Journal of Refractive Surgery

Original Article Supplemental Data

Comparison of Visual Outcomes and Patient Satisfaction After Bilateral Implantation of an EDOF IOL and a Mix-and-Match Approach

Imane Tarib, MD; Insa Kasier; Claudia Herbers, BSc; Philip Hagen, PhD; Detlev Breyer, MD; Hakan Kaymak, MD; Karsten Klabe, MD; Rafaela Lucchesi; Swetlana Teisch; Vasilios F. Diakonis, MD, PhD; Ursula Hahn, BSc; Höhn Fabian, MD; Florian T. A. Kretz, MD, FEBO

Abstract

PURPOSE:

To evaluate visual outcomes at different distances (near, intermediate, and far), depth of focus, optical quality, quantitative dysphotopsia, and patient satisfaction in two groups.

METHODS:

The extended depth of focus (EDOF) only group (n = 40 eyes) was implanted bilaterally with an EDOF intraocular lens (IOL) and the mixed group (n = 40 eyes) was implanted with the same EDOF IOL in the dominant eye and a trifocal IOL in the fellow eye. At the 3-month postoperative visit, refractive outcomes and monocular and binocular uncorrected (UDVA) and corrected (CDVA) distance visual acuities for far UDVA, CDVA, distance-corrected intermediate visual acuity (DCIVA) at 80 cm, uncorrected near visual acuity (UNVA), distance-corrected near visual acuity (DCNVA) at 40 cm, and binocular defocus curve were evaluated.

RESULTS:

The mean spherical equivalent (SE) 3 months postoperatively was −0.16 ± 0.41 diopters (D) in the EDOF only group and −0.39 ± 0.63 D in the mixed group. In the EDOF only group, binocular visual acuities were: UDVA = −0.04 ± 0.07 logMAR (20/18); CDVA = −0.04 ± 0.06 logMAR (20/18); DCIVA (80 cm) = 0.07 ± 0.19 logMAR (20/23); DCNVA (40 cm) = 0.32 ± 0.15 logMAR (20/42); and UNVA (40 cm) = 0.24 ± 0.17 logMAR (20/35). In the mixed group, binocular visual acuities were: UDVA = 0.03 ± 0.09 logMAR (20/21) (P = .08); CDVA = −0.01 ± 0.07 logMAR (20/20) (P = .25); DCIVA (80 cm) = 0.24 ± 0.23 logMAR (20/35) (P = .08); DCNVA (40 cm) = 0.19 ± 0.07 logMAR (20/31) (P = .03); and UNVA (40 cm) = 0.18 ± 0.10 logMAR (20/30) (P = .37).

CONCLUSIONS:

Effective restoration of visual acuity was demonstrated in both groups, with high levels of visual quality and patient satisfaction. Better results in near visual acuity were demonstrated in the mixed group.

[J Refract Surg. 2019;35(7):408–416.]

Abstract

PURPOSE:

To evaluate visual outcomes at different distances (near, intermediate, and far), depth of focus, optical quality, quantitative dysphotopsia, and patient satisfaction in two groups.

METHODS:

The extended depth of focus (EDOF) only group (n = 40 eyes) was implanted bilaterally with an EDOF intraocular lens (IOL) and the mixed group (n = 40 eyes) was implanted with the same EDOF IOL in the dominant eye and a trifocal IOL in the fellow eye. At the 3-month postoperative visit, refractive outcomes and monocular and binocular uncorrected (UDVA) and corrected (CDVA) distance visual acuities for far UDVA, CDVA, distance-corrected intermediate visual acuity (DCIVA) at 80 cm, uncorrected near visual acuity (UNVA), distance-corrected near visual acuity (DCNVA) at 40 cm, and binocular defocus curve were evaluated.

RESULTS:

The mean spherical equivalent (SE) 3 months postoperatively was −0.16 ± 0.41 diopters (D) in the EDOF only group and −0.39 ± 0.63 D in the mixed group. In the EDOF only group, binocular visual acuities were: UDVA = −0.04 ± 0.07 logMAR (20/18); CDVA = −0.04 ± 0.06 logMAR (20/18); DCIVA (80 cm) = 0.07 ± 0.19 logMAR (20/23); DCNVA (40 cm) = 0.32 ± 0.15 logMAR (20/42); and UNVA (40 cm) = 0.24 ± 0.17 logMAR (20/35). In the mixed group, binocular visual acuities were: UDVA = 0.03 ± 0.09 logMAR (20/21) (P = .08); CDVA = −0.01 ± 0.07 logMAR (20/20) (P = .25); DCIVA (80 cm) = 0.24 ± 0.23 logMAR (20/35) (P = .08); DCNVA (40 cm) = 0.19 ± 0.07 logMAR (20/31) (P = .03); and UNVA (40 cm) = 0.18 ± 0.10 logMAR (20/30) (P = .37).

CONCLUSIONS:

Effective restoration of visual acuity was demonstrated in both groups, with high levels of visual quality and patient satisfaction. Better results in near visual acuity were demonstrated in the mixed group.

[J Refract Surg. 2019;35(7):408–416.]

