Journal of Clinical Ophthalmology and Research

ORIGINAL ARTICLE
Year
: 2020  |  Volume : 8  |  Issue : 3  |  Page : 100--103

Comparative study of secondary implantation of iris-claw lens and scleral-fixated intraocular lens in terms of visual outcome and complications


C Navya, Ajay S Hatti 
 Department of Ophthalmology, S S Institute of Medical Sciences and Research Centre, Davangere, Karnataka, India

Correspondence Address:
C Navya
Department of Ophthalmology, S S Institute of Medical Sciences and Research Centre, NH4 Bypass Road, Davangere - 577 005, Karnataka
India

Abstract

Introduction: The modern cataract surgery is involved in implanting the posterior chamber intraocular lens (PCIOL) in the intact posterior capsule. However, the implantation of PCIOL is not possible in case of weak or no capsular support. In such situations, iris-claw lens (ICIOL) and scleral-fixated intraocular lens (SFIOL) remain as treatment options. Objective: The objective was to analyze the efficacy of ICIOL and SFIOL in terms of visual outcomes and complications. Materials and Methods: It was a prospective study with 30 aphakia patients fulfilling inclusion criteria. These patients were divided into two groups with 15 in each group. Group I patients underwent ICIOL and other 15 patients in Group II underwent SFIOL implantation. Patients with preexisting ocular pathologies were excluded. The preoperative and postoperative evaluation was done for the follow-up period of 6 months. Results were analyzed with Chi-square test and t-test using SPSS software. Results: In ICIOL group, 86.67% of patients and 80.6% of SFIOL patients had final best-corrected visual acuity (BCVA) 6/18–6/6. The mean logMAR BCVA in both groups was comparable. The surgical time in ICIOL was significantly less than SFIOL group (P = 0.00). Suture-related complications were significantly more in the SFIOL group. Complications found in the ICIOL group were harmless. Conclusion: The visual outcome was found to be comparable in both groups. ICIOL requiring less surgical time with fewer complications was found to be a good alternative to SFIOL in correction of aphakia.



How to cite this article:
Navya C, Hatti AS. Comparative study of secondary implantation of iris-claw lens and scleral-fixated intraocular lens in terms of visual outcome and complications.J Clin Ophthalmol Res 2020;8:100-103


How to cite this URL:
Navya C, Hatti AS. Comparative study of secondary implantation of iris-claw lens and scleral-fixated intraocular lens in terms of visual outcome and complications. J Clin Ophthalmol Res [serial online] 2020 [cited 2021 Jan 25 ];8:100-103
Available from: https://www.jcor.in/text.asp?2020/8/3/100/302199


Full Text



The crystalline lens capsule is an elastic basement membrane which contains lens substance. The thinnest part of the capsule is located in the posterior pole.[1] Thus, modern cataract surgery is involved in implanting posterior chamber intraocular lens (IOL) in the intact posterior capsule. However, the implantation of posterior chamber IOL is not possible in case of weak or no capsular support. In such situations, angle-supported IOL, iris-claw lens (ICIOL), and scleral-fixated IOL (SFIOL) remain as treatment options.[2],[3],[4],[5]

The technique of retropupillary fixation of ICIOL was reported by Andres Mohr in 2002.[6] This procedure with less surgical time preserves the anatomy of the anterior segment with respect to position of natural crystalline lens and has cosmetic benefit with low-risk method of surgery. There are also few disadvantages such as dislocation, pupillary deformity, and iris atrophy.[5] Even though SFIOL offers better visual outcome, it is associated with certain complications such as suture erosion, IOL decentration and tilting, retinal detachment, cystoid macular edema, and is technically more difficult.[5],[6]

Objectives of the study

The aim of the study was to compare the visual outcome and complications associated with the implantation of iris-claw IOL with that of SFIOL.

 Materials and Methods



It was a prospective interventional comparative study. Thirty patients presented to the outpatient department during the study period from September 2015 to June 2017 were included in the study. These patients were allotted into two groups by simple randomization. Patients were made to toss a coin, and patients with head were assigned to Group I and tail to Group II, with 15 patients in each group. Patients in Group 1 underwent ICIOL and Group II underwent SFIOL. As it was a comparative study and the period of study was limited to 2 years, the sample size was taken as 30.

The study was done after obtaining ethical clearance from the institutional ethics review board with the reference IERB number 96-2015. Adult patients aged between 30 and 75 years with aphakia resulting secondary to surgery and following trauma, in whom vision was improving more than 6/36 with aphakic correction were included in the study. Patients with preexisting ocular pathology were excluded from the study.

Preoperative evaluation involving visual acuity, slit-lamp examination, intraocular pressure measurement, and detailed fundus examination was done. Preoperative biometric values were considered in aphakia patients secondary to surgery, and IOL power was calculated computing A constant of the IOL used.

