The major problem with the scleral-fixated IOL is that it can swivel on the axis of the sutured haptics as it is literally dangling from 2 sutures. The other problem, which this patient faced the first time, is that delicate polypropylene sutures can erode, causing to the lens to become mobile and the IOL to tilt. Decentering and tilting of the IOL are more common if the anterior sclerotomies are not exactly 180 degrees apart and if the sutures are tied at unequal distances from the ends of both haptics in cases with IOLs without eyelets on the haptics. I believe the latter is a very important cause of optic capture. The glare and decreased vision the patient reports is caused by refraction through the lens periphery creating irregular astigmatism and optical aberrations. The fixed pupil also contributes to the optical aberrations.
If the patient is not troubled by the visual symptoms, observation is an option. If he is symptomatic, the approach would be to first determine the integrity of the IOL and haptics. For this, ultrasound biomicroscopy of the anterior segment could be done. Specular microscopy should be used to determine the endothelial cell count. A thorough preoperative retinal examination is also a must. If the IOL and the loops are intact and the endothelial count is adequate, the simplest approach would be to perform synechiolysis and reposit the IOL behind the pupil. The problem with this method is that postoperatively, the IOL generally reverts to the position it was in before surgery and we are back to where we started.
The best approach in such cases is to do a temporary haptic externalization using a pars plana approach (Figure 2), a method first described by Chan1 in 1992. The main features of this method are temporary haptic externalization for suture placement after a pars plana vitrectomy followed by reinternalization of the haptics, which are tied with 9-0 or 10-0 polypropylene sutures for secured anchoring. The details of this technique have been described2,3 and include the following:
- A 3-port pars plana vitrectomy is performed to remove the anterior and central vitreous adjacent to the dislocated IOL to prevent vitreoretinal traction during IOL manipulation.
- Two diametrically opposed, limbal-based, partial-thickness, triangular scleral flaps are prepared along the horizontal meridians at 3 o'clock and 9 o'clock. Anterior sclerotomies are made within the beds under the scleral flaps 1.0 to 1.5 mm from the limbus (Figure 2, A). As an alternative to the scleral flaps, the anterior sclerotomies can be made within scleral grooves placed 1.0 to 1.5 mm from the horizontal limbus.
- A fiber-optic light pipe is inserted through 1 of the posterior sclerotomies while a pair of fine, nonangled, positive-action forceps (eg, Grieshaber 612.8) is inserted through the anterior sclerotomy of the opposing quadrant to engage 1 haptic of the dislocated IOL for temporary externalization (Figure 2, B). A double-armed 9-0 polypropylene suture (Ethicon TG 160-8 Plus) or a 10-0 polypropylene suture (Ethicon CS 160-6) is tied around the externalized haptic to make a secured knot. The same process is repeated with the other haptic.
- The externalized haptics with the tied sutures are reinternalized through the corresponding anterior sclerotomies with the same forceps (Figure 2, C). The surgeon anchors the internalized haptics securely in the ciliary sulcus by taking scleral bites with the external suture needles on the lips of the anterior sclerotomies. The tension of the opposing sutures is adjusted while the polypropylene suture knots are tied by the anterior sclerotomies, centering the optic behind the pupil; the haptics are anchored in the ciliary sulcus.
In the unlikely event the haptic has broken, causing IOL tilt and pupil capture, the best option would be to explant the scleral-fixated IOL through a limbal incision and implant an AC IOL. An iris-claw lens (Artisan) would be preferred over an angle-supported IOL. A well-fixated angle-supported IOL is meant to rest on the scleral spur.
Postoperatively, the patient should be closely followed and instructed not to forcibly rub his eyes.
1. Chan CK. An improved technique for management of dislocated posterior chamber implants. Ophthalmology 1992; 99:51-57
2. Chan CK, Agarwal A, Agarwal S, Agarwal A. Management of dislocated intraocular implants. Ophthalmol Clin North Am 2001; 14:681-693
3. Agarwal A, Chan C, Sachdev M. Complications of Phakonit. In: Agarwal A, ed, Bimanual Phaco: Mastering the Phakonit/MICS Technique. Thorofare, NJ, Slack, 2004