Modern ophthalmology aims to tailor lens surgery outcomes according to the patient's lifestyle. Changes in daily habits from reading to more intermediate distance activities are the main reasons for the latest developments in intraocular lens (IOL) optics.1 Therefore, the patient's desire for spectacle independence after cataract extraction surgery has become an important parameter to take into consideration when choosing an IOL.2–7 The industry has developed a variety of multifocal IOLs attempting to offer full refractive correction at all distances8–13; numerous studies report comparable far distance visual acuity results between multifocal and monofocal IOLs and better near and intermediate vision with multifocal IOLs.14 However, optimal visual quality is provided only for a limited zone around the targeted foci, leaving the patient with blurred vision in between. Moreover, these patients often experience degraded night vision due to halo and glare caused by light scattering induced by the diffractive optical structure of the IOLs, poor contrast sensitivity, and optical quality.15

Today, the large range of commercially available multifocal IOLs based on different technologies allows surgeons to adopt different approaches of implantation according to patients' demands, while aiming to decrease the visual side effects these IOLs demonstrate. Trifocal IOLs have shown good visual acuity at different distances from far to near.8–12 Extended depth of focus (EDOF) IOLs have been developed to combine the advantages of both monofocal and multifocal IOLs, hence providing a wider range of focus, more spectacle independence, and reduced dysphotopsia.1,2,4,16

This prospective, randomized study compared the visual outcomes and satisfaction in patients implanted bilaterally with EDOF IOLs and patients receiving a mix-and-match approach of the same EDOF IOL in the dominant eye and a trifocal IOL in the fellow eye.

Patients and Methods

Patient Selection

This prospective, randomized, comparative study included patients who underwent either refractive lens exchange or cataract surgery in both eyes, performed by the same experienced surgeon (FTAK) between January and December 2018. A total of 40 patients (80 eyes) with a mean age of 62.9 ± 11.5 years (range: 36 to 78 years) were included in the study and were distributed into two groups evenly (20 patients per group, 40 eyes per group). Randomization was performed by sealed envelopes that were drawn and opened on the day of surgery. The mean age was 68.7 ± 9.1 years (range: 51 to 78 years) for the EDOF only group and 57.1 ± 11.2 years (range: 36 to 69 years) for the mixed group. In the EDOF only group, patients were implanted with the EDOF AT LARA 829 (Carl Zeiss Meditec, Jena, Germany) in both eyes. In the mixed group, patients were implanted with the EDOF AT LARA 829 (Carl Zeiss Meditec) in the dominant eye and the trifocal AT LISA tri 839MP (Carl Zeiss Meditec) in the non-dominant eye. The exclusion criteria were history of retinopathy or retinal surgery, irregular corneal astigmatism, regular corneal astigmatism of 1.00 diopter (D) or more, iris abnormalities, macular degeneration, neuro-ophthalmic disease, and history of ocular inflammation. All patients were informed of the study and provided a signed consent form. The study adhered to the tenets of the Declaration of Helsinki and was approved by the local ethics committee.

Patient Examination

All patients had an ophthalmological examination prior to surgery, including manifest refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuity using the Early Treatment of Diabetic Retinopathy Study (ETDRS) charts (Precision Vision, Woodstock, IL) at 5 m in logMAR, corneal tomography (Pentacam HD; OCULUS Optikgeräte, Wetzlar, Germany), slit-lamp bio-microscopy, Goldmann applanation tonometry, pupillometry, biometry using the IOLMaster 700 (Carl Zeiss Meditec), and fundus examination after pupil dilation.

The 3-month postoperative examinations included manifest refraction (sphere, cylinder, and axis), deviation from targeted refraction using the spherical equivalent, monocular and binocular UDVA and CDVA, intermediate (distance-corrected intermediate visual acuity [DCIVA] 80 cm), and near (uncorrected near visual acuity [UNVA], distance-corrected near visual acuity [DCNVA] 40 cm) distance and binocular defocus curves. Furthermore, the ocular optical quality was evaluated using the HD Analyzer (Visiometrics, Costa Mesa, CA), which has been proved to be a valid tool for such purposes.17,18 According to the user's manual,17 it is a double-pass system that gives values to assess optical quality in patients before and after cataract surgery. The modulation transfer function (MTF) cut-off represents the loss of contrast of a real scene after passing through the eye; the human eye maximum value is 60 cycles per degree (cpd), which corresponds to a visual acuity of 20/10 (−0.3 logMAR). The Objective Scatter Index (OSI) allows scattering light analysis and is considered normal when the value is between 0.5 and 1 and abnormal when the value is greater than 1. The Strehl ratio is the ratio of the maximum height of the light intensity of the point spread function of the measured eye and the height of the point spread function “diffraction limited” of an identical pupil diameter. Additionally, a subjective evaluation of photic phenomena using Halo & Glare Simulator software (Carl Zeiss Meditec) was performed. The satisfaction with the surgery outcomes was evaluated using a specific set of questions from the McAlinden Questionnaire (Table A, available in the online version of this article), which allows subjective evaluation of the perception of photic phenomena, their severity, frequency, and bothersomeness, the ability to perform daily activities without spectacles, spectacle independence in different distances, and the satisfaction with the results of the surgery.19

McAlinden Questionnairea

Table A:

