AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

The iris is a thin, colored diaphragm that is situated anterior to the lens. Although the root of the iris is attached to the ciliary body, the rest of the iris is unsupported. In the event of a corneal wound, the iris tends to prolapse out. Iris prolapse occurs when the iris tissue is observed outside of the wound; iris incarceration occurs when the iris tissue reaches the wound without prolapsing outside the eye.

Pathophysiology

Iris prolapse can occur when the cornea is perforated due to any cause. In 1995, using flow mechanics and the Bernoulli principle, Allan provided a theoretical explanation of iris prolapse. With a corneal perforation, the aqueous humor rapidly escapes, and a relative vacuum is created in front of the iris, thus leading to iris prolapse.

Frequency

United States

The exact incidence of iris prolapse in the United States is unknown, but the overall estimated rate of all eye injuries ranges from 8.2-13 per 1000 population. Eye injury rates are highest among individuals in their 20s, males, and whites.

International

The incidence rate worldwide is unknown.

Mortality/Morbidity

Iris prolapse is a serious condition and, if left untreated, can result in infection and loss of the eye. If the prolapsed iris is exposed (eg, corneal laceration), immediate surgical intervention is needed because infection can spread through the iris and into the eye. If the prolapsed iris is covered by the overlying conjunctiva (eg, surgical wound), immediate surgical intervention is usually not needed.

Race

No racial predilection exists.

Sex

Iris prolapse is probably more common in young men than in young women.

Age

Age is not a significant factor for iris prolapse.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• The iris is a sensitive tissue in the eye. At the time of an iris prolapse, patients often experience pain. Patients with a perforated corneal ulcer frequently provide a history of severe pain that has since subsided.
• The iris can prolapse after surgery (eg, cataract, corneal transplant), following trauma (eg, corneal laceration, scleral laceration), through a perforated corneal ulcer, or through a corneal melt associated with rheumatoid arthritis.
• • With improvements in microsurgical techniques, iris prolapse after surgery is uncommon.
  • Iris prolapse with a perforated corneal ulcer is rare.
  • In the author's experience, the most common cause of iris prolapse is following trauma; however, the exact incidence is not known.

Physical

In peripheral iris prolapse, the iris appears as a knuckle of colored tissue, resulting in a partial peripheral synechia. When the prolapse is central, the entire pupillary margin may prolapse, resulting in a total anterior synechia. In patients with a perforated cornea, the prolapsed iris is exposed.

Depending on the duration of prolapse, the appearance of the iris may vary. In cases of recent prolapse, the iris appears viable. With time, the iris appears dry and nonviable. In patients who have undergone corneal transplant surgery or cataract surgery with a clear corneal incision, the appearance of the iris is the same as in a perforated cornea. When the iris prolapses through a scleral wound, it appears as a colored mass beneath the overlying conjunctiva. In this case, the iris remains viable for a long time.

• The pupil appears peaked in the region of the iris prolapse. The anterior chamber is formed as the prolapsed iris seals the wound. Minimal or no wound leakage occurs. Wound leak is verified using the Seidel test. A drop of 2% fluorescein sodium is instilled in the conjunctival sac. The wound is examined under the slit lamp with cobalt blue light. The fluorescein appears greenish. Wound leak can be easily identified when the fluorescein is diluted by the aqueous humor. Gentle pressure on the eye may be needed to induce leakage.
• Intraocular pressure is lower than normal, but hypotony is uncommon after iris prolapse.
• In long-standing iris prolapse, chronic iridocyclitis, cystoid macular edema, or glaucoma may be seen. The prolapsed iris may act as a scaffold for infection, epithelial downgrowth, or fibrous ingrowth. Rarely, sympathetic ophthalmia may occur. Carefully examining the fellow eye for flare and cells is important.

Causes

Iris prolapse can occur following trauma, after surgery, through a perforated corneal ulcer, or through a corneal melt.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Scleromalacia

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Iris prolapse is a clinical diagnosis.

