In this study we evaluated the safety, efficacy and patient satisfaction after bilateral implantation of the trifocal AT LISA tri 839MP IOL in presbyopic eyes. We focused on patients with presbyopia as published data for this sub-group of patients is scarce.
Patients who opt for IOL implantation to treat presbyopia seek spectacle-independence and optimal vision at all distances. Although these patients seek an improvement in their near and intermediate vision, they do not expect that this will be at the expense of distance visual acuity.
Preoperatively, the patients had a very high level of CDVA that was satisfactorily maintained postoperatively. In our study the change from the preoperative baseline value for CDVA was 0.01 ± 0.05 logMAR (p = 0.0478) for monocular measurements and 0.05 ± 0.07 logMAR (p = 0.002) for binocular measurements. These differences were clinically non-relevant, demonstrating the safety of the AT LISA tri 839MP IOL in maintaining a high level of postoperative CDVA.
A change in VA of 0.3 logMAR (3 lines, or 15 letters) is regarded by the NEI and FDA as being the minimum level at which visual change can be deemed clinically significant [22, 23].
Mean visual acuity results were very good and uncorrected binocular vision was equal to or less than 0.08 logMAR for the three distances. Visual acuity outcomes were consistent with previous reports on IOL implantation in presbyopic patients: Mojzis et al. with the same IOL reported binocular values of 0.05 ± 0.08 logMAR, 0.08 ± 0.10 logMAR and 0.20 ± 0.12 logMAR for far, intermediate and near vision respectively, 3 months after implantation . Fernández-García et al. reported binocular values of 0.01 ± 0.02 logMAR, 0.02 ± 0.06 logMAR and 0.04 ± 0.05 logMAR for far, intermediate and near vision respectively, 3 months after implantation of the FineVision trifocal lens . Nicula et al. reported values better than 0.00 logMAR for all three distances 1 year after implantation of the AcrySof PanOptix (Alcon) .
A prerequisite for good visual acuity is an accurate prediction and correction of the refraction errors. The accuracy between the predicted and the postoperative spherical equivalent was -0.10 ± 0.41 D, with 80.9% of the eyes within ± 0.5 D and 97.1% within ± 1.0 D of the predicted value. These results were consistent with the data recently published with the Versario 3F (Valeant Med Sp.z o.o, Warsaw, Poland) or the PanOptix (Alcon Inc., Fort Worth, USA) multifocal IOLs with, respectively, 72% and 82% of the eyes within ± 0.5 D of planned correction [25, 26].
Five patients lost one line of corrected or uncorrected distance VA following the surgery, and one lost two lines. In three patients, the loss could be attributed to posterior capsule opacification (PCO), which was clinically significant in two cases. No explanation for the loss of lines could be found for the remaining three patients. One of these patients was “somewhat” dissatisfied with their surgery, but the other two were very satisfied with the outcome and were spectacle-independent despite the loss of a line of vision. As we have noted above, a difference of less than 0.3 logMAR is not considered to be clinically significant, providing a possible explanation as to why the loss of a line of vision did not lead to dissatisfaction.
Results from the patient questionnaire highlighted the fact that presbyopic patients represent a patient group with high postoperative visual expectations. Overall patient satisfaction was very high, with 93.8% of the patients expressing satisfaction with the surgery outcomes, and 78.1% expressing complete satisfaction with their uncorrected vision following the surgery.
Questions related to near and intermediate vision showed successful restoration of visual function for those distances with more than 93% of patients stating that they had little / no difficulties in reading normal or small prints without glasses, and 87.5% stating that they had little / no difficulties in doing activities necessitating intermediate distance visual functions.
Postoperative dysphotopsia can remain a cause of patient dissatisfaction after implantation of a multifocal IOL . In our study, halos and starbursts were the two most frequently reported symptoms, followed by glare.
Other published reports suggest that dysphotopsias experienced by some patients following surgery are important factors that could limit patient satisfaction [28,29,30]. Our study found that patients were very satisfied with their daytime distance vision (96.9% no / little difficulty in carrying out normal outdoor daytime activities even without glasses, 93.1% no / little difficulty for driving at daytime) but satisfaction with mesopic vision was reduced with 65.5% of the patients expressing little / no difficulty for driving at night without glasses. The reduction of visual function in dim conditions is well documented following implantation of multifocal IOLs  and is thought to be the result of decreased contrast sensitivity [32, 33] and an increased impact of visual symptoms such as halos, glare and starbursts [34, 35].
Five patients said that they would not wish to undertake the surgery again. Three of these patients reported at least one severe dysphotopsia: starbursts were the most commonly cited. A fourth patient reported mild starbursts. These four patients also reported moderate or severe halos and glare. These translated into difficulties with night driving, severe for two patients [#1,2], and moderate or mild difficulties with close work and reading small print [#1–4].
Surprisingly, the fifth patient [#5] reported no dysphotopias and no impact on daily functioning, and reported that she is very happy [with her vision], very satisfied and completely spectacle independent, but would still refuse surgery if it were offered again. Another patient [#2], who reported severe halo and persistent starburst, maintained that he was very happy with his current vision, and was more satisfied with his current vision than his uncorrected pre-surgery vision, but would still not undertake surgery a second time. Another of the patients [#3] who reported severe visual effects, nonetheless claimed to be very satisfied with his vision, and to have an improved quality of life, but would still refuse surgery. Patient [#1] stated that his quality of life had not been affected but would not undergo surgery again. Only one patient [#4] stated that his quality of life was worse, and was dissatisfied with the outcome.
These visual symptoms are relatively common and have been reported by many authors, even if their frequency and severity vary significantly between studies [9, 36,37,38] probably due to factors such as the length of time following the surgery [17, 39, 40], the patient visual acuity level before the surgery , or the heterogeneity of the methods employed.
This study specifically addressed the safety and performance of the AT LISA tri 839MP IOL in the treatment of presbyopia. The patient population undergoing presbyopic lens exchange is younger than the cataract population and, in our opinion, additional long-term studies are necessary to further determine the long-term benefit-risk balance. One of the shortcomings of this study is its single follow-up visit. Neuroadaptation is important in the final visual perception and satisfaction following multifocal IOL implantation. In cataract patients, brain adaptation can take up to 6 months [42, 43]. Patients participating in this study were examined between 4 and 12 months post-surgery and therefore the neuroadaptation process may not have had sufficient time to fully stabilise. As visual acuity and refraction have been demonstrated to be stable from 1 month after surgery [14, 44], this limitation was however, not expected to significantly affect the main outcomes of this study.
Due to the retrospective nature of the initial part of the study (collection of baseline data), there are some gaps in the data for Spherical Equivalent (SE), Anterior chamber Depth (ACD) and UDVA. However, for SE, only 5.4% of data were missing and for ACD and UDVA, < 5% of the data were missing. Statistically, this will have no relevant impact on observations made for these values. Regarding the primary endpoints, data for all patients was available.
Another drawback is that the study was partially retrospective and therefore carries some risks of selection bias and of non-standardisation of the preoperative data. Ideally we would have been able to compare pre- and post-operative UIVA, UNVA and CDVA, but these measurements were not available for all patients. These risks were however, limited by enrolling participants according to objective inclusion and exclusion criteria defined in the protocol and by using externally monitored enrolment logs.
Another potential limitation is that patients were enrolled with a minimum preoperative CDVA of 0.2 logMAR, which is lower than in some other studies. However, patients were inspected with a slit-lamp at entry for signs of cataract, and none were observed.