Cataract surgery with the implantation of an IOL is the most commonly performed surgery in ophthalmology and the only treatment for lens opacification (Moshirfar et al. 2023; Li et al. 2024).

In the era of constantly increasing dependence on electronic devices, such as smartphones and tablets, the demand for clear intermediate and near vision has increased. Therefore, manufacturers are working toward offering a wide variety of IOLs to suit patients’ needs at affordable prices (Dell et al. 2024). With increased access to information, patients with good visual acuity are seeking to undergo cataract surgery. These patients often have a demanding lifestyle and high expectations for their postoperative visual acuity at various distances. It is important to discuss the different IOL options and the expected outcomes in terms of the use of spectacles. Moreover, phacoemulsification is becoming increasingly popular among younger individuals who have not developed a cataract but are seeking to achieve emmetropia with minimal use of spectacles. Enhanced monofocal IOLs such as Evolux™ may be a suitable choice for these patients in terms of visual outcome and cost (Dell et al. 2024).

Standard monofocal lenses provide a fixed focus at one distance. They can be calculated to achieve a focus point for either far or near vision (Li et al. 2024). Most often, patients choose to be emmetropic at a far distance and use spectacles for near vision. On many occasions, patients need a second pair of glasses for intermediate distances, ranging from 60 cm to 1 m, which can be inconvenient for many patients. In contrast, multifocal IOLs aim to provide high-quality vision at all three distances without relying on corrective eyewear. However, they may compromise optical quality, which patients experience as halos, glare, and reduced contrast sensitivity (de Silva et al. 2016; Li et al. 2024). Extended depth of focus (EDOF) IOLs achieve a continuous range of clear vision from intermediate to far distances, reducing the need for glasses compared with traditional monofocal IOLs. Additionally, they are believed to mitigate the drawbacks of multifocal IOLs, such as halos and glare (Kohnen et al. 2019; Fernández et al. 2023; Sihmar et al. 2023).

The Evolux™ enhanced monofocal IOL by the manufacturers AffaMed Therapeutics and SIFI S.p.A. is made from a hydrophobic material and has a non-diffractive profile designed to provide better intermediate vision and equivalent distance clarity compared with a traditional monofocal IOL. The optical technology of the lens provides very low dependence on pupil diameter at far and intermediate distances and similar image contrast at different pupil diameters. Moreover, Evolux™ is reported to be safe in terms of tilt, decentration, and photic phenomena, with good tolerance to residual refractive errors. This study aimed to present the clinical outcomes and patient-reported experiences after implantation of the Evolux™ IOL compared with standard monofocal and EDOFIOLs (Cano-Ortiz et al. 2024).

The novelty of the present study lies in its three-group comparative approach, directly evaluating an enhanced monofocal IOL against both standard monofocal and EDOFIOLs in the same clinical setting. In addition to distance and intermediate visual acuity, contrast sensitivity and patient-reported outcomes related to visual satisfaction, spectacle dependence, halos, glare, nighttime visual difficulties, driving difficulties, and diplopia were assessed. This objective and subjective assessment allows the clinical position of the Evolux™ IOL to be considered not only in terms of the amount of intermediate vision gained but also in terms of the potential trade-offs associated with achieving that broader range of vision.

All patients provided written informed consent for examination and treatment upon hospitalization. The information in this study was obtained through analysis of documentation from the hospitalization and follow-up examinations of the patients. The study protocol was approved by the Ethics Committee of Alexandrovska University Hospital, Sofia (No. 3/23.01.2026). This study adhered to the tenets of the Declaration of Helsinki.

This retrospective comparative study included 56 patients (67 eyes) who underwent phacoemulsification surgery for cataract with IOL implantation in the capsular bag. The inclusion criteria were uncomplicated cataract surgery, absence of any eye disease other than cataract, absence of postoperative complications, and the ability to read and understand questionnaires. All surgeries were performed by a single experienced surgeon. Patients were excluded if they had corneal astigmatism ≥ −0.50 diopters (D) or had a toric IOL implanted.