ICIOL from Freedom Surgicals was used with A constant 115 and SFIOL from Aurolab was used with A constant of 118.5. Both the surgical procedures were done under the peribulbar block. Two different surgeons with expertise in either of the techniques performed the surgery. Anterior vitrectomy was done in both the groups.

ICIOL was implanted by making two paracenteses 90º from the main incision. Intraoperative miosis achieved using 0.2–0.3 ml of 0.5% intracameral pilocarpine (aurocarpine 0.5%). Holding the optic with ICIOL holding forceps, both the haptics are tucked behind the iris one haptic, followed by the other. Viscoelastic was injected at each stage to deepen the anterior chamber and maintain space.

For SFIOL, two partial thickness scleral flaps 1.5–2 mm posterior to the limbus were fashioned at the 3 0‟clock and 9 0‟ clock meridians, 180° apart. A double arm 10-0 prolene suture with a straight needle was used. The needle was railroaded out of the eye through the bed of the opposite scleral flap using a bent 26 g needle introduced through the scleral bed. A limbal section was fashioned and the sutures were drawn out of the eye and cut into two halves. Each half of the sutures was passed through the fixation eyelet on the superior and inferior haptic of the IOL. A single piece, PMMA, large optic IOL (equiconvex 6.5 mm optic, 13 mm overall length) was used for scleral fixation. The IOL was introduced into the posterior chamber, and the sutures were tightened and tied. The suture knots were buried in the scleral bed and the scleral flaps were sutured.

Subconjunctival gentamicin and dexamethasone 0.5cc were given at the end of both the procedures. Patients of both the groups were started on antibiotics with steroid combination drug topically, one drop hourly for the 1st day and gradually tapered over the subsequent follow-ups. Postoperative evaluation was done following each procedure on 1st day, 1st week, 1st month, 3rd month, and 6th month. Uncorrected visual acuity, followed by slit-lamp examination and fundoscopic evaluation was done on each visit to look for complications. Best-corrected visual acuity (BCVA) was done in 6th month. The visual acuity in Snellens was converted to the logarithm of the minimum angle of resolution (logMAR) units for the statistical analysis. The results were analyzed using the Stastical Package for the Social Sciences(SPSS) version10 (IBM statstics,Chicago,USA), using the Chi-square test and t-test. P < 0.05 was considered as statistically significant.

 Results



The patients included in the study were matched in terms of age. Majority of them were between 65 and 69 years. Two groups were equally matched for sex.

The most common etiology for aphakia in our study was complicated cataract surgery. One patient had traumatic lens drop and one patient had postcataract surgery IOL drop. One patient with iris coloboma was included in Group I. Majority of patients had counting finger (CF) 1 m-CF3 m vision in both the groups as shown in [Graph 1].[INLINE:1]

The mean time taken for Group I (27 min) was less when compared to Group II (42 min), and it was found to be statistically significant.

At postoperative 6 months, 46.66% of patients had vision better than 6/12 in Group I, whereas in Group II, 20% of patients had vision better than 6/12. One patient in each group had vision <6/60 as shown in [Graph 2]. In both the groups, more than 80% of patients had BCVA of 6/18 at 6 months [Graph 3]. Postoperative visual outcome was similar in both the groups with no statistically significant difference.[INLINE:2][INLINE:3]

Complications associated with both the procedures are as follows: at postoperative day1, both the groups had common complication, but pupil ovalization was seen more significantly in Group I. At postoperative 1 week, striate keratopathy persisted in five patients in Group I at 1 week because of high anterior chamber reaction, endothelial damage in one patient, whereas two other patients were noncompliant with their steroid drug. They were later switched over to hourly medication of steroids.

Disenclavation of one haptic was noted in one patient in Group I. It was re-enclavated and followed up. Suture-related problems such as scleral flap erosion and suture exposure resulted in IOL tilt which caused astigmatism of 3 diopters in two patients of Group II. [Table 1] describes all postoperative complications seen from 1st week to 6 months.{Table 1}

At the end of the follow-up period of 6 months, pupil ovalization and pigment dispersion were seen statistically significant in Group I, whereas in Group II, four patients had suture-related complication, which was found to be statistically significant.

 Discussion



Anterior and scleral-fixated PC IOLs have been the most popular type of IOLs for the correction aphakia in case of inadequate capsule support,[7] and they avoid the need for aphakic spectacles or contact lenses. However, the choice of IOL in aphakia treatment is still debatable.

