Ab externo technique facilitates IOL scleral fixation

The authors of this article in the August issue of the Journal of Cataract & Refractive Surgery describe an ab externo technique that facilitates IOL scleral fixation and is technically simpler than other techniques. It uses a microvitreoretinal (MVR) blade (Alcon Laboratories, Inc.) to create sclerotomies and internal limiting membrane forceps to retrieve the suture. It does not require needle docking and reduces the surgical time in an open eye and the incidence of intraoperative complications while enhancing postoperative refractive predictability.

The authors say that their technique provides the advantages seen with other scleral fixation techniques, including reduced iris contact and an IOL position at the eye's nodal point, but is more accurate and predictable. To date, no cases have shown significant IOL tilt and all have had good IOL centration. They say it has enhanced their postoperative refractive predictability in cases requiring scleral fixation. Compared with previous techniques in which variability in the actual anteroposterior IOL position was not uncommon, this technique has produced a more consistent effective IOL position. The IOL final position has been accurate enough that in cases of modified CTR scleral fixation, they often implant a toric or multifocal IOL.

Additionally, they say that any area of the sclera can be used with any main incision location without difficulty because the needles are removed from the suture for the transscleral handoff. This is especially important in cases of pseudoexfoliation, where the incision is often made prior to detection of the weakness, which may be adjacent to the main incision.

Another benefit is the reduced likelihood of complications typically associated with scleral fixation, including iris root tuck and vitreous hemorrhage. Such complications are typically the result of excessive tissue manipulation, the authors explain, and in their technique in which the ILM forceps and the MVR blade, to some extent, can be easily bent to achieve nearly any necessary angle, tissue manipulation is reduced and more accurately guided transscleral passes are achieved. The ability to keep the corneal incision small until just prior to IOL insertion reduces the risk of hypotony-related intraocular hemorrhages.