Purpose
To analyze and classify the indications, clinical presentations, and surgical outcomes of intraocular lens (IOL) exchange performed in a recent 5-year period.
Design
Retrospective, interventional case series.
Methods
setting : Private clinical practice. study population : Chart records of 57 eyes of 53 consecutive patients who had undergone IOL exchange between May 2007 and December 2011 were reviewed. observation procedures and main outcome measures : The preoperative clinical characteristics, treatment parameters, intraoperative and postoperative complications, and pre- and postoperative logarithm of the minimal angle of resolution (logMAR) best-corrected visual acuity (BCVA) were recorded and analyzed.
Results
IOL dislocation (46%), incorrect IOL power (23%), patient dissatisfaction (21%), and optic opacification (7%) were the most common indications for IOL exchange. In the IOL dislocation group, posterior capsule opening presented in 57% of eyes (8/14) with in-the-bag dislocation. Of the dissatisfaction patients, 42% (5/11) had undesired visual acuity without symptoms of glare/optical aberrations. Surface calcification of silicone lenses associated with asteroid hyalosis accounted for the most cases (3/4) of optic opacification. Overall, the mean logMAR BCVA improved significantly ( P < .001) and 88% of all eyes were 20/40 or better, including 73% in the IOL dislocation group and 100% in all other groups. No vision-threatening complications occurred in this series.
Conclusions
The request for IOL exchange owing to patient dissatisfaction is increasing, especially for those with undesired visual acuity in the absence of photic symptoms. Surface calcification of silicone lenses suggests that this type of lens is not appropriate in the presence of asteroid hyalosis. Optimal visual results with a low rate of complications can be achieved in each category of indication. The findings of the study may stimulate discussion of a question: Does in-the-bag IOL dislocation occur only in eyes with an intact posterior capsule?
With a dynamic and rapid evolution in cataract surgery and intraocular lens (IOL) technology, the indications for and the outcomes of IOL exchange continue to evolve. In a longitudinal study of IOL exchange performed between 1986 and 2002, Marques and associates found that the primary indication for IOL exchange was intraocular inflammation in patients with an anterior chamber (AC) IOL (53.3%) and IOL malposition in patients with a posterior chamber (PC) IOL (85.3%). In a retrospective study performed between 1998 and 2004, Jin and associates found that the most frequent indications for IOL exchange were incorrect IOL power (41.2%), followed by dislocation (37.3%) and glare (7.8%), whereas corneal decompensation (38.6%), abnormal IOL position (22.8%), cystoid macular edema (CME) (13.9%), and incorrect IOL power (13.9%) were found in a study performed a decade earlier between 1986 and 1990 in the same clinical setting. In the latest survey update (2007) of members of the American Society of Cataract and Refractive Surgeons (ASCRS) and the European Society of Cataract and Refractive Surgeons (ESCRS), Mamalis and associates reported that the most common reasons for removing foldable IOLs were dislocation/decentration, incorrect IOL power, glare/optical aberrations, and IOL calcification. Leysen and associates reported in a prospective study that IOL opacification was the major cause of IOL exchange (31%), followed by IOL decentration (19%), IOL dislocation (18%), and capsule phimosis (14%), during the study period from 2002-2007. In recent years, as more patients with higher visual expectations receive refractive lenses (multifocal and toric IOLs), the request for IOL exchange owing to patient dissatisfaction is on the rise. Limited research has been published on IOL exchange in recent years. We conducted a retrospective interventional case series to analyze and classify the indications, clinical presentations, and surgical outcomes of IOL exchange performed during a recent 5-year period.
Patients and Methods
This retrospective interventional case series study was performed with the approval of the Siouxland Institutional Review Board (Sioux City, Iowa) and conducted in accordance with the tenets of the Declaration of Helsinki. Informed consent for the surgery was obtained from all patients after a complete explanation of the procedures and possible complications.
