The Open Ophthalmology

: Purpose: This study aimed to compare the clinical outcomes of the AcrySof PanOptix intra-ocular lens and AT LISA tri 839MP trifocal IOL, 6 months after cataract surgery. Patients


INTRODUCTION
The advances in intraocular lens (IOL) technology have made cataract surgery a refractive procedure. Intraocular lens day-to-day affairs, the intermediate vision has become a concern for optical manufacturers. Thus, new models of trifocal IOLs were recently developed to address intermediate vision with a third focal point, while maintaining good far and near vision [3 -7].
Efforts have additionally been made to overcome other limitations of bifocal IOL designs, such as loss of contrast sensitivity or photic phenomena. However, unwanted visual effects, most notably halos and glares, remain a limitation for multifocal IOLs [3 -7]. Further, visual acuity might not reflect the quality of vision (QOL), owing to the fact that it does not always correspond to other visual aspects. These include photopic phenomena, contrast issues and performance of the IOL in different daily activities. Hence, patients with better acuity may perceive themselves at a disadvantage. Achieving uncorrected optimal visual outcomes with excellent quality of vision remains the aim of lens surgery [8 -10].
Data on the visual performance of the AcrySof PanOptix diffractive IOL (Alcon Laboratories, Inc.) with its newly introduced intermediate focus (60 cm rather than 80 cm) and its comparison with other diffractive IOLs is limited [11 -16]. The aim of this study was to compare the objective and subjective clinical performances of PanOptix AcrySof and AT LISA tri 839MP intraocular lenses, six months after cataract surgery. The parameters assessed included visual outcomes, spectacle independence, patient satisfaction and subjective visual disturbances. To the best of our knowledge, this is the first study of its kind in our region.

MATERIALS AND METHODS
This retrospective cohort study evaluated patients who underwent bilateral cataract surgery with trifocal IOL implantation was conducted in a single tertiary hospital. The lenses used in this study were Acrysof IQ Panoptix and AT LISA Tri 839MP. This study was conducted at King Fahad University Hospital (KFHU), Easter Province, Khobar, Saudi Arabia, from September 2019 to October 2020. Surgery was performed in both eyes with an interval of approximately two weeks. The patients were interviewed six months after the second eye surgery . All surgeries were performed by four surgeons, and all IOL calculations were performed using IOLMaster. Written informed consent was obtained from all patients after the objectives and protocols of the study were explained. The study was conducted in accordance with the ethical principles specified in the Declaration of Helsinki and was approved by the Institutional Review Board of KFHU.

Inclusion Criteria
Patients who sought post-operative spectacle independence after cataract surgery or refractive lens exchange.

Exclusion Criteria
Past medical and surgical histories were reviewed along with ancillary tests. Patients with previous ocular pathologies, such as glaucoma, macular degeneration and severe dry eye in whom vision-related QOL might be affected, or patients with past ocular surgeries, such as LASIK or photorefractive keratectomy, were excluded from the study. Optical coherence tomography of the macula and corneal tomography were ensured to be structurally normal and fit for non-toric trifocal IOL (corneal astigmatism <1.5 diopters, chord mu <0.5, irregular astigmatism (Root mean square) <0.3). Any patient who did not have one or both imaging modalities for any reason, at the time of the study, was repeated to ensure that all criteria had been applied. Patients with intraoperative or postoperative complications were excluded from the study.
Six months after the second eye surgery, all patients were interviewed and a complete ophthalmologic examination was conducted. They were given a questionnaire on the subjective quality of vision for daily visual activities, photic phenomena, spectacle independence and their visual satisfaction. Based on IOL model implanted, they were divided into two groups. A total of 39 patients participated in the study. All the patients received non-toric trifocal IOLs.

Study Parameters
The study parameters noted were preoperative uncorrected distance visual acuity and history of spectacle use. At the postoperative visit, the patients were examined for the following: binocular and monocular uncorrected distance visual acuity (UDVA) at 6 meters (m), uncorrected intermediate visual acuity (UIVA) at 60 and 80 centimeters (cm), and uncorrected near visual acuity (UNVA) at 40 cm. Other parameters included the incidence of posterior capsular opacification (PCO) in both eyes and with a questionnaire assessing the quality of life and visual function.

