The objective in cataract surgery is not only to reach emmetropia and/or provide spectacle independence for distance, intermediate, and near vision, but also to correct astigmatism for a better refractive outcome.1–3 Multifocal intraocular lenses (IOLs) provide spectacle independence at all distances.4–6 Failing to correct the astigmatism component at the time of cataract surgery will hinder spectacle independence in the future, because we know that postoperative astigmatism of 0.50 diopters (D) or more compromises distance and intermediate visual acuities in eyes with multifocal IOLs.7–10
Astigmatism can be reduced or eliminated by a variety of surgical techniques, including selective positioning of the main incision on the steep meridian, corneal relaxing incisions, limbal relaxing incisions, excimer laser keratectomy, and toric IOLs, to achieve the best postoperative refractive outcome.11–13 However, these procedures are associated with complications, such as limited predictability, dry eye, and wound healing complications.14–16 Toric IOL implantation is another option for the correction of corneal astigmatism in patients with cataract.8,17 Patients who have a corneal astigmatism of more than 0.50 D and wish to correct presbyopia can choose a toric multifocal IOL.
The PanOptix is one example of a toric multifocal IOL that is made for the dual function of simultaneously correcting refractive errors such as myopia, hyperopia, and astigmatism while providing high visual performance at all distances, with its non-toric version providing particularly good visual acuity at intermediate distances.18
The aim of our study was to evaluate the visual outcomes and patient satisfaction after implantation of a toric trifocal IOL with quadrifocal technology 3 months postoperatively in patients with cataract and corneal astigmatism who wished to achieve spectacle independence.
Patients and Methods
This prospective study included patients 3 months after bilateral femtosecond laser phacoemulsification and implantation of a toric trifocal IOL with quadrifocal technology (AcrySof IQ PanOptix toric; Alcon Research LLC).
Enrollment of Participants
The study was conducted from April 26, 2017 to September 17, 2019 and was consistent with the tenets of the Declaration of Helsinki and in compliance with Good Clinical Practice, including International Harmonization Guidelines. The Department of Ophthalmology at Goethe University in Frankfurt, Germany, received ethical approval prior to enrollment and patients signed an informed consent form.
The study enrolled 50 eyes of 25 patients consecutively after bilateral femtosecond laser phacoemulsification and implantation of the toric trifocal IOL (TFNT20-60, AcrySof IQ PanOptix). The surgeries were all performed under topical anesthesia by the same experienced surgeon (TK). All study participants received capsulotomy, lens fragmentation, and corneal incisions using the LenSx femtosecond laser (Alcon Laboratories, Inc) and phacoemulsification was performed using the standard ultrasound technique (Centurion Vision System; Alcon Laboratories, Inc). All patients received corneal incisions of 2.2 mm located temporally. Patients were recruited postoperatively, so the surgery was not part of the study. For IOL power calculation, the total corneal refractive power with the Pentacam (Oculus Optikgeräte GmbH) was used in combination with the Haigis formula according to the measurements of axial length, corneal power, and anterior chamber depth measured by the IOLMaster (IOLMaster 700; Carl Zeiss Meditec) in all cases. Additionally, surgically induced astigmatism of 0.25 D was considered.
The inclusion criteria were a bilateral cataract surgery or refractive lens exchange with implantation of the toric trifocal PanOptix IOL, total corneal refractive power (anterior and posterior astigmatism) greater than 0.75 D measured with the Pentacam (Oculus Optikgeräte GmbH), and a signed informed consent form. Patients were excluded from the study in case of previous ocular surgeries, ocular pathologies, and a reduced endothelial cell count.
The AcrySof IQ PanOptix (Toric) TFNT20-60 is a hydrophobic acrylic, single-piece toric foldable IOL with a diffractive, aspheric, and blue-light filtering trifocal design. The IOL has an anterior aspheric and posterior toric surface with an overall diameter of 13 mm and an optical zone of 6 mm. The diffractive principle of the PanOptix IOL provides four focal distances (Distance: ∞, extended intermediate at 120 cm, preferred intermediate at 60 cm, and near at 40 cm). The light at the extended intermediate focal point (120 cm) is redistributed to the distance focal point (4 m) for amplified performance in the distance. This novel optical design creates a new fourth focal point at 120 cm (quadrifocal technology), but it is not directly accessible to the patient because it is redirected to the distance.
