Sudden Black Spots in Vision: Causes, Symptoms & Emergency Care

Understanding Sudden Black Spots in Vision

As we age, vision changes are common. You may start to notice more floaters, flashing lights, or blurry spots in your field of vision. While these are often normal age-related changes, sudden black spots can signal a more serious eye condition.

If you suddenly notice black spots or blurred areas blocking your vision, its important to see an eye doctor right away. This article covers the key facts about sudden black spots in vision, how to tell the difference from normal eye floaters, and when to seek emergency care.

What Causes Sudden Black Spots in Vision?

There are a few potential causes of sudden black spots or dark areas that block your vision:

• Retinal tear or detachment
• Vitreous detachment
• Posterior vitreous detachment
• Retinal vein occlusion
• Retinal artery occlusion
• Eye stroke

Lets look at each of these causes in more detail.

Retinal Tear or Detachment

One of the most serious causes of sudden black spots or vision loss is a retinal tear or detachment. The retina is a thin layer of tissue on the inner back wall of your eye that senses light and enables you to see.

A retinal tear occurs when the retina develops a small opening or hole. This can happen if the vitreous (gel-like substance inside the eye) pulls away from the retina, causing it to tear. Retinal tears need to be repaired quickly to prevent detachment.

A retinal detachment is more serious and happens when the retina fully separates from the back of the eye. This causes significant vision loss or a black curtain over the field of vision. Retinal detachment is a medical emergency that causes permanent blindness if not treated immediately.

Vitreous Detachment

As you age, the vitreous jelly inside the eye starts to liquefy and pull away from the retina. This is called a vitreous detachment or posterior vitreous detachment (PVD). It usually causes harmless floating spots or strands in vision.

However, if the vitreous tugs hard on the retina before detaching, it can cause a retinal tear. Sudden black spots or vision loss indicate a retinal tear has occurred. Vitreous detachment requires an urgent eye exam to repair retinal tears before they progress to detachment.

Retinal Vein/Artery Occlusion

The retina has a network of tiny blood vessels that supply it with oxygen and nutrients. If one of these blood vessels becomes blocked, it can cause sudden vision loss or black spots.

Retinal vein occlusion (RVO) occurs when a vein is obstructed, while retinal artery occlusion (RAO) is a blockage of an artery. Both conditions require emergency treatment to prevent permanent vision loss.

Eye Stroke

A stroke in the eye is similar to a stroke in the brainits caused by a blocked blood vessel. Eye stroke, or retinal stroke, starves the retina of oxygen causing cell death and blindness.

Symptoms of an eye stroke include sudden painless vision loss or black spots in one or both eyes. Its considered an emergency requiring immediate treatment to save vision.

When to Seek Emergency Care

If you suddenly notice new spots, a gray or black curtain over your vision, or loss of peripheral or central vision, it should be considered a medical emergency.

Go to the emergency room or call 911 immediately if you experience:

• Sudden appearance of spots, strands or strings in your vision
• Black curtain or blocked out area of vision
• Sudden blurry vision or loss of vision
• Flashing lights or floaters along with other symptoms
• Partial loss of vision in one or both eyes

These urgent symptoms could signal a detached or torn retina, vitreous detachment, eye stroke or other sight-threatening condition. Permanent blindness can occur within hours if not treated promptly.

Diagnosing the Cause of Black Spots

To determine the cause of sudden black spots in vision, the eye doctor will perform a couple key examinations:

Dilated Eye Exam

Drops are placed in the eyes to dilate or widen the pupils. This allows the doctor to get a better view inside the back of the eye using a slit lamp microscope.

They will look closely at the optic nerve, macula, retina, and vitreous for any tears, detachments, or abnormalities.

Visual Field Test

A visual field test checks your peripheral vision and side vision. It can help detect any loss of vision or blind spots in your field of view.

Advanced diagnostic tests may include fluorescein angiography to examine retinal blood vessels, optical coherence tomography (OCT) to get high-resolution images of the back of the eye.

Treating the Underlying Cause

Treatment will depend on the cause of sudden vision loss or black spots found during the eye exam. Some key treatments may include:

• Laser surgery: Small retinal tears or areas of lattice degeneration can often be treated in-office with laser therapy to prevent detachment.
• Retinal surgery: For detached retinas or large tears, a vitrectomy surgery is done to reattach the retina. This is a same day outpatient procedure.
• Vascular occlusion treatment: Medication injected directly into the eye, or surgery to remove a blockage, can restore blood flow to a blocked retinal artery or vein.
• Medications: Steroids help reduce inflammation and swelling on the retina. Anti-VEGF drugs may be injected directly into the eye to inhibit abnormal blood vessels.

Rapid treatment is key to preventing permanent vision loss. Close follow up care is needed even after successful treatment to check for complications or recurrence.

Preventing Sudden Vision Loss

While we cant always prevent sudden vision changes, regular eye exams allow early detection and treatment of conditions like:

• Retinal holes, tears or thinning
• Areas of lattice degeneration
• High eye pressure (glaucoma)
• Retinal blood vessel blockages
• Diabetic retinopathy
• Macular degeneration

Loosening eye makeup and rubbing eyes vigorously can also lead to retinal issues, so be very gentle when removing makeup.

A healthy diet, exercise, avoiding smoking, and controlling diseases like diabetes and high blood pressure also help reduce damage to the blood vessels in the eyes.

Watch for Flashing Lights and Floaters Too

While sudden black spots, blocked vision or partial vision require emergency care, symptoms like eye flashes and floaters are less concerning if they occur alone. Lets look at when floating spots or flashing lights can be normal vs. when they indicate a problem:

Normal Eye Floaters

As you age, its common to start seeing small specks that drift or float through your field of vision. These eye floaters occur when the vitreous gel in the eye starts to break down into tiny clumps.

They look like small pieces of hair, dots, circles, squiggly lines, or cobwebs drifting in the path of your vision when you move your eyes. Floaters tend to be more noticeable when looking at a plain bright background like a blue sky or white wall.

While annoying, regular floaters are usually not a cause for concern. However, if you notice a sudden increase in the number of eye floaters, it could signal a posterior vitreous detachment.

Harmless Flashing Lights

Flashing lights in vision can also occur as we get older, often due to vitreous changes or migraines. They are described as flickering lights, sparks, lightning streaks, or light shimmers that come and go.

If flashing lights appear randomly and dont happen too frequently, its usually nothing to worry about. But recurrent flashes, especially with other symptoms, need medical attention.

When Floaters and Flashes Indicate a Problem

While eye floaters and flashes can be normal signs of aging, they warrant an urgent eye exam if you notice:

• A sudden increase in floaters
• New and sudden floaters
• Flashes that occur repeatedly
• Floaters or flashes along with other vision changes like light sensitivity, blurriness, or black spots/curtain

These symptoms indicate a posterior vitreous detachment with traction on the retina that can lead to a tear. Sudden floaters and flashes could also represent the start of a retinal detachment.

Its important to get a dilated eye exam promptly if you notice a sudden increase in eye floaters or repetitive flashing lights. Early intervention can prevent vision loss.

When to See An Eye Doctor

In summary, sudden black spots, dark curtain over vision, or loss of peripheral or central vision signal a potential eye emergency. Seek immediate medical care if you notice these symptoms.

While eye floaters and flashes are typically harmless aging changes, a sudden increase in spots and repetitive flashing lights warrants an urgent eye exam to check for retinal tears or detachment.

Dont take chances with your vision. Schedule regular eye checkups to detect issues early. And see an ophthalmologist right away if you notice any sudden changes in your vision.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.