|Year : 2019 | Volume
| Issue : 1 | Page : 3-7
Clinical outcome of iris-claw intraocular lens implantation
D Anandhi1, M Rekha Sravya2
1 Department of Ophthalmology, Tirunelveli Medical College, Tirunelveli, Tamil Nadu, India
2 Department of Ophthalmology, JIPMER, Puducherry, India
|Date of Web Publication||10-Jun-2019|
Dr. M Rekha Sravya
No. 4, Kanagan Lake Road, Satyamurthy Nagar, Thilaspet, Puducherry - 605 009
Source of Support: None, Conflict of Interest: None
Aim: The aim of this study is to study the indications, visual outcome, and complications in patients undergoing iris-claw intraocular lens (IOL) implantation. Settings and Design: This is a prospective interventional case series conducted between January 2016 and June 2017 in a tertiary care hospital. Materials and Methods: Seventy-nine eyes of 78 patients with aphakia or subluxation of lens of various etiologies were included in the study. Complete ophthalmological examination was conducted. Retropupillary iris-claw IOL implantation was done in the included patients. Patients were followed-up to 6 months for visual acuity, intraocular pressure measurement, and complications. Statistical Analysis Used: Statistical analysis was performed by the Students t-test. Results: The difference between preoperative and postoperative visual acuity was statistically significant in the group of patients undergoing iris-claw IOL implantation as a primary procedure (P < 0.0001). The difference was insignificant in the aphakic patients undergoing secondary IOL implantation. The interval between the primary surgery and the secondary procedure did not make a statistically significant impact on the visual outcome (P = 0.67). Common complications after iris-claw IOL implantation in this study noted were corneal edema, pupil ovalization, raised intraocular pressure, and iris atrophy. Conclusions: Retropupillary iris-claw IOL implantation is a safe and easy method of managing patients with aphakia and subluxation of the lens.
Keywords: Iris claw, ophthalmological examination, retropupillary, secondary intraocular lens
|How to cite this article:|
Anandhi D, Sravya M R. Clinical outcome of iris-claw intraocular lens implantation. TNOA J Ophthalmic Sci Res 2019;57:3-7
| Introduction|| |
Posterior chamber intraocular lens (PCIOL) implantation is a challenge in patients with inadequate capsular support resulting from the posterior capsular (PC) rent during cataract surgery leading to aphakia and in patients with subluxation of the crystalline lens of various causes. Spectacle correction of aphakia has the disadvantages of image magnification of 20%–35%, diplopia, reduced the field of vision, jack in the box phenomenon, and cosmetic unacceptability.
Surgical options available are implantation of the anterior chamber (AC) IOL, scleral-fixated (SF) IOL, anterior or posterior iris-fixated IOL, and glued IOL.
To study the indications, visual outcome, and complications in patients undergoing iris-claw IOL implantation.
| Materials and Methods|| |
This study was conducted at a tertiary care hospital in South Tamil Nadu between January 2016 and June 2017 over a period of 18 months with a follow-up period of 6 months. It is a prospective interventional case series with 79 eyes of 78 patients in the age group of 14–80 years.
Minimum sample size of 59 was proposed with a 95% of confidence interval. However, 78 patients were recruited until the end of 18 months recruitment period. Ethics Committee Clearance was obtained, and adherence to the tenets of the Declaration of Helsinki was followed.
Inclusion criteria were aphakia and subluxation of the crystalline lens. Patients with aphakia following PC rent during cataract surgery where PCIOL could not be implanted and patients with subluxation of the crystalline lens which was congenital or acquired secondary to zonular dehiscence from trauma, pseudoexfoliation syndrome, and advanced cataract were included in the study. Exclusion criteria were corneal edema, inadequate iris tissue, aniridia, raised intraocular pressure (IOP), severe iritis, and macular pathology such as cystoid macular edema (CME) and choroidal neovascular membrane which would preclude a good visual outcome.
Preoperatively, all patients underwent complete ophthalmologic evaluation including:
- Best-corrected visual acuity (BCVA) for distance using Snellen's chart in logMAR
- Slit-lamp examination with emphasis on previous surgical incision, peripheral iridectomy, iritis, and size and shape of the pupil
- Manual keratometry and contact A-scan biometry
- IOL power calculation was performed using SRK/T formula with an A constant of 117.2
- Fundus examination with +90 D lens and indirect ophthalmoscopy
- The Goldmann applanation tonometry
- B-scan ultrasonography was conducted in the selected cases.
