Purpose: We report the clinical outcomes of patients who had primary lens implantation in the capsular bag and subsequently a supplementary trifocal lens implanted in the ciliary sulcus (duet procedure) to create reversible trifocality.
Design: Retrospective interventional case series.
Methods: This single-center clinical study included 25 patients who had undergone either refractive lens exchange for presbyopia correction or cataract surgery. All had lens removal by phacoemulsification and duet procedure to achieve reversible trifocality. Preoperatively and 3 months postoperatively, uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were assessed, as well as uncorrected near visual acuity (UNVA), distance corrected near visual acuity (DCNVA), and corrected near visual acuity (CNVA). At the postoperative examination, uncorrected intermediate visual acuity (UIVA), distance corrected intermediate visual acuity (DCIVA), and corrected intermediate visual acuity (CIVA), defocus curve testing, and dysphotopsia evaluation were also performed.
Results: Monocular UDVA and CDVA improved from 0.71 ± 0.43 logarithm of the minimum angle of resolution (logMAR) and 0.12 ± 0.16 logMAR preoperatively to 0.04 ± 0.10 logMAR and −0.01 ± 0.09 logMAR postoperatively. Monocular UNVA and DCNVA were both 0.06 ± 0.08 logMAR and UIVA and DCIVA 0.00 ± 0.10 logMAR and −0.02 ± 0.10 logMAR postoperatively. Monocular defocus curve testing revealed a visual acuity of 0.2 logMAR or better from +0.75 to −3.5 diopters.
Conclusions: Duet procedure using a trifocal supplementary intraocular lens provided excellent results for far, near, and intermediate distance, comparable to those reported for capsular bag fixated trifocal intraocular lenses. The duet procedure offers the advantage of an exit strategy in cases with a future loss of function or side effects associated with the optics.
P atients wishing to be independent from spectacles can choose from a variety of presbyopia-correcting intraocular lenses (IOLs), and trifocal IOLs can offer the highest level of spectacle independence , because they are superior to monofocal IOLs at near and intermediate distances , and provide better optical quality at intermediate distance than bifocal IOLs. , Trifocal IOLs can also provide superior near visual acuity compared with the extended depth of focus IOLs. However, there are a variety of limitations to the implantation of trifocal IOLs: because of their diffractive optics, these IOLs reduce contrast sensitivity and can induce photic phenomena. Therefore, they are not recommended for patients with impaired retinal or binocular function or low individual tolerance to these side effects.
The duet procedure, in which the implantation of a capsular bag–fixated monofocal or monofocal-toric IOL is combined with a supplementary trifocal sulcus-fixated IOL, can create a trifocality that is potentially reversible.
The underlying assumption of the duet procedure is that a trifocal lens placed in the sulcus will, if it is necessary, be easier to remove (and thus be potentially less traumatic) than removing a trifocal lens fixed in the capsular bag. It can be difficult to predict in some patients their tolerance to halo, glare, and reduced contrast sensitivity, which are all potential side effects of trifocal optics, whether the IOL is located in the sulcus or the bag. In such patients, a reversible option would appear desirable. Furthermore, patients with healthy eyes at the time of surgery may develop ocular pathologies such as macular degeneration, glaucoma, or retinal detachment in the future—all of which can impair retinal function. Patients with a borderline indication for trifocal IOL implantation may benefit from the possibility of future reversibility.
Young patients with cataracts should be mentioned here, who could not only develop an ocular pathology in the course of their lives but also a change in refraction. We included several young patients with cataracts in this analysis. Patients with borderline results in binocular function testing or subtle morphologic changes of unclear significance with unimpaired function at the time of presentation also fall within this category.
In this retrospective interventional study, we report the clinical outcomes of patients who had the duet procedure to create reversible trifocality.
PATIENTS AND METHODS
PATIENTS
The local Ethics Committee of the University of Heidelberg approved this study prospectively, and it is registered on the German Clinical Trials Register (Deutsches Register Klinischer Studien; reference numbers DRKS00007837 and DRKS00011251). Informed consent for both the treatment and participation in the research was obtained. The study was conducted in accordance with the tenets of the Declaration of Helsinki.
Twenty-five patients who had either refractive lens exchange for presbyopia correction or had cataract surgery were included in this retrospective study. Each had undergone phacoemulsification and implantation of either a monofocal or monofocal-toric IOL into the capsular bag and subsequently the implantation of a supplementary trifocal IOL into the ciliary sulcus to achieve reversible trifocality. We decided to perform a duet procedure instead of the implantation of 1 capsular bag fixated trifocal or 1 trifocal-toric IOL, using, case-by-case, ≥1 of the following criteria:
- (1)
Patients with cataract at a young age might develop ocular pathologies such as glaucoma, retinal detachment, or macular degeneration in the future, even if there are no signs of such ocular pathology at the time of their cataract surgery. In case of a loss of function, the supplementary IOL could be removed relatively easily even decades after the initial cataract surgery.
- (2)
In patients with a high refractive error there is a higher risk for a deviation from the target refraction. This may lead to a considerable residual refractive error, which is one of the most important reasons for dissatisfaction after trifocal IOL implantation. , This problem can be addressed by exchanging the supplementary IOL.