The patients were divided into three groups based on the IOL implanted. The IOL was chosen by the patients after a preoperative discussion with the surgeon. The monofocal IOL group consisted of 25 patients (29 eyes), four of whom underwent bilateral surgery. The monofocal lenses included CT Lucia 621PY by Zeiss, CT Lucia 221P by Zeiss, Alcon Clareon, Synthesis Acrylic monofocal by Cutting Edge, AcrySof IQ SN60WF, and Hoya Vivinex. The Evolux™ IOL group included 17 patients (22 eyes), with five patients undergoing bilateral surgery. The EDOFIOL group consisted of 14 patients (16 eyes), two of whom underwent bilateral surgery. The EDOF lenses used were AT LARA 829MP by Zeiss, Synthesis Plus PYPLUS by Cutting Edge, and RayOne EMV by Rayner. The surgical procedures, when both eyes were operated on, were performed 30 days apart.

All patients underwent preoperative optical biometry using the IOLMaster 700 (Carl Zeiss Meditech, Jena, Germany), and the IOL power was calculated for postsurgical refraction in the range of −0.00 to −0.25 spherical diopters for distance vision. Ophthalmological examination also included best-corrected visual acuity (BCVA), biomicroscopy, ophthalmoscopy, tonometry, optical coherence tomography (OCT), and B-scan ultrasonography.

BCVA at the far distance was evaluated with the Snellen chart calibrated at 6 m and expressed in decimal notation, where 1.0 (20/20 or 6/6) is normal vision and lower values indicate poorer vision. Visual acuity at the intermediate distance was tested with an intermediate-distance chart calibrated at 66 cm. The chart has a cord attached to it for easier distance measurement.

Surgery was performed by an experienced surgeon after administering topical anesthesia. Two corneal incisions were made at the 3 and 9 o’clock positions, and one 2.75 mm incision was made at the 12 o’clock position. The incisions were followed by the injection of ophthalmic viscosurgical devices (OVDs) using the soft-shell technique, with dispersive and cohesive OVDs in the anterior chamber (AC). Curvilinear capsulorrhexis was performed using capsulorrhexis forceps, followed by hydrodissection and phacoemulsification with the horizontal chop technique. The IOL was then implanted into the capsular bag. Patients were excluded from the study if they had intraoperative complications during any stage of the procedure.

Following cataract surgery, the patients underwent postoperative visits to assess their visual acuity and ophthalmological status on the seventh and 30^th postoperative days. All patients were administered the same topical therapy, including ofloxacin four times daily during the first week after surgery and a combination of neomycin sulfate/polymyxin B sulfate/dexamethasone 3500 IU/6000 IU/1 mg/mL four times daily for the first week, three times daily for the second week, followed by two times daily for the third week and finally once daily for the fourth week. The examination consisted of postoperative visual acuity (VA) without correction at far (6 m) and intermediate (66 cm) distances, biomicroscopy, and ophthalmoscopy. On the 30^th postoperative day, patients were given a questionnaire regarding their satisfaction with their vision with the operated eye at far and near distances, difficulties in everyday tasks, the appearance of halos, glare, diplopia, and whether they experienced any inconvenience while driving.

Quantitative variables were analyzed using the Kruskal–Wallis test for comparison of the three groups and post hoc analysis (Dunn–Bonferroni) for pairwise comparisons. The level of statistical significance was set at p < 0.05.

In total, 56 patients (67 eyes) were evaluated in this study. The participants had a mean age of 71.80 years (range 54–91 years), of whom 30 were female (53.57%).

The mean preoperative BCVA for far vision (6 m) in the monofocal group was 0.18 (ranging from hand movement to 0.5 or 20/40) and 0.25 for intermediate vision at 66 cm (ranging from hand movement to 0.6 or 20/32). For the Evolux™ IOL group, the BCVA for far distance was 0.20 (ranging from PPLC to 0.4 or 20/50) and 0.28 for intermediate distance (ranging from PPLC to 0.6 or 20/32). The EDOFIOL group showed a mean BCVA value of 0.21 at 6 m (ranging from PPLC to 0.5 or 20/40) and 0.30 at 66 cm (ranging from PPLC to 0.6 or 20/32). Table 1 presents the results.