Patients were examined 3 months after the second eye surgery to investigate the visual outcome and patient satisfaction.
The examination at the 3-month postoperative visit included manifest refraction using the 100% contrast Early Treatment Diabetic Retinopathy Study (ETDRS) chart under photopic light conditions (167 cd/m2), as well as monocular and binocular uncorrected distance (UDVA) and distance-corrected (DCVA) visual acuity at far (4 m), intermediate (80 cm, 60 cm), and near (40 cm) distance, given in logMAR units (ETDRS). The visual acuity in 60 cm was measured by means of the 40 cm chart and converted afterward. Binocular contrast sensitivity was measured under photopic, mesopic (0.167 cd/m2), and mesopic with glare lighting conditions using the “Frankfurt-Freiburg Contrast and Acuity Test System.”19 Furthermore, an examination of the anterior and posterior eye segment by means of a slit lamp and tomography (Pentacam) was performed postoperatively. A defocus curve (monocular and binocular) was tested from −5.00 to +2.00 D in 0.50-D steps under photopic lighting conditions (ETDRS). Additionally, the patients were tested with a vision analyzer (Carl Zeiss Meditec), which simulated halos and glare on a scale of 0 to 100 (Visual Analog Scale) in size and intensity.20
Finally, all patients completed a short quality of vision questionnaire that covered four categories: the presence of visual disturbances or photopic phenomena (glare, halos, double vision, ghosting, color perception, and distorted vision); visual lifestyle activities (driving at day, driving at night, theatre/concert, watching television, at home, cooking, using a computer/musical instrument, domestic work, and reading a newspaper); spectacle independence for distance, intermediate, and near vision; and overall satisfaction (“Would you choose this IOL again?”). The response rating scale for the visual disturbances and the spectacle independence was either yes or no. For lifestyle activity items, a scale of 1 (very good) to 6 (very bad) was used. This questionnaire is a summarized version of one used by Kohnen et al21 previously. The visual disturbance questions and lifestyle activities were based on a survey distributed in the U.S. Food and Drug Administration clinical trials (Alcon Laboratories, Inc; AcrySof IQ ReSTOR, physician labelling, 2009) and subscales of the National Eye Institute Visual Functioning Questionnaire-25.22 The spectacle independence questions were similar to those in the modified Cataract Type Specification quality of life instrument.23
Sample size calculation was conducted using a minimal mean difference of 0.15 logMAR between preoperative and postoperative distance visual acuity values and an assumed standard deviation of 0.2 logMAR of the pairwise differences based on another study by our study team.18
If 21 patients are included in the study, then the assumed difference can be demonstrated with the one-sample t test with a power of 90%. To compensate for a non-normal distribution of the values and for possible drop outs, it was planned to include 25 patients in this study.
Data are presented as the mean ± standard deviation. The statistical analysis was performed using Microsoft Excel 2016 (Microsoft Corporation) and SPSS Statistics (version 26; IBM Corporation) software.
The mean patient age was 60 ± 10.3 years (range: 36 to 74 years) and 68% (17 of 25 patients) were female. Cataract surgery was performed in 18 patients and a refractive lens exchange in 7 patients. The mean lens power was +18.73 ± 5.07 D (range: 9.50 to 32.00 D) and the target refraction was −0.01 ± 0.127 D. The IOL models PanOptix TFNT20 (16 eyes) and TFNT30 (24 eyes) were implanted in 40 eyes and higher cylinder power models TFNT40 (2 eyes), TFNT50 (5 eyes), TFNT60 (3 eyes) were implanted in 10 eyes. Spherical equivalent changed from −1.77 ± 3.845 D (range: −10.00 to +4.00 D) preoperatively to +0.12 ± 0.380 D (range: −1.125 to +1.00 D) 3 months postoperatively. A total of 88% of the eyes showed a spherical equivalent between −0.50 and +0.50 D (Figure 1A). Refractive cylinder was −1.22 ± 0.994 D (range: 0.00 to 4.00 D) preoperatively and −0.21 ± 0.237 D (range: 0.00 to 1.00 D) 3 months postoperatively. A significant decrease in refractive cylinder was observed postoperatively (P < .05), with 98% showing a postoperative astigmatism below 0.75 D (Figure 1B). In 49 of the eyes, the lens rotation 3 months postoperatively was 5° or less. Just one eye showed a difference of 7° in comparison to the implanted axis. No lens needed to be rotated until 3 months postoperatively.
