Fig. 25.1
Fixed pupillary capture. The IOL optic is present anterior to the iris accompanied by posterior capsular opacification (PCO)
IOL dislocation: It can be divided into two types, i.e., in-the-bag dislocation, which means that zonular abnormalities cause part of or the entire capsular bag containing the IOL to dislocate into the anterior chamber (Fig. 25.2) or the vitreous cavity [6], and out-of-the-bag dislocation (Fig. 25.3), which often occurs secondary to a defective capsular bag or asymmetric IOL fixation, leading to partial or complete dislocation of the IOL [7].
Fig. 25.2
In-the-bag IOL dislocation into the anterior chamber
Fig. 25.3
Out-of-the-bag IOL dislocation. (a) Out-of-the-bag IOL dislocation into the anterior chamber; (b) UBM reveals out-of-the-bag IOL dislocation into the anterior chamber (white arrow); (c) Out-of-the-bag IOL dislocation into the vitreous cavity, with the IOL being anterior to the retina
25.1.2 Indications for IOL Reposition
As for the management of IOL malposition, if the majority of the IOL optic is still in the pupillary zone without any associated serious complications, the surgeon may elect to manage such patients by conservative observation and correction of refractive error. But if severe visual loss or other complications are caused by significant decentration of the IOL optic and the IOL remains intact with minor adhesion to surrounding tissues, then IOL reposition should be considered [1]. Preoperative evaluation of the ocular condition and the IOL is essential and may include the following items [8–10]:
- 1.
Ocular condition: Presence of any corneal or fundus problems that are considered contradictions of IOL implantation.
- 2.
IOL power: Try to determine whether the power of the original IOL is suitable, as well as the severity of refractive error.
- 3.
IOL diameter: If ciliary sulcus fixation is considered after IOL reposition, the diameter of the original IOL should be assessed, because an IOL with a short diameter placed in the ciliary sulcus may result in IOL redislocation.
- 4.
Presence of IOL damage: Transparency of the IOL optic and the shape of the haptics.
- 5.
IOL haptic material: The material of the original IOL haptics should meet the requirements of reposition. A PMMA haptic, non-foldable IOL or a three-piece foldable IOL is appropriate for suture fixation.
25.1.3 Surgical Techniques for IOL Reposition
Surgical techniques for reposition of posterior chamber IOL or an iris-claw anterior chamber IOL are described, respectively, as follows.
25.1.3.1 Reposition of Posterior Chamber IOLs
The surgeon should carefully inspect the capsular bag and try to identify the presence of any posterior capsular defects. Severity of synechia must be assessed, and synechiolysis is recommended if necessary. Reposition of a posterior chamber IOL can be performed via an anterior or posterior approach.
Anterior Approach
- 1.
Incision: An incision made at the site of synechia should be avoided.
- 2.
Separating the adhesion between the IOL and its surrounding tissues: Synechia can be separated with the use of ophthalmic viscosurgical device (OVD), and a pair of Vannas Capsulotomy Scissors may be used for sharp dissection in difficult cases. The surgeon should try to avoid surgical disturbance to the iris tissue to reduce postoperative inflammatory response. The IOL optic and haptics should always be kept intact during the surgery.
- 3.
Creating space for IOL reposition (Fig. 25.4a): Full separation of the adhesion between the iris and the lens capsule may be required for creating space for IOL reposition. When there is a complete synechia between the pupillary margin and the capsule, the incision should be made superiorly with peripheral iridectomy at the site of the incision. The synechia is carefully separated by injecting OVD through the iridectomy, so as to create space. Try to preserve as much of the lens capsule as possible.
Fig. 25.4
IOL ciliary sulcus fixation. (a) Separate the adhesion between the iris and the capsule by injecting OVD, so as to create space for IOL reposition; (b) Placing the leading haptic into the ciliary sulcus; (c) Placing the trailing haptic into the ciliary sulcus
- 4.
Reposition of the IOL: When the residual peripheral capsule is adequate, the IOL can be directly repositioned into the ciliary sulcus (Fig. 25.4b, c). But in the absence of adequate capsular support, single-loop or double-loop suture fixation of the IOL should be considered. The surgical techniques for double-loop suture fixation are described in detail as follows (Fig. 25.5):
Fig. 25.5
IOL reposition (double-loop fixation). (a) Two half-thickness triangular limbal-based scleral flaps are made 3 mm posterior to the limbus. (b) After OVD injection, the IOL is carefully dissected with two Sinskey hooks and then dialed into the anterior chamber. (c) One haptic is dialed out of the incision with smooth forceps. (d) The needle of a 10-0 polypropylene suture is introduced into the eye through the sclera; passes through the posterior chamber, the pupil, and the anterior chamber; and exits through the peripheral cornea. (e) The suture needle is removed and the suture thread is withdrawn through the incision. (f) The suture on the right side of the incision is securely tied to the dialed-out haptic (at the lateral 1/4–1/3 of the haptic). (g) The sutured haptic is dialed back into the eye. (h) The second haptic is also dialed out. (i) The suture on the left side of the incision is tied to the second haptic (at the lateral 1/4–1/3 of the haptic). (j) The second haptic is also reinserted into the eye. (k) The sutures are gently pulled to secure centration of the IOL with two pairs of smooth forceps, and then the sutures are knotted under the scleral flaps. (l) The residual lens cortex and capsule are removed with an anterior vitrector. (m) The limbal incision is closed. (n) Slit-lamp image 1 day after IOL double-loop reposition
- (a)
Two fornix-based conjunctival flaps are made opposite to each other, followed by scleral cautery for hemostasis.
