|Year : 2017 | Volume
| Issue : 3 | Page : 207-212
Comparison of retropupillary fixated iris-claw lenses and sulcus placed intraocular lenses for the treatment of aphakia
Sanitha Sathyan, Renjini Kurian
Little Flower Hospital and Research Centre, Angamaly, Kerala, India
|Date of Web Publication||30-Jan-2018|
Dr. Sanitha Sathyan
Nellikunnath House, Pudukad, Thrissur - 680 301, Kerala
Source of Support: None, Conflict of Interest: None
Purpose: The purpose of this study is to compare the visual outcomes and safety profile of retropupillary fixated iris claw lenses (RPICLs) and sulcus placed posterior chamber intraocular lenses (SIPCIOL) in the management of aphakia.
Materials and Methods: This was a comparative, observational study, which included 87 eyes of 84 patients who underwent RPICL or SIPCIOL for aphakia. BCVA at 6 weeks, mean prediction error, post-eperative complications were compared between the two groups.
Results: Group 1 (RPICL group) consisted of 47 eyes of 45 patients and Group 2 (SIPCIOL group) consisted of 40 eyes of 39 patients. Mean age was 67.13 ± 9.33 years in Group 1 and 59.91 ± 16.62 years in Group 2. There was statistically significant difference between preoperative best-corrected visual acuity (BCVA) and post op BCVA at 6 weeks in Group 1 (P = 0.001, paired t-test) and Group 2 (P = 0.001, paired t-test). There was no significant difference in BCVA between the groups at 6 weeks (P = 0.54, unpaired t-test). There was no statistically significant difference in BCVA at 6 weeks between primary surgery and secondary surgery in Group 1 (P = 0.34, unpaired t-test) and Group 2 (P = 0.59, unpaired t-test). The mean prediction error in Group 1 was 0.41 ± 0.58 D and in Group 2 was 0.18 ± 0.20 and was not significant (P = 0.61, unpaired t-test). There was no significant difference between the two groups in mean intraocular pressure at 1 week (P = 0.43, paired t-test) and at 6 weeks (P = 0.83, paired t-test). There was no significant difference between the two groups in operative complications.
Conclusion: RPICL was comparable with SIPCIOLs in terms of BCVA at 6 weeks, intraocular lens prediction error, and operative complications.
Keywords: Aphakia surgical management, retropupillary iris-claw lens, sulcus placed intraocular lens
|How to cite this article:|
Sathyan S, Kurian R. Comparison of retropupillary fixated iris-claw lenses and sulcus placed intraocular lenses for the treatment of aphakia. Kerala J Ophthalmol 2017;29:207-12
|How to cite this URL:|
Sathyan S, Kurian R. Comparison of retropupillary fixated iris-claw lenses and sulcus placed intraocular lenses for the treatment of aphakia. Kerala J Ophthalmol [serial online] 2017 [cited 2018 Sep 19];29:207-12. Available from: http://www.kjophthal.com/text.asp?2017/29/3/207/224303
| Introduction|| |
The correction of aphakia resulting from complicated cataract surgery is a challenging deal. Various options include anterior chamber intraocular lenses (ACIOLs), scleral fixated IOLs (SFIOLs), suclus implanted posterior chamber intraocular lens (SIPCIOL), and anterior or retropupillary fixated iris claw lenses (RPICLs).
ACIOLs are associated with long-terms complications including corneal decompensation, intraocular pressure (IOP) elevation, persistent inflammation and are not the preferred for management of surgical aphakia, as shown by several studies. As for SFIOLs, the surgery is technically more difficult, time-consuming and often involves significant ocular manipulation, high risk of intra-operative and postoperative complications., Although implantation of iris-claw lens above the iris for aphakic eyes has been cited as successful procedure in many studies, these are associated with significant decrease in endothelial cell count.,,,,,
Sulcus placed IOLs provide a useful and safe method for the placement of posterior chamber IOL in eyes with intraoperative complications such as posterior capsule rents. However, they cannot be used in cases with large zonulodialyses or when the status of the anterior capsule rim is not sure. It is well acknowledged that ciliary sulcus is the chosen site for IOL implantation in cases where the IOL cannot be placed in the bag. This is due to their proximity to the effective lens position used for biometric calculations, more physiological location, and less chance to cause corneal decompensation. RPICLs provide good visual outcomes with a favorable safety profile and can be used for a wide range of indications in eyes without adequate capsule support. However, they are not very popular in many centers due to the high rate of IOL displacement, IOP rise, and technically demanding surgery.,
We conducted this comparative study to evaluate the outcomes of RPICLs and SIPCIOLs for the management of surgical aphakia.