Postoperative Examination
Six months after the second eye procedure, binocular and monocular values of UDVA, UIVA, and UNVA (in decimal) were examined using Snellen's chart and recorded along with a slit-lamp examination of the anterior and posterior segments. The visual acuity was then converted into LogMAR for ease of comparison with previous studies. In addition, the incidence of posterior capsular opacification and power of the implanted IOL implanted were recorded. Quality of life and visual function were assessed using a questionnaire administered face-to-face that included photic phenomena such as the presence of dysphotopsia (halos and glare), difficulty in recognizing colours and double vision. The frequency of the photic phenomena ranged from 0 (never) to 4 (always). In addition, the patients were asked whether the photic phenomenon was bothersome. The questionnaire assessed nine visual activities at different distances, far, intermediate and near. The far activities included driving at night or during the day and watching TV. Seeing steps or climbing stairs, doing fine household work, and using a computer were considered intermediate activities, while the near activities included reading a newspaper, reading numbers using a telephone, and recognizing people when they were close. These were evaluated on a scale ranging from very bad to very good. Patients were also queried upon their spectacle independence at far, intermediate or near distances. In addition, the degree of satisfaction (very satisfied, fairly satisfied, fairly dissatisfied and very dissatisfied) about their vision, if they would recommend the same IOL to others and if they would choose it again for themselves.

Statistical Analysis
All Continuous data were presented as mean with standard deviation, median and range used for data that were not normally distributed. Significance was tested using the t-test and ANOVA for normally distributed variables, and the Mann-Whitney U test and Kruskal Wallis test were used for abnormal data. Chi-square and Fisher exact test were used to test the significance of categorical data. All analyses were performed by using SPSS version 23.0, and a value less than 0.05 was considered significant(p<0.05).

RESULTS
The demographic characteristics of 39 patients (78 eyes) included in this study are shown in ( Table 2). The age of 23 patients with the AT LISA tri 839MP IOL implant ranged from 41 years to 68 years, with a mean of 55.65 and a standard deviation (SD) of (7.1) while 16 patients with the PanOptix IOL showed a mean age and SD of 52.69 and 6.8 respectively, ranging from 41 years to 63 years. In both groups, the number of women was higher than that of men, reaching 60% in the AT LISA IOL group and 62.5% in the PanOptix group. The reason for lens surgery was a cataract in 100% of the patients in both groups. In addition, in both groups, the option of the trifocal lenses was suggested mostly by the surgeons; 65.2% for the former and 68.7% for the latter. There were no significant associations between any of the demographic variables (mean age, gander, choice of IOL by the surgeon) and the lenses used (p-value = 0.20, 0.87, 0.74, respectively). All patients underwent a pre-operative (UDVA) examination and the results were recorded ( Table 3). In the AT LISA tri 839MP IOL group, the median left and right UDVA were 0.6 and 0.5, respectively (range 0.1-0.8), while in the PanOptix group, they were almost equal at 0.55 and 0.50, respectively. The majority of the patients had no history of spectacle use before the surgery (60.9% in the AT LISA group and 62.5% in the PanOptix group). The median power of the implanted IOL was 21.5 D in the first group, with a range from 15-26 D, while in the second, the median power was 21 D, with a range from 16 to 24 D. None of the pre-operative values (left UDVA, right UDVA and glasses use) showed any significant associations with the lens type (p-values= 0.90, 0.79, 0.59 respectively). Table 3. Preoperative uncorrected distance visual acuity, history of glass uses, and IOL power. Postoperatively, the range of binocular UNVA and UIVA in both groups and the range of binocular UDVA at 6 m in the panOtix group, were 0.10 to 0.00 LogMAR. However, binocular UDVA was 0.40 to 0.00 LogMAR in the AT LISA IOL group. The median binocular UNVA and UDVA were the same in both the IOL groups at 0.00 LogMAR. The median UIVA at 60 cm was lower in the AT LISA group at 0.10 LogMAR when compared to 0.00 LogMAR of the PanOptix group. However, the median binocular UIVA at 80 cm was higher in the AT LISA group at 0.00 LogMAR when compared to the PanOptix group (0.10 LogMAR). The same values were obtained for the monocular examination on the right side. For the left side, the range of UNVA and UIVA was 0.20 -0.00 LogMAR, and the range for UDVA was 0.4 -0.00 LogMAR in the AT LISA. The range in PanOptix in all distances remained the same at 0.10 -0.00 LogMAR. The median values were 0.00 LogMAR for all categories except for UIVA at 60 cm in the AT LISA group (0.10 LogMAR) and UIVA at 80 cm in the PanOptix group (0.10 LogMAR). Neither group of IOLs had any significant associations with the UNVA, UIVA or UDVA values ( Table 4).
Postoperative ophthalmic examination for the incidence of PCO ( Through the questionnaire, photic phenomena, namely, glare and halos, difficulty in recognizing colours and double vision, were evaluated at the post-operative visit ( Table 6).
Both lenses showed similar results. The majority of the patients (39.1% and 37.5%) reported an occasional glare for both IOLs (AT LISA and PanOptix, respectively), while a minority of the patients in both groups (4.3% and 12.5%, respectively) always had glare. For halos, the majority had an occasional occurrence (43.5%) in the AT LISA group, and many (34.8%) had it often, whereas a small number (8.7%) always experienced it. On the contrary, in the PanOptix group, the majority (37.5%) experienced halos often, and 31.3% had it occasionally. A notable 12.5% had it always. Neither symptom (glare and halos), however, had a significant correlation to the IOL type (p-value=0. 8, 0.86, respectively). None of the patients had double vision using either lens. Three patients (two in the AT LISA and one in the PanOptix group) had difficulty in recognizing colour at the post-operative visit. These symptoms were found troublesome by less than 20% of the patients in either group (17.4% in AT LISA group and 18.8% in PanOptix group) with insignificant p-value (0.62).    In both groups, most of the patients did not need spectacle correction post-operatively (AT LISA, 87%; PanOptix, 93.8%). Only one patient required spectacles for distant vision in the PanOptix group and three patients (one for distance, one for intermediate and one for near) in the AT LISA group. Most of the patients were very satisfied with both lenses (AT LISA, 78.3%; PanOptix, 81.3%). One patient was fairly dissatisfied in the AT LISA group. All patients who had PanOptix IOL, approved that they would choose this IOL again or recommend it to others, while with the AT LISA, around 4% showed disapproval. The patient who was fairly dissatisfied was asked about the reason, and he reported difficulty in vision and was scheduled for Yag capsulotomy for PCO ( Table 7).
The same questionnaire subjectively evaluated the quality of vision in nine daily visual activities performed at far, intermediate or near (Table 8). The following items were included: driving (at night and during the day), watching TV, doing fine household work, using a computer, using or reading numbers in a telephone, climbing stairs, reading a newspaper and recognizing people when they are close. Most of the patients reported very good quality of vision in most visual activities. However, only 21.7% in the AT LISA group and 18.8% in the PanOptix groups reported very good quality of vision while driving at night. Moreover, it was the only visual activity reported as bad (AT LISA, 17.4%; PanOptix, 25%). PanOptix IOL showed higher subjective performance in intermediate vision when compared to AT LISA, such as using a computer and doing fine household work (62.5% and 30.4%), as well as seeing steps/climbing stairs (50% vs 39.1%). However, these values did not show any statistically significant associations with the type of lens used, similar to all other items.