Imaging Studies

• In long-standing iris prolapse, if cystoid macular edema is suspected, fluorescein angiography may be performed. Cystoid macula edema appears as a flower petal in the late stages of the angiogram.
• CT scan of the orbits is indicated with traumatic iris prolapse to aid in diagnosing other ocular and orbital trauma. CT scan of the orbits may help in localizing intraocular foreign bodies and in assessing the status of the posterior segment of the eye.
• In traumatic iris prolapse, ocular ultrasound may be gently performed by experienced personnel. This imaging modality may help to locate intraocular foreign bodies and to assess the status of the posterior segment of the eye. Care should be taken while performing the ocular ultrasound because undue pressure can cause prolapse of the intraocular contents.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

Iris prolapse is a serious condition that requires prompt medical management. As soon as the diagnosis is made, an eye shield should be applied to prevent further damage. Medical treatment is only indicated when the prolapse is small, is covered by the conjunctiva, and is without any other complications. In these cases, the eye may be observed.

Antibiotic eye drops and cycloplegics may be used during the acute stage. Intravenous antibiotics should be considered because infection from an iris prolapse can spread to the intraocular contents. Intravenous cefazolin is recommended. Tetanus toxoid may be considered depending on the immunization status and the wound type.

Surgical Care

Prompt surgical management is necessary when conjunctival coverage is not present or in the presence of complications. The primary goal of surgery is to restore the anatomical integrity of the eye. Visual restoration is only a secondary goal.

• General anesthesia should be used during surgery. Retrobulbar anesthesia and peribulbar anesthesia are not recommended because they increase both intraorbital pressure and loss of additional intraocular tissue; however, they may be used if general anesthesia is contraindicated.
• In cases of peripheral iris incarceration and a well-formed anterior chamber, acetylcholine (Miochol) may be administered.
• • Acetylcholine is instilled through a paracentesis incision into the anterior chamber with gentle stroking of the iris. Acetylcholine constricts the pupil and may release the iris incarceration.
  • Similarly, if the iris incarceration is central, intraocular epinephrine may be administered. Epinephrine dilates the pupil and helps to release the iris incarceration.
• If unsuccessful through a paracentesis incision, a viscoelastic agent is injected into the anterior chamber in the region of the iris prolapse. This mechanical force may be enough to release the prolapse and to reposition the iris.
• • If the prolapse occurred within the previous 24-36 hours and if the iris is viable, the iris is reposited.
  • If the iris does not appear viable, then it is excised. The iris should be excised if signs of epithelialization are present.
  • To excise, the prolapsed iris is cut flush with the corneal surface. The iris defect may be closed using a 10-0 polypropylene suture on a vascular needle.
• If the viscoelastic method is unsuccessful, then a cyclodialysis spatula with the longer end is introduced through the paracentesis incision. The spatula is swept from the center to the periphery of the prolapse to avoid unnecessary tension on the iris root. The corneal wound may be sutured depending on its length and integrity.
• If the iris prolapse occurs after surgery, the same principle is used. The wound must be revised, or additional sutures should be applied to make the wound watertight.
• When the iris prolapse occurs after a corneal perforation, the iris can be reposited. Cyanoacrylate glue and a bandage contact lens may be used to seal the perforation. If unsuccessful or if the perforation is large, an emergency corneal transplant is necessary.

Consultations

In patients with a corneal melt due to medical causes (eg, rheumatoid arthritis), appropriate consultations must be obtained.

Activity

The patient should not engage in contact sports because even a minor trauma can cause significant damage in an already compromised eye. The patient should be instructed to wear polycarbonate eyeglasses while working with mechanical devices and tools.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Systemic antibiotics are used for prophylaxis against infection, especially in cases of iris prolapse following trauma. Endophthalmitis is uncommon but has a poor prognosis in the setting of ocular trauma. Antibiotics should cover both gram-negative organisms and gram-positive organisms, including Bacillus, which is the most common cause of posttraumatic endophthalmitis.

Drug Category: Antibiotics

Prophylaxis against infection.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Inpatient Care

• After surgery, patients may be monitored on either an inpatient basis or an outpatient basis. Admitting patients for at least 1 day after surgery is recommended.

