26.6  Anterior Chamber Intraocular Lens

An anterior chamber IOL (AC-IOL) may be considered when there is inadequate capsular support in the setting of a normal iris and deep chamber.

Relative contraindications for AC-IOL:

1. Corneal endothelial disease (e.g. Fuchs endothelial dystrophy)
2. Iridocorneal angle damage (e.g. peripheral anterior synechiae)
3. Shallow anterior chamber
4. Lack of substantial iris tissue

Surgical planning for AC-IOL:

1. Determine the AC-IOL diameter: measure horizontal limbal white-to-white length and add 1 mm
2. AC-IOL will be about 2-3 fewer diopters lower power than a PC-IOL—the A constant of an AC-IOL takes this into account; if the IOL print out includes an AC-IOL, use that IOL power

1. Begin a scleral tunnel but do not enter the anterior chamber. A distance 1.5 to 2mm posterior to the limbus and 6-6.5mm wide is usually sufficient (Figure 26.6.1)
2. Perform pars plana vitrectomy and IOL removal (if necessary) as described in previous chapters (Figure 26.6.2)
3. Prior to AC-IOL insertion, inspect the fundus under wide-angle viewing for vitreous hemorrhage or choroidal detachments. Perform 360-degree scleral depression to look for retinal breaks (requiring endolaser)
4. Inject intracameral viscoelastic prior to placement of the AC-IOL to minimize endothelial damage
5. Enter the scleral tunnel
6. The infusion may need to be temporarily switched off to avoid egress of viscoelastic from the anterior chamber. The infusion can be switched on and off by an assistant to maintain the intraocular pressure
7. Pharmacologically constrict the pupil with intracameral acetylcholine chloride and consider inserting a lens glide. If used, it is important to avoid traumatizing the iris (Figure 26.6.3)
8. Place the AC-IOL directly into the anterior chamber with Kelmann-McPherson or curved tying forceps. It is important that the haptics of the AC-IOL lie in the anterior chamber angle and do not pinch on iris or rub on the peripheral corneal endothelium (Figure 26.6.4)
9. Using a Sinskey or Kuglen hook, lift each haptic in turn to ensure that it is free and rotate so the haptics lie horizontally
10. Create a peripheral iridectomy with the vitrectomy cutter (or scissors) (Figure 26.6.5)
11. Close the main corneal wound with 10-0 nylon
12. If necessary close the sclerostomies with 7-0 vicryl