Article

Aphakia options in the OR

Secondary IOLs are your best bet.

For most cataract and anterior segment surgeons, surgical management of aphakia is infrequently encountered. Advances in cataract surgery technology have further decreased the incidence of iatrogenic aphakia; however, complicated cataract surgery, trauma and systemic conditions, such as Marfan syndrome, still account for aphakia in a variety of patient populations. Surgeons may occasionally have to deal with these scenarios, and knowing the various treatment options is useful.

Although it is reasonable to consider spectacles or contact lenses for visual rehabilitation of these patients, secondary IOLs have many advantages over both options. Given that many of these patients will have little or no capsular support, surgeons may choose from the following five options for secondary IOL placement:

  • an angle-supported anterior chamber intraocular lens (ACIOL)
  • a sulcus-placed posterior chamber IOL (PCIOL)
  • an iris-fixated PCIOL
  • a suture-supported, scleral-fixated PCIOL
  • a sutureless scleral-fixated PCIOL, both with use of tissue glue and without.

It is imperative that with any of these options, surgeons ensure no vitreous is present in the anterior chamber. As such, a thorough anterior vitrectomy or pars plana vitrectomy (PPV) is of critical importance.

A combined PPV at the time of secondary IOL implantation also offers the advantage of posterior chamber infusion to maintain intraocular pressure while performing these technically demanding intraocular maneuvers.

ACIOLS

ACIOLs remain a reasonable choice for surgeons who prefer an IOL option that requires minimal intraocular maneuvering and advanced surgical techniques. The current generation of Kelman-style, open-loop ACIOLs have an excellent safety profile, especially when placed in conjunction with a concurrent surgical iridectomy to minimize the risk of pupillary block. Modern ACIOLs are easy to insert, have an optic with excellent biocompatibility in the anterior chamber and have flexible haptics that minimize sizing issues.

Disadvantages of ACIOLs include a large incision (5 mm to 6 mm) that will require multiple sutures. Low-grade inflammation may develop, causing either pigment deposits on the ACIOL optic or uveitis-glaucoma-hyphema (UGH) syndrome. In patients at risk for endothelial decompensation, ACIOLs may make endothelial keratoplasty more challenging for a corneal surgeon. Use of ACIOLs is not recommended in eyes that have insufficient iris tissue, a shallow AC or extensive peripheral anterior synechiae.

SULCUS-PLACED PCIOL

If there is sufficient anterior capsule support, a three-piece IOL may be placed in one of three ways: simple sulcus placement; sulcus placement with optic capture (i.e., the optic is placed in the capsular bag, haptics remaining in the sulcus); and sulcus placement with reverse optic capture (i.e., haptics placed in the capsular bag and optic placed in the sulcus). Each option offers a good management strategy, especially if a posterior capsule tear is encountered during an initial cataract extraction procedure. In general, any of the above options reduces the need for a secondary procedure. If placing the optic in the sulcus, surgeons should be mindful to appropriately decrease the lens power to account for the change in effective lens position.

IRIS-FIXATED PCIOL

An iris-fixated PCIOL is a reasonable management choice, especially if a surgeon feels uncomfortable working extensively in the posterior chamber. This is particularly useful if an existing IOL is decentered or unstable. Polypropylene (Prolene), a monofilament polymer composed of propene, has good biocompatibility as suture material for this procedure. A Siepser sliding knot technique or McCannel transcorneal-retrievable suture technique may be employed for this purpose. Many surgical techniques have been described, but one approach is to place a three-piece PCIOL in the eye such that the optic is anterior to the pupil while the haptics are posterior to the iris. This optic capture can stabilize the PCIOL so that the surgeon can pass a suture through clear cornea and the iris, under the peripheral part of the haptic, and then out through the iris and clear cornea. A Siepser sliding knot may be used to secure this suture pass; alternatively, surgeons may create a paracentesis over the haptic and then pull the two ends of the suture through this wound to tie and secure the knot. A pair of intraocular microforceps and microscissors can help make these maneuvers much easier.

Iris-fixated PCIOLs should not be used in patients with significant iris trauma or at risk for iris pathology (such as floppy iris syndrome). In addition, surgeons should be cautious in employing this surgical technique on young patients as the polypropylene suture has been known to slip or tear after an extended period of time.

SCLERAL-FIXATED PCIOLS

This option comprises three choices: suture fixation; sutureless fixation using flaps and fibrin tissue glue; and sutureless fixation without use of flaps or glue.

Suture fixation, the oldest choice, is still a popular one for many surgeons. It offers the advantage of multiple, secure fixation points (two-point vs. four-point fixation). When performing this technique, surgeons may choose from either 9-0 polypropylene or 8-0 Gore-Tex (W.L. Gore & Associates). Many surgeons also feel that 9-0 polypropylene is a risky option given reports in the literature regarding dislocation.1 As such, many anterior segment surgeons prefer the off-label use of 8-0 Gore-Tex as this suture material offers a more robust and secure method of securing the knot. Depending on the PCIOL chosen, two-point or four-point may be chosen; most surgeons use a two-point fixation using a cow hitch knot method with a commonly used three-piece lens, such as the MA60AC (Alcon, acrylic), ZA9003 (AMO, acrylic) or the SofPort Li60AO (Bausch + Lomb, silicone). The Alcon CZ70BD IOL (Alcon) is a PMMA IOL that may be a bit bulky to work with in the anterior chamber and will require a larger incision, but offers the advantage of a 7.0-mm optic and two eyelets within the haptic that facilitate suture fixation. The Akreos AO60 hydrophilic IOL (Bausch + Lomb) is another reasonable choice as it contains four eyelets for four-point suture fixation.

