Radial type
Frequency: Most common (57.1%)
Appearance: Blood vessels run along the radial direction of the iris
Features: Tortuous blood vessels extend from the ciliary body toward the pupillary margin
Iris varix
1. What is iris varix?
Section titled “1. What is iris varix?”Iris varix is a benign vascular lesion characterized by abnormal dilation and tortuosity of iris vessels. It appears as an isolated tortuous vessel in the anterior segment, and no malignant transformation has been reported.
The pathogenesis is largely unknown. Congenital predisposition and local hemodynamic changes are thought to be involved, but a clear association with a causative disease has not been established.
It is commonly observed in adults, with some reports in children. There is no clear association with fundus or systemic diseases, and it is often discovered as an incidental finding.
Q
What is an iris varix?
A
It is a benign lesion characterized by abnormal dilation and tortuosity of iris blood vessels. Most cases are asymptomatic and discovered incidentally, following a stable course over a long period. There are no reports of malignant transformation, and observation is generally recommended.
2. Main symptoms and clinical findings
Section titled “2. Main symptoms and clinical findings”Subjective symptoms
Section titled “Subjective symptoms”Many cases are asymptomatic. Patients rarely notice it themselves, and it is often discovered incidentally during regular checkups or examinations for other diseases.
If hyphema is present, patients may complain of decreased vision, blurred vision, and eye pain.
Clinical Findings
Section titled “Clinical Findings”Slit-lamp examination reveals dilated and tortuous blood vessels on the iris surface.
Distribution characteristics:
- Unilateral: 92.3%
- Inferotemporal: 75%
- Bilateral cases are rare
Classification by morphology:
Circular type
Frequency: 21.4%
Appearance: Blood vessels run concentrically around the iris
Features: Tortuous vessels along the greater and lesser iris rings
Mixed type
Frequency: Residual cases
Appearance: Has both radial and annular components
Characteristics: Shows more complex vascular patterns
Anterior chamber hemorrhage may occur. Bleeding is usually mild and resolves with conservative treatment.
Q
Where do iris varices commonly occur?
A
They are mostly unilateral (92.3%) and commonly occur in the inferotemporal quadrant (75%). The most common morphology is radial (57.1%), followed by annular (21.4%).
3. Causes and Risk Factors
Section titled “3. Causes and Risk Factors”The cause of iris varix is unknown. Hypotheses include congenital vascular malformation, local venous pressure elevation, and vascular wall fragility, but none have been confirmed.
No clear association with systemic diseases (such as hypertension, diabetes, or connective tissue diseases) has been reported. Although some cases coexist with local ocular conditions (such as glaucoma or uveitis), a causal relationship is unclear.
No cases with a family history have been reported, and no association with hereditary diseases has been demonstrated at present.
4. Diagnosis and Examination Methods
Section titled “4. Diagnosis and Examination Methods”| Examination | Findings/Purpose |
|---|---|
| Slit-lamp microscopy | Confirmation of dilated and tortuous blood vessels |
| Fluorescein angiography (FA) | Differentiation from rubeosis |
| Anterior segment OCT | Assessment of vessel depth and extent |
| Ultrasound biomicroscopy (UBM) | Evaluation of ciliary body and posterior chamber |
Importance of fluorescein angiography (FA):
In FA, iris varices show hyperfluorescence, but unlike rubeosis (iris neovascularization associated with diabetic retinopathy, retinal vein occlusion, etc.), there is no clear leakage of contrast agent. This finding plays an important role in differential diagnosis.
Differential diagnosis:
| Disease | Key differentiating features |
|---|---|
| Rubeosis iridis | Marked dye leakage on FA; associated systemic disease |
| Iris hemangioma | Elevated lesion; well-defined borders |
| Iris melanoma | Pigmented elevation, growth tendency, abnormal internal structure on ultrasound |
| Iris telangiectasia | Dilation of fine blood vessels, often associated with increased intraocular pressure |
| Persistent pupillary membrane | Embryonic remnant, young age, connection with anterior lens surface |
5. Standard Treatment
Section titled “5. Standard Treatment”Most asymptomatic iris varices can be managed with observation alone. Long-term follow-up studies show that 96.4% remain stable over 10 years.