- (3)
Subtle morphologic changes (eg, alterations of the retinal pigment epithelium) may provide reasons to avoid implanting a capsular bag–fixated trifocal IOL without, however, presenting a clear contraindication. If these patients do develop an ocular pathology that impairs retinal function, like macular degeneration or glaucoma, the supplementary IOL could later be rather easily explanted.
- (4)
The subjective impairment from dysphotopsia induced by trifocal optics may vary considerably between patients. Some patients are unsure about their individual tolerance of such side effects and ask for a reversible option. The patient may be counselled that a sulcus-fixated trifocal IOL may be removed in case of severe side effects that the patient cannot tolerate.
- (5)
Patients who present with equally good visual acuity on both eyes but who have a history of strabismus surgery in their childhood may have borderline binocular function and mild amblyopia. In these cases, the results after trifocal IOL implantation may not be optimal. The same applies to patients who undergo unilateral implantation of a trifocal IOL. Patients who are not satisfied with the result have the possibility to undergo the explantation of the supplementary IOL.
Table 1 shows the detailed reasons for duet procedure of all patients included in this analysis.
| Patient No. | Age (y) | Reason for Surgery | Reason for Duet Procedure | Category |
|---|---|---|---|---|
| 1 | 57 | Cataract surgery | Anisometropia, uncertainty regarding binocular function | 5 |
| 2 | 21 | Cataract surgery | Cataracta coerulea at a young age | 1 |
| 3 | 18 | Cataract surgery | Hyperferritinemia cataract syndrome at a young age | 1 |
| 4 | 63 | Refractive lens exchange | Alterations of the retinal pigment epithelium, unilateral implantation, status post-Intracor treatment on fellow eye | 3 + 5 |
| 5 | 51 | Refractive lens exchange | Alterations of the retinal pigment epithelium | 3 |
| 6 | 48 | Refractive lens exchange | Patient desired a reversible option due to uncertainty regarding individual tolerance of dysphotopsia | 4 |
| 7 | 51 | Refractive lens exchange | High hyperopia (spherical equivalent of +6.75 and +6.0 D for the right and left eye, respectively) | 2 |
| 8 | 18 | Cataract surgery | Subcapsular cataract of unknown etiology at young age | 1 |
| 9 | 78 | Cataract surgery | Patient desired a reversible option because of uncertainty regarding individual tolerance of dysphotopsia | 4 |
| 10 | 64 | Cataract surgery | Borderline retinal nerve fiber layer thickness of the temporal superior sector of the right eye and of the temporal inferior sector of the left eye | 3 |
| 11 | 55 | Cataract surgery | Status post–strabismus surgery, uncertainty regarding binocular function | 5 |
| 12 | 48 | Refractive lens exchange | Drusen of the macula, recurring episcleritis, status post–argon laser coagulation for retinal tear | 3 |
| 13 | 24 | Cataract surgery | Traumatic cataract of 1 eye at a young age, unilateral implantation | 1+5 |
| 14 | 49 | Refractive lens exchange | Alterations of the retinal pigment epithelium | 3 |
| 15 | 55 | Refractive lens exchange | Alterations of the retinal pigment epithelium | 3 |
| 16 | 61 | Refractive lens exchange | Status post–radiation therapy, dry eye syndrome with irregular astigmatism | 2 |
| 17 | 55 | Cataract surgery | Patient desired a reversible option because of uncertainty regarding individual tolerance of dysphotopsia | 4 |
| 18 | 38 | Cataract surgery | Cataracta complicata at a young age after systemic glucocorticoid treatment for rheumatoid arthritis | 1 |
| 19 | 46 | Cataract surgery | Cataracta complicata at a young age after systemic glucocorticoid treatment after kidney transplantation, status post–retinal bleeding | 1 + 3 |
| 20 | 50 | Refractive lens exchange | Patient desired a reversible option because of uncertainty regarding individual tolerance of dysphotopsia | 4 |
| 21 | 38 | Cataract surgery | Subcapsular cataract of unknown etiology at a young age | 1 |
| 22 | 64 | Cataract surgery | High myopia (spherical equivalent of −10.0 and −10.25 D for the right and left eye, respectively) | 2 + 3 |
| 23 | 55 | Cataract surgery | Binocular traumatic cataract after nose fracture, status post–strabismus surgery, anisometropia | 5 |
| 24 | 49 | Refractive lens exchange | Anisometropia, uncertainty regarding binocular function | 5 |
| 25 | 49 | Cataract surgery | High hyperopia, map-dot-fingerprint corneal dystrophy | 2 + 3 |
SURGICAL PROCEDURE
In preparation for the surgery, patients had optical biometry measured with the IOL Master 500 or IOL Master 700 (Carl Zeiss Meditec AG, Germany). Two patients underwent monocular surgery and 23 patients delayed sequential binocular surgery.
The Sulcoflex trifocal 703F IOL (Rayner Intraocular Lenses Ltd; Worthing, West Sussex, UK) was used as the supplementary IOL in all patients.
