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Ten-Year Results of Anterior Chamber Fixation of the Posterior Chamber Intraocular Lens
Tsutomu Hara, MD
Takako Hara, MD
Arch Ophthalmol. 2004;122:1112-1116.
ABSTRACT
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Objective To report the outcomes in eyes in which a Sinskey-type conventional posterior chamber intraocular lens (PC-IOL) was fixed in the anterior chamber and followed up for an average of 10 years.
Methods Twenty-one eyes were included in the study. The IOLs were conventional hard PC-IOLs, 13.0 mm in overall length with 6.0-mm polymethylmethacrylate optic and polyvinylidene fluoride loops that tilted 10° anteriorly.
Results At implantation the corneal endothelial cell density in 13 of 21 eyes was 382 to 1580 cells/mm2 owing to the previous implantation of iris-clip or iridocapsular IOLs. The overall postoperative corneal endothelial cell loss was 30.9%. Six of 14 eyes with a preoperative corneal endothelial cell density less than 2000 cells/mm2 developed bullous keratopathy. Although serious complications did not occur in 7 eyes with a cell density exceeding 2000 cells/mm2, an average corneal endothelial cell loss of 26.5% still occurred. Except for 2 eyes, all loops were fixed at the scleral spur and a slight pupillary transformation occurred in only 1 eye.
Conclusion Although this procedure is easy to perform and pupillary transformation does not occur, it is not recommended for aphakic eyes owing to the high corneal endothelial cell loss after an average 10-year follow-up.
INTRODUCTION
It is widely accepted that ciliary sulcus fixation is the method of choice for secondary intraocular lens (IOL) fixation in aphakic eyes with sufficient capsular support. In aphakic eyes with insufficient capsular support, the alternative methods are posterior chamber (PC) fixation of a PC-IOL with a scleral or iris suture, or anterior chamber (AC) fixation of an AC-IOL. It seems to be generally accepted that PC-IOL implantation with a scleral suture provides stable results. However, complications such as IOL tilt, decentration, hyphema, and others were reported.1 After the dislocation of 7 IOLs secured with scleral sutures 7 years after surgery, Kim et al2 reported that patients should be warned that their transscleral sutured IOL might subluxate 6 to 7 years postoperatively. In addition, the surgical technique is complicated and time consuming. Also, good results of iris sutured PC-IOLs were reported3 in the eye without capsular support. However, to pursue the simpler method, we did not try it this time. Thus, we tried a simpler and safer method.
There are 3 types of AC-IOL fixation: (1) AC angle fixation of an AC-IOL with rigid or semirigid loops, (2) AC angle fixation of an AC-IOL with flexible open loops, and (3) iris fixation of an iris claw lens. Although good results have been reported,4 an IOL with rigid or semirigid loops requires careful selection of the lens size, and complications including postoperative inflammation, pupillary transformation, glaucoma, and loss of corneal endothelial cells were reported.5 In 1989, we had a case in which a normally fixated PC-IOL dislocated into the vitreous cavity. The IOL was pulled from the vitreous and placed in the AC to await subsequent PC fixation with scleral suturing. However, the PC-IOL placed in the AC was stable. After following up the patient's condition for several months, we decided to pursue the current method of AC fixation of the conventional PC-IOL. If the results of this method are stable, it may become an acceptable procedure because the IOL is one-size-fits-all and the surgical method is easy.
In 2003, Drolsum6 reported good results with implantation of a flexible open-loop AC-IOL after 7 years of follow-up. Budo et al7 also reported good results with an iris-fixated AC-IOL. However, when the present study began, these 2 methods had not yet been definitely accepted. In 1992, we reported the results from the first 10 eyes (9 patients) that had undergone AC implantation of a PC-IOL (average follow-up, 17 months).8 Because clinically relevant complications were not observed and the mean (SD) corneal endothelial cell loss was 4.9% (2.4%), the results looked promising.
We were not the first to attempt this procedure. Girard et al9 and Nashiro et al10 performed a similar procedure and reported good postoperative outcomes. However, Girard et al reported results after only 11 months of follow-up, and Nashiro et al after 4 to 7 months of follow-up. To determine the long-term results of the new procedure, we report the outcomes of 21 eyes with an average 10-year follow-up.
