Retrospective Outcomes and Patient Satisfaction with Previous Refractive Surgery and Multifocal Intraocular Lens Implantation

Aim: To report pre, post-surgical visual outcomes and satisfaction after cataract or clear lens surgery, with multifocal intraocular lens implantation, in patients with previous refractive surgery. Methods: Retrospective study of postoperative outcomes and satisfaction in patients with previous refractive surgery and Multifocal Intraocular Lens (MF-IOL) implantation. Preoperative variables: time LASIK performed, visual acuity, Uncorrected (UCVA) and best corrected (BCVA), Spherical Equivalent (SE), Addition (Add), SimK and pachymetry, pupillometry. Postoperative data: UCVA, BCVA, SE, and Add. Results grouped as: general, cataracts vs. clear lens (CL), segmented vs. trifocal MF-IOL, and myopes vs. hyperopes. Patients completed a satisfaction and difficulty questionnaire (Q). Data was analyzed using paired student-t test, with Bonferroni adjustment. Linear regression analysis between normally distributed preoperative variables and survey data were reported. Results: Mean results recorded for 30 eyes, mean age 52.3 ± 6.2 years; pre-LASIK SE -2.8 ± 3.8D, segmented MF-IOL in 22 eyes and 8 eyes with trifocal IOL. Pre/postoperative results: SE: -0.02 ± 2.5/-0.1 ± 0.25D, far UCVA: 0.34 ± 0.2/0.90 ± 0.1, near UCVA: 0.43 ± 0.4/1.0 ± 0.02, Add: 1.4 ± 1.2/0.2 ± 0.6D, far BCVA: 0.90 ± 0.2/0.95 ± 0.1, and near BCVA: 0.99 ± 0.04/1.0 ± 0.0. Mean Q satisfaction points (0-10): far VA: 7.5 ± 2, near VA: 8.1 ± 2.3, intermediate VA 8.1 ± 1.7. Mean questionnaire difficulty points (0-4) results were: far VA 1.3 ± 1.5, near VA 1.5 ± 1.5, halos 1.5 ± 1.6, and 94% would repeat their choice. Near vision and night driving difficulties scored higher for myopes with greater preoperative SE (R2=0.5; p=0.05 and R2=0.7; p=0.02, respectively). Conclusion: Multifocal intraocular lens implantation, in patients with previous refractive surgery, significantly improved mean near and far UCVA, and addition. Satisfaction was high and post LASIK SE correlated significantly with near vision and night driving difficulty in myopic patients.

Although reports are limited, cases could be challenging due to postoperative refractive surprises, with posterior lens exchange or laser surgery enhancement, and little is known regarding patient presurgical characteristics or postoperative satisfaction, spectacle independence, or the effect of LASIK induced corneal aberration [1,6,7].
Trifocal diffractive IOLs, like FineVision IOL (25% hydrophilic acrylic and 6.15 mm optic diameter, PhysIOL, Liége, Belgium) combine two diffraction gratings, one with +1.75D and the other with +3.5D for near vision, which truly offers trifocality during myosis [13,16]. The segmented refractive MF-IOL (Lentis Mplus ,Oculentis GmbH, Berlin, Germany) is a one-piece zonal intraocular lens with plate haptics having large aspheric distance-vision zone and a sectorshaped zone with 3.0D of near addition (Add), embedded on the posterior surface [12]. signed a written informed consent form before undergoing any surgical procedure. Medical charts were reviewed, pre and postoperative data (last visit) was recorded for analysis, and patients were later asked to fill out a satisfaction and difficulty questionnaire (Q), the cataract TyPE Spec questionnaire translated to Spanish and modified to include: General far and near vision satisfaction (0-10 points each) and difficulties (0-4 points each) for far, near, intermediate visions, halos, specific activities, and whether or not they would repeat the procedure. Patients personally filled out the questionnaire (Q), on the medical center or online [18]. Preoperative data included: time LASIK had been performed, far and near (30 cm) uncorrected visual acuity (UCVA), best corrected (BCVA; decimal scale), spherical equivalent (SE), addition (Add), topography data (SimK, corneal astigmatism, and corneal thinnest pachymetry; ORBSCAN DP-3002 model, v. 3-14; Technolas Perfect Vision, GmBH), pupillometry (Colvard, Oasis medical, Glendora, California, USA), RMS in µm (Zywave II Aberrometer v 5.2, Bausch & Lomb), and MF-IOL implanted (segmented or trifocal). Postoperative data records for far/near UCVA, BCVA, SE, and ADD followed up for at least one year. Biometry was performed by one technician, using the IOLMASTER 500 (Carl Zeiss Meditec AG, Jena, Germany), and MF-IOL power calculated with the Haigis-L formula [7].