The retropupillary iris-claw IOL was implanted as a primary procedure when PCIOL could not be implanted as a result of PC rent or zonular dehiscence. The iris-claw lens was implanted as a secondary procedure in patients with aphakia who underwent prior cataract extraction. All surgeries were performed by a single surgeon.
In case of secondary procedure, conjunctiva was separated from adhesions, exposing the previous scleral incision. Two-side ports were made diagonally opposite, i.e., at 3 o' clock and 9 o' clock positions. The AC was formed with a viscoelastic substance, and the tunnel was opened with the iris repositor. If the vitreous was noted in the AC, automated anterior vitrectomy was done. Geuder machine was used with 800–1000 cut rate and 350 vacuums with the manually controlled flow rate. Iris-claw IOL was introduced into the AC such that haptics were in line with the side ports. Holding the optic of the lens with a Shepard lens holding forceps, one haptic was pushed under the iris with gentle manipulation. Simultaneously, dialor was passed through the respective side ports and haptics of the IOL enclaved to the iris. Endpoint was noting the dimple at the site of enclavation. Similarly, haptic enclavation on the other side was done. Peripheral iridectomy was performed at 12 o' clock position. AC was cleared off viscoelastic substance, side-port hydrated, and wound integrity verified. Subconjunctival dexamethasone injection was given. Postoperatively, topical moxifloxacin and dexamethasone eye drops in a tapering schedule over 6 weeks were given, and topical bromfenac eye drops were administered for a period of at least 6 weeks. Oral acetazolamide and ibuprofen BD were given in the immediate postoperative period.
In case of primary procedure, a standard manual small-incision cataract surgery was performed. Following PC rent or capsular bag extrusion along with the nucleus, AC was cleared off the vitreous by automated anterior vitrectomy. When PCIOL implantation was not possible, iris-claw lens was placed posterior to the iris as described above.
Pupil was dilated in cases of subluxation of the lens. In eyes with aphakia, undilated pupil was preferred. The iris-claw lens used in this study was of Excel Optics, Size. 8.00 mm × 5.50 mm, Model No. PIC 5580. It is a single-piece polymethyl methacrylate lens.
Patients were followed-up after 1 week, 1 month, 3 months, 6 months, and looked for BCVA, IOP, and anterior segment and fundus examination.
| Results|| |
This study comprised 79 eyes of 78 patients. Patients' age ranged from 14 years to 85 years with a mean age of 63.4 ± 11.5 years. Males comprised 41 and females 37. There were 44 (55.7%) right eyes and 35 (44.3%) left eyes.
Of the total 79 eyes studied, 59 patients had aphakia, 17 patients had the subluxated lens, 2 patients had a decentered PCIOL, and 1 patient had IOL haptic in AC which were removed and exchanged with iris-claw IOL. [Table 1] shows the indications of iris-claw IOL implantation in this study.
Iris-claw IOL implantation was performed as a primary procedure in 27 eyes of which 17 eyes were operated for subluxation of the lens and ten for aphakia following PC rent during primary cataract surgery. Iris-claw IOL implantation as a secondary procedure was done in 52 eyes of which 49 eyes were aphakic and three eyes had an exchange of dislocated IOL. [Figure 1] shows well-centered iris-claw IOL which was placed.
We found that the most common indication for iris-claw IOL implantation in the primary procedure was PC rent. PC rents occurred in the following types of cataract in the decreasing order of frequency–nuclear sclerosis (NS) V, NS IV, mature cataract (MC), and hyper-MC. Lower grades of cataract were involved when pseudoexfoliation was associated. [Figure 2] shows subluxated cataractous lens.
Mean preoperative BCVA was 1.14 ± 0.49 logarithmic minimum angle of resolution (logMAR), and mean postoperative BCVA at 6 months follow-up was 0.75 ± 0.46 logMAR. This was statistically significant (P < 0.0001).
It implies that all subgroups had a significant improvement in postoperative BCVA over the preoperative BCVA. Preoperative and postoperative BCVA among the various groups are compared in [Table 2]. It shows that there is a significant difference in the preoperative and postoperative BCVA for the cases done as primary procedure. This may be due to the additional factor of cataract extraction in the primary procedure. However, there is no significant difference between preoperative and postoperative BCVA for the cases taken on a later date as a secondary procedure.
|Table 2: Pre and post operative best-corrected visual acuity among various groups|
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[Graph 1] depicts the distribution of the difference between the preoperative and postoperative BCVA in logMAR in relation to number of days after the primary procedure. Patients falling on the negative side of zero have worsened BCVA (i.e., Postoperative BCVA logMAR is greater than preoperative BCVA logMAR) in comparison to patients on the positive side of zero.
