This review explores postoperative challenges arising from cataract surgery, including intraocular lens (IOL) decentration or dislocation, refractive surprises, dysphotopsias, and IOL opacifications. IOL decentration or dislocation is rare. Refractive surprises may be managed conservatively or surgically, with the most accurate results achieved by laser vision correction. Positive and negative dysphotopsias may continue to be intolerable for patients, and may require lens exchange as well. IOL opacifications vary by IOL material and may be visually significant, requiring lens exchange. The authors underscore the importance of nuanced management and providing optimal patient care in post-cataract surgery and IOL implantation complications.
Key points
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Intraocular lens (IOL) dislocation, refractive surprises, dysphotopsias, and IOL opacifications may lead to patient dissatisfaction, necessitating a thorough understanding of the etiology, risk factors, and management options.
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Management of IOL decentration or dislocation involves repositioning or exchanging the IOL, with studies showing significant visual improvement with both methods.
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Management of refractive surprise includes conservative measures, laser vision correction, or lens-based procedures like IOL exchange, though laser vision correction has shown the most promise.
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Management of dysphotopsias involves conservative measures such as glasses or eye drops and, in certain cases, IOL exchange.
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Management of IOL opacifications includes monitoring for asymptomatic patients or IOL explantation with or without exchange for those with intolerable visual symptoms.
Introduction
Cataract surgery is one of the most common and safest surgeries performed worldwide, leading to highly predictable and reproducible improvements in vision. Although most patients have good outcomes, a minority of patients can suffer from visually limiting issues postoperatively either soon after surgery or over time. Intraocular lens (IOL) decentration or dislocation, refractive surprises, dysphotopsias, and IOL opacifications are among the challenges that may arise postoperatively resulting in patient dissatisfaction. Here, the authors explore the definition, etiology, risk factors, and management options for these complications. From assessing the pertinent anatomic and surgical considerations to discussing the latest advancements and future directions, the authors offer a thorough overview of the complexities associated with managing these post-operative challenges.
Initial patient evaluation
Regardless of the presenting symptom, all patients should undergo a thorough history including a review of prior surgical history with specific attention to the preoperative- and postoperative care after cataract surgery. A slit lamp and comprehensive dilated examination should be performed to rule out alternative causes for the patient’s visual symptoms, such as retinal pathology (eg, vitreoretinal traction, and retinal tears or detachments), especially in patients at higher risk for these complications. Imaging modalities such as anterior segment optical coherence tomography and ultrasound biomicroscopy may better visualize anterior segment anatomy, particularly in those patients with lens-related symptoms. If surgical intervention is being considered, as with every patient, one must weigh the risks and benefits of the proposed intervention, with critical factors including patient age, medical comorbidities, visual potential, and patient and surgeon preferences.
Lens decentrations or dislocations
Definition, etiology, and risk factors
IOL decentration or dislocation is a rare complication that can occur early or years after cataract surgery, with incidence varying between 0.2% and 1.7% ( Fig. 1 ) [ ]. Risk factors include male gender, younger age, and others, as listed in Table 1 ; the most common predisposing conditions include pseudoexfoliation (PXF) syndrome (45%–67%), prior vitreoretinal surgery (5%–19%), and trauma (5%–6%), with a recent review finding a pooled odds ratio (OR) of 6.02 (95% confidence interval [CI], 3.7–9.79) of IOL dislocation in patients with PXF [ ]. Lens dislocation can be asymptomatic or present with refractive error (RE), decreased contrast, dysphotopsias, oscillopsia, diplopia, polyopia, higher order aberrations, or uveitis-glaucoma-hyphema syndrome [ ].
| Preexisting conditions | Congenital conditions | Intraocular lens-related | Surgeries |
|---|---|---|---|
|
|
|
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Management
In patients with longstanding and/or intolerable symptoms, the IOL may be repositioned or exchanged. Options for surgical management depend on patient anatomy and capsular bag integrity ( Fig. 2 ). The nature of the lens must also be considered, that is, polymethyl methacrylate (PMMA) lenses require externalization through large incisions while acrylic or silicone can be cut, 1-piece lenses can be more challenging to secondarily fixate, and 3-piece lenses can be secondarily fixated without removal. Here, the authors provide an example of Gore-Tex fixation of a secondary IOL for a dislocated 1-piece IOL ( Fig. 3 ).
