasionally (<50%)	0	0
	Sometimes (50%)	0	0
	Often (>50%)	0	0
	Always	0	0
Using a computer	Never	33	36	1.00
	Occasionally (<50%)	0	0
	Sometimes (50%)	0	0
	Often (>50%)	0	0
	Always	0	0
Reading print / cell phone	Never	22	34	0.01
	Occasionally (<50%)	8	2
	Sometimes (50%)	1	0
	Often (>50%)	0	0
	Always	0	0

Discussion

This study revealed distinct performance profiles for the two presbyopia-correcting IOLs. PanOptix TFNT00 achieved a significantly greater near visual acuity reserve (SN), whereas Symfony ZXR00 demonstrated a significantly greater intermediate reserve (SI). No significant differences were detected in total (ST) or distance (SD) reserves, and MTF values were comparable.

The defocus curve of the PanOptix IOL in our cohort did not exhibit the bifocal peaks, some studies showing similar curve morphology in some trifocal cohorts [20, 24], with the second peak appearing slightly lower than the first peak. This morphology may be attributed to factors such as the cohort’s pupil size, effective neural adaptation, and potentially enhanced IOL centration achieved through femtosecond laser-assisted cataract surgery [25]. Our findings align with and extend previous understanding. Consistent with prior reports, Symfony demonstrated an advantage in the intermediate functional range, while PanOptix excelled in the near range [26, 27]. The core innovation of our analysis lies in quantifying these differences using visual acuity reserve. This metric is calculated as the AUC of the distance-corrected defocus curve relative to a functional threshold. The AUC methodology for analyzing defocus curves was first introduced by Buckhurst et al. [28]. We applied and extended this approach by building upon the validated visual acuity reserve framework subsequently established by Lapid-Gortzak et al. [19]. Unlike traditional metrics—such as the singular depth-of-focus (DOF) value which obscures design nuances, or defocus curves which only provide acuity at discrete points [22, 29]—the AUC provides a single, holistic index. It incorporates the entire curve’s morphology and height, effectively quantifying performance across a continuous functional range. Therefore, maintaining adequate visual acuity reserve is essential for supporting fluent functional vision across intermediate to near distances.

Regarding optical quality, the comparable MTF values between the two groups suggest that both IOLs achieve a similar upper limit of optical performance under distance-corrected conditions. This is supported by previous studies reporting no significant difference in distance MTF between the PanOptix and Symfony [30, 31]. In the present study, the MTF results are consistent with the comparable BCDVA, indicating that the key difference between the IOLs lies not in peak distance image quality, but in the distribution of light across the extended focal range. The postoperative myopic refraction observed in the Symfony group may be associated with the absence of an individualized A-constant adjustment. Due to its EDOF design, a slight myopic shift has a limited impact on uncorrected distance visual acuity while effectively shifting the defocus curve, thereby potentially enhancing satisfaction with intermediate vision [13].

Subjective outcomes in our cohort, assessed via a symptom-focused questionnaire, indicated that approximately 20% of patients in both groups experienced glare and halos, though none reported significant impairment in night driving. A lower incidence of self-reported hazy vision was noted in the Symfony group, which may be attributed to its diffractive design featuring fewer and wider rings, potentially affecting light distribution differently than the trifocal design of PanOptix [9, 32]. At the 1-month postoperative follow-up, two patients in the PanOptix group reported significant symptoms of hazy vision and stated that they would not choose the same trifocal IOL again for their second eye. By the 3-month visit, the hazy vision had markedly improved in both cases. This transient symptom was considered likely related to individual differences in the rate of neural adaptation.

Using binocular visual acuity data can introduce variability due to individual differences in binocular fusion, thereby obscuring the assessment of visual quality, dynamic vision, and the continuous range of vision achieved with functional IOL implantation. We reasoned that ocular dominance (dominant vs. non-dominant eye) would not substantially affect monocular optical performance measurements under controlled testing conditions, as the primary outcome relies on the inherent optical quality of the implanted IOL. Therefore, postoperative monocular visual acuity was assessed, further minimizing variability from individual differences in binocular fusion and providing a more accurate evaluation of the IOLs’ optical performance.

In conclusion, the optical designs of contemporary premium IOLs are highly refined, making subtle clinical distinctions challenging. The visual acuity reserve (AUC) methodology employed here addresses this gap. By providing a quantifiable metric that summarizes performance across a functional vision range, it complements traditional acuity measurements and MTF. This approach can furnish surgeons with additional, objective data to inform personalized IOL selection based on a patient’s specific visual lifestyle demands.

Study limitations

This study has several limitations. First, the relatively small sample size may reduce statistical power. While significant differences were found in intermediate and near performance, the risk of Type II errors remains for other parameters (ST, SD, MTF) where no differences were observed. Second, the collection of unilateral postoperative data precludes the assessment of binocular visual performance, which is the functional state in daily life. Consequently, critical patient-reported outcomes such as spectacle independence and binocular dysphotopsia could not be fully evaluated, representing a significant shortcoming. Third, the follow-up period was limited to 3 months. Although sufficient for visual acuity stabilization, it does not capture long-term outcomes such as the potential impact of posterior capsule opacification or long-term IOL stability and satisfaction. Therefore, the generalizability of our findings may be constrained. Future larger-scale studies with bilateral implantation data, longer follow-up durations, and comprehensive patient-reported outcome measures are warranted. Despite these limitations, this prospective, head-to-head comparison provides valuable insights into the distinct visual performance profiles of these two prevalent presbyopia-correcting IOLs under standardized conditions.

Conclusions

In conclusion, AUC analysis, as a metric of visual acuity reserve across a functional range, successfully differentiated the performance profiles of the PanOptix and Symfony IOLs. Symfony exhibited a greater intermediate AUC, while PanOptix showed a superior near AUC, aligning with their respective optical designs. This quantitative AUC comparison complements traditional visual acuity measurements and may aid in individualized IOL selection based on patients’ specific visual lifestyle demands.

Supplementary Information

Below is the link to the electronic supplementary material.

Abbreviations

AUC

Area under the defocus curve

ST

Total area under the defocus curve

SD

Distance area under the defocus curve

SI

Intermediate area under the defocus curve

SN

Near area under the defocus curve

MTF

Modulation transfer function

BCDVA

Best corrected distance visual acuity

IOLs

Intraocular lenses

EDOF

Extended depth of focus

OD

Right eye

OS

Left eye

PCIOLs

Presbyopia-correcting IOLs

Author contributions

Y. H.: Investigation, Data Curation. J. W.: Investigation (Supporting). Q. G.: Data Curation, Writing – Original Draft. Y. Y.: Writing – Review & Editing. J. T.: Supervision, Project Administration, Methodology.

Funding

This study was funded by Science Research Foundation of Aier Eye Hospital Group (Grant No. IIT #68347493).

Data availability

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

The study was approved by the ethics committee of Chongqing Aier Eye Hospital, China (approval number IRB2022003). All procedures complied with the Helsinki Declaration. Written informed consent was obtained from all patients prior to participation.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.