METHODS
SUBJECTS
Twenty-one aphakic eyes of 20 patients (15 females and 5 males) were included in this study. The patients underwent surgery for implantation of a conventional PC-IOL in the AC at the Hara Eye Hospital, Utsunomiya, Japan, from November 20, 1989, to June 2, 1992. The mean (SD) patient age at the time of surgery was 70 (8.8) years (age range, 48-83 years). Table 1 gives the demographic data.
Our selection of subjects was biased toward significant previous endothelial trauma. Of the 21 eyes, 13 eyes had previously been implanted with either a Binkhorst iris-clip 4-loop IOL (B4-IOL) or a Binkhorst iridocapsular 2-loop IOL (B2-IOL). Because of the continuous corneal endothelial cell loss, those IOLs were removed immediately before the present procedure was performed. Five patients had undergone intracapsular cataract extraction without subsequent IOL implantation; and in 3 eyes the PC-IOL subluxated into the vitreous cavity. All patients were followed up until December 30, 2001; the longest follow-up was 12 years and 1 month and the shortest 9 years and 6 months (mean [SD], 10 years and 6 months [8 months]).
The results from the initial 10 eyes (9 patients) at an average 17 months of follow-up (range, 10-22 months) were reported in Japanese.8 Because of senile dementia, 3 patients could not be followed up after about 5 years, and those eyes were excluded from this study. Following a full explanation, all patients provided informed consent.
EXAMINATIONS
Preoperative and postoperative examinations included a determination of visual acuity (VA), tonometry, gonioscopy, laser flare cell measurement with the laser flare cell meter (Kowa Co, Tokyo, Japan), and keratometry. A corneal endothelial study of the central cornea was done using a contact specular microscope (Konan Co, Osaka, Japan). Cell density (cells per square millimeter) was calculated automatically by a computerized analyzer attached to the microscope. Follow-up examinations were conducted daily until the second postoperative week and then monthly until 1 year after surgery. Additional examinations were performed annually. Patients who had complications were examined more frequently as necessary.
SURGICAL PROCEDURE
In cases 1 to 20, local anesthesia was induced by retrobulbar injection of 2% lidocaine hydrochloride (Xylocaine). In case 21, anesthesia was induced with topical 4% lidocaine eyedrops. Except for pupillary control, all preoperative and postoperative steps were identical to those used in standard cataract IOL surgery.11
In eyes with a B2-IOL or a B4-IOL and those with a PC-IOL that subluxated into the vitreous, mydriasis was achieved using 0.5% tropicamide and 0.5% phenylephrine hydrochloride (Mydrin P). In aphakic eyes, 1% pilocarpine (Sanpilo) was used to maintain miosis.
The B2-IOLs and B4-IOLs were removed through a 6-mm scleral incision. To maintain sufficient AC depth, 1% sodium hyaluronate (Healon) was used. When vitreous prolapse occurred, an anterior vitrectomy with the use of scissors or vitrectomy machine was performed; 1% acetylcholine (Ovisot) then was injected into the AC. After confirming sufficient miosis, a PC-IOL was inserted into the AC by sliding it on the lens glide. The PC-IOL was inserted at the position where the loops tilted anteriorly, similar to when it is implanted into the PC. After inserting the inferior loop, the lens was rotated clockwise and finally fixed horizontally. No eyes developed hyphema. After rotation, a peripheral iridectomy was performed in one area. Before the incision was closed completely with a 10-0 nylon suture, thin forceps were inserted into the AC and slipped under the IOL to grasp the iris near the pupil and pull it toward the center; this maneuver prevents both lens loops from tugging the iris root. The spatula then was inserted beneath the IOL for the final iris manipulation. These procedures were useful to prevent future pupillary transformation. Finally, the viscoelastic material in the AC was slowly exchanged with balanced salt solution.