(A) Accuracy of spherical equivalent (SEQ) and (B) refractive cylinder of the toric AcrySof IQ PanOptix intraocular lens (Alcon Research LLC) and (C) comparison of uncorrected (UDVA) versus corrected (CDVA) distance visual acuity at 3 months postoperatively (50 eyes). D = diopters
The monocular UDVA 3 months after lens implantation was 0.02 ± 0.117 logMAR at 4 m, 0.08 ± 0.142 logMAR at 80 cm, 0.12 ± 0.107 logMAR at 60 cm, and 0.10 ± 0.111 logMAR at 40 cm. Monocular DCVA was −0.05 ± 0.095 logMAR at far distance, 0.10 ± 0.127 and 0.14 ± 0.109 logMAR at intermediate distance (80 and 60 cm, respectively), and 0.05 ± 0.129 logMAR at near distance. None of the patients lost a line in monocular distance visual acuity 3 months after lens implantation (Figure 1C).
Binocular UDVA was −0.06 ± 0.100 logMAR at 4 m, 0.05 ± 0.100 logMAR at 80 cm, 0.11 ± 0.086 logMAR at 60 cm, and 0.02 ± 0.097 logMAR at 40 cm. Binocular DCVA was −0.11 ± 0.086 logMAR at far distance, 0.02 ± 0.099 and 0.11 ± 0.093 logMAR at intermediate distance (80 and 60 cm, respectively), and 0.00 ± 0.093 logMAR at near distance.
Cumulative monocular UDVA and DCVA are shown in Figure 2. The results showed 43 eyes (86%) with a monocular UDVA of 0.10 logMAR or better and all 50 eyes (100%) with a DCVA of a minimum of 0.3 logMAR at 3 months postoperatively (Figure 2A). A total of 45 eyes (90%) at 80 cm and 50 eyes (100%) at 60 cm showed an uncorrected intermediate visual acuity of at least 0.2 logMAR (Figures 2B–2C). Additionally, at 60 cm all eyes (100%) reached an uncorrected intermediate visual acuity of better than 0.125 logMAR (Figure 2C). All eyes had a monocular distance-corrected near visual acuity of a minimum of 0.3 logMAR and 44 eyes (88%) had a monocular uncorrected near visual acuity of 0.2 logMAR or better. A monocular uncorrected near visual acuity of at least 0.1 logMAR (Figure 2D) was achieved in 72% of the cases (36 of 50 eyes).
(A) Cumulative uncorrected (UDVA) and corrected (CDVA) distance visual acuity at (A) 4 m distance, (B) 80 cm distance, (C) 60 cm distance, and (D) 40 cm distance (in logMAR) of the toric AcrySof IQ PanOptix intraocular lens (Alcon Research LLC) at 3 months postoperatively (n = 50 eyes). UIVA = uncorrected intermediate visual acuity; DCIVA = distance-corrected intermediate visual acuity; UNVA = uncorrected near visual acuity; DCNVA = distance-corrected near visual acuity
The best results of the monocular defocus curve were −0.03 and 0.04 logMAR with defocus of 0.00 and −2.00 D, which simulate the 4 m and 50 cm distances. Furthermore, the monocular defocus curve showed a visual acuity of 0.07 logMAR with −2.50 D, which represents the 40 cm distance. The lowest peak (0.11 logMAR) of monocular defocus curve (between +0.50 and −2.50 D) was seen with −1.00 D, which marks the 1 m distance. Furthermore, between −1.50 and −2.00 D, which mimic the 67 and 50 cm distances, the intermediate visual acuity ranged from 0.07 to 0.04 logMAR, respectively (Figure 3).
