Incisions play an important role in cataract surgery.1,2 Whether placed on the cornea, the limbus, or the sclera, the incision is the gate to reaching the capsular bag—where the main surgical event takes place. No surgeon wants to see the iris prolapse following the first incision, but it can happen. Because incision complications are quite common, surgeons should pinpoint strategies to manage such situations.
Depending on size and function, a cataract incision is referred to as either a main phaco incision or a sideport incision. In this article, we discuss how to avoid and manage cataract surgery incision complications. As scleral incisions are less common in the phaco era,3 this article focuses on clear corneal incisions.
The cause. Long incisions (greater than 4 mm) that cause the meridian of the incision to flatten can induce astigmatism.
The solution: Make strategic incisions. Astigmatic keratotomy or peripheral corneal incisions can be used separately or in conjunction with the main cataract incision to eliminate astigmatism in patients with preexisting primary astigmatism and cataract.4 However, one should avoid choosing the wrong (flat) axis, as it will induce additional astigmatism.
WOUND CONSTRUCTION PROBLEMS AND SOLUTIONS
Short tunnel. If the tunnel is too short, the corneal valve may not self-seal, resulting in wound leakage. When this occurs, placement of sutures may be necessary.
Long tunnel. For any given incision site, the closer the incision is to the central cornea, the greater its tendency is to alter cylinder along that axis. Proximity to the central cornea will also increase endothelial cell loss. One way to avoid these problems is to create a longer tunnel incision. However, this brings its own set of problems. Instruments introduced through a long tunnel will be inclined upward toward the endothelium, but work in the anterior chamber requires the surgeon to force the instruments downward. This may result in traction folds, which decrease visibility in the anterior chamber. In this scenario, surgical maneuvers are more difficult.
Superficial incision. A thin corneal flap can be damaged by the phaco tip or other instruments and may eventually tear. Such an incision is usually not watertight and must be sutured.
Deep incision. Using precalibrated instruments may avoid creating incisions that are too deep. If the eye becomes hypotonic, a 10-0 nylon suture can be placed to close the original incision; another entry can then be made.
Big wound. If the keratome entry is too large for the phaco handpiece, excessive fluid outflow can lead to shallowing of the anterior chamber. This situation can be managed by placing an interrupted suture across the main incision.
Poorly shaped incision. If the shape of the incision is not accurate, it may result in unequal distribution of tension and induced astigmatism.
Detached Descemet membrane. Improper insertion of the instrument used for incision creation may tear the Descemet membrane at the anterior chamber entry site. This commonly occurs when the instruments are blunt or if penetration into the anterior chamber is too tangential, as the tip of the instrument may drag the Descemet membrane with it. To avoid this, the leading tip should be directed posteriorly whenever an instrument is inserted. It is important to recognize an early tear in the Descemet membrane to avoid its extension. At the end of the procedure, the membranes can be reattached using an injection of ophthalmic viscosurgical device (OVD) or an air buble into the anterior chamber. Larger tears may require more extensive suturing.
Conjunctival infiltration by balanced saline solution. A limbal incision placed too posteriorly may allow balanced saline solution to fill the conjunctival sac adjacent to the wound. This can produce a pool of fluid over the cornea and distort the view of anterior chamber structures. A small peritomy allows the balanced saline solution to escape.
The cause. Premature or too posterior entry of the incision may invite iris prolapse, which can damage the stroma or iris sphincter and result in postoperative pupil irregularities, transillumination defects, peripheral anterior synechia, or uveal incarceration into the incision. Intraoperatively, pupil constriction and iris bleeding may further complicate the operation.
Tamsulosin use increases the incidence and severity of iris prolapse,5 as does an acute rise in intraocular pressure (IOP). However, constructing the incision well, minimizing iris trauma, and reducing positive pressure will decrease the likelihood of iris prolapse. Additionally, care should be taken to avoid excessive injection of fluid and OVD behind the iris.
The solution: Identify and treat the underlying cause. If iris prolapse occurs despite your precautions, proper management starts with identifiying the underlying cause:
- Spontaneous prolapse with anterior chamber shallowing may be caused by suprachoroidal hemorrhage.