The medical records of all patients who had IOL exchange performed at Jones Eye Clinic from May 1, 2007 to December 30, 2011 were reviewed. Data collected include the following: age, sex, systemic disease, coexisting eye condition, history of ocular surgery, indications for IOL exchange, time interval between IOL implantation and exchange, IOL design and material of the original and replacement IOL, location of optic and haptics of the original IOL, and the conditions of anterior capsulorrhexis, zonules, posterior capsule, and vitreous. Intraoperative information was obtained from surgical records and surgical videos. The use of a capsular tension ring (CTR), lens model, location and fixation methods of the replacement IOL, and surgical complications were recorded. Postoperative data collected include best-corrected visual acuity (BCVA), complications, and additional procedures.
The IOL power for exchange was calculated based on IOLMaster measurements using the Holladay I, SRK/T, and Holladay R as well as the formula based on residual refractive error after previous IOL implantation. For sulcus fixation, the IOL power was reduced by 0.5 to 1.0 diopter (D) from the capsular bag power.
Dissatisfied patients include those with and without photic symptoms. In the patients with complaints of undesired visual outcomes without photic symptoms (glare, halos, dysphotopsia) or other causative findings (such as posterior capsular opacification [PCO], lens opacification, dislocation/decentration), the indication for IOL exchange was classified as patient dissatisfaction if the spherical refractive equivalent (SE) was equal to or less than ±0.50 D of the intended target. If the SE was greater than ±0.50 D from the intended target, the indication for exchange was classified as incorrect IOL power.
Descriptive statistics (patient age, preoperative and postoperative visual acuity) were analyzed using SPSS for Windows (version 13.0, SPSS, Inc, Chicago, Illinois, USA). Data analysis was based on the number of eyes. Snellen acuity was converted to logarithm of the minimal angle of resolution (logMAR) values. The Student t test was used to evaluate the significance of the difference. Data were expressed as mean ± standard deviation, and a P value < .05 was considered statistically significant.
Surgical Technique
The same surgeon (J.J.J.) performed all IOL exchange surgeries using techniques dependent on the indications of IOL exchange, the type and material of the lens, and the conditions during surgery. Topical and intracameral anesthesia with intravenous sedation were used for all procedures. For eyes that had a stable zonular apparatus and an in-the-bag PC IOL, 2 paracenteses and a temporal clear cornea incision (2.5 mm) were created followed by irrigation of the AC with a mixture of nonpreserved lidocaine and epinephrine. Ophthalmic viscoelastic device (OVD) was used to inflate the AC, and additional OVD on a 30 gauge hypodermic needle was used to dissect the lens from the capsular bag. The IOL was rotated out of the bag and into the AC. The IOL was then trisected using IOL cutting microscissors and the pieces removed from the eye. A bimanual anterior vitrectomy was performed in all cases of vitreous prolapse. The new lens was introduced with an injector and rotated into the capsular bag. In the case of posterior capsule opening, the IOL was placed in the sulcus with or without iris suture, depending on the situation of capsular and iris tissues. In most cases, a modified McCannel iris suture fixation technique was performed to secure each haptic to the peripheral iris using 10-0 polypropylene in a sliding knot. The optic was then prolapsed through the pupil and centered. The technique of complete removal of the capsular bag during IOL exchange because of total zonular deficiency has been previously described by other authors. At the end of the operation, a drop of antibiotic was placed on the surface of the eye. Further postoperative treatment included topical antibiotic for 1 week and steroidal and nonsteroidal drops for 4 weeks.
Results
Patient Characteristics
The study included 57 eyes of 53 patients (41 women, 12 men) with a mean age of 72.6 years (range 42-95 years) who were followed after IOL exchange for a mean time of 14.9 months (range 1-43 months) ( Table 1 ). The number of IOL exchange procedures performed per year was 7 in 2007, 14 in 2008, 18 in 2009, 12 in 2010, and 6 in 2011. The rate of IOL exchange was 0.53% of all cataract surgeries during the time period under study.
