Safe removal of intraocular posterior segment foreign body

We read with great interest the article titled “Intraocular lens-blocking technique for intraocular foreign body removal.”[1] The authors have described a novel yet simple technique for the safe removal of the intraocular foreign body (IOFB) from the vitreous cavity.[1]

Ocular trauma with retained IOFB in the vitreous cavity is often a complex surgical scenario due to the associated injuries and difficulty in removal of the IOFB from the ocular coats.[2] The associated injuries may include lenticular opacity, vitreous hemorrhage, retinal detachment, encapsulated or impacted foreign body (FB).[2] The standard approach to treatment is pars plana vitrectomy (PPV) followed by IOFB removal via a scleral or corneal incision. The route of removal depends upon the size and shape of the FB, the presence of significant cataract, and the surgeon’s preference. Although smaller or linear foreign bodies may easily be removed along their long axis through a small sclerotomy incision, a large scleral incision is generally avoided due to feared complications such as vitreous hemorrhage, choroidal hemorrhage, and intraoperative hypotony.[2]

In eyes with significant cataract, lens extraction may either be done from the anterior route or lensectomy may be performed from the pars plana route if there is poor capsular support. Combined cataract extraction not only takes care of the lenticular opacity but also allows IOFB removal from the corneal incision through the existing or planned posterior capsular opening. The majority of the surgeons implant an intraocular lens (IOL) after bringing the IOFB out from the corneal wound.

The most feared step in the surgery is the retrieval of the IOFB from the posterior segment into the anterior chamber. The IOFB may slip from the intraocular forceps/magnet while changing the hand or there may be resistance at the corneal incision. The described techniques to overcome this difficulty are removal via handshake technique, viscoelastic assisted removal, IOL scaffold technique, and IOL-blocking technique (described by the authors).[1347] In the handshake technique, the surgeon picks up the IOFB perpendicular to the long axis with a non-dominant hand under the fundus viewing lens and brings it posterior to the capsular opening.[67] Then under direct visualization, the FB is removed through the corneal incision with the dominant hand by holding with a forceps along the long axis. Although the use of the dominant hand may allow stable and safer removal, the resistance at the corneal incision may dislodge the FB and it may retreat to the posterior segment. Viscoelastic support and IOL scaffold are of use once the FB has already been brought into the anterior chamber and now need to be removed through the corneal incision.[345] Viscoelastic support may not bear the weight of FB and FB may slip posteriorly. IOL insertion may also displace the FB and cause it to retreat into the vitreous cavity. The IOL-blocking technique described by the authors allows the FB to be brought into the anterior chamber alike the handshake technique. In addition, the IOL blocks the FB from falling back and one may easily and safely remove the FB through the corneal incision. The concerns in this technique are the manipulation of FB through the posterior capsule opening, extension of the capsular opening making the IOL unstable, slippage of the haptic posteriorly through the opening, IOL decentration, and damage to the optic from sharp edges of the FB. Although the capsulotomy is made in a controlled manner after implanting the IOL, a three-piece IOL in the bag should generally be avoided if posterior capsule rent or opening with frayed edges is present as it may stretch the capsular bag and extend the opening. A foldable IOL may serve the same function and be safer in this regard. The IOL orientation is also crucial as the superior haptic of a vertically oriented IOL may slip posteriorly through a large capsular opening. A central or paracentral opening may be safer in this regard than a superior peripheral opening. A larger capsular opening (>4 mm), which may be required for very large FB, may also have a risk of IOL dislocation if IOL is implanted in the bag.

Hence in our opinion, very small or linear FB in the vitreous cavity may be removed through the scleral incision with intraocular forceps if the lens is clear. FB of the transverse size up to 4 mm may be removed using a combination of handshake technique and IOL-blocking technique through the corneal incision and larger FB (> 4 mm transverse size) should be removed with handshake technique and then the IOL should be implanted in the sulcus.