Data was introduced on a Microsoft 2013 Excel sheet (Microsoft Corporation). Results were recorded as mean and standard deviation (SD), student t-test (with Bonferroni adjustment) used for data results comparison [19]. Bonferroni adjustment set a stricter threshold to define significance (multiplying the p-values for each of the pair-wise comparisons by the number of comparisons) and thus reducing type I error. Bonferroni correction for p ≤ 0.05 was set at p ≤ 0.002 for general and CL variables (N=30 and N=24 eyes, respectively), p ≤ 0.01 for myopic and hyperopic group variables, and p ≤ 0.003 for questionnaire variables (N=15).
Pre and post-operative results were recorded for all eyes, eyes with cataracts, and clear lens (CL) eyes. Patients were also grouped into those implanted with trifocal vs. segmented IOL, and with either hyperopic or myopic LASIK, for comparative purposes (based on pre LASIK refractive error).
The Shapiro-Wilkes normality tests run for preoperative nominal variables. Linear regression analysis for normally distributed dependent variables matched to survey data scores.
Two cataract patients (45 and 46 year old), with monocular +1.5 Add segmented IOL, and 1 clear lens patient, with bilateral +3.0 Add segmented IOL, needed additional glasses for reading or sewing (18%).  Linear regression analysis for pupil in hyperopic patients and halos difficulty points was R 2 =0.51, p=0.07 (Figure 4).

Discussion
Premium IOL implantation improves UCVA in patients with previous refractive surgery but few reports address outcomes and satisfaction in this patient group [1][2][3][4][5][6]. LASIK patients usually have no differences in VA with controls but this patient group is more prone to postoperative refractive surprise, requiring further laser enhancement, halos, and degradation in contrast sensitivity [5,12,[15][16][17].
Vega et al. provided evidence that implanting an aspheric multifocal IOL in eyes, after myopic LASIK, resulted in similar optical and visual quality to phakic myopic LASIK eyes [3]. They concluded that visual results and quality were superior to the use of a spherical MF-IOL [3]. Newer MF-IOLs, segmented and trifocal, implanted in this patient group, are effective in visual restoration, for specific cases [7][8][9][11][12][13][14][15]17].
Segmented MF-IOLs have one addition sector, which is the only area that directs light to a near focal point, thus allowing for the remainder of the optic to act as a monofocal IOL for distance vision [12]. They are more suitable for larger pupils and provides adequate VA and patient satisfaction [10,12].
We analyzed post-operative results in patients with previous refractive surgery and post MF-IOL (segmented or trifocal) implantation for cataract or presbyopia with CL. Overall, postoperative far and near UCVA improved significantly, after MF-IOL implantation (p ≤ 0.002). In this small retrospective study, 97% of previous LASIK eyes had final SE within ± 0.50D, 90% at least 0.7 far UCVA, four eyes gained postoperative BCVA (13%), and no eyes lost BCVA. These results are similar or better than other reports with MF-IOL implantation in post refractive surgery patients [4,5,15,17].
We also found no VA differences between all patients and those requiring subsequent enhancement (0.9 ± 0.12; 0.88 ± 0.13); (p>0.002). One eye (20%) lost one VA line due to herpetic leukoma, postoperatively, 4 eyes with cataract and 2 CL eyes gained VA lines. We also recorded refractive surprise on one eye (3%), which underwent uneventful MF-IOL exchange.
All cataract eyes had previously undergone myopic LASIK and we recorded significant improvement for post-operative far UCVA, p=0.001. Their post-operative Add results were not significant, probably due to the inclusion of younger patients implanted with a +1.5 Add segmented IOL and the small sample case series. Mean postoperative SE was higher to that already reported by Miyajima et al. LASIK [17].
Visual satisfaction and difficulty information are lacking for this patient group, post MF-IOL implantation for presbyopia or cataract. Satisfaction was high in patients with segmented IOLs but one point lower than patient reports with no previous corneal surgery, (>7 points for all distances vs. 8.1 points, respectively), as reported by Muñoz et al. [12]. Ninety percent of the segmented IOL group would recommend their MF-IOL choice compared to the 98% reported by Venter et al. in patients with no previous corneal surgery [9].