The recruited patients had no corneal edema, Descemet’s folds, or AC inflammatory reactions on the first postoperative day. VA was evaluated again on the seventh and 30^th days after surgery, and no complications were documented during this period.

At the first follow-up, the patients in the monofocal IOL group showed a mean visual acuity at 6 m of 0.79, ranging from 0.4 (20/50) to 1.0 (20/20), with 11 of 29 eyes achieving 1.0 (20/20) vision (37.93%). The evaluation of intermediate-distance visual acuity showed a mean value of 0.53, ranging from 0.2 (20/100) to 0.8 (20/25).

The mean values for the Evolux™ IOL group were as follows: 0.80 for far distance, ranging from 0.4 (20/25) to 1.0 (20/20), with eight of 22 eyes reaching 1.0 vision (36.36%), and 0.78 for the intermediate distance of 66 cm, ranging from 0.4 (20/50) to 1.0 (20/20), with six eyes achieving 1.0 vision (27.27%).

The EDOFIOL group demonstrated a mean value of 0.81 for uncorrected VA at 6 m, ranging from 0.5 (20/40) to 1.0 (20/20), with five of 16 eyes reaching 1.0 (31.25%). The mean value for uncorrected VA at 66 cm was 0.83, ranging from 0.4 (20/50) to 1.0 (20/20), with six eyes reaching 1.0 vision (37.50%). Only two eyes had a VA of 0.4 (12.50%).

On the seventh postoperative day, there was a statistically significant difference in distance visual acuity among the three groups (Kruskal–Wallis test, p < 0.01). The EDOFIOL group demonstrated the highest VA at both distances. It showed significantly higher VA than the monofocal IOL group (p < 0.01) and results closer to those of the Evolux™ IOL group (p < 0.05).

At the second follow-up, on the 30^th postoperative day, the patients in all three groups showed improvement in VA at both distances, while others showed no improvement. None of the included patients showed worsening on examination.

The results were as follows:

The mean VA in the monofocal group was 0.80 at 6 m and 0.54 at 66 cm. The Evolux™ IOL group showed a mean VA of 0.83 for far distance and 0.79 for intermediate distance. The patients in the EDOFIOL group demonstrated a mean VA of 0.84 at 6 m and 0.93 at 66 cm. The results are presented in Table 2.

On the 30^th postoperative day, intergroup differences remained statistically significant, although with a smaller magnitude (p < 0.05).

Post hoc analysis revealed better intermediate VA with the EDOFIOL than with the Evolux™ IOL (p < 0.05) and the monofocal IOLs (p < 0.001).

On postoperative day 30, the patients in the monofocal IOL group showed a 5.06% increase in mean VA at 6 m and an 8.69% increase in mean VA at 66 cm. The percentage increase in the Evolux™ IOL group was 3.75% at 6 m and 6.76% at 66 cm. The EDOFIOL group demonstrated a 3.70% increase in VA at 6 m and a 12.05% increase in VA at 66 cm, which was the highest increase among all groups. This is likely due to neuroadaptation for intermediate distance occurring over the 30-day period while adjusting to the specific characteristics of the EDOFIOL optics (Rosa et al. 2017).

During the same examination, contrast sensitivity (CS) was evaluated using the Pelli-Robson chart. The chart was placed 1 m from the patient. The test was performed using the patient’s best-corrected visual acuity for this distance. The Pelli-Robson score quantifies the subject’s contrast sensitivity on a logarithmic scale ranging from 0.00 to 2.15. Scores of approximately 2.00 log units indicate normal CS, while lower scores indicate poorer CS.

