In intraocular lens dislocation terminology, subluxation denotes which degree of support failure?

Loss of centration with intact zonules and capsule

Total zonular and capsular instability

Capsular opacification without any instability

Intraocular lens dislocation has been reported at approximately what rate?

0.2% to 3% IOL dislocation is a rare but serious complication, reported at a rate of 0.2% to 3%.

Which condition is the single most common risk factor for intraocular lens dislocation?

Pseudoexfoliation syndrome Pseudoexfoliation syndrome is the most common risk factor, accounting for more than 50% of cases, ahead of other causes of zonular weakness such as Marfan syndrome and axial myopia.

In-the-bag dislocation of an intraocular lens arises from which underlying defect?

Zonular weakness destabilising the capsular bag When the capsular bag support system fails, for example through zonular weakness, the entire IOL together with the capsular bag dislocates as a unit.

Radial tear of the anterior capsulotomy edge

Fibrotic contraction of the posterior capsule

Posterior capsule tear letting the optic slide out

Out-of-the-bag dislocation of an intraocular lens follows which structural problem?

A posterior capsule defect or tear If there is a posterior capsule defect or tear, the IOL can slide out of the bag, giving an out-of-the-bag dislocation.

Zonular dehiscence with an intact capsular bag

Haptic erosion through the ciliary sulcus

Pupillary capture of the optic by iris adhesions

Ocular pain or headache in a patient with a dislocated intraocular lens is attributed to which mechanism?

Intermittent angle closure and inflammation Patients may report ocular pain or headaches from intermittent angle closure and inflammation, alongside reduced or changed vision, diplopia, glare, and sometimes seeing the edge of the IOL.

Raised episcleral venous pressure

Traction on the optic nerve sheath

Corneal endothelial decompensation

When a detailed dilated retinal exam is not feasible in suspected intraocular lens dislocation, which investigations help?

B-scan echography and ultrasound biomicroscopy If a detailed examination is not feasible, B-scan echography and anterior segment OCT or ultrasound biomicroscopy help evaluate a lens dislocated behind the iris into the anterior vitreous cavity.

Fluorescein angiography with late-phase frames

Corneal topography with pachymetry mapping

Standard automated perimetry of the central field

Which patient with a malpositioned intraocular lens is the best candidate for observation alone?

Pseudophacodonesis with no inferior dislocation Observation suits minimal subluxation with no significant visual impact or damage to surrounding structures; such patients are usually asymptomatic, and refraction with close follow-up may be enough.

Monocular diplopia with the optic edge in the axis

Inferior dislocation with a visible lens edge

Dislocation into the vitreous with vitreous prolapse

What are the most common indications for surgery in intraocular lens dislocation?

Reduced acuity, monocular diplopia and halos Decreased visual acuity, monocular diplopia and halos are the commonest indications; retinal detachment, glaucoma and uveitis-glaucoma-hyphema syndrome prompt surgery less often.

Retinal detachment, glaucoma and UGH syndrome

Corneal decompensation with persistent edema

Cystoid macular edema with vitreous haemorrhage

Surgery for a dislocated intraocular lens typically involves which sequence?

Pars plana vitrectomy then secondary IOL implantation Surgery typically uses pars plana vitrectomy to remove the dislocated lens, either with an IOL cutter or through a scleral tunnel or sclerocorneal incision, followed by secondary IOL implantation.

Scleral buckling followed by IOL repositioning

Nd:YAG capsulotomy then anterior chamber IOL

Anterior vitrectomy with iris-suture fixation only

Dislocated Intraocular Lens (IOL): case study, entity and diagnosis

CASE REPORT

A 60-year-old female presented to an ophthalmology clinic complaining of sudden vision loss and distorted vision in the right eye, six months after undergoing uneventful cataract surgery.

She described a sudden onset of visual impairment accompanied by floaters and a sensation of movement in the affected eye, denying any recent trauma, ocular injury, or systemic illnesses.