The PC-IOL used in this study was a conventional Sinskey-type IOL (Menicon Co, Nagoya, Japan) with 6-mm polymethylmethacrylate optic and J-shaped polyvinylidene fluoride loops, 0.14 mm in diameter, which angled 10° anteriorly. The total length of the IOL was 13.0 mm. After surgery, 1% pilocarpine eyedrops were instilled 6 times daily for 1 month, 3 times daily for the next 6 months, and then this therapy was discontinued. Because we feared postoperative iritis due to intraoperative iris manipulation and postoperative use of pilocarpine eyedrops to prevent the postoperative pupillary transformation in all cases, and B2-IOL or B4-IOL removal in some cases, we prescribed a higher dose of a systemic corticosteroid than that used in routine cataract surgery. This was combined with topical 0.1% dexamethasone methasulfobenzoate sodium eyedrops (DM-solon; Nihon Tenganyaku Kenkyusho Co, Nagoya) 6 times daily between 1 day preoperatively and 2 weeks postoperatively. Oral medications included 30 mg of prednisolone (Predonisolon; Sanwa kagaku Co, Nagoya) from 1 day preoperatively until 3 days postoperatively; this was then decreased at 4-day intervals to 20, 10, and 5 mg, and then this treatment was discontinued. A nonsteroidal anti-inflammatory drug was then prescribed for 2 weeks and this treatment was discontinued. Antibiotics eyedrops were prescribed 6 times daily from 1 day preoperatively to 7 days postoperatively that contained 0.5% erythromycin lactobionate and 0.5% colistin sodium methanesulfonate (Ecolicin ophthalmic solution; Santen Pharmaceutical Co, Osaka). Kitasamicin (Leucomycin; Asahi Kasei Co, Osaka), 1000 mg/d, was used orally from 1 day to 7 days postoperatively. Acetazolamide (Diamox; Wyeth Lederle Japan Co, Tokyo), 250 mg also was prescribed from 1 day until 3 days postoperatively.
RESULTS
CHANGES IN CORNEAL ENDOTHELIAL CELL DENSITY
The mean (SD) preoperative and postoperative corneal endothelial cell densities of all eyes were 1607 (985.4) cells/mm2 and 1105 (786.3) cells/mm2, respectively. The difference was statistically significant (P<.05). The percentage of postoperative cell loss in all eyes was 30.9% (30.10%). When the analysis was limited to 7 eyes with preoperative corneal cell density exceeding 2000 cells/mm2, the postoperative cell loss remained 26.5%.
BEST-CORRECTED VISUAL ACUITY
Compared with the preoperative best-corrected VA (BCVA), 7 eyes (33%) had the same VA level or 1 line of improvement or decrease on the eye chart, 6 eyes (29%) had an improvement of 2 lines or more, and 8 eyes (38%) had a decrease of 2 lines or more. Of the 8 eyes with a decreased BCVA, the decrease was the result of bullous keratopathy (BKP) in 5 eyes and development of a macular hole, progressive diabetic retinopathy, and retinal detachment in 1 eye each.
INTRAOCULAR PRESSURE
Except for 1 eye with preoperative glaucoma (case 2), the intraocular pressure (IOP) was within the normal range in all eyes.
LOOP FIXATION AT THE AC ANGLE
Except for 2 eyes (cases 2 and 4) with marked BKP that did not allow us sufficient observation of the angle, we confirmed that both loops of the remaining 19 IOLs (38 loops) were firmly fixed at the scleral spur; 31 loops (81.6%) had no fibrous adhesion (Figure 1). The other 7 loops (18.4%) had mild fibrous adhesion involving the loop genu and the iris root. Four of these loops were bilateral loops of 2 lenses.
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Figure 1. Case 7. The frontal view.
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COMPLICATIONS
Six eyes developed BKP. The mean (SD) corneal endothelial cell density in these 6 eyes before PC-IOL implantation in the AC was 932 (614.6) cells/mm2 (range, 381-1932 cells/mm2). Most of these eyes had received either a B2-IOL or a B4-IOL. In 15 eyes in which BKP did not develop, the mean (SD) preoperative corneal endothelial cell density was 1878 (989.4) cells/mm2. The preoperative difference between the 2 groups was statistically significant (P<.05). Slight pupillary transformation developed in only 1 eye (4.8%) (Figure 2).