There has been much discussion on the best method for secondary IOL implantation that offers the lowest complication rate and best possible visual rehabilitation over several years.[8],[9] Each of the available options has its own risks and complications. Transscleral fixation of posterior chamber IOLs is an extremely technically demanding procedure with relatively high risk of intraoperative and postoperative complications and requires a large amount of dissection into the conjunctiva and the sclera.[10] Angle-supported anterior chamber IOL implantation, although technically easier, has been associated with several complications related to the iridocorneal angle and the corneal endothelium.[11]

Retropupillary fixation of an iris-claw IOL has the advantages of true posterior chamber implantation, which results in a deeper anterior chamber and greater distance to the corneal endothelium. This has a lower intraoperative and postoperative risk profile than anterior fixation.[12],[13]

The mean surgical time taken for ICIOL in this study was 27 ± 4 min, whereas it was 12 ± 4.71 min in a study by Ashwini and Narendra.[14] The mean surgical time for SFIOL in this study was 42 ± 5 min and 30.9 ± 5.81 min by Ashwini.[14] The mean surgical time was more in our study because of inclusion of anterior vitrectomy procedure, however this was found to be statistically significant.

Thirteen patients (86%) of ICIOL group and 80% (12 patients) got BCVA >6/18 at the end of 6 months and one patient in the ICIOL group got <6/60 which was same as preoperative vision because of intraoperative endothelial damage. In a study done by Ashwini,[14] 73% of eyes with ICIOL and 70% with SFIOL achieved BCVA >6/18.

The mean postoperative BCVA of our study was found to be comparable with Ashwini[14] and Farrahi et al.[15] The mean BCVA of ICIOL and SFIOL in Ashwini was 0.41 ± 0.32 and 0.45 ± 0.37, respectively. In Farrahi et al. study, the mean BCVA was 0.44 ± 0.24 and 0.61 ± 0.25 for ICIOL and SFIOL, respectively, whereas in our study, it was found to be 0.34 ± 0.3 for ICIOL and 0.36 ± 0.24 for SFIOL group. Gonnermann et al.[16] found the mean BCVA of 0.38 ± 0.31 in their study on ICIOL which is comparable to our results. Even though our results were better than the above studies, statistical significance was not found between the two groups.

At the 1st postoperative day, striate keratopathy and anterior chamber reaction were present in all patients of both the groups, which gradually reduced over subsequent follow-ups. Pupil ovalization was observed in four patients (26%) of ICIOL group, and it remained the same till the last follow-up day and no such complication in any patient in SFIOL group. This was comparable to a study done by Ashwini,[14] and they found pupil ovalization in five patients of ICIOL group and one patient in the SFIOL group. This complication can occur due to asymmetrical and very tight fixation of haptic. It was less than a study conducted by Gonnerman.[16] Baykara et al.[13] found persistent pupil ovalization after posterior iris-claw IOL implantation in 12.7% of eyes.

The secondary rise of IOP was seen in one patient of ICIOL group. This came down with control of inflammation at the end of the 1st week. There was no clinically significant glaucoma, which was found to be same as in a study conducted by Ashwini[14] and wherein study by Gonnerman et al.[16] Six patients had elevated IOP. One patient in the SFIOL group had elevated IOP at 1-week follow-up. On examination, there was angle recession noted on gonioscopy as it was a case of aphakia secondary to trauma. Secondary glaucoma due to angle recession was treated with antiglaucoma medication. Despite that, no other patient in SFIOL group had elevated IOP unlike four cases in the study by Ashwini.[14]

Pigment dispersion was noted in four cases in the ICIOL group which was more when compared to a study done by Forlini et al.,[17] who found four cases in 320 eyes which is lesser. The explanation given for its fewer occurrences was the vaulted design of the Artisan aphakic lens and its inverted position which provides adequate space between the iris-pigmented epithelium and the optical zone of the lens. However, it was not associated with secondary elevated IOP.

One patient had disenclavation of ICIOL at 1-month follow-up, and it was repositioned back and followed up. Similarly, subluxation was noted in one patient in the study by Ashwini[14] and similar citing was seen by Gonnerman[16] who found dislocation rate up to 8.7%. Three cases of spontaneous disenclavation of one haptic occurred in the study by Forlini et al.[17] It is a known complication and is corrected by surgical experience. Suture-related complications such as conjunctival erosion and IOL tilt were seen in four cases of our series and are same as that found in the study by Ashwini.[14]

Cystoid macular edema was found in one patient in both the groups and was treated with steroids. CME of ICIOL group reduced and in SFIOL group remained the same. CME was not observed in ICIOL group but seen in two cases of SFIOL group in the study by Ashwini,[14] whereas in a study by Gonnerman et al.,[16] the incidence of postoperative macular edema was 8.7% after 6.7 months. Although this CME rate was higher than 4.1% and 4.8% seen in study by Mohr A[18] and Wolter Roessler M[19] respectively. CME rate in ICIOL is still lower than the rate after implantation of scleral-fixated PC IOLs (5.8% to 33%).[20],[21]

However, our study had some demerits such as small sample size and short duration of follow-up.

 Conclusion



The visual outcome after retropupillary iris-claw IOL implantation was found to be comparable with that of the SFIOL. However, ICIOL had a shorter surgical time period with acceptable complication rates. Hence, ICIOL can be a promising alternative to SFIOL in aphakic eyes with inadequate posterior capsular support.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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