The adapted design of modern supplementary sulcus-fixated IOLs is crucial to prevent contact between the supplementary IOL and the IOL in the capsular bag or the iris tissue and thus the associated complications. The concave posterior surface ensures that there is enough space between the 2 IOLs to prevent interlenticular opacification. As the supplementary IOL is implanted proximate to the iris, the edges of the haptics and the optic are rounded to avoid pigment abrasion. To optimize uveal biocompatibility, the lens material is hydrophilic acrylate.
IOL calculation for monofocal as well as toric IOLs was performed for each case and the IOL that would cause the least amount of residual astigmatism was selected thereafter. In cases where a toric IOL would have provided no benefit, astigmatism was reduced by placing the main incision on the steep axis. The smallest amount of preoperative corneal astigmatism that was corrected with a toric IOL was −0.66 diopters (D).
The capsular bag–fixated IOL was the RayOne IOL (Rayner Intraocular Lenses Ltd) in 15 eyes, the RayOne toric (Rayner Intraocular Lenses Ltd) in 23 eyes, the Vivinex XY1 (Hoya Surgical Optics, Singapore) in 2 eyes, and the Vivinex toric XY1AT2 IOL (Hoya Surgical Optics) in 6 eyes. One patient received the Tecnis ICB00 (Johnson & Johnson, New Brunswick, NJ) in 1 eye and the Tecnis PCB00 (Johnson & Johnson) in the fellow eye.
In patients with myopia, the target refraction of the primary capsular bag–implanted IOL can be set at approximately −2.5 D to optimize the refraction for near distance in case of the removal of the supplementary IOL. We opted for this approach in 2 patients in this study. For the supplementary sulcus-fixated IOLs, the RayTrace Premium IOL calculator (Rayner Intraocular Lenses Ltd) was used in these 2 cases, targeting for emmetropia to compensate for the myopic target refraction of the primary IOL. The target refraction of the capsular bag–fixated IOL was emmetropia in the 23 other cases and a supplementary sulcus-fixated IOL with plano power was selected for these patients. For monofocal capsular bag–fixated IOLs, the Haigis formula was used for IOL power calculation. For monofocal-toric capsular bag–fixated IOLs, we used either the RayTrace Premium IOL calculator (Rayner Intraocular Lenses Ltd) for the RayOne toric IOLs or the Hoya toric calculator (Hoya Surgical Optics) for the Hoya Vivinex toric XY1AT2 IOLs.
Depending on the patient’s cost-related preference, the surgery was femtosecond laser–assisted or it was a manual procedure. All surgeries were performed by 1 of 2 experienced surgeons (G.U.A., R.K.). Postoperative treatment typically consisted of topical antibiotics and steroids for 3 weeks.
FOLLOW-UP EXAMINATIONS
All patients included in this study were examined preoperatively and at approximately 3 months postoperatively. The mean follow-up time was 3.58 ± 1.87 months. The examinations performed at these 2 visits varied within our patient collective because this is a retrospective evaluation that included patients with refractive lens exchange and patients with cataracts. Therefore, the number of patients examined is indicated for every examination.
Preoperatively, visual acuity testing was performed at far (4-m) and near (40-cm) distances. At the postoperative follow-up 3 months postsurgery, visual acuity was also tested at intermediate (60-cm) distance. The manifest refraction was obtained pre- and postoperatively. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), uncorrected near visual acuity (UNVA), distance corrected near visual acuity (DCNVA), and corrected near visual acuity (CNVA), and uncorrected intermediate visual acuity (UIVA), distance corrected intermediate visual acuity (DCIVA), and corrected intermediate visual acuity (CIVA) were obtained with Early Treatment Diabetic Retinopathy Study charts suitable for the respective distance measured.
Defocus curve testing was performed at the postoperative follow-up visit with distance correction. Photic phenomena evaluation was performed at the postoperative visit using a halo and glare simulator (Eyeland Design Network GmbH, Vreden, Germany). The simulator allows the patient to choose between 3 different types of halos (classic, starburst, or irregular types) and 2 different types of glare (classic or asymmetric). The size and intensity of both parameters can be adjusted on a scale from 0 to 100 to match the patients’ own perception. When either size or intensity are set to 0, the effect in question is not shown in the simulation.
STATISTICAL ANALYSIS
Statistical analysis was performed using Excel for Mac (version 16.32; Microsoft Corp) for Mac and jamovi version 1.2.27 for Mac OS. We calculated the mean values and standard deviations for all quantitative parameters. The Shapiro-Wilk test was used to test for normal distribution. For the evaluation of the refractive outcome, the Student t test for paired samples was used and P < .05 was considered statistically significant.
RESULTS
VISUAL ACUITY AND REFRACTIVE OUTCOMES
The mean target spherical equivalent (SE) was −0.12 ± 0.11 D whereas the mean achieved SE was −0.14 ± 0.31 D. The difference between target and achieved SE was −0.02 ± 0.34 D, which was not statistically significant ( P = .89).
Table 2 shows the results for monocular and binocular visual acuity testing at far, intermediate, and near distances.