| Characteristic | Value |
|---|---|
| Eyes/patients | 57/53 |
| Right, n (%) | 34 (59.6) |
| Left, n (%) | 23 (40.4) |
| Sex, n (%) | |
| Male | 12 (22.6) |
| Female | 41 (77.4) |
| Age (y) | |
| Mean ± SD | 72.6 ± 13.4 |
| Range | 42–95 |
| Bilateral IOL exchange, n (%) | 4 (7.0) |
| Type of original IOL, n (%) | |
| AC iris-clip IOL | 4 (7.0) |
| PC IOL | 53 (93.0) |
| Interval between original implant and exchange (mo) | |
| Mean ± SD | 78.6 ± 98.2 |
| Range | 1–444 |
| Follow-up (mo) | |
| Mean ± SD | 14.9 ± 13.6 |
| Range | 1–60 |
Preoperative status of the study eyes was recorded at the time of diagnosis. Table 2 shows the ocular comorbidities, preexisting conditions, and previous surgical history of these eyes. The presence of pseudoexfoliation (PEX) was the most commonly associated factor in eyes with IOL dislocation. Ten out of 11 eyes (90.9%) with PEX had in-the-bag dislocation. An open posterior capsule was present in 22 of the 57 eyes (38.6%), in which 6 had neodymium–yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy (YAG) after original cataract surgery. In 15 eyes, vitreous loss at the time of original cataract surgery was associated with posterior capsular rupture (PCR). Open posterior capsule was found in 57.1% of eyes (8/14) with in-the-bag dislocation and 55.5% of eyes (5/9) with out-of-the-bag dislocation. Pseudophacodonesis was recorded in 10 eyes before IOL exchange; of these, 9 were in-the-bag IOL dislocation and 1 was iris-clip IOL dislocation. In 4 eyes with IOL opacification, 3 were status post YAG posterior capsulotomy, with 1 of these having had 2 additional YAG treatments to dust off calcified particles.
| Status | Eyes (N = 57) |
|---|---|
| n (%) | |
| Ocular comorbidities | |
| Open-angle glaucoma | 12 (21.1) |
| PEXG | 6 |
| POAG | 6 |
| Pseudoexfoliation | 11 (19.3) |
| Age-related macular degeneration | 8 (14.0) |
| Epiretinal membrane | 5 (8.8) |
| Preexisting conditions | |
| Discontinuous posterior capsule | 22 (38.6) |
| With vitreous loss | 15 (26.3) |
| Without vitreous loss | 7 (12.3) |
| CTR | 2 (3.5) |
| Pseudophcodonesis | 10 (17.5) |
| Previous surgeries a | |
| YAG | 6 (10.5) |
| LASIK | 8 (14.0) |
| RD repair | 2 (3.5) |
| ALT or SLT | 2 (3.5) |
a Previous surgeries included pre-original and pre-exchange procedures.
Indications for Intraocular Lens Exchange
Table 3 shows the indications for IOL exchange and time intervals between the original implantation and lens exchange in the 57 study eyes. The most frequent indications for IOL exchange were lens dislocation/decentration (26 eyes, 45.6%), incorrect lens power (13 eyes, 22.8%), patient dissatisfaction (12 eyes, 21.1%), and lens opacification (4 eyes, 7.0%). Other, less frequent reasons included 1 case of UGH (uveitis-glaucoma-hyphema) syndrome and a case of unplanned IOL exchange during anterior vitrectomy for prolapsed vitreous.
| Indications/Category | Eyes N (% of Total) | Eyes N (% of Each Category) | Time From Original to IOL Exchange, Months (Range) |
|---|---|---|---|
| IOL dislocation/decentration | 26 (45.6) | 120.9 (7-360) | |
| AC iris-clip IOL | 3 (11.5) | 276.0 | |
| PC-IOL | 23 (88.5) | ||
| In-the-bag | 14 (60.9) | 90.4 | |
| Out-of-the-bag | 9 (39.1) | 116.9 | |
| Incorrect IOL power | 13 (22.8) | 5.6 (1-36) | |
| Post-refractive surgery | 8 (61.5) | 7.3 | |
| No previous refractive surgery | 5 (38.5) | 3.0 | |
| Patient dissatisfaction | 12 (21.1) | 15.0 (1-43) | |
| Glare/halos | 6 (50.0) | 12.3 | |
| Undesired visual acuity | 5 (41.7) | 21.0 | |
| Diplopia | 1 (8.3) | 1.0 | |
| IOL opacification | 4 (7.0) | 135.2 (96-204) | |
| UGH | 1 (1.8) | 444.0 | |
| Unplanned surgery | 1 (1.8) | 96.0 |
In the lens dislocation group, PC IOLs accounted for 88.5% of the type of decentered lens, in which in-the-bag dislocation occurred in 14 eyes (60.9%) and out-of-the-bag in 9 eyes (39.1%). In eyes with incorrect IOL power, 8 eyes (61.5%) had refractive surgery before original cataract surgery. All of these refractive procedures were myopic laser-assisted in situ keratomileusis (LASIK). Among the patients who had IOL exchange because of dissatisfaction, 6 (50.0%) were attributable to glare/halos and 5 (41.7%) to undesired visual acuity. Of the 4 eyes with lens opacification, 3 had dense asteroid hyalosis. UGH syndrome developed in a 75-year-old male patient who had an AC iris-clip lens implanted 37 years prior, and this IOL was exchanged for a 3-piece PC collamer lens placed in the sulcus and secured with iris suture fixation.