McAlinden Questionnaire

Surgical Technique

All surgeries were performed under topical anesthesia through a 2-mm incision on the steep axis of the cornea. The anterior capsule was opened using either manual continuous curvilinear capsulorhexis with a diameter of approximately 5 mm, femtosecond laser–assisted capsulotomy (5 mm in diameter) (Lensar, Inc., Orlando, FL), or a precision pulse capsulotomy device (5 mm in diameter) (Mynosys cellular devices; Zepto, Fremont, CA). The clear lens extraction or cataract surgery was then performed using the Visalis 500 phaco machine (Carl Zeiss Meditec) followed by bimanual cortex peeling and capsular polishing. For the implantation, both the AT LARA and the AT LISA tri were inserted using the Bluemixs injector (Carl Zeiss Meditec) with the irrigation port and continuous balanced salt solution flow through the side port. The corneal incisions were hydrated with balanced salt solution and an antibiotic was injected intracamerally (cefuroxime). Postoperatively, all patients received a combination of antibiotic, steroid, and non-steroidal anti-inflammatory drug topical regimen three times a day for 2 weeks.

All patients underwent the surgery for both eyes 1 week apart.

All patients were seen for the regular postoperative examinations that we performed the following day and 1 week, 1 month, and 3 months postoperatively.

Statistical Analysis

Data analysis was performed using STATA software (version 13.1; Stata Corp, College Station, TX). The Student's t test for independent samples or Welch test for unequal variances was used for comparisons between groups and non-parametric comparisons were performed using the Mann–Whitney U test. Normality of data samples was evaluated by the Shapiro–Wilk test. Intergroup comparisons of categorical baseline characteristics were performed using Fisher's exact test. To detect differences in binocular defocus curves between the two groups, a two-way analysis of variance was applied. A P value of less than .05 was considered statistically significant.

IOLs

The EDOF AT LARA 829MP is an EDOF IOL based on an aspheric, aberration-neutral low-add trifocal profile. It is a single-piece, foldable hydrophilic acrylic IOL with a water content of 25% and hydrophobic surface properties. It is available in powers ranging from −10.00 to +32.00 D in increments of 0.50 D. The AT LARA has a 6-mm biconvex optic and an overall length of 11 mm, and the surface features smooth microphase technology that minimizes light scattering. The light bridge optical design with a diffractive optical pattern aims to improve vision within the interfocal distances between the far and intermediate foci. To achieve this optical design, the IOL has two focus additions of 1.90 and 0.95 D for intermediate and far-intermediate distances. It is aberration neutral and features a chromatic aberration neutral optic design.

Trifocal AT LISA 839mp

The AT Lisa tri 839MP is a preloaded IOL with a single-piece diffractive multifocal design. Its surface features the smooth microphase technology, which results in reduced sharp edges and corners on the surface of the IOL and, accordingly, less light scattering and better optical quality. It has a 6-mm biconvex optic and an overall length of 11 mm. It is a foldable hydrophilic acrylic IOL with a water content of 25% and hydrophobic surface properties. The near add is +3.33 D and the intermediate add is +1.66 D. The central 4.34 mm follows the described trifocal design, whereas the peripheral part is only bifocal. It is available in a range from 0.00 to +32.00 D in 0.50-D increments.

Results

A total of 40 patients (80 eyes) were included in the study. The preoperative spherical equivalent was 1.36 ± 1.65 D (range: −1.50 to +4.00 D) in the EDOF only group and 0.79 ± 3.95 D (range: +0.125 to +6.375 D) in the mixed group. The patients in the EDOF only group had mean values of 8.03 ± 0.24 and 7.94 ± 0.25 mm for flat (K1) and steep (K2) keratometry, respectively. Patients in the mixed group had mean values of 7.86 ± 0.36 and 7.78 ± 0.32 mm for K1 and K2, respectively.

The median IOL power in the EDOF only group was 22.00 D (range: 18.00 to 31.00 D) with a targeted refraction of −0.08 ± 0.13 D. The median IOL power in the mixed group was 23.70 D for the AT LARA and 23.42 D for the AT LISA (range: 19.00 to 31.00 D) with a targeted refraction of 0.08 ± 0.19 D in all eyes.

Mean postoperative spherical equivalent was −0.16 ± 0.41 D in the EDOF only group, with 85% of eyes within ±0.50 D and 95% of eyes within ±1.00 D (Figure 1C). In the mixed group, mean spherical equivalent was −0.39 ± 0.63 D and 60% of eyes were within ±0.50 D and 80% of eyes within ±1.00 D (Figure 2C). The mean preoperative corneal astigmatism was −0.90 ± 0.82 D and −0.61 ± 0.38 D in the EDOF only and mixed groups, respectively, and the mean postoperative corneal astigmatism was −0.60 ± 0.41 D (60% of patients within ±0.50 D and 80% within ±1.00 D) (Figure 1D) and −0.47 ± 0.31 D (65% of patients within ±0.50 D and 100% within ±1.00 D) (Figure 2D), respectively. There was no statistically significant change in corneal astigmatism due to the surgery (EDOF only group: P = .08; mixed group: P = .16).

Standard graphs for lens-based refractive surgery of the extended depth of focus (EDOF) only group (binocular implantation of EDOF intraocular lens targeted emmetropia [AT LARA 829; Carl Zeiss Meditec, Jena, Germany]). UDVA = uncorrected distance visual acuity; CDVA = corrected distance visual acuity; D = diopters

Figure 1.