During ocular examination, her visual acuity in the right eye was reduced to counting fingers at one foot. Slit-lamp examination revealed a visibly displaced intraocular lens (IOL) into the vitreous cavity, with no signs of inflammation or increased intraocular pressure.

Additional diagnostic tests, including ultrasound biomicroscopy and optical coherence tomography (OCT), confirmed the dislocation of the intraocular lens and revealed vitreous prolapse.

Consequently, the patient was diagnosed with a dislocated intraocular lens in the right eye.

Dislocated intraocular lens (IOL) DISEASE entity

Dislocated intraocular lens (IOL) is a rare, yet serious complication whereby the intraocular lens moves out of its normal position in the eye.

IOL dislocation has been reported at a rate of 0.2% to 3%. It may occur as a result of an early or late complication of cataract surgery, prior vitreoretinal surgery, trauma, or an inherent pathological process or connective tissue disorder contributing to lens zonular weakness.

Dislocation may present as phacodonesis, simple decentration within the bag or in the sulcus, partial subluxation, or complete dislocation of the lens within and outside of the bag.

Decentration usually refers to loss of IOL centration without zonular or capsular instability. Subluxation refers to partial zonular or capsular instability.

Dislocation is due to total zonular or capsular instability. However, the terms are commonly interchanged. Once the dislocated IOL is identified, there are several possible management options.

IOL dislocation is typically related to the integrity of the capsular bag and its support system (zonules) and their ability to support an IOL.

There are many predisposing conditions that increase the risk of capsular bag instability and zonular weakness including cataract surgery, prior vitreoretinal surgery, aging, axial myopia, inflammation/uveitis, trauma, retinitis pigmentosa, diabetes mellitus, atopic dermatitis, mature cataract, previous episodes of acute angle-closure attack, connective tissue disorders e.g. pseudoexfoliation syndrome (being the most common risk factor with more than 50% of cases), Marfan syndrome, homocystinuria, hyperlysinemia, Ehlers-Danlos Syndrome, scleroderma, Weill-Marchesani syndrome, ectopia lentis.

Test your knowledge 10 questions from this article

Dislocated intraocular lens (IOL) Diagnosis

History, signs, and symptoms:

Given that many predisposing conditions increase the risk of IOL dislocation, a thorough history is necessary in patients.

Patients with a dislocated IOL may experience a decrease or change in vision, diplopia, and/or glare.

Additionally, they may report ocular pain or headaches from intermittent angle closure and/or inflammation. Some patients also report seeing the edge of the IOL.

Diagnostic procedures:

A complete ophthalmologic exam is necessary in the diagnosis of a dislocated IOL including an anterior and posterior segment exam.

Dislocated Intraocular Lens

A detailed dilated retinal exam with scleral depression is important. If a detailed exam is not feasible, Bscan echography and/or an anterior segment OCT/ultrasound biomicroscopy (UBM) may be helpful in evaluating a posteriorly dislocated lens behind the iris in the anterior aspect of the vitreous cavity.

Types of Dislocated intraocular lens (IOL)

IOL dislocation may present as phacodonesis, simple lens decentration within an intact capsular bag or in the sulcus, partial lens subluxation out of the capsular bag, or complete dislocation of the lens within or outside of the bag into the anterior or posterior chamber.

If there is a posterior capsule defect or tear, the IOL may slide out of the bag, hence out-of-the-bag dislocation.

If there is a defect in the stability of the capsular bag support system e.g. zonular weakness, the entire IOL with the capsular bag may dislocate, hence in-the-bag dislocation.

MANAGEMENT

Observation may be a possible management option in cases where IOL subluxation is minimal without a significant impact on vision and damage to surrounding ocular structures.

Those with pseudophacodonesis and without inferior dislocation are usually asymptomatic and tend to be such candidates.

In such cases, refraction may help sharpen the patient’s vision with close monitoring thereafter. Close follow-up is imperative to ensure patients do not develop potential IOL dislocation sequelae that may necessitate surgical intervention.