The aim of this study is to compare the outcomes and safety of RPICLs and sulcus placed posterior chamber IOLs in the management of surgical aphakia in terms of best-corrected visual acuity (BCVA) and complications.
| Materials and Methods|| |
This was a comparative, observational study on the outcomes of RPICL implantation versus ciliary sulcus implanation of the posterior chamber intra ocular lens (SIPCIOL) for the correction of surgical aphakia conducted at a tertiary care eye facility between January 2014 and January 2016, by a single surgeon. The study adhered to the guidelines of the Declaration of Helsinki, and the study protocol was approved by the Institutional Review Board.
Group 1: Subjects with aphakia following complicated cataract extraction or subluxation of the crystalline lens/posterior chamber IOL without adequate capsular support, who underwent RPICL implantation. Group 2: Subjects with aphakia following complicated cataract extraction or subluxation of the crystalline lens/posterior chamber IOL with adequate capsular support, those who underwent PCIOL implantation in the sulcus. RPICL and SIPCIOL implantations were done during the primary surgery or as a secondary procedure. The decision regarding the choice of IOL and timing of IOL surgery was based on the discretion of the surgeon.
Group 1: Rubeosis iridis, aniridia, total/near total iris defects precluding adequate iris support for enclavation of RPICL, proliferative diabetic retinopathy or any condition warranting vitreoretinal surgery in the near future. Group 2: Absence of adequate posterior capsular support, especially in the inferior quadrant precluding SIPCIOL implantation, gross zonular weakness due to pseudo exfoliation, or trauma.
Preoperatively, all the patients underwent estimation of BCVA using Snellan chart, IOP (Goldmann applanation tonometer), keratometry (NIDEK automated keratometer), biometry (IOL-Master/Ultrasound A-scan), anterior segment slit lamp examination, and dilated fundus examination. B-mode ultrasound examination was performed in cases where media opacities precluded adequate view of the fundus. In cases with doubtful posterior capsular support, biometry was done using the parameters for RPICL and SIPCIOL, and the choice of IOL was decided intraoperatively as per the clinical discretion of the surgeon.
The lens used in this study for iris fixation was the Exelens Model PIC 5580 (Excel Optics Private Ltd., India) which is a polymethyl methacrylate (PMMA) IOL with an 8.0-mm length and 5.50-mm optical zone width. The lens used for sulcus placement was Aurolens-Modified C PMMA loops (Aurolab Surgical, India), 13.5 mm length, and 6.0 mm biconvex optic. IOL power was calculated using SRK-2 for eyes with axial length between 20.5 and 23 mm and using SRK-T formula for axial lengths >23 mm, with the aim of achieving emmetropia. In planned RPICL/SIPCIOL surgeries, IOL power was obtained as per the specifications for these IOLs after adjusting for the A-constants. When RPICL or SIPCIOL had to be implanted on a “unplanned” basis as in the primary implantation cases when preoperative biometric values were not available, the power of IOL implanted was determined by reducing 2 D for RPICL, and 0.5 D for SIPCIOL, respectively, from the value determined for in the bag implanted PCIOLs. All surgeries were performed by a single experienced surgeon under peribulbar anesthesia using a uniform technique. Group 1: Two diametrically opposite corneal paracenteses were performed corresponding to the proposed enclavation site of the haptics. The sclerocorneal tunnel was opened up in case of secondary procedures and freshly made in case of primary procedures. Anterior vitrectomy was done using automated vitrectomy machines. Intracameral pilocarpine 1% was used to induce pupillary miosis. Dispersive viscoelastic substance was injected to the anterior chamber. RPICL was inserted using the IOL holding forceps below the iris plane using the surgeon's dominant hand. IOL dialer was used to enclave the haptic at the side of the nondominant had first, and then, the same hand was used to enclave the opposite haptic. After ensuring RPICL enclavation, which was determined with the visible tuck in of the iris at the sites of enclavation, the IOL holding forceps was gently withdrawn. End-point was noting the dimple at the site of enclavation. In case of residual vitreous in the anterior chamber, automated vitrectomy was used to clear it from the anterior chamber. Viscoelastic was washed off and the chamber formed with saline. Section was closed with 10-monofilament nylon sutures in needed cases, and side ports were hydrated. We did not perform peripheral iridectomies in any of the cases, except when it was performed by the primary surgeons. Group 2: Sideport incision was made at the side of the dominant hand, and anterior chamber was inflated with viscoelastic substance. The sclerocorneal tunnel was opened up. Automated anterior vitrectomy and chamber reformed with viscoelastic substance. After ensuring that adequate capsular support was present, a 3 piece PCIOL was introduced into the sulcus using IOL holding forceps, and the trailing haptic was dialed into the sulcus using a dialer. Viscoelastic substance was removed by irrigation and aspiration, the chamber were formed with saline and the section closed with 10-0 monofilament nylon sutures.