Standard graphs for lens-based refractive surgery of the extended depth of focus (EDOF) only group (binocular implantation of EDOF intraocular lens targeted emmetropia [AT LARA 829; Carl Zeiss Meditec, Jena, Germany]). UDVA = uncorrected distance visual acuity; CDVA = corrected distance visual acuity; D = diopters

Standard graphs for lens-based refractive surgery of the mixed group (group 2) (extended depth of focus [EDOF] intraocular lens [AT LARA 829; Carl Zeiss Meditec, Jena, Germany] in the distance dominant eye and a trifocal IOL in the fellow eye [AT LISA tri 829; Carl Zeiss Meditec]). UDVA = uncorrected distance visual acuity; CDVA = corrected distance visual acuity; D = diopters

Figure 2.

Standard graphs for lens-based refractive surgery of the mixed group (group 2) (extended depth of focus [EDOF] intraocular lens [AT LARA 829; Carl Zeiss Meditec, Jena, Germany] in the distance dominant eye and a trifocal IOL in the fellow eye [AT LISA tri 829; Carl Zeiss Meditec]). UDVA = uncorrected distance visual acuity; CDVA = corrected distance visual acuity; D = diopters

In the EDOF only group, postoperative mean monocular visual acuities were: UDVA = 0.01 ± 0.10 logMAR (20/20), CDVA = −0.03 ± 0.07 logMAR (20/19), DCIVA (80 cm) = 0.11 ± 0.14 logMAR (20/26), DCNVA (40 cm) = 0.36 ± 0.16 logMAR (20/46), and UNVA (40 cm) = 0.25 ± 0.17 logMAR (20/36). Binocular visual acuities were UDVA = −0.04 ± 0.07 logMAR (20/18) and CDVA = −0.04 ± 0.06 logMAR (20/18). All patients achieved a UDVA and CDVA of 20/25 or better (Figure 1A), and 80% achieved a UDVA that was the same or better than preoperative UDVA (Figure 1B). The mean DCIVA 80 cm was 0.07 ± 0.19 logMAR (20/23), DCNVA 40 cm was 0.32 ± 0.15 logMAR (20/42), and UNVA 40 cm was 0.24 ± 0.17 logMAR (20/35).

In the mixed group, postoperative mean monocular visual acuities in eyes implanted with the EDOF AT LARA were: UDVA = 0.17 ± 0.12 logMAR (20/30), CDVA = 0.00 ± 0.06 logMAR (20/20), DCIVA 80 cm = 0.32 ± 0.28 logMAR (20/42), DCNVA 40 cm = 0.34 ± 0.17 logMAR (20/44), and UNVA 40 cm = 0.23 ± 0.18 logMAR (20/34); whereas eyes implanted with trifocal AT LISA tri were: UDVA = 0.11 ± 0.12 logMAR (20/26), CDVA = 0.00 ± 0.06 logMAR (20/20), DCIVA 80 cm = 0.36 ± 0.24 logMAR (20/46), DCNVA 40 cm = 0.24 ± 0.14 logMAR (20/35), and UNVA 40 cm = 0.31 ± 0.10 logMAR (20/41). Binocular visual acuities were UDVA = 0.03 ± 0.09 logMAR (20/21) and CDVA = −0.01 ± 0.07 logMAR (20/20). All patients achieved UDVA and CDVA of 20/32 or better (Figure 2A) and 80% achieved a UDVA that was the same or better than preoperative UDVA (Figure 2B). The mean DCIVA 80 cm was 0.24 ± 0.23 logMAR (20/35), DCNVA 40 cm was 0.19 ± 0.07 logMAR (20/31), and UNVA 40 cm was 0.18 ± 0.10 logMAR (20/30). Table 1 summarizes the visual acuity findings in both groups.

Visual Acuity (logMAR) Results

Table 1:

Visual Acuity (logMAR) Results

The binocular DCNVA was better in the mixed group (P = .03). The binocular defocus curves (Figure 3) showed a visual acuity of 0.3 logMAR (20/40) or better (range: −2.50 to +1.00 D) in the EDOF only group and 0.3 logMAR (20/40) or better (range:−3.00 to +1.00 D) in the mixed group. We found statistically significant differences at four defocus levels. The EDOF only group had better visual acuity at −0.50 and −0.00 D. The mixed group had better visual acuity at −2.50 and −3.00 D.

Binocular defocus curves in the extended depth of focus intraocular lens (EDOF IOL) only group (group 1) (binocular EDOF IOL AT LARA 829; Carl Zeiss Meditec, Jena, Germany) and mixed group (group 2) (Mix & Match with EDOF IOL AT LARA 829; Carl Zeiss Meditec) in the distance dominant eye, and a trifocal IOL (AT LISA tri 829; Carl Zeiss Meditec) (logMAR). D = diopters

Figure 3.

Binocular defocus curves in the extended depth of focus intraocular lens (EDOF IOL) only group (group 1) (binocular EDOF IOL AT LARA 829; Carl Zeiss Meditec, Jena, Germany) and mixed group (group 2) (Mix & Match with EDOF IOL AT LARA 829; Carl Zeiss Meditec) in the distance dominant eye, and a trifocal IOL (AT LISA tri 829; Carl Zeiss Meditec) (logMAR). D = diopters

We analyzed the occurrence of dysphotopsia with the Halo & Glare Simulator. The incidence of dysphotopic phenomena was higher in the mixed group but not statistically significantly different. Halos were perceived by 70% in the EDOF only group and 100% in the mixed group (P = .216). Glare was reported by 30% in the EDOF only group and 50% in the mixed group (P = .630).