In cases where vision is affected and/or there is damage to surrounding ocular structures, surgery plays a large role in IOL dislocation management.

The most common indications for surgery are decreased visual acuity, monocular diplopia, and halos. Less commonly, retinal detachment, glaucoma, and/or uveitis-Glaucoma-Hyphema (UGH) syndrome portend surgical intervention.

Several surgical options exist in the management of dislocated IOL and should be tailored to each individual.

Surgery typically includes pars plana vitrectomy to remove the dislocated lens with either an IOL cutter or through a scleral tunnel or sclerocorneal incision. This is followed by secondary IOL implantation.

REFERENCES

Stark, W.J., Jr., et al., Intraocular lenses: complications and visual results. Trans Am Ophthalmol Soc, 1983. 81: p. 280-309.
Stark, W.J., et al., The FDA report on intraocular lenses. Ophthalmology, 1983. 90(4): p. 311-17.
Kratz, R.P., et al., The Shearing intraocular lens: a report of 1,000 cases. J Am Intraocul Implant Soc, 1981. 7(1): p. 55-7.
Gimbel, H.V., et al., Late in-the-bag intraocular lens dislocation: incidence, prevention, and management. J Cataract Refract Surg, 2005. 31(11): p. 2193-204.
Ascaso, F.J., V. Huerva, and A. Grzybowski, Epidemiology, Etiology, and Prevention of Late IOL-Capsular Bag Complex Dislocation: Review of the Literature. J Ophthalmol, 2015. 2015: p. 805706.
Davis, D., et al., Late in-the-bag spontaneous intraocular lens dislocation: evaluation of 86 consecutive cases. Ophthalmology, 2009. 116(4): p. 664-70.

Test yourself

A few questions straight from this article.

1 / 10 0 correct

In intraocular lens dislocation terminology, subluxation denotes which degree of support failure?
Decentration is loss of IOL centration without zonular or capsular instability, subluxation is partial zonular or capsular instability, and dislocation implies total instability.
Intraocular lens dislocation has been reported at approximately what rate?
IOL dislocation is a rare but serious complication, reported at a rate of 0.2% to 3%.
Which condition is the single most common risk factor for intraocular lens dislocation?
Pseudoexfoliation syndrome is the most common risk factor, accounting for more than 50% of cases, ahead of other causes of zonular weakness such as Marfan syndrome and axial myopia.
In-the-bag dislocation of an intraocular lens arises from which underlying defect?
When the capsular bag support system fails, for example through zonular weakness, the entire IOL together with the capsular bag dislocates as a unit.
Out-of-the-bag dislocation of an intraocular lens follows which structural problem?
If there is a posterior capsule defect or tear, the IOL can slide out of the bag, giving an out-of-the-bag dislocation.
Ocular pain or headache in a patient with a dislocated intraocular lens is attributed to which mechanism?
Patients may report ocular pain or headaches from intermittent angle closure and inflammation, alongside reduced or changed vision, diplopia, glare, and sometimes seeing the edge of the IOL.
When a detailed dilated retinal exam is not feasible in suspected intraocular lens dislocation, which investigations help?
If a detailed examination is not feasible, B-scan echography and anterior segment OCT or ultrasound biomicroscopy help evaluate a lens dislocated behind the iris into the anterior vitreous cavity.
Which patient with a malpositioned intraocular lens is the best candidate for observation alone?
Observation suits minimal subluxation with no significant visual impact or damage to surrounding structures; such patients are usually asymptomatic, and refraction with close follow-up may be enough.
What are the most common indications for surgery in intraocular lens dislocation?
Decreased visual acuity, monocular diplopia and halos are the commonest indications; retinal detachment, glaucoma and uveitis-glaucoma-hyphema syndrome prompt surgery less often.
Surgery for a dislocated intraocular lens typically involves which sequence?
Surgery typically uses pars plana vitrectomy to remove the dislocated lens, either with an IOL cutter or through a scleral tunnel or sclerocorneal incision, followed by secondary IOL implantation.