With suture fixation, both an ab externo and an ab interno approach may be used, though the former is more popular than the latter. With ab externo fixation, the surgeon passes sutures from the outside to the inside of the eye, taking care to identify the ciliary sulcus using external landmarks. Either a straight (STC-6) or curved (CTC-6 or CIF-4) needle may be used in a tunnel/groove pattern, in conjunction with a 27-gauge needle as a docking guide, to assist with the safe and accurate exit of the needle through the sclera. Care must be taken to ensure the knots are rotated and buried accordingly to prevent patient discomfort and suture erosion.

Recently, several sutureless techniques for scleral fixation have been reported in the literature. One technique is intrascleral haptic capture with scleral flaps and fibrin tissue as popularized by Amar Agarwal, MD.2 In this technique, two scleral flaps are created 180° away from each other. A three-piece IOL is placed in the eye such that the trailing haptic remains outside the eye for protection; the leading haptic is externalized via the “left-sided” flap (relative to the surgeon) using a pair of 25-gauge microforceps passed through a 25-gauge sclerotomy. The trailing haptic is then externalized via the “right-sided” flap using two 25-gauge microforceps in a “handshake” technique. The externalized haptics are then secured via partial-thickness scleral tunnels, and fibrin-tissue glue is used to close the flaps at the conclusion of the case.

There is a learning curve, but once a surgeon becomes confident with this technique, he/she may find this to be an easier, faster and safer method than suture fixation of a PCIOL.

Another technique is the transconjunctival intrascleral IOL fixation with double-needle technique as described by Shin Yamane, MD (Figures 1 and 2).3 In this technique, each haptic of a three-piece IOL is externalized onto the conjunctiva using a 30-gauge needle that has been used to create a grooved scleral tunnel. The double needle allows for simultaneous extraction and centration of the PCIOL. The externalized haptics are then melted using disposable cautery to create a “mushroom” bulb that can be then deposited and tucked into the scleral tunnels. It is an elegant, efficient technique that allows for good centration and stability of the PCIOL, while removing the surgical burden, time and cost of having to create scleral flaps, and use of tissue glue.

Figure 1. Demonstration of the Yamane technique for scleral fixation of a posterior chamber intraocular lens (IOL), part 1. The leading haptic of a three-piece IOL (EC-3 PAL; Aaren Scientific, Inc., Ontario, CA) is guided into a thin-wall 30-gauge needle (TSK Laboratory, Tochigi-Ken, Japan) (A) and subsequently externalized through a scleral tunnel (B). A silicone clamp from a set of iris retractors is placed to prevent slippage of the leading haptic. The trailing haptic is similarly fed into a second thin-wall 30-gauge needle (C).

Figure 2. The Yamane technique for scleral fixation of a posterior chamber intraocular lens (IOL), part 2. The trailing haptic is subsequently externalized through a scleral tunnel located 180 degrees away from the first tunnel (A). Disposable cautery is used to gently melt the haptic tips until a mushroom shape is achieved (B). Both haptics are then tucked into the sclera, with fine adjustments made until there is good centration and stability of the IOL (C).

The choice of equipment is vital to the success of this technique. Surgeons should use a thin-wall 30-gauge needle (such as the TSK ultra-thin-wall 30-gauge needle, available from Delasco.com ) to ensure the needle lumen is of a sufficient size to dock and externalize the haptic. The choice of IOL is also crucial: while a typical three-piece acrylic IOL may be used, the haptics are often brittle, unforgiving during the intraocular gymnastics and may break during externalization. This procedure can be done with the more commonly used three-piece acrylic IOLs, but great care must be taken during the externalization process, and the bulb created during the melting process assumes an oval-mushroom shape rather than a button-mushroom shape.

In conclusion, surgical management of aphakia can be a challenging task for even the most skilled and experienced anterior segment surgeon. There are a variety of management and surgical techniques and device options for surgeons to use for this unique patient population. Each of the strategies discussed offers advantages and disadvantages, both to the surgeon and to the patient. For surgeons who wish to add this service to their surgical armamentarium, recent developments in techniques and technology offer a way forward for the future. OM

REFERENCES

  1. Price MO, Price FW Jr, Werner L, et al. Late dislocation of scleral-sutured posterior chamber intraocular lenses. J Cataract Refract Surg. 2005;31:1320-1326.
  2. Agarwal A. Glued IOL live surgery@ IIRSI 2011. https://www.youtube.com/watch?v=wlBaYceOYcY . Accessed June 28, 2017.
  3. Yamane S. Intrascleral IOL fixation with double-needle technique. https://www.youtube.com/watch?v=oLKeH_YwkpU Accessed July 7, 2017.

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