A wide variety of surgical methods are currently used for aphakic correction, including angle-fixated anterior chamber intraocular lenses (AC IOLs), iris-enclavated AC IOLs, iris-sutured posterior chamber IOLs (PC IOLs), and scleral sutured PC IOLs. Each technique has disadvantages. Anterior chamber IOLs may result in corneal endothelial damage and uveitis-glaucoma-hyphema (UGH syndrome).1 Iris-fixated IOLs may result in pupil distortion or UGH. Sutured PC IOLs may be tilted or decentered and can experience late IOL dislocation.2 With scleral-sutured PC IOLs alone, a bevy of suturing and fixation techniques abound. Although “glued” IOLs have been gaining popularity, concerns about long-term safety remain.3 The quest for a gold-standard procedure remains elusive. We present a technique of no-tilt scleral-sutured PC IOL implantation in which IOL centration can be fine-tuned.
A side-port paracentesis is created nasally for anterior chamber maintainer (ACM) access, and a conjunctival peritomy centered on the 4:30 and 10:30 meridians is performed. Hemostasis is achieved using a wet-field cautery in the area of the planned scleral tunnel but not at the sites where the sutures are to be placed to reduce scleral devitalization and, perhaps, decrease the risk for future scleral thinning.
A temporal 7.0 mm scleral groove is carved posterior to the limbus and tunneled anteriorly into the margin of clear cornea. An ACM is placed into the paracentesis and the globe pressurized with irrigation.
A thorough anterior vitrectomy is achieved via a single-port pars plana cannula to remove residual vitreous strands in the pupillary, retropupillary, and retroiridial space. After the anterior segment is clear of vitreous gel, the vitrector is removed and the cannula plugged.
Two sets of 0.5 mm paired openings are created in the scleral wall at the level of the ciliary sulcus using a 15-degree blade (Figure 1, A and B). The estimated location of the sulcus from external landmarks can vary significantly. Human stereopsis seems to be the most effective mechanism to find the right level. The blade is passed into the eye parallel to the iris plane, entering the scleral wall until half the blade has entered the wound. If the blade is seen in front of the iris, the pass is too anterior and another pass slightly more posterior is made, leaving the initial opening unsutured and abandoned. Although the distance from the limbus might vary from 1 eye to another depending on the estimated position of the sulcus by stereopsis, each pair of openings should be at the same distance from the limbus.
The openings in each pair are separated by 3.0 to 4.0 mm, and the sets are placed 180 degrees from one another. A needleless Gore-Tex (expanded polytetrafluoroethylene [ePTFE]) CV-8 suture (W.L. Gore & Associates, Inc.) (off label for ophthalmic use) is then placed in the anterior chamber through the main wound (Figure 2) and retrieved by a 25-gauge microforceps via one of the scleral openings. The other end of the needleless suture is similarly retrieved through the paired opening, leaving a suture loop exiting the eye through the primary wound (Figure 3). The process is repeated with a second piece of suture at the opposing set of openings, 180 degrees away.
At this stage, the ePTFE suture loops are exiting the eye through the main scleral incision and the distal ends of the sutures are exiting through each of the 4 sclerotomies. Meticulous attention is required to maintain suture loop orientation and avoid tangling or twisting the suture loops.
A CZ70BD (Alcon Laboratories, Inc.) poly(methyl methacrylate) PC IOL is brought to the operating field and put over an instrument wipe, stabilized by a dollop of an ophthalmic viscosurgical device (OVD) on the surface of the instrument wipe. The proximal ePTFE loop is then folded over itself, creating a girth hitch (Figure 4), which is affixed to the trailing haptic of the IOL. Each arm of the hitch should rest on 1 side of the haptic eyelet, effectively separating the 2 arms of the suture by approximately 1.5 mm (Figure 5, A and B). The IOL is then oriented with the unattached haptic toward the wound, and the same fixation process is repeated with the distal suture loop and the leading haptic of the IOL. With a properly executed girth hitch, the arms of the suture should rest above the haptic or both below the haptic, thereby avoiding torque.
After all sutures are secured, the ACM is turned off to decrease intraocular pressure, thus decreasing the likelihood of iris prolapse, and the IOL is guided into the ciliary sulcus, gently pulling the externalized distal sutures to take up excess slack. The trailing haptic is similarly placed.
After the IOL is placed in the posterior chamber, the anterior chamber is put back into its on position and the wound is secured with a running 10-0 nylon suture. The ePTFE sutures at 1 site are snugged firmly, pulling the haptic–hitch fixation site to underlie the more counterclockwise of the 2 paired openings (Figure 6). A knot is tied over the more counterclockwise opening with a 2-1-1 configuration. The process is repeated for the opposing site and the other haptic, also over the more counterclockwise of the 2 openings. Both knots are trimmed and then rotated inside the eye wall, effectively rotating the IOL 1 to 2 clock hours in the clockwise direction at each location (Figure 7).