- (b)
Two half-thickness, triangular, limbal-based scleral flaps are made beneath the conjunctival flaps.
- (c)
A 3.2-mm limbal tunnel incision is made temporally or superiorly (or a superior scleral tunnel incision for young children), and then a paracentesis is made at the limbus 90 degrees clockwise to the incision with a 15-degree blade.
- (d)
The anterior chamber is filled with OVD and the IOL is carefully dissected. The dislocated IOL is dialed into the anterior chamber with a Sinskey hook with one of its haptics outside the incision.
- (e)
The needle of a 10-0 polypropylene suture is introduced into the eye under the scleral flap 1.5 mm posterior to the limbus, which can be achieved by either of these two techniques. In the first technique, the triangular scleral flap is lifted, and a single-armed suture passes from the superficial layer of the sclera and then enters into the eye through the sclera. After passing through the posterior chamber, the pupil, and the anterior chamber, the needle exits through the peripheral cornea. The suture needle is removed and the suture thread is withdrawn through the incision (Fig. 25.5). In the second technique, a double-armed 10-0 polypropylene suture is used. The first needle is introduced into the eye under the scleral flap, while a 25-gauge needle is introduced into the eye under the opposite scleral flap, and then the first needle is inserted into the barrel of the 25-gauge needle in the pupillary area under direct visualization. The 25-gauge needle is then removed, and the suture thread is withdrawn along with it under the scleral flap. Finally, the suture thread is exited from the eye through the incision and cut into two parts for subsequent fixation (Fig. 25.6).
Fig. 25.6
Ciliary sulcus double-loop suture fixation (the second technique). (a) The first needle is introduced into the eye under the scleral flap. (b) A 25-gauge needle is introduced into the eye under the opposite scleral flap, and then the first needle is inserted into the barrel of the 25-gauge needle in the pupillary area under direct visualization. (c) The 25-gauge needle is removed and the suture is withdrawn through the incision. (d) The suture is cut into two parts for subsequent fixation
- (f)
One haptic of the IOL is dialed out of the incision, and then the suture on the right side of the incision is securely tied to the haptic (at approximately the lateral 1/4–1/3 of the haptic). The sutured haptic is dialed back into the ciliary sulcus.
- (g)
The second haptic is also dialed out, tied to the suture on the left side of the incision, and reinserted into the eye in a similar fashion.
- (h)
The sutures are gently pulled to secure centration of the IOL with microsurgical smooth forceps, and then the sutures are knotted under the scleral flaps.
- (i)
The OVD is removed and the anterior chamber is filled with balanced saline solution (BSS). The scleral flaps are then closed using 10-0 nylon sutures, and the conjunctival flaps are closed with cautery or suturing.
- (a)
The key points during the procedure of IOL double-loop suture fixation are summarized below. The line connecting the two points of needle entry through the sclera should pass through the center of the cornea; each point of entry should be of equal distance to the limbus; besides, the distances from each point where the haptic is tied to the haptic–optic junction should be the same.
Posterior Approach
When the IOL is dislocated into the mid-posterior vitreous, the surgeon may perform posterior vitrectomy via the pars plana. With the help of the optical fiber, the vitreous cutter, or microsurgical forceps, the dislocated IOL is lifted into the anterior chamber and then repositioned. The key to this approach is to separate the adhesions between the IOL and its surrounding tissues and then remove the prolapsed vitreous body.
25.1.3.2 Reposition of Iris-Claw Anterior Chamber IOLs
There are controversies over the use of iris-claw anterior chamber IOLs in pediatric patients. We do not recommend using these IOLs in pediatric lens surgery, but cases of an IOL with a detached iris claw have been encountered occasionally in our clinical practice. In such cases, the decision on whether or not to perform IOL reposition or explantation should be based on an overall evaluation which includes the corneal endothelial cells, the anterior chamber depth, and the iris. Surgical reposition of these IOLs can be considered in older children. Reposition techniques are described as follows:
- 1.
A 3.2-mm superior scleral tunnel incision is made and then a paracentesis is made at the 2 o’clock or 10 o’clock position using a 15-degree blade (depending on where fixing the IOL haptics). OVD is injected on both anterior and posterior surfaces of the IOL to create adequate space for manipulation. The incision is enlarged to 3.5–4 mm with a keratome.
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