A new study in PLOS One investigated the clinical features and risk factors associated with intraocular lens (IOL) dislocation, along with outcomes of surgical management.
Give me some background first.
With a rising prevalence of cataract surgery and intraocular lens implantation procedures, researchers of this study noted that IOL dislocation (though still relatively rare), is a notable risk factor.
- The reported rates: 0.1% to 3%
This serious complication can lead to visual impairment, increased intraocular pressure (IOP), retinal detachment, and vitreous hemorrhage—imposing both medical risks and financial burdens on patients.
- As such, a better understanding of IOL dislocation will allow for earlier detection and individualized treatment planning.
Now, talk about the study.
Researchers from Central China conducted a retrospective study of the clinical features, risk factors, and postoperative visual outcomes among adult patients diagnosed with IOL dislocation.
Tell me about these patients.
A total of 155 patients (166 eyes) from the period 2016 to 2024 were included.
Patients were required to have:
- A history of IOL implantation
- Documented IOL or IOL–capsular bag complex dislocation
- Complete clinical and follow-up data
Patients were excluded if they had:
- Other uncontrolled ocular conditions (ie. endophthalmitis, severe corneal pathology)
- Incomplete clinical data
And what data was collected?
- Other data collected included: demographics
- Characteristics of the IOL dislocation
- Comorbidities (ie. hypertension and diabetes mellitus)
- Surgical interventions
- Uncorrected-distance visual acuity (UDVA)
- Postoperative IOP and other complications
And how did investigators determine their findings?
Continuous variables were compared using independent samples t-tests. Categorical variables were assessed using χ² test.
… and what did these include?
Two major factors determined the likelihood for IOL dislocation:
- Sex: Men were more likely to have IOL dislocation, and at an earlier age (though not statistically significant)
- Risk factors: Trauma, high myopia, history of vitrectomy, acute glaucoma, hypertension, diabetes, and smoking were all frequently seen among patients with IOL dislocation
Tell me more.
The majority of patients (89%) had late onset (>3 months following surgery) IOL dislocation, which researchers attributed to be likely due to progressive age-related zonular insufficiency.
In contrast: Early onset (within 3 months of surgery) IOL dislocation was likely related to zonular trauma from surgical manipulation.
Those aforementioned risk factors would be consistent with this rationale:
- High myopia: Strain on the zonular fibers
- Prior vitrectomy: Surgical disruption of fibers
- Glaucoma: High IOP leads to progressive zonular weakening
In addition: One-fourth of patients in the study reported a smoking habit. While previous research has linked smoking to retinal nerve fiber degeneration, this finding suggests that smoking’s connection to zonular fiber weakening should be further explored.
What about treatments for IOL dislocation?
Three surgical techniques for correcting IOL dislocation were used:
- Repositioning
- Exchange
- Explantation
Both the repositioning and exchange procedures resulted in significant improvement in UDVA with the most common postoperative complication being increased IOP—however, this was usually transient and manageable.
Since there were no significant differences in IOP outcomes between the two surgeries, the researchers concluded that selection of the surgical method can be individualized to patient factors and the surgeon’s preference.
Were there any limitations to this research?
A few … including that pseudoexfoliation syndrome was not included in this analysis, given its low prevalence in China. However, it has been shown to be a risk factor for IOL dislocation in Western populations.
Further: Retrospective studies are known to carry inherent biases; as such, future studies may opt for a prospective design, on a larger scale and involving multiple institutions.
Duly noted. Now to the take home.
What we know: IOL dislocation, though relatively uncommon, is a notable risk factor following ophthalmic surgeries.
Based on this study: Investigators identified key risk factors—including trauma, high myopia, glaucoma, and smoking—that may help clinicians identify high-risk patients and guide surgical planning.
And for the future: Further research is needed on the role of zonular fiber weakening in IOL dislocation.