Due to demographic changes in society, science and industry are developing improved pseudophakic IOL designs. Multifocal IOL technology has made room for refractive lens exchange (RLE) in our armentarium of procedures. This case report reviews one patient who visited our clinic after undergoing unsuccessful RLE elsewhere. We will review how we managed his blurred vision and photic phenomena.
CASE PRESENTATION
A 50-year-old white insurance agent came to the University Eye Clinic complaining of blurred vision from 0.75 m to distance. He began experiencing photic phenomena in both eyes 5 weeks after a refractive lens exchange (RLE) was performed at another clinic. He had hyperopia of 1.00 D. The patient had presbyopia prior to the initial RLE. He has never worn contact lenses.
As reported on the patient's IOL identification card, a Tecnis ZM900 (Advanced Medical Optics, Inc., Santa Ana, California) was implanted in each eye during RLE. Both IOLs were 24.00 D with a 4.00 D add.
The patient's medical, ocular, and family history was normal. Although he reported never seeing flashes, he said he occasionally recognized floaters. He denied taking any medications or having any allergies.
Anterior segment evaluation by slit lamp in both eyes showed quiet bulbar and palpebral conjunctivas, even tear films with break up times of 12 seconds, and clear lashes. The cornea appeared clear and regular, and the anterior chamber was clear. We estimated the anterior chamber angle in both eyes as 4/4.
Evaluation of the posterior segment under full pupil dilation revealed isolated floaters in the vitreous of both eyes. The capsular bag of the right eye showed anterior synechia with the posterior capsule inferiorly, leading to superior displacement of the Tecnis IOL (Figure 1A). The displacement was caused by the capsular buttonhole effect. Compared with the original placement during the RLE, the left IOL showed a slight shift nasally (Figure 1B). These findings were responsible for the photic phenomena and blurred vision.
Fundus assessment revealed healthy and distinct optic nerves (cup-to-disc ratio, 0.4 OU). The optic nerve heads were pink, healthy, and distinct. Both maculas were intact, dry, and flat; we did not find any drusen, edema, or hemorrhages. The patient's retinal vessels appeared normal, and his arterial-venous ratio was 2/3 OU. No peripheral detachments, breaks, or degenerations were detected. We used aberrometry to analyze the patient's coma values [Z(3,-3), Z(3,-1), Z(3,1), Z(3,3)], which were high in both eyes . These values may be attributed to the dislocated IOLs (Table 1).
HOW WOULD YOU PROCEED?
Upon evaluating this patient, we had to decide among the following treatments: (1) exchange the multifocal IOL for a monofocal IOL, (2) exchange the current multifocal IOL for a higher-power multifocal IOL, (3) open the posterior capsule with a Nd:YAG laser, (4) recenter the currently placed multifocal IOL with or without the aid of a capsular tension ring (CTR), (5) perform an excimer laser treatment for the patient's residual hyperopia, or (6) leave it as is.
If this were your patient, how would you proceed?
HOW WE PROCEEDED
Before proceeding surgically, we educated the patient about the relationships among his blurred vision, photic phenomena, and dislocated IOL. After reviewing our ocular findings, we suggested performing capsular synechiolysis in his right eye, rotating and recentering both multifocal IOLs under retrobulbar anesthesia, and implanting a closed foldable equator ring (CFER Type 2A; Morcher GmbH, Stuttgart, Germany; Figures 2 and 3). We also discussed the possibility of further refractive intervention, such as PRK or LASIK; however, that would depend on the refractive outcome. The patient received and signed a written informed consent.
Why did we keep the Tecnis IOL? In contrast to accommodating IOLs, multifocal IOLs provide multiple focal distances independent of ciliary body function and capsular mechanics. Once securely placed in the capsular bag, these lenses functions are not expected to change or detoriate. The Tecnis ZM900 has a modified prolate anterior surface, compensating for average corneal spherical aberration and reducing total aberrations in the eye.2 The Tecnis' anterior aspheric design protects against decentration, and the posterior surface offers a diffractive, multifocal design over the entire optic. The benefit of the diffractive principle is that in each position of the optic, the same image comes into existence. Therefore, the bifocal effect is independent of pupil diameter.3
Why did we use a CFER? This device is designed to (1) maintain the configuration and stability of the capsular equator in the presence of compromised zonular integrity and (2) reduce traction on the zonules. We chose to place a CFER to maintain the natural circular contour of the capsular bag and improve the centration of the previously implanted IOL. Most commercially available CTRs are open and made of one-piece, rigid PMMA.4 The angulation of the segments in the CFER provides stiffness and shape memory and also increases resistance to capsular bag shrinkage across 360?. The hydrophilic segments narrow in the middle for flexibility.
We hospitalized the patient for 1 night and performed uncomplicated surgery on his right eye. The synechia of the inferior anterior capsule was carefully detached, the IOL was rotated, and the CFER was implanted.