Contrast sensitivity in all three groups ranged from 1.55 to 2.00 log units. In the monofocal IOL group, there was only one recording of 1.55 log units of CS (3.45%) and one recording of 1.70 log units. Four eyes showed 1.85 log units of CS (13.79%), and the remaining 23 eyes demonstrated a CS of 2.00 log units (79.31%).

The patients in the Evolux™ IOL group had similar results, with one eye having 1.55 log units (4.55%), two eyes having 1.70 log units (9.09%), five eyes showing 1.85 log units of CS (22.73%), and the other 15 eyes recording 2.00 log units (68.18%).

The results for the EDOFIOL group were as follows: one eye with 1.55 log units of CS (6.25%), two eyes with 1.70 log units (12.50%), nine eyes with 1.85 log units (56.25%), and the remaining four eyes with 2.00 log units of CS (25%).

On the 30^th postoperative day, patients were asked to complete a questionnaire regarding their satisfaction with their vision after surgery. They were required to evaluate their vision at far and intermediate distances without any optical correction on a scale from 0 to 10, where 0 was “very poor” and 10 was “excellent.” The patients were asked whether they experienced any glare or halos around light sources. In addition, they were required to answer “YES” or “NO” regarding whether they had any difficulties with their vision at night, experienced double vision, or had trouble driving.

Regarding visual satisfaction among patients in the monofocal IOL group, the values varied from “6” to “10” in the questionnaire. Of the 29 operated eyes, only two patients reported a value of “9” (6.90%), and one patient marked an “8” for distance vision and a “6” for intermediate vision (3.44%). The remaining patients were sufficiently satisfied to report a “10” for both their far and intermediate uncorrected visual acuity. Moreover, one patient reported noticing halos around light sources, and the same patient had difficulties driving at night. One patient stated that they had double vision, and another experienced glare.

The results in the Evolux™ IOL group were similar, with only one patient reporting a “9” for both distances (4.55%), while the others reported a “10.” Regarding halos and glare, only one patient reported experiencing glare, whereas none of the others had any complaints.

Of the 16 eyes with an EDOFIOL, one patient marked a value of “9” for VA (6.25%), while all others evaluated it as a “10.” For intermediate distance, one patient reported a “6” and another an “8.” Three patients reported photic phenomena, such as glare or halos, when looking at light sources (18.75%).

The comparative analysis demonstrated excellent post-cataract surgery results in patients who chose the Evolux™ IOL, with excellent VA at both evaluated distances. Compared with patients with a monofocal IOL, uncorrected visual acuity after surgery was significantly better with the Evolux™ IOL at the intermediate distance and similar at 6 m. Patients with an EDOFIOL showed comparable results to the Evolux™ IOL group, with slightly higher values for intermediate VA. Additionally, six patients in the Evolux™ IOL group reached a VA of 1.0 (20/20) for intermediate vision, while the best result in the monofocal group was 0.8 (20/25). Gabrić et al. (2025) conducted a study that included 81 patients (116 eyes) and found that the Evolux™ IOL demonstrated good distance vision and enhanced intermediate vision without the visual disturbances commonly associated with multifocal or EDOFIOLs.

On postoperative day 30, mean distance VA was similar among the three groups, ranging from 0.80 to 0.84. This finding is clinically relevant because improvement in intermediate vision should ideally not occur at the expense of distance visual clarity.

The difference among the groups was more pronounced at the intermediate distance of 66 cm. On postoperative day 30, the mean intermediate VA was 0.54 for the monofocal group, 0.79 for the Evolux™ group, and 0.93 for the EDOFIOL group. The Evolux™ group demonstrated a substantial improvement over conventional monofocal IOLs, while the EDOF group, as expected, achieved the highest VA at the intermediate distance. These findings are consistent with the intended optical characteristics of the IOL categories.

Patients with an EDOFIOL showed the highest percentage increase in intermediate-distance visual acuity compared with the preoperative values (210%), followed by the Evolux™ IOL group (182%). Patients with monofocal IOLs showed the lowest increase (116%). These results indicate greater spectacle independence for intermediate-distance activities in patients with the Evolux™ IOL, potentially improving their quality of life.