The results showed a mean strength value of 34.44% in the EDOF only group and 39.70% in the mixed group (P = .68). In the EDOF only group, 30% of patients reported no halo or glare, 30% reported mild halo and glare, and 40% reported moderate halo and glare. In the mixed group, 75% and 25% of patients reported mild and moderate halo and glare, respectively. Figure A (available in the online version of this article) shows the minimum, maximum, and mean values for each parameter (size, intensity, and strength) for halo and glare in both groups. However, the statistical analysis did not find any significant difference between size, intensity, and strength for both halo and glare in the two groups.

Mean, minimum, and maximum values of size, intensity, and strength of (A) halo and (B) glare in the extended depth of focus (EDOF) only group (binocular EDOF intraocular lens [IOL] AT LARA 829; Carl Zeiss Meditec, Germany), and (C) halo and (D) glare in the mixed group (mixed with extended depth of focus [EDOF] IOL AT LARA 829; Carl Zeiss Meditec, Germany) in the distance dominant eye and a trifocal IOL (AT LISA tri 829; Carl Zeiss Meditec) in the fellow eye.

Figure A.

Mean, minimum, and maximum values of size, intensity, and strength of (A) halo and (B) glare in the extended depth of focus (EDOF) only group (binocular EDOF intraocular lens [IOL] AT LARA 829; Carl Zeiss Meditec, Germany), and (C) halo and (D) glare in the mixed group (mixed with extended depth of focus [EDOF] IOL AT LARA 829; Carl Zeiss Meditec, Germany) in the distance dominant eye and a trifocal IOL (AT LISA tri 829; Carl Zeiss Meditec) in the fellow eye.

Regarding the HD Analyzer results, we calculated the mean values of all eyes in the EDOF only and mixed groups separately, according to the implanted IOL, eyes implanted with the AT LARA, and eyes implanted with the AT LISA tri. In the EDOF only group, the mean MTF cut-off value was 34.79 ± 9.65 cpd, the mean Strehl ratio was 0.16 ± 0.04, and the OSI mean value was 1.76 ± 0.89. In the mixed group, the mean values for the eyes implanted with the AT LARA were MTF cut-off of 42.01 ± 6.15 cpd, Strehl ratio of 0.23 ± 0.05, and OSI of 0.82 ± 0.10, and the mean values for the eyes implanted with AT LISA tri were: MTF cut-off value of 37.69 ± 12.83 cpd, Strehl ratio of 0.22 ± 0.07, and OSI of 1.80 ± 1.14. All measurements were made for a mean pupil size of 3.4 mm. The only statistically significant difference was in Strehl ratio between the two groups (P = .008). The EDOF only group that received the same IOL bilaterally had a higher Strehl ratio than the mixed group.

Table B (available in the online version of this article) describes results for the chosen set of questions from the McAlinden Questionnaire. There were more patients reporting dysphotopsia and focusing difficulties, which they described as occurring more often, being more severe, and being bothersome in the mixed group than the EDOF only group. However, the results showed more spectacle independence in all distances in the mixed group, which was also confirmed in question 14 about the frequency of spectacle use in far, intermediate, and near distances activities, whereas fewer patients in the mixed group reported the need for spectacles compared to the EDOF only group.

Comparison of McAlinden Questionnaire ResultsComparison of McAlinden Questionnaire Results

Table B:

Comparison of McAlinden Questionnaire Results

Discussion

The primary aim of development of multifocal IOL designs was to improve visual acuity at different distances by increasing the depth of vision, thus providing patients with the most spectacle freedom possible.20 As intermediate focus became more important in daily life, one approach was the development of trifocal IOLs inducing a third focal point by a second diffractive structure reducing loss of light when compared to diffractive bifocal IOLs, thus offering a separate intermediate visual acuity.21 Another approach was to reduce the add-power of the multifocal IOL to shift the focal point closer to an intermediate distance.4–7 The recent concept of EDOF aims to enhance near and intermediate vision without compromising far distance vision, and with the least possible visual disturbances.1,2,4 The primary concern is dysphotopic phenomena because they are often reported with diffractive multifocal IOLs and are the first dissatisfaction factor that leads in some cases to the explantation of the IOL.15

The results in both groups in our study showed good refractive predictability, with a mean spherical equivalent closest to emmetropia in the EDOF only group, although no statistically significant difference was found between the mean values of spherical equivalent.

The mean binocular visual acuities were better for far and intermediate distances (UDVA, CDVA, and DCIVA 80 cm) in the EDOF only group and for uncorrected near vision UNVA 40 cm and significantly better for DCNVA 40 cm in the mixed group, according to our statistical analysis.

