Retinal Vein & Artery Occlusions
Definition
A retinal tear occurs when the vitreous (the clear, gel-like substance inside the eye) pulls on the retina strongly enough to create a small rip or break in the retinal tissue. While a retinal tear is not the same as a retinal detachment, it can lead to a retinal detachment if left untreated.
A retinal tear is considered an eye emergency because prompt treatment can prevent serious vision loss.
Causes and Risk Factors
Causes
The most common cause of a retinal tear is posterior vitreous detachment (PVD), a natural age-related process in which the vitreous gel shrinks and pulls away from the retina. In some people, this traction is strong enough to tear the retina.
Other causes include:
- Eye trauma or injury
- Previous eye surgery, especially cataract surgery
- Areas of retinal thinning (such as lattice degeneration)
Risk Factors
People are more likely to develop a retinal tear if they:
- Are older adults (particularly over age 50–60)
- Are highly nearsighted (high myopia)
- Have lattice degeneration or a thin retina
- Have had previous eye surgery
- Have a family history of retinal tears or retinal detachment
- Have suffered eye trauma
Symptoms
Some retinal tears cause no symptoms, but many produce sudden visual changes.
Common Symptoms
- Sudden onset of floaters (spots, cobwebs, threads, or specks)
- Flashes of light (photopsias)
- Blurred vision
- Darkening of vision
- A shadow or curtain-like effect in peripheral vision (may indicate progression toward retinal detachment)
Emergency Warning Signs
Seek immediate eye care if you experience:
- A sudden increase in floaters
- New flashes of light
- A gray curtain, shadow, or loss of side vision
- Sudden blurred or decreased vision
These symptoms may indicate a retinal tear or retinal detachment and require urgent evaluation.
Retinal Tear vs. Retinal Detachment
| Retinal Tear | Retinal Detachment |
| Small rip or break in the retina | Retina separates from underlying tissue |
| Often treatable in the office | Usually requires surgery |
| May cause floaters and flashes | May cause vision loss and a curtain over vision |
| Can progress to retinal detachment if untreated | Medical emergency with risk of permanent vision loss |
Diagnosis
Dilated Eye Examination
The primary method of diagnosis is a comprehensive dilated retinal examination, allowing the eye specialist to inspect the retina for tears, holes, bleeding, or detachment.
Specialized Retinal Evaluation
Retina specialists may use:
- Special retinal lenses
- Scleral depression (gentle pressure applied to the eye during examination)
- Retinal imaging when necessary
to identify even small retinal tears.
Treatment
The goal of treatment is to seal the retinal tear before retinal detachment develops.
Laser Photocoagulation
- A laser creates small burns around the tear.
- Scar tissue forms and seals the retina to underlying tissue.
- Common office-based procedure.
- Success rates are typically greater than 90%.
Cryopexy (Freezing Treatment)
- A freezing probe is applied to the outside of the eye.
- Creates scar tissue that seals the retinal tear.
- Often used when laser treatment is difficult to perform.
Treatment of Associated Retinal Detachment
If fluid passes through the tear and detaches the retina, more advanced surgery may be needed, such as:
- Vitrectomy
- Pneumatic retinopexy
- Scleral buckle surgery
Prevention
Not all retinal tears can be prevented, but risk may be reduced by:
- Regular eye examinations for high-risk individuals
- Protecting the eyes from injury during sports and hazardous activities
- Prompt evaluation of new flashes or floaters
- Monitoring retinal thinning or lattice degeneration when identified by an eye doctor
Summary
A retinal tear is a break in the retina most commonly caused by age-related vitreous changes. Symptoms often include sudden floaters, flashes of light, blurred vision, or a shadow in the visual field. While a retinal tear is not the same as a retinal detachment, it can progress to one if untreated. Early diagnosis and treatment with laser photocoagulation or cryopexy are highly effective and can prevent permanent vision loss.
Retinal Artery Occlusion
Definition
Retinal artery occlusion (RAO) occurs when blood flow through a retinal artery becomes blocked, depriving the retina of oxygen. It is considered an ocular emergency and is often described as the eye’s equivalent of a stroke. Immediate evaluation is critical to reduce the risk of permanent vision loss and identify potential cardiovascular disease.
Types
1. Central Retinal Artery Occlusion (CRAO)
- Blockage of the main retinal artery.
- Usually causes severe vision loss affecting most of the retina.
2. Branch Retinal Artery Occlusion (BRAO)
- Blockage of one of the smaller retinal artery branches.
- Causes vision loss in only part of the visual field.
Causes and Risk Factors
Causes
The most common causes include:
- Cholesterol or blood clot emboli blocking the retinal artery
- Carotid artery atherosclerosis (plaque in neck arteries)
- Cardiovascular disease and emboli from the heart
- Inflammatory diseases affecting blood vessels (arteritis)
- Hypercoagulable blood disorders
Risk Factors
- Age over 50 years
- High blood pressure
- Atherosclerosis
- Diabetes mellitus
- Heart disease
- Smoking and vascular disease
Symptoms
Symptoms are typically sudden, painless, and affect one eye.
Common Symptoms
- Sudden severe loss of vision in one eye
- Partial visual field loss (especially with BRAO)
- Sudden dimming or blackout of vision
- Usually no eye pain
Why It Is an Emergency
Patients with retinal artery occlusion have an increased risk of:
- Stroke
- Heart attack
- Other serious cardiovascular events
Because of this association, rapid medical evaluation is recommended.
Diagnosis
Dilated Retinal Examination
- Allows direct visualization of retinal ischemia and arterial blockage.
Retinal Imaging
- OCT and fluorescein angiography may help evaluate retinal damage and blood flow.
Systemic Evaluation
- Carotid artery imaging
- Cardiac evaluation
- Stroke assessment
Retinal artery occlusion often requires coordination between ophthalmology, neurology, and primary care teams.
Treatment
Emergency Medical Evaluation
- Immediate referral is recommended because RAO is treated similarly to an acute stroke.
Identify and Treat Underlying Cause
- Evaluate carotid artery disease
- Assess for heart disease
- Manage vascular risk factors
Vision Prognosis
- Unfortunately, no consistently effective treatment exists to restore vision once significant retinal damage has occurred.
- Prompt diagnosis may help reduce the risk of future strokes and cardiovascular events.
Prevention
- Control blood pressure, cholesterol, and diabetes
- Stop smoking
- Manage cardiovascular disease risk factors
- Seek immediate care for sudden vision loss
Summary
Retinal artery occlusion is a sudden blockage of blood flow to the retina and is considered an eye stroke. Patients typically experience painless, sudden vision loss in one eye. Because RAO is strongly associated with future stroke and cardiovascular disease, it requires urgent medical evaluation. Prevention focuses on controlling vascular risk factors and maintaining cardiovascular health.