After adequate stability of the IOL is confirmed, centration can be fine-tuned by sliding the external portion of the ePTFE suture along the scleral surface using the Purkinje reflexes (Figure 8, A and B; Video 1, available at http://jcrsjournal.org). The OVD is removed using the vitrector from the anterior chamber and also from behind the IOL via the pars plana cannula. The cannula is then removed, and the wounds are confirmed tight-sealed. The conjunctiva and Tenon fascia are closed over the wound and suture sites.
Several techniques of scleral-sutured IOLs with diverse modifications have been described through the years, yet most of them lack control over IOL centration, passive tilt, torque-induced tilt, long-term stability, or a combination thereof. In 1991, Lewis4 described an ab externo 1-armed suture tied to each IOL haptic eyelet technique for sulcus fixation. This technique, although it helps to position each IOL haptic in the desired location, has no control over passive tilt, which, considering that most eyes requiring scleral fixation are unicameral, may result in an IOL with diverse degrees of tilt.
In 2012, Slade et al.5 described an ab externo, 2-armed ePTFE suture-through-the-eyelet technique using microforceps for suture retrieval through 2 sclerotomy pairs separated by 180 degrees. This technique has the advantage of eliminating the need for needles inside the anterior chamber, reducing intracameral manipulation, and, theoretically, the risk for endothelial damage. Expanded ePTFE sutures have the advantage of being nondegradable compared with polypropylene, which lasts an average of 10 years (7 to 14 years2) before biodegradation. However, when passed through an IOL eyelet, the thicker caliber suture will induce torque, which will induce tilt unless similar torque is applied in the opposite direction at the opposing haptic. Furthermore, this technique requires both pairs of sclerotomies to be separated by exactly 180 degrees to ensure IOL centration and does not have the ability to fine-tune centration after the IOL has been implanted.
Although techniques for glued IOL successfully address tilt-related concerns, the only intermediate-term report on the safety of this technique excluded common comorbid pathologies in which IOL fixation is commonly required, such as preoperative glaucoma and traumatic lens subluxation. Still, late complications, including intrusion, extrusion, and IOL movement, occurred in just under 19% of cases.3
The technique of using ePTFE sutures to create a girth hitch for each haptic fixation, with each arm of the hitch separated by the fixation eyelet of the haptic, provides effective lifelong 4-point fixation of the IOL to the scleral wall, avoiding tilt. Furthermore, that each fixation point is located in the same plane relative to the IOL prevents torque-induced tilt created by the suture width. Finally, since the suture is fixated to the haptic by the girth hitch, unlike its passage through the fixation eyelet, it enables the surgeon to move the position of each haptic by rotating each suture, therefore fine-tuning the final centration of the IOL. Since each fixation element can be rotated and positioned all along the suture track, the sclerotomy pairs do not have to be exactly 180 degrees apart. Centration can be achieved if any point along the scleral track of 1 side is 180 degrees from any point along the opposite scleral track. This feature is particularly helpful when any scleral area has to be avoided because of previous conjunctival blebs, focal scleral thinning, conjunctival or scleral scarring, or other concomitant pathology. Further, after a miotic is applied, it is sometimes discovered that the pupil center is not concentric with the geometric center of the anterior segment. This technique permits us to compensate for such a corectopia.
What Was Known
- Current surgical management of aphakia includes angle-fixated AC IOLs, iris-enclavated AC IOLs, iris-sutured PC IOLs, scleral-glued PC IOLs, and scleral-sutured PC IOLs. The latter category includes several techniques in which lack of long-term stability and control over centration and tilt could prevent a successful visual outcome.
What This Paper Adds
- The true 4-point PC IOL fixation technique using ePTFE suture provides long-term stability, prevents passive or torque-induced tilt, and allows fine-tuning of centration after PC IOL placement.
1. Carlson AN, Stewart WC, Tso PC. Intraocular lens complications requiring removal or exchange. Surv Ophthalmol
2. Price MO, Price FW Jr, Werner L, Berlie C, Mamalis N. Late dislocation of scleral-sutured posterior chamber intraocular lenses. J Cataract Refract Surg
3. Kumar DA, Agarwal A, Packiyalakshmi S, Jacob S, Agarwal A. Complications and visual outcomes after glued foldable intraocular lens implantation in eyes with inadequate capsules. J Cataract Refract Surg
4. Lewis JS. Ab externo sulcus fixation. Ophthalmic Surg
5. Slade DS, Hater MA, Cionni RJ, Crandall AS. Ab externo scleral fixation of intraocular lens. J Cataract Refract Surg
Video 1 The video demonstrates our step-by-step approach to scleral-sutured posterior chamber intraocular lenses (PC IOLs) for the correction of aphakia. Sulcus fixation of a poly(methyl methacrylate) PC IOL is achieved using 2 needleless expanded polytetrafluoroethylene sutures to create a girth hitch around both IOL fixation haptics on each opposite side. Centration of the IOL is fine-tuned by rotating each suture and confirmed based on the Purkinje reflexes.