Postoperatively, all the patients were treated with tapering doses of topical prednisolone actete 1% and oflaxacin 0.3%. Topical homatropine 1% eye drops were used in the selected cases of increased inflammatory reaction, and antiglaucoma drugs were used in those with IOP hike during the postoperative period. Postoperatively, all the patients were examined patients on postoperative day-1, 1 week, and 6 weeks. At postoperative follow-up assessments, all patients underwent BCVA using Snellan chart, IOP (Goldmann applanation tonometer), anterior segment examination with slit lamp and dilated fundus examination. B scan ultrasound was done in cases with reduced media clarity.
The data were analyzed using SPSS version 20.0 Package(IBM, United States) program. Comparison between pre- and postoperative BCVAs and IOP in the two groups was analyzed using paired t-test. Absolute prediction error was calculated for each patient as the difference between the targeted emmetropic power and the postoperative spherical equivalent of refraction at 6 weeks postsurgery. Mean prediction error was calculated as the mean of the absolute prediction errors in the two groups. Difference in the IOL power between the biometric value and the power of the actual IOL implanted was calculated for each patient. It was correlated with the mean IOL prediction error in each of the groups using Pearson's correlation coefficient. Statistical significance was set at P < 0.05.
| Results|| |
This study comprised 87 eyes of 84 patients who underwent surgical correction of aphakia between January 2014 and January 2016 at a tertiary care eye facility. Group 1 (RPICL group) consisted of 47 eyes of 45 patients, and Group 2 (SIPCIOL group) consisted of 40 eyes of 39 patients. Mean age was 67.13 ± 9.33 years in Group 1 and 59.91 ± 16.62 years in Group 2. Group 1 consisted of 27 (57.47%) males and 20 (42.53%) females, Group 2 consisted of 24 (59.52%) males and 16 (40.48%) females. Etiology of surgical aphakia in Group 1 was zonulodialysis >6 clock h 32 (67.81%), posteriorly displaced primary PCIOLs 8 (17.24%), and large posterior capsule rents precluding placement of in the bag PCIOL 7 (14.94%). In Group 2, posterior capsule rents accounted for 35 (86.90%) cases, zonulodialysis >6 clock h 3 (7.14%) cases, and displaced primary PCIOLs 2 (5.95%) cases. 11 (23.40%) eyes in Group 1 and 13 (32.50%) eyes in Group 2 underwent RPICL or SIPCIOL implantation during the primary surgery itself. 36 (76.60%) eyes in Group 1 and 27 (67.50%) eyes in Group 2 underwent RPICL or SIPCIOL implantation as secondary procedure. Timing of surgery and type of IOL implanted was decided as per the discretion of the surgeon. [Table 1] shows the demographic characteristics of the two groups:
Preexisting ocular pathology was present in the form of pseudoexfoliation syndrome (n = 27, 31.03%), trauma (n = 18, 20.69%), macular degeneration (n = 3, 3.44%), postcongenital cataract surgery with amblyopia (n = 3, 3.44%), epiretinal membrane (n = 3, 3.44%), and Marfans syndrome (n = 1, 1.15%). Mean prediction error was 0.41 ± 0.58 D in Group 1 and 0.18 ± 0.20 D in Group 2. Biometric characteristics of the two groups are given in [Table 2].