Monocular and binocular defocus curves of the toric AcrySof IQ PanOptix intraocular lens (Alcon Research LLC) at 3 months postoperatively (50 eyes). D = diopters
The peaks (−0.09 and 0.00 logMAR) of binocular defocus curve were seen with 0.00 and −2.00 D, whereas the lowest value of 0.04 logMAR was recorded with −1.00 D (for the range of +0.50 to −2.50 D). If we look at the intermediate range of visual acuity, the binocular defocus curve illustrates a value of −0.02 logMAR at −1.50 D (67 cm), 0.00 logMAR at −2.00 D (50 cm), and 0.04 logMAR at −2.50 D (40 cm) (Figure 3).
The contrast sensitivity measured under photopic, mesopic, and mesopic with glare lighting conditions was 1.40 ± 0.40, 0.88 ± 0.14, and 0.79 ± 0.13 logCSWeber, respectively. In comparison to the non-toric version of the PanOptix IOL,18 the PanOptix toric IOL showed similar results (Figure 4). Both lenses showed slightly worse contrast sensitivity compared to an aspheric IOL.19
Contrast sensitivity (CS) of the toric AcrySof IQ PanOptix intraocular lens (IOL) (Alcon Research LLC) in comparison to the nontoric PanOptix IOL and an aspheric monofocal IOL in three different light conditions at 3 months postoperatively.
All 25 patients participated in a survey about the optical quality of vision. They were asked to rate their quality of uncorrected vision for daily routine tasks on a scale of 1 (very good) to 6 (very bad). The mean score for all daily activities was 1.97 ± 0.22. The mean score was 1.92 ± 0.68 for far distance, 2.02 ± 0.27 for intermediate distance, and 2.12 ± 0.97 for near distance activities. Additionally, the patients were asked about the presence of optical phenomena: 19 of 25 (76%) reported halos, 52% (13 of 25 patients) glare, 16% (4 of 25 patients) starbursts, 8% (2 of 25 patients) ghosting, and 8% (2 of 25 patients) distorted vision. The results of the vision analyzer (Carl Zeiss Meditec) showed a halo size of 22.5 ± 21.98 with an intensity of 15.0 ± 12.62 and a glare size of 11.0 ± 11.09 with an intensity of 9.1 ± 8.44. A total of 80% (20 of 25 patients) of the patients reported spectacle independence and 88% (22 of 25 patients) would recommend the IOL to others. No adverse or serious adverse events occurred during the study.
The goal of the toric PanOptix IOL is to provide patients who have corneal astigmatism with good vision in far, intermediate, and near distance by correcting the refractive errors, including astigmatism. In line with other studies on multifocal IOLs,6,18,24,25 in our study the toric PanOptix IOL showed good uncorrected monocular visual acuity results at far (0.02 ± 0.117 logMAR), intermediate at 80 cm (0.08 ± 0.142 logMAR) and 60 cm (0.12 ± 0.107 logMAR), and near (0.10 ± 0.111 logMAR) distance. The same was found for binocular vision (−0.06 ± 0.100, 0.05 ± 0.100, 0.11 ± 0.086, and 0.02 ± 0.097 logMAR, respectively). Interestingly, the results of the mean visual acuity at 80 cm intermediate vision were better than at 60 cm despite the focal point shift of the PanOptix IOL from 80 to 60 cm. Cumulative visual acuity showed that all patients had a visual acuity of 0.1 logMAR or better in 60 cm in comparison to 80 cm, where the variation of visual acuity was larger and 72% had a visual acuity of 0.1 logMAR or better.