DISCUSSION
Two trifocal IOLs, AcrySof PanOptix and AT LISA tri 839MP, were compared in this study. Both IOLs provided similar favorable results for most parameters. The findings of UDVA, UIVA, UNVA, spectacle independence and quality of life related to vision were close to each other in both IOL groups, and similar to findings in previous studies with an identical postoperative follow-up period [11, 12, 17 -20]. In addition, both trifocal IOLs compared in our study provided distance and near visual performance that is similar to that of bifocal IOLs, in addition to good intermediate vision [6, 10, 14, 21 -23]. Overall, it can be determined that trifocal IOLs provide acceptable visual outcomes at all three distances, far, intermediate and near [23 -25].
In a review article, the visual outcomes of different studies of PanOptix and AT LISA IOL showed good visual outcomes at all three distances. [16,15] Previous studies found that while both lenses (PanOptix and AT LISA) provided excellent binocular (≤0.1 LogMAR) distance (97.1% and 100%) and comparable near vision (82.6% and 67%) respectively, PanOptix IOL provided better visual performance at 60 cm (75.4%) than AT LISA IOL (50%) [26,27]. Despite a higher proportion (87% and 83%) of the patients in our study having excellent near vision (≤ 0.1 LogMAR), the other findings were actually similar in this study, as both IOLs gave ≤ 0.1 LogMAR visual acuity at a distance of 94% in the PanOptix group and in 87% in the AT LISA group. Additionally, intermediate vision testing depicted ≤ 0.1 LogMAR in 94% of patients with PanOptix IOL and 52% with AT LISA IOL at 60 cm. However, the reverse was true at 80 cm, as 63% of our patients with Panoptix IOL and 91% of the patients with AT LISA IOL group had visual acuity of ≤ 0.1 LogMAR. A recent study by Böhm et al. [28] included 80 patients with similar results to ours, where the visual outcomes at 60 cm (PanOptix) and at 80 cm (AT LISA) were ≤ 0.2 LogMAR. This signifies the importance of determining the preferred intermediate distance for each patient. In this study, a larger number of our patients in the Panoptix group showed better performance at intermediate activities than the AT LISA group, which included cooking (62.5% vs 30.4%) and using a computer (62.5% vs 30.4%). This might indicate that a distance of 60 cm for intermediate vision is preferred by a higher percentage of people. Although it did not show a statistically significant pvalue (0.645) as our sample size was small, it could still be clinically significant. In addition, another study established similar findings regarding the intermediate vision outcomes in both lenses, concluding that the PanOptix IOL could be a better option in patients requiring closer intermediate viewing [29].
The quality of life of the patient was assessed subjectively, in the present study, using a questionnaire enquiring about the spectacle independence, perception of photic phenomena and the ease of performing visual activities. High spectacle independence was observed in previous studies reaching up to 95% for PanOptix and 93% for AT LISA IOLs [11,14,26,30,31]. In our study, comparable percentages showed a lack of spectacle correction requirements at any distance for both types of the IOLs (PanOptix, 93.8%; AT LISA 87%).
The perception of photic phenomena is expected to be high with multifocal IOLs, ranging between 15-95%. However, these phenomena decrease with time and are not considered bothersome by most patients [11,14,30,31]. The present study reported a total photic phenomenon incidence of 87% in the AT LISA group and 82% in the PanOptix group. The incidence of glare (61.9% and 69.6%) and halos (87% and 81.2%) was similar for both IOLs, with insignificant p-values (0.80 and 0.86, respectively). However, only 17.4% of the AT LISA group and 18.8% of the PanOptix IOL group considered these symptoms significant or bothersome. Thus, most of the patients in both groups were satisfied (AT LISA, 95.7%; PanOptix, 100%), of which 78.3% in the former and 81.3% in the latter group were actually very satisfied. In a comparative study between these two IOLs, the photic phenomena were reported in 95% of the PanOptix group and 85% of the AT LISA group, which were mainly of halos [28]. These high percentages of reporting photic phenomena could be induced by the direct questioning about them, as in fact, more than 80% in each group confirmed that the symptoms were not disturbing in terms of their daily activities, with a comparably high level of satisfaction (100% and 95.7%; respectively). None of the groups had double vision in our study. This phenomenon was reported in a previous study using PanOptix IOL [16]. The lack of this occurrence in our study might be related to the small sample size.
Significantly fewer eyes developed PCO with PanOptix IOL (n=1 out of 16 (6.2%)) than with AT LISA IOL (n=4 out of 23, (17.4%)), which is consistent with the previous studies (PanOptix, 0.5%; AT LISA, 6-15%) [16]. However, the relatively high percentage of occurrence in the PanOptix IOL group in comparison to the previous studies is due to the small sample size. In addition, the low incidence rendered the pvalue in our study inapplicable between the two groups. The difference in the incidence of PCO between the two IOLs can be explained by the difference in hydrophilicity and edge design of the two IOLs. [28,31].