Indications for observation:
- Regular slit-lamp examination (every 6–12 months)
- Intraocular pressure measurement
- Visual acuity testing
- Observe for vascular dilation or morphological changes
Management of hyphema:
When hyphema is present, conservative treatment is the mainstay. Rest, head elevation, and use of mydriatics to prevent complications (peripheral anterior synechiae, pupillary block) are performed. If intraocular pressure is elevated, pressure-lowering medications are used.
Spontaneous resolution is often expected, and surgical intervention is rarely needed. In cases of recurrent bleeding or significant visual impairment, surgical excision or photocoagulation may be considered.
Q
Does iris varix require treatment?
A
In many cases, treatment is unnecessary and only observation is required. Over 10 years, 96.4% remain stable, and no reports of malignant transformation exist. However, if complications such as hyphema occur, conservative treatment is performed; if recurrent, surgical excision may be considered.
6. Pathophysiology and Detailed Mechanism
Section titled “6. Pathophysiology and Detailed Mechanism”The mechanism of iris varix is currently unknown. Proposed hypotheses are listed below.
Vascular wall fragility hypothesis: Congenital weakness of smooth muscle or connective tissue in the iris vessel wall leads to dilation and tortuosity due to inability to withstand venous pressure.
Local venous pressure elevation hypothesis: Local blood flow disturbance or outflow obstruction in the venous system increases pressure within the iris vein, causing dilation. An association with intraocular pressure has been considered but not clearly demonstrated.
Developmental abnormality theory: A theory that the lesion is a remnant of a localized abnormality in vascular development during the embryonic period. It is sometimes used to explain cases of juvenile onset or association with congenital eye diseases.
Neither theory has been confirmed, and multiple mechanisms may be involved. Elucidation through future molecular biological and genetic research is awaited.
7. Latest Research and Future Prospects
Section titled “7. Latest Research and Future Prospects”Iris varices are relatively rare diseases, and large-scale prospective studies are limited. Knowledge accumulation through case series and case reports is the main approach.
Long-term prognosis: Existing retrospective studies have shown a favorable prognosis with a 10-year stability rate of 96.4%. Further long-term, large-scale follow-up studies are expected to identify prognostic factors.
Non-invasive evaluation using FA and anterior segment OCT: Advances in anterior segment OCT angiography (OCTA) are enabling detailed evaluation of iris vessels with less invasiveness than conventional FA. Improved diagnostic accuracy is expected in the future.
Etiology Elucidation: Advances in etiological research using genetic analysis and molecular biology techniques may lead to further clarification of the molecular mechanisms involved in varicose vein formation.
8. References
Section titled “8. References”- Jain P, Finger PT. Iris varix: 10-year experience with 28 eyes. Indian J Ophthalmol. 2019;67(3):350-357. doi:10.4103/ijo.IJO_1253_18. PMID: 30777952.
- Shields JA, Bianciotto C, Kligman BE, Shields CL. Vascular tumors of the iris in 45 patients: the 2009 Helen Keller Lecture. Arch Ophthalmol. 2010;128(9):1107-1113. doi:10.1001/archophthalmol.2010.188. PMID: 20837792.
- Broaddus E, Lystad LD, Schonfield L, Singh AD. Iris varix: report of a case and review of iris vascular anomalies. Surv Ophthalmol. 2009;54(1):118-127. doi:10.1016/j.survophthal.2008.10.005. PMID: 19171213.
- Shields JA, Shields CL, Pulido J, Eagle RC Jr, Nothnagel AF. Iris varix simulating an iris melanoma. Arch Ophthalmol. 2000;118(5):707-710. doi:10.1001/archopht.118.5.707. PMID: 10815165.
- Matlach J, Kasper K, Kasper B, Klink T. Successful argon and diode laser photocoagulation treatment of an iris varix with recurrent hemorrhage. Eur J Ophthalmol. 2013;23(3):431-435. doi:10.5301/EJO.5000242. PMID: 23483511.