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Anterior chamber lens can be replaced with glued IOL in complicated eyes
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For the past 2 decades, anterior chamber IOLs have been an established method of IOL implantation in eyes with deficient capsules either as a primary or secondary procedure. Anterior chamber IOLs are preferred over sulcus-sutured IOLs because they are technically easier to implant, are reasonably well-tolerated, and have a low rate of postoperative IOL decentration or tilt. However, anterior chamber IOLs have also become one of the causes of IOL exchange and explantation.
Implant-related problems such as discrepancies between anterior chamber biometry and IOL size may cause pseudophakodonesis in the aqueous, resulting in progressive endothelial cell loss. Infrequently, anterior chamber IOL-iris contact may lead to pigment dispersion with subsequent inflammation. Occasionally, secondary angle closure and glaucoma with corneal decompensation due to haptic displacement may develop. Due to these reasons, eyes with shallow anterior chambers or early corneal guttata have been treated as relative contraindications for anterior chamber IOLs. The main advantage of a glued IOL in these cases is its anatomical position similar to the normal lens with no suture-related complications.
Study
Thirty-eight eyes with a mean follow-up of 24.1 ± 15.4 months were analyzed. The indications for IOL exchange were corneal decompensation (39.4%), malpositioned anterior chamber IOL (28.9%), chronic uveitis (15.7%), glaucoma (13.1%) and broken haptic (2.6%). Thirty-four eyes showed an increase in corrected distance visual acuity after IOL exchange. There was a significant decrease in the central corneal thickness after anterior chamber IOL removal. Mean endothelial cell loss was 3.4% ± 2.4%.
Surgical technique
To prepare the glued IOL, localized peritomy at the intended site of the scleral flaps was done under peribulbar anesthesia. Two partial-thickness limbal-based scleral flaps about 2.5 mm × 2.5 mm were created, using a scleral marker, exactly 180° diagonally apart. A 23- or 20-gauge infusion cannula or anterior chamber maintainer was inserted for infusion. Two straight sclerotomies with a 20-gauge needle were made about 1 mm to 1.5 mm from the limbus under the existing scleral flaps.
For anterior chamber IOL removal, a small scleral tunnel incision was made with a 3.2-mm keratome, and the incision was beveled forward. The anterior chamber was filled with an ophthalmic viscoelastic device (OVD). Anterior vitrectomy in the anterior chamber and pupillary region was done to cut the vitreous traction. The scleral wound was then extended to 6 mm (Figure 1). The existing IOL in the anterior chamber was removed by McPherson forceps under the cushioning effect of the OVD to prevent intraoperative endothelial touch. Techniques used for anterior chamber IOL explantation included synechiae release, OVD injection, hinging, moving the optic, rotating the remainder of the lens through the incision and transection with Vannas scissors, if necessary.
Figure 1. Anterior chamber IOL explantation. Intraoperative image of the anterior chamber IOL with the haptic in the angle and the keratome entry was made (top left), anterior chamber was formed with viscoelastics (top right), anterior chamber haptic was pulled through the extended scleral incision (bottom left), and the anterior chamber IOL was explanted (bottom right).
Images: Agarwal A
Figure 2. Glued IOL. Anterior vitrectomy in the pupillary plane was done (top left) after anterior chamber IOL explantation, followed by posterior chamber IOL insertion through the main incision (top right). The haptics were externalized through the sclerotomies under the scleral flaps and tucked in the scleral tunnels (bottom left). The anterior chamber was formed with an air bubble, and the wound was sutured (bottom right).
For the glued transscleral IOL fixation, the posterior chamber IOL, held with McPherson forceps, was passed through the scleral wound, and the glued IOL forceps were passed through the sclerotomy. The tip of the leading haptic was grasped and externalized by the glued IOL forceps. The haptic was held by an assistant. The second haptic was then flexed into the anterior chamber and pulled through the opposite sclerotomy by the glued IOL forceps using the handshake technique (Figure 2). When both the haptics were externalized under the flaps, they were tucked into the limbus parallel to intralamellar scleral tunnels made with a 26-gauge needle. Reconstituted fibrin glue (Tisseel, Baxter) was injected under the scleral flaps; local pressure was given for 10 seconds. The scleral wound was closed with 10-0 monofilament nylon suture. The conjunctiva was closed with the fibrin glue. Topical 0.3% ofloxacin and 1% prednisolone acetate eye drops were prescribed four times daily for 4 weeks.
Discussion
Pseudophakic bullous keratopathy has been the most common cause for IOL exchange in the majority of eyes with anterior chamber lenses. In our series, corneal decompensation was the most common indication. The shallow anterior chamber and incorrect size of the IOL might be the probable causes for chronic endothelial damage in those eyes. If the haptics were not placed properly or if the anterior chamber IOL has been inverted, the IOL can migrate anteriorly and contact the peripheral corneal endothelium, resulting in endothelial cell loss and corneal edema. When studied by ultrasound biomicroscope, a glued IOL provided a deeper anterior chamber and good iris vault as compared with an anterior chamber IOL. The benefit of anterior chamber IOL explantation will be attained only if the IOL exchange was performed before a critical degree of endothelial cell loss or dysfunction developed.
The second common indication for IOL exchange in our series was a luxated anterior chamber IOL. Two eyes with luxated anterior chamber IOLs had significant corneal edema and pseudophakodonesis. Incorrect sizing of the anterior chamber IOL with respect to anterior chamber depth and sulcus-to-sulcus diameter was the probable cause. Sphincter damage or a chronic dilated pupil with vitreous in the pupillary plane may also lead to luxation of the IOL. The luxated IOL caused the endothelial damage either by continuous haptic-endothelial contact or pseudophakodonesis. There was no glued IOL decentration in the postoperative period, which showed the good IOL stability in the complicated eyes.
Glued IOLs may be more cost-effective because there is no need for special IOL designs. Our study showed that IOL exchange with a glued IOL can improve clinical signs in more than 90% of eyes. Therefore, a glued transscleral-fixated IOL is a good alternative in eyes with shallow anterior chambers or low endothelial cell counts.