Further Outpatient Care

• Corneal sutures may be removed when they become loose or in stages after 4-6 weeks.
• Long-term follow-up care is necessary to monitor intraocular pressure and cataract formation. In patients who are medically treated, the eye should be carefully examined for iritis and cystoid macular edema. The fellow eye should be carefully examined for signs of sympathetic ophthalmia.

In/Out Patient Meds

• Postoperatively, patients are prescribed antibiotics, steroid drops, and cycloplegics for 3-6 weeks.

Deterrence/Prevention

• The patient should be instructed to wear protective eyeglasses that cover the eye from the front and the sides while working with mechanical devices and tools or during contact sports. (The author recommends avoiding contact sports.) The protective eyeglasses should be made of polycarbonate, a shatterproof material.

Complications

• Several complications can occur because of an iris prolapse, as follows:
• • The prolapsed iris may act as a scaffold and introduce intraocular infection, such as endophthalmitis.
  • If left untreated, the prolapsed iris becomes covered by epithelial and fibrous tissue, which may then grow into the eye.
  • Although rare, sympathetic ophthalmia can occur.
  • Iritis and cystoid macular edema can result from traction on the iris tissue.
  • Secondary glaucoma may occur as result of iritis, synechiae, or epithelial downgrowth.

Prognosis

• Prognosis depends on several factors. The smaller the prolapse, the better the prognosis.
• • Patients with other injuries and intraocular foreign bodies are likely to have a poor prognosis.
  • The presence of infection carries a poor prognosis.
  • Epithelial downgrowth and fibrous ingrowth are difficult to treat and have a poor prognosis.

Patient Education

• For excellent patient education resources, visit eMedicine's Eye and Vision Center. Also, see eMedicine's patient education article Eye Injuries.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• An iris prolapse that is not covered by an overlying conjunctiva should be promptly treated with surgery. Delay can lead to complications.
• Infection prophylaxis must be considered, especially with a delay in treatment. Tetanus status and prophylaxis must be addressed.
• In some circumstances, patients may not want to provide a history of trauma; children do not often admit to trauma during the first encounter. All patients who have an iris prolapse without previous eye surgery should have a careful eye examination with possible ultrasound or a CT scan to rule out intraocular foreign bodies.
• Patients should be cautioned about sympathetic ophthalmia in the fellow eye. Patients should be instructed to make an appointment with an ophthalmologist if symptoms occur that involve the fellow eye.
• Patients should be instructed to wear protective polycarbonate eyeglasses to prevent further ocular injury.
• In patients who have an iris prolapse caused by corneal melt secondary to rheumatologic conditions (eg, rheumatoid arthritis), even if joint symptoms are stable, rheumatology should be consulted for adequate treatment of the systemic disease.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• Albert DM. Ophthalmic Surgery: Principles and Techniques. Vol 1. Blackwell Science;1999:137-138.
• Allan BD. Mechanism of iris prolapse: a qualitative analysis and implications for surgical technique. J Cataract Refract Surg. Mar 1995;21(2):182-6. [Medline].
• Brinton GS, Topping TM, Hyndiuk RA. Posttraumatic endophthalmitis. Arch Ophthalmol. Apr 1984;102(4):547-50. [Medline].
• Francis PJ, Morris RJ. Post-operative iris prolapse following phacoemulsification and extracapsular cataract surgery. Eye. 1997;11 ( Pt 1):87-90. [Medline].
• McGwin. '.
• McGwin G, Hall TA, Xie A. Trends in eye injury in the United States, 1992-2001. Invest Ophthalmol Vis Sci. Feb 2006;47(2):521-7. [Medline].
• McGwin G, Xie A, Owsley C. Rate of eye injury in the United States. Arch Ophthalmol. Jul 2005;123(7):970-6. [Medline].
• Naylor G. Iris prolapse; who? When? Why?. Eye. 1993;7 ( Pt 3):465-7. [Medline].
• Taguri AH, Sanders R. Iris prolapse in small incision cataract surgery. Ophthalmic Surg Lasers. Jan-Feb 2002;33(1):66-70. [Medline].

Article Last Updated: Jun 26, 2006