In the case of unplanned IOL exchange surgery, a significant amount of vitreous had presented in the AC around a sulcus-placed lens, causing increased IOP after a YAG posterior capsulotomy. While performing a bimanual anterior vitrectomy, the sulcus lens decentered with vitreous entangling the lens; IOL exchange was then performed to permit thorough removal of the prolapsed vitreous.
Removed Intraocular Lenses: Lens Type and Position
Information about the original IOL type was not available in 4 eyes of patients who had cataract surgery done elsewhere. Therefore, 53 eyes were eligible for preoperative analysis. IOL type and positions of the removed IOLs are summarized in Table 4 . One-piece acrylic lenses were the most often removed IOLs in the incorrect power and patient dissatisfaction groups. These were the most frequently implanted lenses during the study period.
| IOL Dislocation N = 22 a | Incorrect Power N = 13 | Dissatisfaction N = 12 | Opacification N = 4 | Total (N = 53 d ) N (%) | |
|---|---|---|---|---|---|
| Type of IOL | |||||
| 3-Piece silicone | 9 | 0 | 0 | 3 | 12 (22.6) |
| 1-Piece PMMA | 8 | 1 | 0 | 0 | 9 (17.0) |
| 3-Piece PMMA | 3 | 0 | 0 | 0 | 4 b (7.5) |
| 1-Piece acrylic | 1 | 10 | 8 | 0 | 19 (35.8) |
| 3-Piece acrylic | 1 | 2 | 4 | 1 | 9 c (17.0) |
| Position of IOL | |||||
| AC iris-clip | 3 | 0 | 0 | 0 | 4 b (7.5) |
| PC IOL | 19 | 13 | 12 | 4 | 49 c (92.5) |
| PC in bag | 12 | 12 | 11 | 4 | 39 (73.6) |
| PC in sulcus | 3 | 1 | 1 | 0 | 6 c (11.3) |
| Bag-sulcus fixation | 4 | 0 | 0 | 0 | 4 (7.5) |
a Preoperative information of IOL type was missing for 4 eyes in IOL dislocation group.
b Data included 1 eye with uveitis-glaucoma-hyphema syndrome.
c Data included 1 eye with unplanned surgery.
d Data included other 2 eyes with uveitis-glaucoma-hyphema syndrome and unplanned surgery.
Replacement Intraocular Lenses: Lens Type and Fixation
Table 5 shows the IOL type and fixation methods used for IOL exchange. Three-piece acrylic IOLs were the most commonly used PC IOLs (62.5%, 35/56). Most of these lenses were placed in the sulcus (58.9%, 33/56), in which 75.8% (25/33) were iris suture fixated. In the IOL dislocation group, 92.3% of lenses (24/26) were placed in the sulcus and 79.2% of them (19/24) were iris suture fixated. Reverse optic capture (ROC) of a 1-piece acrylic PC IOL in the bag was performed in 1 eye of the incorrect power group, in which PCR occurred during the IOL exchange procedure. In the dissatisfaction group, monofocal lenses (SN60WF or MN60AC; Alcon Laboratories Inc, Fort Worth, Texas, USA) were used to replace the original multifocal lenses (ReSTOR; Alcon Laboratories Inc; ReZoom; Abbott Medical Optics, Santa Ana, California, USA). Toric lenses were exchanged with same type of toric lens.