FOLLOW-UP
One day after surgery, his visual acuity was 20/20 with pinhole. Three weeks later, the patient returned with a UCVA of 20/80 OD and 20/25 OS. His objective refraction was +2.5 -1.5 X 0 OD and +1.0 -1.0 X 168 OS. The patient's subjective refraction was +1.75 -0.25 X 170 OD, and his BCVA was 20/20. In the other eye, subjective refraction was +1.0 -0.5 X 155 and BCVA was 20/20.
At this time, the patient reported a reduction in photic phenomena and said he experienced no blurred vision; however, he was disappointed with his UCVA. The patient requested additional surgical correction. Based on our clinical assessments, the refractive results of the initial RLE were insufficient for the patient's expectations. Therefore, we recommended LASIK for the correction of the residual refractive error.
Three weeks later, he underwent uncomplicated, nonwavefront-guided LASIK on his right eye using the Amadeus microkeratome (Ziemer Group AG, Port, Switzerland) with a nasal hinge, and the MEL 80 excimer laser (Carl Zeiss Meditec AG, Jena, Germany).
One day later, the patient's UCVA in the right eye was 20/32, and his objective refraction was 0.00 -0.25 X 125. Slit-lamp examination of the anterior segment showed quiet bulbar and palpebral conjunctiva in the right eye. The flap was adapted and in the right position. No signs of diffuse lamellar keratitis were visible, and corneal topography showed a regular and perfectly centered 6-mm ablation zone. The cornea showed only mild edema. The aberrometry showed further improvement in coma values and suggested an overcorrection objectively.
One month later, the patient's UCVA was 20/25 in his right eye and 20/32 in his left. At near vision, he was J2. Under slit-lamp examination, the conjunctiva and cornea were quiet in both eyes. We rescheduled surgery for his left eye for 2 weeks later, when we would rotate the IOL and implant a CFER. There was also potential for an IOL replacement under retrobulbar anesthesia.
Second eye surgery. The patient was hospitalized for 1 night before undergoing uncomplicated surgery on his left eye. During the procedure, we rotated the IOL and placed the CFER; we did not need to replace the IOL in this case.
One day later, the patient's UCVA was 20/40. In the left eye, slit-lamp examination of the anterior segment showed a quiet bulbar and palpebral conjunctiva. The cornea showed only mild edema at the incision area. The anterior chamber appeared quiet with cells 1+ and Tyndall 1+ (faint). The original multifocal IOL was perfectly centered and the capsular bag presented as open.
Final outcome. At the patient's last follow-up, we tested his UCVA and BCVA as well as objective and subjective refraction. We also performed slit-lamp, topography, and intraocular pressure evaluations.
The patient was satisfied with the final result in his right eye and regrets his initial decision to undergo RLE (performed elsewhere) on his left eye.
WHAT HAVE WE LEARNED FROM THIS CASE?
This case exemplifies the basic necessity of choosing and calculating the adequate IOL. With particular regard to RLE, selecting the correct IOL and its power are essential for satisfactory UCVA. RLE should not be performed in eyes with presbyopia only. Even in healthy eyes, higher-order aberrations may affect the quality of vision. If significant, the aberrations may lead to glare, halos, starbursts, and poor night driving—even with spectacles or contact lenses.7 When recommending RLE to a patient, we should stress the importance of light sensations; it should be an integral part of informed consent. Our patient's initial surgeon may not have educated him sufficiently.
When we reviewed this patient's case preoperatively, we decided not to use wavefront-guided LASIK because wavefront measurements with the Hartmann-Shack aberrometer likely vary in eyes with a diffractive multifocal IOL.8
Achieving emmetropia in refractive lens surgery depends on accurate biometry and IOL power calculation. Partial coherence interferometry (IOLMaster; Carl Zeiss Meditec AG) accurately determines axial length, an indispensable technique for IOL power calculation.9 Calculating the IOL power in clear lenses is always possible with the IOLMaster. It also simultaneously detects staphylomas in myopic eyes or decentration of the line of sight in hyperopic eyes.
For improved centration and reduced posterior capsular opacification, RLE should be combined with implantation of a capsular tension ring, especially with a larger or decentered capsulorrhexis. The capsular equator ring keeps the capsular bag open and facilitates IOL replacement.
Sabine Buchner, MSc (Salus University) is an Optometrist and Chief Study Coordinator at the University Eye Hospital, Bochum, Germany. Ms. Buchner states that she has no financial interest in the products or companies mentioned. She may be reached at tel: +49 234 299 3142; e-mail: sabine.buchner@kk-bochum.de.
H. Burkhard Dick, MD, is the Chairman of the University Eye Hospital, Bochum, Germany. Professor Dick is a member of the CRST Europe Editorial Board. He states that he has no financial interest in any of the products or companies mentioned. Professor Dick may be reached at tel: +49 234 299 3101; e-mail: burkhard.dick@kk-bochum.de.
