Phakic IOLs: when things go wrong
As with any IOL implantation technique, there are some potential complications that must be considered. In general, the number of complications is low, and most of them are either easy to avoid or easy to repair
When considering which patients would benefit from a phakic IOL, I tend to select those with high myopia; -8 D or higher, with an anterior chamber depth of at least 3.2 mm. In patients with thin corneas (<500 µm), I consider using a phakic IOL, even in myopia of –5 D or higher. I also consider patients with high hyperopia as excellent candidates for an iris-supported anterior chamber phakic IOL. For these patients, I would consider those who were +4 D or higher if the anterior chamber depth is 3.2 mm or more in patients younger than 40 years old; for older patients, I would consider refractive lens exchange and implantation of a multifocal IOL (e.g., ReZoom, Tecnis multifocal) as a better option.
The implantation technique
I first inject Lidocaine 1% under the conjunctiva at 12'o clock. Then, I open the conjunctiva at the limbus and use bipolar cautery to minimize bleeding.
Next, the frown incision is performed, creating a 6 mm scleral tunnel which is, in most cases, self-sealing, although I prefer to add a suture to play it safe.
For enclavation, I prefer the dual-forceps technique; holding the phakic IOL with holding forceps and grasping the iris with iris forceps. I then push the haptic of the IOL over the iris forceps, thereby enclavating the iris. I then re-grasp the iris just beneath the enclavation site and push the haptic over the forceps again to increase the amount of iris tissue enclavated.
After enclavation, I perform a small surgical iridectomy at 12 o'clock. Because of the tunnel incision, the iridectomy is not very peripheral, but usually still covered by the upper lid. Finally, I use a 10-0 nylon running X-suture, wash out the Healon GV with BSS, and tie the suture. The conjunctiva is closed with a single 10-0 nylon suture.
Postoperatively, I use a combination of dexamethasone and tobramycin three times daily for one week and pred forte twice daily for four weeks. The conjunctival suture is removed after one week, the scleral suture is usually left in place but cut at three to four weeks in case it induces an astigmatism of more than one diopter.