There was a statistically significant difference between preoperative BCVA and postop BCVA at 6 weeks in Group 1 (P = 0.001, paired t-test) and Group 2 (P = 0.001, paired t-test). However, there was no significant difference in BCVA between the groups at 6 weeks (P = 0.54, unpaired t-test).
RPICL was done as a primary procedure in 11 (23.40%) patients and as a secondary procedure in 36 (76.60%) patients. SIPCIOL was done as a primary procedure in 13 (32.50%) patients and a secondary procedure in 27 (67.50%) patients. There was no statistically significant difference in BCVA at 6 weeks between primary surgery and secondary surgery in Group 1 (P = 0.34, unpaired t-test) and Group 2 (P = 0.59, unpaired t-test). The mean prediction error in Group 1 was 0.41 ± 0.58 D and in Group 2 was 0.18 ± 0.20 and was not statistically significant (P = 0.61, unpaired t-test).
In Group 1, the mean IOP was 17.32 ± 3.44 mm of Hg at 1 week and 13.99 ± 1.05 mm of Hg at 6 weeks postsurgery. In Group 2, the mean IOP was 15.74 ± 2.94 mm of Hg at 1 week and 15.52 ± 2.00 mm of Hg at 6 weeks postsurgery. There was no statistically significant difference between the two groups at 1 week (P = 0.43, paired t-test) and at 6 weeks (P = 0.83, paired t-test). The postoperative visual outcomes of the two groups are compared in [Table 3].
|Table 3: Comparison of postoperative best-corrected visual acuity and intraocular pressure of the two groups|
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Postoperative complications noted were IOP rise in the 1st week postsurgery, 4 cases in Group 1, and 2 cases in Group 2. The maximum IOP rise observed was 30 mm of Hg in patient who underwent RPICL implantation. All the cases with IOP rise responded to medical management and were controlled by 6 weeks, afterwhich antiglaucoma drugs were withdrawn. Three (6.38%) cases in Group 1 and 2 (5.00%) cases in Group 2 suffered from intraoperative vitreous hemorrhage, which resolved after 1 month. IOL tilt was observed in 1 (2.13%) patient in Group 1, resulting in 6 D of astigmatism. However, as this patient had macular scarring due to age-related macular degeneration with poor visual prognosis, further procedures were not performed. Five (5.75%) patients with diabetic retinopathy had worsening of retinopathy and developed macular edema after the IOL implantation. Two (2.30%) patients were treated medically, and 2 (2.30%) patients were treated with laser photocoagulation. One (1.15%) patient was lost to follow-up after 3 months. One (1.15%) patient developed marked anterior uveitis and had pigment dispersion on the IOL in Group 1. Uveitis responded to medical treatment, but BCVA at 3 months did not improve beyond 0.6 logMAR units. Epiretinal membranes were noted in 3 (3.44%) patients postsurgery and their BCVA did not improve beyond 1 logMAR unit. Hypotony and choroidal detachment was seen in one (1.15%) patient, but settled after conservative management and attained BCVA of 0.2 logMAR units following medical treatment. Enclavation of at least one of the haptics over the iris was seen in 8 (17.02%) cases in Group 1, but there was not undue anterior segment inflammation even in these patients. Marked iridodonesis was noted in 8 (17.02%) of the patients in Group 1, however, none of the patients complained of visual symptoms attributable to this finding. There was no case of IOL slippage/dislocation or further procedures performed in any of the patients. There were no patients who developed corneal decompensation or retinal detachment in this series.
| Discussion|| |
Our study shows comparable outcomes between RPICL group and SIPCIOL group in terms of BCVA at 6 weeks. In both the groups, there was a statistically significant difference between the preoperative and postoperative BCVA at 6 weeks (P = 0.001 in both the groups, paired t-test). The mean BCVA in the RPICL group was 0.11 ± 0.03 logMAR units and in the SIPCIOL group was 0.13 ± 0.02 logMAR units. Although it can be seen that the mean BCVA of RPICLs was slightly better than SIPCIOL group, it was not statistically significant (P = 0.76, unpaired t-test).