In a study by Pedrotti et al.22 in which the extended range of vision IOL (Tecnis Symfony IOL; Abbott Medical Optics, Santa Ana, CA) was implanted in 25 patients, the authors used a distance of 60 cm for DCIVA, which was different than the 80 cm used in the current study. Postoperative spherical equivalent was within ±1.00 diopters in 94%. In comparison, our EDOF only group achieved better spherical equivalent (95% patients within ±1.00 D). They also achieved better monocular and binocular UDVA, whereas the CDVA and DCNVA were better in the Tecnis group for monocular and binocular. In the mixed group, the spherical equivalent was less accurate, with only 80% of patients within ±1.00 D, but the mixed group had better binocular CDVA and DCNVA; the latter was probably due to the addition in the trifocal lens that provided patients with a near focus in addition to the EDOF from far to intermediate distance offered by the EDOF IOL.

In a comparative study by Ruiz-Mesa et al.23 including 68 eyes of 34 patients, 14 patients were implanted with the same Tecnis Symfony IOL compared to 20 patients with Alcon's trifocal IOL (PanOptix IOL; Alcon Laboratories, Inc., Fort Worth, TX). In our study, the binocular visual acuities of patients in the EDOF only group showed better CDVA and DCIVA 80 cm but worse DCNVA when compared to patients from both groups in this study (Tecnis Symfony and PanOptix). Results from the mixed group showed better visual acuities for DCNVA than patients implanted with the EDOF Tecnis Symfony IOL.

In another comparative study by Ruiz-Mesa et al.,24 including 20 patients in each group, the visual outcomes of the trifocal FineVision IOL (Bausch & Lomb, Rochester, NY) and the Symfony IOL were analyzed, comparing the results 1 year after surgery. The mean spherical equivalent was −0.19 ± 0.18 D and the binocular UDVA was 0.01 ± 0.02 logMAR (20/20) in the Symfony group, and the mean spherical equivalent was −0.15 ± 0.25 D and the UDVA was 0.11 ± 0.08 logMAR (20/26) in the FineVision group. We found a spherical equivalent closer to emmetropia and better UDVA in the group with the EDOF AT LARA implanted in both eyes. UDVA was better in the mixed group than in patients implanted with the trifocal FineVision in the current study.

Concerning the defocus curve, it is a representative analysis of the visual behavior of the IOLs in different levels of defocus that are equivalent to different viewing distances. We analyzed the binocular defocus curves in a comparative manner to study the extent of depth of focus with a good visual acuity in both groups. In the shape of a continuous curve in the EDOF only group and a double peak curve in the mixed group, the results of the current study indicate that the patients were able to maintain a good visual acuity at different distances, with a peak visual acuity at 0.00 D defocus in both groups, which is equivalent to far distance, and a visual acuity of 0.3 logMAR (20/40) or better over 3.50 D (range: −2.50 to +1.00 D) in the EDOF only group and over 0.004 D in the mixed group (range: −3.00 to +1.00 D). The −3.00 D defocus corresponds to a visual distance of 33.33 cm from the eye plan. This is consistent with the near addition of the trifocal AT LISA of +3.33 D. These results indicate a good range of vision across a wide range of distances in both groups, especially in the mixed group because the interval measured for near and intermediate (40 to 80 cm) vision within the study does not aim for the main foci of any of the lenses of this group. These findings showed wider ranges of focus with a good visual acuity than the binocular defocus curves in the study cited above,24 where similar ranges of −2.50 to +1.00 D with visual acuity of 0.3 logMAR (20/40) or better were achieved in both groups (bilateral Tecnis Symfony and bilateral FineVision).

We used the subjective Halo & Glare Simulator to have a better understanding of patients' dysphotopic phenomena perception in real life. The simulator shows a driving at night image in which the patients personally adjust the different parameters according to their perception in a similar situation. The simulator uses a scale of intensity and size for both halo and glare from 0 to 100, according to three types of halo (H1, H2, and H3) and two types of glare (G1, G2 “angel wings”). For intensity and size, the simulator uses a scale from 0 to 100. Patients reported higher values (median, minimal, and maximal) of size, intensity, and strength for halo and glare in the mixed group (Figure A). The strength formula that we used allows classifying the photic disturbances into four categories. In the EDOF only group, fewer patients (70%) reported halo and glare, with strength ranging from “mild” to “none” and a mean strength of 34.44%. This is lower than the mean value found in the mixed group (39.70%), in which all patients (100%) reported halo and glare. Even the strength value did not show a statistical difference between both groups; the incidence of halo and glare was still higher in the mixed group compared to the EDOF only group.

The ocular optical quality was evaluated using the HD Analyzer. The Strehl ratio allows evaluating the optical quality; the maximal value theoretically is 1. In general, for a pupil diameter of 6 mm, a healthy young human eye is approximately 0.15.17,18

The best mean values for ocular MTF spatial frequency with complete loss of contrast (MTF cut-off), OSI, and Strehl ratio were found in eyes implanted with the EDOF AT LARA in the mixed group. The results in all eyes revealed good contrast sensitivity and optical resolution, good optical quality, and considerable light scattering in eyes implanted with the trifocal AT LISA, which might explain a part of the physiopathology of the photic phenomena that were reported more in this group.

Furthermore, the analysis of answers given by patients to the McAlinden questionnaire showed high satisfaction from the surgery, the choice of IOLs, and spectacle independence in both groups. Although dysphotopsia such as halo, glare, and starburst were reported more in the mixed group, the same patients showed a superiority in spectacle independence in all distances in 90% or more. In the EDOF only group, patients did not need spectacles for far and intermediate distances in 70% or more, but 50% of the patients still needed spectacles in activities requiring near distance vision.