From the graph, we can derive that of the total 52 cases done as secondary procedures, six cases were obtained after 45 days of primary surgery, and 46 cases were obtained within 45 days of primary surgery.
Number of patients having worsened vision or equal or better postoperative vision with respect to the duration of secondary procedure is depicted in [Table 3].
|Table 3: Number of cases done as secondary procedure with difference of pre and postoperative BCVA in LogMAR|
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There is no significant difference in postoperative BCVA in the two groups of patients (secondary surgery <45 days and >45 days) as shown in [Table 3]. This shows that the time of second-surgery postaphakia does not affect the final visual outcome provided there is no corneal edema, IOP is maintained within the normal range, and inflammation is well-controlled.
Immediate postoperative complications were iritis, corneal edema, and raised IOP which were relieved within 1 week. Other complications included ovalization of the pupil, IOL decentration, and iris atrophy in long term as depicted in [Table 4]. None of the eyes had CME, bullous keratopathy, or retinal detachment during 6 months follow-up. None of the eyes had pigment dispersion and the need for reenclavation. [Figure 3] shows iris atrophy following iris-claw IOL implantation.
|Figure 3: Iris atrophy following iris-claw intraocular lens implantation|
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| Discussion|| |
There are various options of IOLs available for aphakia. ACIOL, SFIOL, and iris-supported IOLs are among these. ACIOLs have a higher risk of corneal decompensation, uveitis, and raised IOP. Implantation of SFIOL is technically more difficult to perform even though the results are good.
Simpler procedure, positioning of IOL near the nodal point, and absence of the need for a suture or glue are the advantages of retropupillary iris-fixated IOL.
In this study, we used retropupillary iris-claw IOL to lower the risk of' corneal decompensation as in Hazar et al. study. Patients were followed-up for 6 months. The two main parameters measured were BCVA and the rate of complications.
There was no significant difference between preoperative and postoperative BCVA in cases of aphakia (P = 0.111) and IOL exchange (P = 0.423). However, there was a significant improvement between pre-and post-operative-BCVA in the subluxation group (P < 0.0001). Iris-claw IOL implantation as a primary procedure showed a significant improvement in BCVA (P < 0.0001), whereas in secondary procedure, there was no significant difference at any duration postaphakia in this study (P = 0.075). On an average, all subgroups had a significant improvement in postoperative BCVA over the preoperative BCVA (P < 0.0001) as compared to the Gonnermann et al. study.
In our study, iris-claw IOL was implanted in 17 eyes with subluxated lens, four being secondary to trauma, four had congenital subluxation of the lens with Marfan syndrome, and four were due to advanced cataract. Iris-claw IOL implantation is considered to be a better option in such situations as also observed by Bhandari et al. study and Forlini et al. study. IOL exchange was done in two eyes with decentered PCIOL and one eye with IOL haptics placed in the AC.
In our study, ovalization of the pupil was observed in 9.8% of eyes comparable to 13.9% eyes in Gonnermann et al. study as against 5% in Forlini et al. study. Corneal edema was observed in four eyes (5.6%) which was controlled by 5% Hypersol eye drops for 2 weeks postoperatively. Iris atrophy was observed in eight eyes (11.2%) which was permanent, comparable to Faria et al. study. Elevated IOP was observed in three (4.2%) eyes within the first-postoperative week similar to 4.3% in Gonnermann et al. study. Injection mannitol IV for 3 days and oral acetazolamide BD were administered. IOP was normal at the end of 1 week and did not further require any anti-glaucoma medication. No eye had significant pigment dispersion or secondary glaucoma requiring additional postoperative treatment. Gonnermann et al. reported disenclavation in 8.7% of the eyes. None of our patients had disenclavation within the follow-up period. None of our patients had chronic AC inflammation as described by Forlini et al. Macular edema or spontaneous IOL dislocation were not observed in our patients as described in the other studies.
Some limitations of our study were short follow-up, lack of data about other parameters such as endothelial cell count and induced astigmatism and a single surgeon.
| Conclusions|| |
Posterior iris-claw IOL implantation is a safe and easy method of rehabilitating the patients with aphakia and subluxation of the lens. Proper selection of patients for iris-claw IOL implantation with meticulous surgical technique would ensure minimum vision-threatening complication rate. Low incidence of intraoperative and postoperative complications makes it a viable option for every cataract surgeon to manage without a vitreoretinal surgical backup.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]