We also compared IOL prediction error between these two IOLs and found that there was no significant difference between them. This indicates that the prediction accuracy was also comparable between these two IOL types. This was true even in those cases with “unplanned” primary implantation of IOLs and indicates the precision of the normograms used.
In our series, there was no difference in visual outcome and complications between the primary and secondary IOL implantation surgeries. One important factor which has to be stressed here is the vitreous clearance from the anterior chamber. Provided there is satisfactory vitreous clearance, primary surgery outcomes are comparable to those following secondary surgery, as per the results obtained from our study.
The anatomical stability of the implanted IOLs was comparable, and there was no case with posterior dislocation/disenclavation of IOL. There was one patient in the RPICL group who developed IOL tilt following blunt trauma 1 month after surgery. Even in this case, there was no RPICL disenclavation or dislocation, only a tilt resulting in astigmatism of 4.5 D. As this patient also had macular scar from age-related macular degeneration, no further procedures were performed in view of guarded visual prognosis. The previous studies have reported dislocation of iris-claw lenses ranging from 1.5% to 3%, especially in rigid traumatizes irides.,,
Four (8.51%) patients in RPICL group and 5 (12.5%) patients in SIPCIOL group had vitreous strands in the anterior chamber. These were caused by inadequate vitrectomy subsequent to reduced visualization of anatomical details intraoperatively. There was no endothelial or wound touch of the vitreous strands in any of these patients, and it did not interfere with postoperative BCVA.
There was no significant difference in the IOP between the two groups (P = 0.34, unpaired t-test) and none of the patients required surgical treatment for secondary glaucoma. This finding was consistent with the previous reports., Out of those who developed IOP rise, two had vitreous in pupillary area, two had a history of trauma, and one patient had residual viscoelastic substance in the anterior chamber. IOP rise in these cases could be attributed to anterior chamber angle pathology resulting from blunt trauma. We did not do peripheral iridectomy routinely in all the cases, and no cases of pupillary block occurred. This could be explained by the availability of adequate space between the lens optic and the back of the iris for aqueous drainage.
We had 6 (6.89%) cases of macular edema detected in the postoperative period. This was due to the complications encountered during primary surgery (n = 3), worsening of diabetic retinopathy (n = 3). The previous studies indicate that pigment dispersion was more common in RPICL implantation., However, it was seen only in a single patient in our series. This could be due to the design of RPICL used provided adequate space between the iris-pigmented epithelium and the optical zone of the lens. This could explain the low number of iris dispersion cases in our study.
One patient had severe hypotony resulting in choroidal detachment in Group 1. This patient was managed with systemic and topical steroids, and the condition settled after 3 weeks, with BCVA of 0.2 at 6 weeks. Three patients had intraoperative breakage of the trailing haptic of the RPICL. These were retrieved, and another IOL was enclaved at a different site. Ovalization of the pupil was seen in 2 (4.51%) of the patients in our series. In our opinion, this is a minor finding and did not interfere with visual outcome. There were 6 cases with part of the haptic seen in front of the iris. This complication has not been previously reported. We presume that this was due to the increased pressure exerted by the instrument during enclavation in atrophic irides. 4 of these patients had BCVA of zero logMAR and 2 patients had 0.2 logMAR at 6 weeks postsurgery. There was no glare disability, evidence of increased intraocular inflammation, or uveitis in these patients. However, part of the haptic could be seen anterior to the iris on slit lamp examination. Marked iridodonesis could be seen in 8 patients who had RPICOL implantation, as observed in previous reports also. All these eyes had undergone automated vitrectomy during the primary surgery, and the tremulousness was presumed to be due to lack of vitreous support in these eyes. However, none of the patients had complaints attributable to this finding. Therefore, no further interventions were performed. There were no patients who developed corneal decompensation or retinal detachment in this series. This indicates the relative safety of these procedures.
Merits of our study include relatively large sample size, analysis of multiple parameters including IOP, IOL prediction error, and timing of IOL implantation. Limitations include the short duration of follow-up.
| Conclusion|| |
In our study, RPICL faired equally well as SIPCIOLs in terms of BCVA, IOL prediction error, IOP, and safety profile. Outcomes of primary IOL implantation and secondary IOL implantation were comparable between the two groups.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]