| IOL Dislocation N = 26 | Incorrect Power N = 13 | Dissatisfaction N = 12 | IOL Opacification N = 4 | Total (N = 57 a ) N (%) | |
|---|---|---|---|---|---|
| Type of IOL | |||||
| 1-Piece PMMA (AC) | 1 | 1 (1.8) | |||
| 1-Piece acrylic | 10 | 9 | 19 (33.3) | ||
| 3-Piece acrylic | 25 | 3 | 2 | 4 | 35 b (61.4) |
| 3-Piece collamer | 1 | 2 c (3.5) | |||
| Fixation of IOLs | |||||
| AC IOL | 1 | 1 (1.8) | |||
| PC IOL | 25 | 13 | 12 | 4 | 56 (98.2) |
| PC IOL in bag | 1 | 12 | 10 | 23 (40.4) | |
| Using ROC | 1 | 1 (1.8) | |||
| PC IOL in sulcus | 24 | 1 | 2 | 4 | 33 d (57.9) |
| With iris fixation | 19 | 1 | 3 | 25 d (43.9) | |
| No iris fixation | 5 | 1 | 1 | 1 | 8 (14.1) |
b Including 1 eye with unplanned surgery.
c Including 1 eye with uveitis-glaucoma-hyphema syndrome.
d Including 1 eye with uveitis-glaucoma-hyphema syndrome and 1 eye with unplanned surgery.
Visual Outcomes
The visual results of each indication category at the most recent follow-up visit are presented in Table 6 . Overall, the mean logMAR BCVA had improved significantly from preoperative 0.40 to postoperative 0.14 ( P < .001, Student t test). Ninety-one percent of eyes (52/57) had stable or improved BCVA. Eighty-eight percent of the total eyes (50/57) attained 20/40 or better BCVA after IOL exchange, with 73.1% (19/26) in the IOL dislocation group and 100% in all other groups attaining this level of vision. In the IOL dislocation group that had replacement PC IOLs in the sulcus with iris suture fixation, the postoperative mean logMAR BCVA improved significantly, from 0.72 to 0.28 ( P < .001, Student t test). Seventy-nine percent of eyes (16/19) had stable or improved BCVA after surgery, and of these, 12 eyes (63.2%) gained 2 or more lines (2-24 lines).
| IOL Dislocation N = 26 | Incorrect Power N = 13 | Dissatisfaction N = 12 | IOL Opacification N = 4 | Total N = 57 a | |
|---|---|---|---|---|---|
| Pre-exchange BCVA | |||||
| LogMAR mean ± SD | 0.69 ± 0.64 | 0.11 ± 0.13 | 0.14 ± 0.12 | 0.29 ± 0.18 | 0.40 ± 0.52 |
| 20/40 or better, n (%) | 8 (30.8) | 12 (92.3) | 11 (91.7) | 2 (50.0) | 35 (61.4) |
| Post-exchange BCVA | |||||
| LogMAR mean ± SD | 0.25 ± 0.27 | 0.06 ± 0.08 | 0.03 ± 0.09 | 0.05 ± 0.06 | 0.14 ± 0.21 |
| 20/40 or better, n (%) | 19 (73.1) | 13 (100.0) | 12 (100.0) | 4 (100.0) | 50 (87.8) |
| 20/50 or worse, n (%) | 7 (26.9) | 0 | 0 | 0 | 7 (12.3) |
| Change of lines of BCVA | |||||
| Loss of 1-2 lines | 3 (11.5) | 1 (7.7) | 1 (8.3) | 0 | 5 (8.8) |
| Same | 1 (3.8) | 6 (46.2) | 2 (16.7) | 0 | 10 (17.5) |
| Gain of more than 1 line | 22 (84.6) | 6 (46.2) | 9 (75.0) | 4 (100.0) | 42 (73.7) |
| Cause of BCVA 20/50 or worse (n = 7) | |||||
| ARMD | 4 | 0 | 0 | 0 | |
| Advanced glaucoma | 3 | 0 | 0 | 0 | |
| Postoperative follow-up (mo) | |||||
| Mean ± SD | 12.9 ± 10.9 | 19.6 ± 16.1 | 10.5 ± 9.6 | 26.0 ± 25.8 | 14.9 ± 13.6 |
| Range | 1-40 | 1-52 | 1-32 | 4-60 | 1-60 |
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