Managing a Subluxated IOL

IOL subluxation is a rare but serious complication. In most cases, dislocation occurs within 3 months of IOL implantation.¹ Accumulating evidence links early IOL dislocation with poor fixation in the capsular bag; late dislocation is generally caused by progressive zonular insufficiency and contraction of the capsular bag years after uneventful cataract surgery.^1-5

Despite technological and surgical advances, IOL subluxation remains challenging to manage.^6-9 Many techniques have been described for fixating and repositioning a partially dislocated IOL. Some involve the use of sutures,^10-15 and some do not.^16-20 Each technique offers advantages and disadvantages, so the choice of strategy is made on a case-by-case basis.

DIAGNOSIS

A comprehensive history is the first step in the clinical assessment of a patient with a subluxated IOL. A detailed slit-lamp examination of the anterior and posterior segments is required. Direct ophthalmoscopy, anterior segment OCT, and B-scan ultrasound may be useful for locating a subluxated IOL. It is important to evaluate the position of the IOL while the patient is seated and again while the patient is supine. The severity of the dislocation can be assessed by measuring the change in the lens position.

TREATMENT OPTIONS

Observation. This is an option in the following situations:

• The severity of subluxation is low;
• The impact of IOL subluxation on visual acuity is insignificant;
• There is no evidence of an inflammatory response;
• The patient is not experiencing monocular diplopia or halos;
• No retinal complications are observed;
• The patient does not have glaucoma;
• Uveitis-glaucoma-hyphema syndrome is not observed; and
• There is a low risk of damage to neighboring ocular structures.

Otherwise, surgery may be indicated.^21-26

IOL exchange. This is one of the most popular surgical strategies for managing a subluxated IOL. Many effective techniques to remove a dislocated IOL have been described. Most of them entail cutting the lens into two or three pieces with intraocular scissors before removing them.

Transscleral suture fixation. This is an effective surgical option for eyes with insufficient capsular support. The IOL is fixated between the vitreous cavity and the iris by blindly passing sutures from outside to inside (ab externo approach) or from inside to outside (ab interno approach) the eye.

A zigzag intrascleral suture or Z-suture is a knotless, rapid technique devised to fixate different IOL models in the ciliary sulcus. The use of a Z-suture eliminates the need for a lamellar groove or scleral flap. This technique can effectively reduce suture-related complications such as suture erosion, scleral atrophy, and infection. To our knowledge, a double-blinded randomized trial has not been conducted to compare the relative risks of each suture and lens type for transscleral fixation, so these decisions are based on the surgeon’s experience and preferences.^11,15,27-34

Transscleral haptic fixation. If capsular support is inadequate, the Yamane technique for sutureless instrascleral fixation is an option. Two needles are used to externalize the haptics of a three-piece IOL. A flanged haptic tip is created and cauterized to be fixated intrasclerally (Figure 1). This technique reduces the risk of postoperative hypotony by minimizing the creation of sclerotomies. (For more on this subject, see “Yamane Tips and Tricks.”)

A recently described technique involves the use of a scleral-fixated, foldable, sutureless IOL (Carlevale, PhysIOL). This lens’ T-shaped harpoons are not subject to rupture, deformation, or dislocation after fixation to the sclera (Figure 2). Studies have shown implantation of the Carlevale lens to be safe and fast, and the lack of scleral pockets reduces the risk of suture-related complications.^35-37

COMPLICATIONS AND PROGNOSIS

Evidence suggests that IOL subluxation can cause complications such as infection, hypopyon, retinal detachment, inflammation, bleeding, recurrent IOL dislocation, and elevated IOP.^38-40 Transscleral suture fixation to address exposed sutures can increase the risk of infection, tissue erosion, and IOL subluxation.^22,41,42 When transscleral haptic fixation is performed, the implantation of the IOL haptics through uveal tissue is associated with an increased risk of hemorrhage.¹⁹

Surgery successfully addresses IOL subluxation in a majority of cases. Poor outcomes are more likely in patients with diabetic retinopathy, preexisting ocular pathology, iris neovascularization, preoperative corneal disease, glaucoma, a history of retinal detachment, iritis, and corneal edema.⁴³ Careful surgical planning based on the patient’s expectations, symptoms, and history of trauma can reduce the risk of complications in these cases.