Studies have shown IOL exchange to be beneficial in cases of decentrations and dislocations. One retrospective review of 47/118 cases requiring IOL exchange for decentration or dislocation found a statistically significant improvement in visual acuity (VA) at the last follow-up with in-the-bag, sulcus, iris-sutured, scleral-sutured, and iris-clip IOLs; common complications included vitreous prolapse with previous capsulotomy as a significant risk factor, zonule loss, and posterior capsular rupture [ ]. Another retrospective review of 45 eyes that underwent IOL exchange for dislocation or decentration found significant improvement in VA with scleral-sutured, iris-sutured, anterior chamber IOL (ACIOL), and iris-clip IOLs, with 62% of patients achieving VA of at least 20/40 [ ].
In a review comparing IOL repositioning versus exchange of 81 PXF cases with late in-the-bag IOL dislocation, 17 underwent repositioning with iris-sutured or scleral-sutured lenses and 64 underwent exchange with ACIOLs, with VA improving significantly in both groups with few complications, the most frequent being transient hypotony [ ]. In a meta-analysis of 14 studies, pooled analyses comparing IOL repositioning versus exchange showed no significant difference in best-corrected VA (BCVA), rate of IOL re-dislocation, intraocular pressure, endothelial cell density, surgically induced astigmatism, incidence of retinal detachment, intraocular hemorrhage, or pupillary block; IOL exchange had significantly lower postoperative RE (spherical equivalent [SE]), but also significantly greater incidence of cystoid macular edema and anterior vitrectomy compared to repositioning [ ]. Finally, a randomized controlled trial comparing repositioning with scleral-sutured IOLs (n = 54) and exchange with iris-claw IOLs (n = 50) found no difference in BCVA, with more than 75% of patients having better than 20/40 vision and similar postoperative complications; IOL repositioning was associated with longer operative times, higher risk for intraocular hemorrhage, and late residual myopia, while IOL exchange was associated with higher vitrectomy rates and decreased endothelial cell density [ , ].
Overall, patients can achieve better vision with either IOL exchange or repositioning. The decision to undergo either procedure depends on the patient’s current lens, anatomic considerations, medical and ocular history, surgeon comfort, and more. There are always risks for re-entering an eye, and patients should be counseled on potential outcomes to manage their expectations. Careful postoperative monitoring is necessary to ensure the IOL remains well placed or fixated, and the patient’s symptomatology is improving.
Refractive surprise
Definition, etiology, and risk factors
With the development of more precise IOL calculations, accuracy in refractive outcomes has improved, with patients now achieving ± 0.5D within their refractive target in 70% to 91% of cases [ , ]. However, there is always a risk of refractive surprise, defined as the failure to achieve the intended postoperative refractive target, leading to patient dissatisfaction secondary to anisometropia, dominance switch, and overall, unmet expectations. Inaccurate refractive outcomes may reflect a failure in 1 or many factors that go into IOL calculation, selection, and/or the surgery itself [ ].
Intraocular lens calculation and selection
Factors with the greatest impact on IOL selection are axial length (AL), whereby a 1-mm error can lead to a refractive surprise of approximately 2.5D, and keratometry (K), whereby an error of 1D translates to a postoperative RE of approximately 1D. This is demonstrated by the original Sanders-Retzlaff-Kraff formula (Power = A constant – 0.9 x K – 2.5 x AL). Many factors contribute to the accuracy of AL measurements ( Table 2 ) [ ] and K measurements ( Table 3 ) [ ].
| Category | Factors affecting axial length measurements |
|---|---|
| Biometry |
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| IOL formulas |
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| Globe shape and irregularities |
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| Intraocular material |
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| Poor ocular fixation |
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| Human error |
|
| Category | Factors affecting keratometry measurements |
|---|---|
| Corneal abnormalities |
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| Corneal manipulation |
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| History of keratorefractive surgery |
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| Human error |
|
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