A prior study on the POD Toric FineVision,26 another toric multifocal IOL, showed an uncorrected distance visual acuity of 0.04 ± 0.02 logMAR, which is comparable to the toric PanOptix results of our study (0.02 ± 0.117 logMAR). The same can be said about the intermediate and near visual acuity at 80 and 40 cm, where the toric FineVision IOL showed 0.17 ± 0.02 logMAR (80 cm) and 0.10 ± 0.07 logMAR (40 cm) and 0.10 ± 0.127 logMAR (80 cm) and 0.05 ± 0.129 logMAR (40 cm) for the toric PanOptix. Finally, the rotational stability showed good results in both toric multifocal IOLs (POD toric FineVision 1.65 ± 0.89°, toric PanOptix 2.02 ± 1.65°). Rementería-Capelo et al27 showed that the visual acuity was comparable to the non-toric version of the PanOptix IOL.
The results of contrast sensitivity of the toric PanOptix showed similar results compared to the non-toric version and the AT LISA trifocal IOL6 in mesopic (toric PanOptix 0.88 logCS, PanOptix 0.91 logCS, and AT LISA tri 0.96 logCS) and mesopic with glare (toric PanOptix 0.78 logCS, PanOptix 0.86 logCS, and AT LISA tri 0.98 logCS) conditions. Compared to an aspheric monofocal IOL28 (Tecnis Z9000) (1.71 logCS), all multifocal IOLs had lower contrast sensitivity values in all light conditions (Figure 4) (toric PanOptix 1.40 logCS, PanOptix 1.55 logCS, and AT LISA tri 1.58 logCS).
In the survey about quality of vision, the patients reported good quality in daily life activities (1.97 ± 0.22). This is in line with prior publications of the same study team about multifocal IOLs (non-toric PanOptix18 2.0 ± 0.42 and AT LISA tri6 1.98 ± 1.07). Quality of vision at far distance was rated best (1.92 ± 0.68) but even in intermediate and near distances the mean values were good with just slight differences (2.02 ± 0.27, 2.12 ± 0.97). The best quality of vision indicated by the patients was in driving a car (daytime), cooking, watching television, and domestic work (mean: 1.5 to 1.8). The lowest score was reported for driving at night (3.14 ± 1.44), which is similar to the results of the non-toric PanOptix (3.0 ± 1.31) and AT LISA tri (3.4 ± 1.4) IOLs and other studies on optical quality of vision of multifocal IOLs.29,30 In line with other studies on multifocal IOLs, mesopic and scotopic light conditions lead to lower quality of vision results because of the high prevalence of optical phenomena as pupils are larger than in photopic light conditions. A total of 88% (22 of 25 patients) reported the presence of optical phenomena, which was comparable to other multifocal IOLs.6,8,18,31 A total of 76% of patients (19 of 25 patients) reported halos, 52% (13 of 25 patients) had glare, and just a few had starbursts, ghosting, and distorted vision. Although the patients reported optical phenomena, they were not disturbed that much. However, prior studies showed that the complaints associated with optical phenomena often decrease over time due to the process of neuroadaptation.32–35 A total of 80% (20 of 25 patients) of the patients were spectacle independent and 88% (22 of 25 patients) would recommend the IOL to others. Even when taking into account that direct comparisons to prior studies must be done carefully because of the different study designs and patient populations, the toric PanOptix showed good results of visual acuity at different distances and good optical quality.
This study has a few limitations. First, the patient population is not homogenous because we included patients with cataract (18 patients) and refractive lens exchange (7 patients). These two groups have different expectations and preoperative concerns regarding the reason for surgery. This can have an influence on all subjective results of the study. Further studies should include a larger sample size for an intergroup statistical analysis. The date of study inclusion is also a limitation. The patients were asked to take part in the study after surgery, leading to a selection bias. The surgery of the second eye was done within 2 weeks after the first eye. The patients were recruited to participate in the study after the first or second IOL implantation. Finally, the number of patients included in the study is relatively low.
The toric PanOptix shows excellent visual acuity at all distances, good optical quality results at all distances, and rotational stability through 3 months of postoperative follow-up. Defocus curve demonstrated 0.11 logMAR or better visual acuity at far to near. Despite some optical phenomena as usually reported in multifocal lenses, the patients were satisfied with this toric multifocal IOL.
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