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Temporary haptic externalization helps control IOL repositioning procedure
The technique eases suture placement for repositioning of posterior chamber IOLs with curvilinear haptics.
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One of the most difficult steps of repositioning a dislocated posterior chamber IOL is securing a suture on the haptics. In 1992, Clement K. Chan, MD, FACS, first introduced the concept of temporary haptic externalization to enhance the ease of suture placement, and changed IOL repositioning from an uncontrolled to a highly controlled procedure that allows fixation of the dislocated IOL in the ciliary sulcus on a consistent basis. Dr. Chan, director of Southern California Desert & Inland Retina Consultants, Palm Springs, and assistant clinical professor at Loma Linda University, Loma Linda, Calif., is my special guest in this month’s column.
Indications
This temporary haptic externalization technique is an option for repositioning any subluxated or dislocated one- or three-piece posterior chamber IOL that has curvilinear haptics. It is not suitable for securing a malpositioned one-piece plate IOL.
Technique
Amar Agarwal |
A three-port pars plana vitrectomy is performed for the removal of the anterior and central vitreous adjacent to the dislocated IOL in order to prevent any vitreoretinal traction during the process of manipulating the IOL.
Two diametrically opposed limbal-based partial-thickness triangular scleral flaps are prepared along the horizontal meridians at 3 o’clock and 9 o’clock. Cauterization is done to prevent bleeding (Figure 1). Anterior sclerotomies within the beds under the scleral flaps are made 1 mm to 1.5 mm from the limbus. As an alternative to the scleral flaps, the anterior sclerotomies may be made within the scleral grooves 1 mm to 1.5 mm from the horizontal limbus.
A fiber-optic light pipe is inserted through one of the posterior sclerotomies, while a pair of fine nonangled positive-action forceps (eg, Grieshaber 612.8) are inserted to hold the IOL and bring it anteriorly (Figure 2). The forceps are then passed through the anterior sclerotomy of the opposing quadrant to engage one haptic of the dislocated IOL for the temporary externalization (Figure 3a). A double-armed 9-0 (Ethicon TG 160-8 plus) or 10-0 polypropylene (Ethicon CS 160-6) suture is tied around the externalized haptic to make a secured knot (Figure 3b). The same process is repeated for the other haptic after the surgeon switches the instruments to the opposite hands (Figure 3c).
The externalized haptics with the tied sutures are reinternalized through the corresponding anterior sclerotomies with the same forceps. The internalized haptics are anchored securely in the ciliary sulcus by taking scleral bites with the external suture needles on the lips of the anterior sclerotomies. By adjusting the tension of the opposing sutures while tying the polypropylene suture knots by the anterior sclerotomies, the optic is centered behind the pupil, and the haptics are anchored in the ciliary sulcus.
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| Images: Reprinted with permission from CA Chan, Inc. | |
Problems
Damage of haptic during externalization:
This potential problem can be prevented by making a relatively wide 2-mm to 4-mm incision on the anterior sclerotomy; using positive-action nonangled and nontoothed forceps (eg, Grieshaber 612.8 or 612.12); and avoiding excessive pinching of the haptic. The surgeon should carefully follow the curvature of the haptic to its tip when externalizing the haptic.
IOL decentration or tilting:
This potential problem can be minimized by several measures: placing both anterior sclerotomies precisely at 180° from each other along the horizontal meridians; tying the suture at approximately the same distance from the tip of each haptic; placing two sutures on each externalized haptic and anchoring each suture on separate ends of the anterior sclerotomy, resulting in a four-point fixation of the IOL (Figure 4).
The fear of damaging the ciliary neurovascular bundle along the horizontal meridians that may lead to anterior segment ischemia is only a theoretical concern. Clinical experience with this technique has shown not a single case of anterior segment ischemia. One should nevertheless avoid excessive cauterization of the horizontal neurovascular bundle during the repositioning process.
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Important features
The horizontal meridians are chosen for the location of the anterior sclerotomies for easier manipulation of the forceps, haptics and sutures during the repositioning process. The location of the anterior sclerotomies determines the final position of the IOL. Previous anatomic studies have reported the ciliary sulcus to be 0.46 mm to 0.8 mm from the limbus. Thus the distance of 1 mm to 1.5 mm from the limbus places the anterior sclerotomies close to the external surface of the ciliary sulcus. Making the anterior sclerotomies at less than 1 mm from the limbus increases the risk of injuring the anterior chamber angle or the iris root.
In Dr. Chan’s series, the average age of the patients was 74. The average follow-up time was 17.5 months. The average preoperative best corrected visual acuity was 20/400 (range: light perception to 20/30), and the average postoperative BCVA was 20/50 (range of no light perception to 20/20). There were no major complications, such as retinal breaks or detachment, macular pucker, endophthalmitis or ocular ischemia.
Summary
The repositioning of the dislocated posterior chamber IOL in the ciliary sulcus with modern vitreoretinal techniques provides an optimal environment for visual recovery. The temporary haptic externalization method avoids difficult maneuvers and allows consistent IOL fixation in the ciliary sulcus.
For Your Information:
- Amar Agarwal, MS, FRCS, FRCOphth, director of Dr. Agarwal’s Group of Eye Hospitals, trains surgeons internationally in phacoemulsification, phakonit, LASIK and retinal lasers. Dr. Agarwal is author of several books published by SLACK, Incorporated, publisher of Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery, and Presbyopia: A Surgical Textbook. He can be reached at 19 Cathedral Road, Chennai 600 086, India; fax: 91-44-28115871; e-mail: dragarwal@vsnl.com; Web site: www.dragarwal.com.
- Clement K. Chan, MD, FACS, can be reached at P.O. Box 2467, Palm Springs, CA 92263; e-mail: pschan@aol.com.
References:
- Agarwal S, Agarwal A, Agarwal A, eds. Phacoemulsification. 3rd ed. Thorofare, NJ: SLACK Incorporated; 2004.
- Agarwal A. Phaco Nightmares: Conquering Cataract Catastrophes. Thorofare, NJ: SLACK Incorporated; 2006 (in press).
- Chan CK. An improved technique for management of dislocated posterior chamber implants. Ophthalmology. 1992;99:51-57.