Visual acuity alone does not fully characterize the quality of vision after implantation of an IOL. Contrast sensitivity is important because optical strategies that extend the depth of focus may alter the distribution of light and consequently affect the ability to distinguish objects of similar luminance, especially under less favorable visual conditions.

In the present study, CS measured using the Pelli-Robson chart was generally preserved in the conventional monofocal and Evolux™ groups. A score of 2.00 log units was recorded in 79.31% of eyes in the monofocal group and 68.18% of eyes in the Evolux™ group. In contrast, only 25% of eyes in the EDOF group achieved 2.00 log units, while more than half of the EDOF eyes recorded 1.85 log units. Although the sample size limits definitive conclusions, this distribution suggests that the broader range of vision provided by EDOFIOLs may be accompanied by a reduction in contrast sensitivity.

Kohnen et al. (2019) evaluated the visual performance of an EDOFIOL. In their analysis, the EDOFIOL showed lower CS than the monofocal lenses, which is consistent with the present data. This could potentially compromise visual clarity in some patients, leading to lower satisfaction.

An important aspect of the present study was the inclusion of patient-reported outcomes. Despite the small sample, patients in all three groups generally reported high satisfaction with their postoperative vision. In terms of photic phenomena, these were most notable in the EDOF group according to the questionnaire provided. The lower frequency of photic phenomena in the Evolux™ group is consistent with its non-diffractive enhanced monofocal design. This result further supports the efficacy of the Evolux™ lens, as it offers a lower incidence of halos or glare while providing visual acuity results similar to those of EDOFIOLs.

A similar study on the performance of the Evolux™ IOL, conducted by Cano-Ortiz et al. (2024), showed results similar to those of the present study. This observational study included 18 patients and 36 eyes implanted with the Evolux™ IOL. The study showed that the evaluated IOL is a promising solution for cataract surgery, offering remarkable visual acuity at far and intermediate distances with a low incidence of photic phenomena.

The clinical relevance of the findings is not simply that Evolux™ improves intermediate visual acuity. Rather, the findings suggest a trade-off between the range of vision and visual quality across the three IOL categories. Conventional monofocal IOLs provided good distance vision but the poorest intermediate performance. EDOFIOLs provided the highest intermediate acuity but demonstrated lower contrast sensitivity and more frequent photic symptoms. Evolux™ provided intermediate visual clarity between these two strategies, with a substantial gain in intermediate VA compared with monofocal lenses while retaining contrast sensitivity and a low frequency of photic complaints.

This balance may be clinically meaningful when counseling patients about IOL selection. Not every patient requires maximal spectacle independence at all distances. Some patients prioritize excellent distance vision, good intermediate vision, and minimal photic phenomena over achieving the highest VA at near distance. For such patients, an enhanced monofocal IOL may represent an attractive alternative to an EDOF or multifocal IOL.

The economic aspect may also be relevant to clinical decision-making because enhanced monofocal IOLs may offer an alternative for patients for whom the additional cost of premium IOLs is a limiting factor.

The principal strengths of this study include the direct comparison of three clinically distinct IOL strategies and the assessment of both objective and subjective postoperative outcomes. In particular, combining distance and intermediate visual acuity with contrast sensitivity and patient-reported photic phenomena provides a more comprehensive assessment than VA alone. The use of a single experienced surgeon and standardized postoperative treatment also reduced some sources of procedural variability.

The present study offers a comprehensive analysis of objective visual acuity results and patient satisfaction with the Evolux™ IOL and provides a broad view of IOL performance. The Evolux™ IOL was shown to be a promising solution for patients undergoing cataract surgery who seek to achieve lower spectacle dependence for daily activities at an intermediate distance. The low incidence of photic phenomena and the results of the contrast sensitivity evaluation indicate that the Evolux™ IOL achieves these results with minimal compromise in the quality of vision.