In a study conducted by Kretz et al.4 using the Lentis-313MF15 IOL, which is a refractive EDOF IOL with an add power of 1.50 D on the lens plane, 30 patients were bilaterally implanted, with target refraction closest to emmetropia in all 60 eyes. The monocular defocus curve revealed a functional visual acuity of 0.3 logMAR (20/40) or better over a range of more than 2.00 D. Subjective questionnaire results were collected, showing high satisfaction among all patients, with no halo or glare reported. In our study, 70% and 100% of the patients reported halo and glare at different strengths in the EDOF only and mixed groups, respectively. However, the binocular UDVA in the EDOF only group was better. Both groups in our study had better DCNVA at 40 cm and larger ranges of focus with a visual acuity of 0.3 logMAR (20/40) or better.

In a study published by Kretz et al.,16 the same EDOF IOL (AT LARA) was evaluated after binocular implantation targeting closest to emmetropia in 11 patients. They found a binocular UDVA of −0.07 logMAR (20/17) compared to a binocular UDVA in our study of −0.04 logMAR (20/18) in the EDOF only group and 0.03 logMAR (20/21) in the mixed group. They reported a binocular DCNVA (40 cm) of 0.33 logMAR (20/43), whereas our patients had a binocular DCNVA in the same distance of 0.24 logMAR (20/35) in the EDOF only group and 0.19 logMAR (20/31) in the mixed group, showing a higher degree of spectacle independence in near distances.

Our study has limitations. The optical quality assessment with the HD Analyzer only has one wavelength that does not represent the whole visible light spectrum. It gave us an overview of different optical qualities, but because the IOLs used are optimized for the visible light spectrum, a real conclusion is limited. Because our randomization resulted in different age groups, it is possible that the tear film might have influenced the optical quality measurements, which were not analyzed in this study. Also, we had a total of 10 eyes in both groups with residual spherical equivalent outside ±0.50 D for which the effect of residual refraction on the other parameters was not evaluated. In those cases, the absolute error would have been a better parameter for taking into account and describing refractive deviation from emmetropia.

Finally, the closest approach to our study design we found in the literature was conducted by de Medeiros et al.,25 who compared outcomes in patients bilaterally implanted with the trifocal PanOptix (+3.25 D near addition) to patients with a blended implantation of the EDOF Tecnis Symfony in the dominant eye and the diffractive bifocal Tecnis ZMB00 (Abbott Medical Optics) in the non-dominant eye (+4.00 D near addition). The results in the blended vision group of this study found better visual restoration across all distances and more spectacle independence, with peaks on the defocus curve of the same group in focus corresponding to near vision (−3.00 D) and intermediate/far distances (continuous enhancement from −1.50 D to highest values at 0.00 D). These results correspond to the visual acuity outcomes and spectacle independence rates found in the mixed group of the current study.

Conclusion

Both groups achieved good quality of vision, with a superiority of the EDOF only group in far and intermediate vision and better visual behavior in near distance in the mixed group. Both groups resulted in ranges of focus where patients maintained good visual acuity corresponding to extended fields of vision. However, the high rate of spectacle independence at different distances in the mixed group came at the cost of more photic phenomena, which did not seem to affect patients' satisfaction from the outcomes of the surgery.

References

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Visual Acuity (logMAR) Results

VisionUDVACDVADCIVA 80 cmDCNVA 40 cmUNVA 40 cm
EDOF only
  Monocular0.01 ± 0.10−0.03 ± 0.070.11 ± 0.140.36 ± 0.160.25 ± 0.17
  Binocular−0.04 ± 0.07−0.04 ± 0.060.07 ± 0.190.32 ± 0.150.24 ± 0.17
EDOF + Toric IOL
  Monocular
    AT LARA0.17 ± 0.120.009 ± 0.060.32 ± 0.280.34 ± 0.170.23 ± 0.18
    AT LISA0.11 ± 0.120.00 ± 0.060.36 ± 0.240.24 ± 0.140.31 ± 0.10
  Binocular
    Mix & Match0.03 ± 0.09−0.01 ± 0.070.24 ± 0.230.19 ± 0.070.18 ± 0.10

McAlinden Questionnairea

Question No. 1Question No. 2Question No. 3Question No. 9
A: How often do you experience glare?A: How often do you experience halos?A: How often do you experience starburst?A: How often do you experience focusing difficulties?
  Never  Never  Never  Never
  Occasionally  Occasionally  Occasionally  Occasionally
  Quite often  Quite often  Quite often  Quite often
  Very often  Very often  Very often  Very often
B: How severe is the glare?B: How severe are the halos?B: How severe are the starburst?B: How severe are the focusing difficulties?
  Not at all  Not at all  Not at all  Not at all
  Mild  Mild  Mild  Mild
  Moderate  Moderate  Moderate  Moderate
  Severe  Severe  Severe  Severe
C: How bothersome is the glare?C: How bothersome are the halos?C: How bothersome are the starburst?C: How bothersome the focusing difficulties?
  Not at all  Not at all  Not at all  Not at all
  A little  A little  A little  A little
  Quite  Quite  Quite  Quite
  Very  Very  Very  Very
Question No. 12Question No. 13Question No. 14
If you had to choose again, would you pick a multifocal intraocular lens again?Did the surgery offer you spectacle independence?How often do you wear glasses?
  Yes  A: Distance  A: Distance
  No    Yes    Never
  Explanation if no    No    Seldom
  B: Intermediate    Half of the time
    Yes    Most of the time
    No    Always
  C: Near  B: Intermediate
    Yes    Never
    No    Seldom
    Half of the time
    Most of the time
    Always
  C: Near
    Never
    Seldom
    Half of the time
    Most of the time
    Always