LIMITATIONS
This study was limited by its small sample size, which does not allow the generalizability of the results. In addition, the follow-up period was short (6 months), and the efficacy of the lenses might be different if the period was longer. Another limitation is the lack of post-operative refraction, contrast sensitivity and objective measurements of the photopic phenomena. In addition, the difference in surgical techniques among the four surgeons might render our results variable.

CONCLUSION
Both trifocal IOLs showed similar favourable visual outcomes with a low frequency and severity of photic phenomena. Additionally, spectacle independence was high and comparable in both groups at all distances. Lower risk of PCO with the PanOptix IOL was noted when compared with the AT LISA lenses. The better performance of PanOtptix IOL in activities performed at intermediate distances is most likely the result of the different intermediate add power and, subsequently, the focal point. Hence, considering the patient's own preferred intermediate distance might be crucial prior to making a decision regarding the choice of trifocal IOL. However, further studies with a larger number of patients are recommended to confirm these outcomes.

HUMAN AND ANIMAL RIGHTS
No animals were used in this research. All human research procedures followed were in accordance with the ethical standards of the committee responsible for human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2013.

CONSENT FOR PUBLICATION
Informed consent was obtained from the participants.

STANDARDS OF REPORTING
STROBE guidelines were followed.

AVAILABILITY OF DATA AND MATERIALS
The data supporting the findings of this study are available from the corresponding author [M.F], upon reasonable request.

FUNDING
None.