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Figure 2. Case 1. Slight pupillary transformation.
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No eyes developed clinically relevant inflammation. The mean (SD) amount of AC flare measured in 19 eyes at the last examination was 13.0 (6.92) photon counts per millisecond.
There were 10 patients (10 eyes) in which a PC-IOL was implanted in the AC in 1 eye and a PC-IOL in the PC in the second eye (Table 2). The mean postoperative percentage of cell loss in eyes with a PC-IOL fixated in the AC was significantly higher than in those eyes in which the IOL was fixed in the PC (P<.05). Although there was no significant difference, the postoperative AC flare was higher in association with the PC-IOL with AC fixation.
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Table 2. Comparison of Different Intraocular Lens (IOL) Fixation in Both Eyes of the Same Patient*
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COMMENT
The procedure under discussion has the following advantages: (1) it is simpler and easier than PC fixation with scleral sutures, and (2) IOL fixation is secure and causes no complications that commonly occur with AC-IOL fixation such as pupillary transformation,12-14 inflammation at the clinical level, or glaucoma.
However, the major disadvantage is the reduction in the corneal endothelial cell density. One reason is the low preoperative corneal cell density (mean value, 1607 cells/mm2). Almost half of the eyes had undergone a previous surgery that could most likely cause the endothelium to be subject to damage. However, when the analysis was limited to 7 eyes with a preoperative corneal cell density exceeding 2000 cells/mm2, the postoperative cell loss was still 26.5%. This tendency was also found in eyes with a contralateral control procedure when a PC-IOL had been implanted in the PC. A significantly higher cell loss was found with AC implantation of the PC-IOL.
Except for the preoperative low corneal endothelial cell count, is there another cause of the severe postoperative cell loss? The location of the IOL optic can be excluded. Because the loops of the IOL bend 10° anteriorly, the optic is located at the farthest distance possible from the corneal endothelium. Although the genu of most loops were at the scleral spur without any apparent sign of inflammation, pupillary transformation, or glaucoma, we suspected that the peripheral corneal endothelium was damaged mechanically by the loop. Another potential cause could be iris chaffing by the loop of the IOL. As the pupil moves, the iris surface could rub the loop and this could produce low-grade inflammation. The damage was slight (with a low laser flare photometry value) but might have been sufficiently continuous to cause marked cell loss after 10 years. Regarding the direction of the loop, initially we positioned the IOL with the loops posteriorly, similar to other AC-IOLs. However, the fixation of the loop genu was unstable, and the distance between the corneal endothelium and the IOL optic was too narrow. Thereafter, we began using the present position. Still, the results were unsatisfactory. One factor in our study is the preoperative low corneal endothelial cell density due to B4-IOL or B2-IOL implantation in almost half the patients. It may be generally understood that even if a new procedure is useful, damaged corneal endothelium will be subject to more damage. Initially we thought this may be the case. However, when we observed the stable condition of the temporally placed PC-IOL in the AC, as stated initially, we hoped that the procedure might be useful. We then explanted the B4-IOLs or B2-IOLs from the eyes with decreasing cell density and performed the present method. In the early report of the present procedure at 1 year 5 months' follow-up, the cell loss was 4.9%.8 However, at 10 years 6 months' follow-up, it increased to 30.9%. This clearly indicates that to judge the efficacy of a new procedure, long-term observation is indispensable. If stable results at least 10 years postoperatively are desired, this procedure cannot be recommended for secondary IOL implantation.
AUTHOR INFORMATION
Correspondence: Tsutomu Hara, MD, Hara Eye Hospital, 1-11 Nishi 1-Chome, Utsunomiya-shi, Tochigi, 320-0861 Japan (office{at}haraganka.com).
Submitted for publication February 17, 2003; final revision received December 18, 2003; accepted January 1, 2004.
From the Hara Eye Hospital, Utsunomiya, Japan. The authors have no relevant financial interest in this article.
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