Comparison of McAlinden Questionnaire Results

Question No.EDOF OnlyMixed
1A: How often do you experience glare?
  Never30.00%30.00%
  Occasionally50.00%70.00%
  Quite often20.00%
  Very often
1B: How severe is the glare?
  Not at all30.00%30.00%
  Mild30.00%50.00%
  Moderate30.00%20.00%
  Severe10.00%
1C: How bothersome is the glare?
  Not at all40.00%40.00%
  A little40.00%50.00%
  Quite10.00%10.00%
  Very10.00%
2A: How often do you experience halos?
  Never50.00%10.00%
  Occasionally10.00%50.00%
  Quite often30.00%20.00%
  Very often10.00%20.00%
2B: How severe are the halos?
  Not at all50.00%10.00%
  Mild0.00%40.00%
  Moderate40.00%40.00%
  Severe10.00%
2C: How bothersome are the halos?
  Not at all60.00%20.00%
  A little30.00%50.00%
  Quite30.00%
  Very10.00%
3A: How often do you experience starburst?
  Never70.00%40.00%
  Occasionally10.00%50.00%
  Quite often20.00%10.00%
  Very often
3B: How severe are the starburst?
  Not at all70.00%40.00%
  Mild10.00%40.00%
  Moderate20.00%20.00%
  Severe
3C: How bothersome are the starburst?
  Not at all80.00%40.00%
  A little0.00%50.00%
  Quite10.00%10.00%
  Very10.00%
9A: How often do you experience focusing difficulties?
  Never80.00%50.00%
  Occasionally20.00%50.00%
  Quite often
  Very often
9B: How severe are the focusing difficulties?
  Not at all80.00%50.00%
  Mild20.00%40.00%
  Moderate10.00%
  Severe
9C: How bothersome are the focusing difficulties?
  Not at all80.00%50.00%
  A little20.00%30.00%
  Quite20.00%
  Very
12: If you had to choose again, would you pick a multifocal intraocular lens again?
  Yes90.00%90.00%
  No10.00%
  Not sure10.00%
13: Did the surgery offer you spectacle independence?
  B: Distance
    Yes80.00%90.00%
    No20.00%10.00%
  B: Intermediate
    Yes70.00%100.00%
    No30.00%
  C: Near
    Yes50.00%90.00%
    No50.00%10.00%
14: How often do you wear spectacles?
  B: Distance
    Never70.00%100.00%
    Seldom10.00%
    Half of the time
    Most of the time10.00%
    Always10.00%
  B: Intermediate
    Never70.00%100.00%
    Seldom10.00%
    Half of the time
    Most of the time10.00%
    Always10.00%
  C: Near
    Never50.00%90.00%
    Seldom10.00%
    Half of the time10.00%10.00%
    Most of the time20.00%
    Always10.00%
Authors

From Augentagesklinik Rheine, Rheine, Germany (IT, IK, CH, RL, ST, FTAK); the Military Teaching Hospital, Mohammed V, Rabat, Morocco (IT); the Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany (IT, IK, CH, PH, DB, HK, KK, RL, ST, HF, FTAK); the Breyer–Kaymak Klabe Augenchirugie, Düsseldorf, Germany (PH, DB, HK, KK); the Eye Institute of West Florida, Largo, Florida (VFD); OcuNet Verwaltungs GmbH, Düsseldorf, Germany (UH); and the Marienhospital, Osnabrück, Germany (HF).

Supported in part by grants from Carl Zeiss Meditec.

Drs. Hagen, Breyer, Kaymak, Klabe, and Kretz received consulting, travel reimbursement, and speaker fees from Alcon, Allergan, AlimeraSciences, AMO, Bayer, Carl Zeiss Meditec, Domilens, Ellex, Fluoron, Geuder, iOptics, LensAR, Medicem, Novartis, Oculentis, Oertli, Revision Optics, Santen, Sifi Medtech, Staar Surgical, Thea, Topcon, Visufarma, and Ziemer. The remaining authors have no financial or proprietary interest in the materials presented herein.

AUTHOR CONTRIBUTIONS

Study concept and design (FTAK); data collection (IT, IK, CH, PH, RL, ST); analysis and interpretation of data (IT, DB, HK, KK, VFD, UH, HF, FTAK); writing the manuscript (IT, IK, CH, PH, RL, ST); critical revision of the manuscript (PH, DB, HK, KK, VFD, UH, HF, FTAK); statistical expertise (HF, FTAK); supervision (FTAK)

Correspondence: Florian T. A. Kretz, MD, FEBO, Augentagesklinik Rheine, Osnabrücker Str. 233-235, 48429 Rheine, Germany. E-mail: mail@florian-kretz.de

Received: January 03, 2019
Accepted: April 15, 2019

10.3928/1081597X-20190417-02

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