In this case, all instruments should promptly be removed from the eye. An OVD or balanced saline solution can be injected through the sideport incision to tamponade the bleeding. If the incision does not self-seal, pressure can be applied over the wound with a gloved finger. It is advisable to use intravenous mannitol to shrink the vitreous volume. In the case of nonprogressive focal choroidal hemorrhage, the surgeon can drain it via a sclerotomy created 3.5 mm behind the limbus. If IOP is still high and the anterior chamber is shallow after 15 minutes, surgery should be stopped and completed in a later session.
- If iris prolapse is caused by excessive IOP, it may be reduced by repositioning the speculum, adding an orbicularis block to the eyelid, or aspirating a small amount of fluid or OVD from a separate incision site. The iris can be repositioned gently using a small amount of OVD or a blunt iris spatula via a paracentesis incision. If these methods fail, a peripheral iridectomy may help to neutralize the pressure gradient between the anterior and posterior chambers and facilitate iris repositioning.
- If the prolapse results from posterior entry, hydrodissection can be performed via a paracentesis site. Phacoemulsification can then be performed after the tip is safely introduced into the anterior chamber, keeping it in place and thus plugging the incision. If these measures are unsuccesful, the surgeon may consider making an incision at an another location.
Aggressive attempts to reposition the iris without alleviating the underlying cause may result in serious iris damage.
The cause. Inadequate closure of the wound may result in leakage in the first few days after surgery. Clinical signs of wound leak include poor vision, ocular hypotony, shallow anterior chamber, broad corneal folds, choroidal effusion, and optic nerve edema. Definitive diagnosis can be made by fluorescein test.
The solution: Achieve a self-seal or suture the wound. Management of wound leak depends on several factors including etiology, timing, severity, and the structural appearance of the incision. Wound leaks noted in the first or second day after surgery often self-seal; leaks that persist often require medical management or surgical repair. Medical management can include decreasing corticosteroid therapy, initiating cycloplegia (preferably with long-acting agents), prescribing full-time patching in severe cases, use of soft contact lenses, or collagen shields and topical aqueous inhibitors. Surgical repair with resuturing is indicated in several circumstances such as flat anterior chamber, low IOP lasting for several days, and iris prolapse. Increased incidence of endopthalmitis associated with clear corneal incisions is a subject of debate,6 but any incision that is not self-sealing at the conclusion of surgery should be sutured.
Hüseyin Bayramlar, MD, is an Associate Professor of Ophthalmology, Ümraniye Egitim ve Arastirma Hastanesi, Ümraniye, Turkey. Dr. Bayramlar states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +90 216 6321818 1600; fax: +90 216 6327121; e-mail: firstname.lastname@example.org.
Cihan Ünlü, MD, practices at the Ümraniye Egitim ve Arastirma Hastanesi, Ümraniye, Turkey. Dr. Ünlü states that he has no financial interest in the products or companies mentioned. He may be reached at e-mail: drcihanunlu@ yahoo.com.
- Gills JP,Fenzl R,Martin RG,eds.Cataract Surgery.The State of the Art.Thorofare,NJ:Slack;1998.
- Steinert RF,ed.Cataract Surgery:Techniques,Complications and Management, Philadelphia,PA:Saunders;2004.
- Monica ML,Long DA.Nine-year safety with self-sealing corneal tunnel incision in clear cornea cataract surgery. Ophthalmology.2005;112(6):985-986.
- Bayramlar H,Daglioglu MC,Borazan M:Limbal relaxing incisions for the treatment of primary and post-cataract surgery mixed astigmatism. J Cataract Refract Surg.2003;29:723-728.
- Oshika T,Ohashi Y,Inamura M,et al.Incidence of intraoperative floppy iris syndrome in patients on either systemic or topical alpha (1)-adrenoceptor antagonist.Am J Ophthalmol.2007;143(1):150-151.
- Cooper BA,Holekamp NM,Bohigian G,Thompson PA.Case-control study of endophthalmitis after cataract surgery comparing scleral tunnel and clear corneal wounds.Am J Ophthalmol.2003;136(2):300-305.