The aim of this study was to determine pre-operative and post-operative factors contributing to subjective dissatisfaction following implantation of a multifocal IOL during cataract surgery. We focused on patients who had the PanOptix trifocal IOL implanted, as this is a common, high performing multifocal IOL, and one that is used frequently in our facility. Further, there have been few studies comparing objective results with subjective satisfaction post-cataract surgery.
We found patients are generally very satisfied with their trifocal IOLs. Ninety percent of patients in our study were satisfied and 79% achieved spectacle independence. These rates are similar to those found by other authors [8–10].
We were surprised to find very few pre-operative characteristics that demonstrated statistical significance on subjective satisfaction following implantation of the PanOptix IOL. Specifically, age, sex, dry eye syndrome, epiretinal membrane, prior myopic LASIK, the degree of vision impairment from the cataract, as well as the degree of refractive error demonstrated statistically insignificant differences in patient satisfaction. A study published in 2018 supports the idea that preoperative visual acuity has low predictive value on patient satisfaction [11]. Conversely, Ronbeck et al found young age, low pre-operative CDVA, and no ocular comorbidities led to significantly greater improvement in subjective visual function [12]. The only pre-operative characteristic that impacted satisfaction was having flatter preoperative keratometry. While previous studies have evaluated the impact of preoperative keratometry following LASIK, no studies have compared preoperative keratometry with patient satisfaction following cataract surgery [13]. Additionally, the rates of prior myopic LASIK were equivalent between the satisfied and dissatisfied groups, indicating that a history of myopic LASIK did not account for the flatter keratometry preoperatively. None of the patients in our study had a history of hyperopic LASIK, as our clinic does not offer multifocal IOLs to those patients.
It’s unclear why flatter keratometry is significantly correlated with dissatisfaction following cataract surgery. Several pre-existing conditions known to affect keratometry readings include dry eye, Salzmann nodular degeneration, epithelial basement membrane dystrophy, and other corneal dystrophies [14]. These disease entities are particularly detrimental when evaluating patients for multifocal intraocular lens implants [14]. There were no statistically significant differences between the number of patients with dry eye syndrome between satisfied and dissatisfied patients. Any patients with epithelial basement membrane dystrophy or other corneal dystrophies were excluded from the study.
One post-operative characteristic that demonstrated a statistically significant difference in visual satisfaction was greater cylinder on MRx post-operatively. As residual manifest astigmatism increased, patients became more dissatisfied (Table 4). Residual astigmatism has long been considered a source of dissatisfaction after implantation of a multifocal IOL [15]. Small amounts of astigmatism may limit the visual performance significantly. Carones demonstrated that multifocal IOLs correlate with a significantly greater reduction in visual acuity at the same astigmatism as monofocal IOLs [16]. It is possible that residual astigmatism has more impact on visual performance as a result of the multifocal IOL distributing light to a larger number of foci. None of the patients in our study received an astigmatism correcting PanOptix IOL as they were not offered in our clinic; instead, patients with corneal astigmatism under two diopters were either offered a monofocal astigmatism correcting IOL or a presbyopia correcting IOLs in conjunction with limbal relaxing incisions, either manually or via femtosecond laser. Patients with greater than two diopters of corneal astigmatism were not offered presbyopia correcting IOLs.
There was no significant difference in reported rates of bothersome glare or halos between satisfied and unsatisfied patients. The PanOptix IOL has been reported to cause significantly increased glare and halos compared to non-multifocal IOLs such as monofocal IOLs or enhanced depth of focus (EDOF) IOLs [10]. All patients in our clinic who are offered a multifocal IOL are educated about the likelihood that they will experience glare and halos with such a lens. Perhaps this study shows that patients are not bothered by glare and halos because the patients who would have been bothered had self-selected monofocal or EDOF IOLs. Alternatively, it may be that the PanOptix IOL does not produce as much bothersome glare or halos as we expect.
The present study has several limitations which include its retrospective design, data collection at a single center, and the small sample size. Our patient population was operated on by two different ophthalmic surgeons at the same center. Despite these limitations, this is the first study to our knowledge evaluating such a broad range of variables with patient satisfaction.
In future studies, it would be interesting to assess whether personality has an impact on patient satisfaction post-cataract surgery. One previous study shows anxiety leading up to cataract surgery has an impact on patient satisfaction post-operatively [17]. A second study found that patients with neuroticism as their dominant personality trait were the least happy with postoperative outcomes while patients with conscientiousness and agreeableness were the happiest with postoperative outcomes [18]. It would be valuable to expand on these studies to explore whether other personality traits correlate with greater subjective satisfaction and dissatisfaction postoperatively.
In conclusion, patients are generally very satisfied with their trifocal IOLs. For those dissatisfied, flatter preoperative keratometry and greater cylinder on post-operative MRx correlates with greater dissatisfaction. Additionally, higher absolute and higher than expected rates of dependence on spectacle correction may play a larger role than dysphotopsia in satisfaction.