Gatinel et al. reported that diffractive IOL showed better near focal point resolution than segmented IOLs [16]. The trifocal group reported higher satisfaction for all VA distances compared to the segmented IOL group. We recorded higher, though non-significant, near VA satisfaction in the trifocal IOL group (p=0.04) and 100% answered they would repeat their MF-IOL selection. The fact that only 4 patients with trifocal and 11 with segmented IOL answered the questionnaire, could explain these non-significant findings, while final conclusions could be drawn when the former sample increases.
Regarding difficulty scores for daily activities, the trifocal group reported less difficulty, significant when reading supermarket labels. The latter finding may be an attributable to the superior near focus for the trifocal IOL, while segmented IOL provides less adequate near UCVA [12,16].
Halos has already been reported in 10.6% regular patients with segmented IOLs while Muñoz et al. concluded it should be expected, in a small number of patients, despite very good functional results [12,20]. In this study, sixty-three percent reported some degree of halos difficulty, particularly in patients with previous hyperopic LASIK or segmented IOL. Hyperopic patients reported higher halos difficulty scores (mean 2 ± 1.2 points) than myopes (1.3 ± 1.8 points); p=0.4, and could be explained by the fact that hyperopic LASIK correction induces greater changes in corneal asphericity, is associated to smaller effective optical zones, and slightly more third order aberrations than in myopes could explain this finding [21,22]. In addition, higher halos difficulty scores were associated to larger post LASIK pachymetry and smaller pupil size in hyperopic patients. Hyperopic LASIK treatment is peripheral and the further from the center of the cornea the more the ablation is having a different effect on each quadrant because it acts at different depths and with varying hydration along the surface [5].
A recent study concluded that, after phacoemulsification, unsatisfied patients reported worse OSDI scores and would need to determine, to what extent postoperative dry eye could also be responsible for these findings [23].
Regarding the negative correlation between pupil size and halos, Oshika et al. have reported the higher influence of coma-like aberrations on visual performance in LASIK patients with smaller pupils, and could also explain our findings [24]. This could also explain why myopic LASIK patients reported higher satisfaction, for all VA distances, and less difficulties than those with hyperopic laser treatment (p=0.08). In addition, the MF-IOL aspheric design might be contributing to improving visual quality in myopes and Alfonso et al. found no differences in corneal aberrations for patients with previous myopic LASIK implanted with diffractive IOL [2]. We found higher RMS in myopes than hyperopes (3.6 vs. 1.1 µm; p=0.3), which can be attributed to the small case sample, and aberrations will be accounted for in future studies with larger samples. Linear regression analysis concluded greater near vision difficulty was associated to higher post LASIK negative SE and sphere (R 2 =0.60 and R 2 =0.70), significant for the former (p ≤ 0.01). Bissen-Miyajima et al. concluded degradation in contrast sensitivity was greater for post-LASIK eyes with higher myopic corrections, after implantation of diffractive IOL for cataracts [17]. Although both hyperopic and myopic patients reported similar night driving difficulties (2 ± 1.8 and 1.6 ± 1.7 points, respectively; p=0.7), we can highlight that linear regression analysis showed significant association with greater post LASIK negative SE in myopes (R 2 =0.90; p=0.001). This result is consistent with a previous report associating greater night difficulties on myopic patients with higher attempted degree of LASIK corrections [25]. Pop et al. also reported no association between pupil diameter and night driving difficulties in myopes after LASIK, as our study also showed, (R 2 =0.14) [26,27].
It remains unclear whether these worsened after a MF-IOL implantation and a pre-operative questionnaire could help.
After at least 12 months, UCVA for all patients improved a mean of five lines, BCVA significantly improved in 20% of all eyes, patients are highly satisfied, 63% manifested halos or night driving difficulties, 38% near vision difficulties, and most are spectacle free. Despite scoring visual difficulties, 94% would repeat the procedure.
This study is limited due to its retrospective nature of a small sample case series, the inclusion of different MF-IOL models for clear lens and cataract patients, lack of objective intermediate VA data, no preoperative questionnaire, and need for longer post-operative followup. In addition, MF-IOLs were not chosen according to refractive error however another study reported results of implanting the same diffractive and segmental IOL in both hyperopes and myopes [28]. However, it provides us with information regarding a patient group, which will be seeking presbyopia correction with the latest premium IOLs.
Patients with previous refractive surgery and trifocal or segmented MF-IOL implantation were generally satisfied and significantly improved post-operative far and near UCVA. Post LASIK SE, in myopic patients with MF-IOL implantation, could determine postoperative visual difficulties, although further study and follow-up is required.