As an eye doctor, diagnosing a red eye can be challenging. Are we dealing with an infection, allergy, inflammation or dryness?

One of the most common questions I get is, “Doc, my eyes are red, burning, itchy, and tearing. Is this dry eye or from allergies?” The short answer is it could be one, both or neither. I’ll outline various ways these conditions present clinically and the treatments for them.

The hallmark symptom of allergy – meaning if you have this symptom you almost definitely have the condition – is itching. Red, watery, ITCHY eyes are almost invariably due to an allergen, whether environmental or medicinal. It is one of the most common ocular conditions we, as eye doctors, treat - especially when plants are filling the air with pollen as they bloom in the spring and then die off in the fall.

The itching occurs because an immune cell called a Mast cell releases histamine, causing the itching sensation. It can be quite unbearable for the sufferer, causing them to rub their eyes constantly, which unbeknownst to them, actually increases the amount of histamine in the eye, leading to worsening of the symptoms.

Treatments may include:

• Over-the-counter or prescription allergy drops (mostly anti-histamines or mast cell stabilizers).
• Topical steroids (to get the inflammation under control).
• Cool compresses applied to the eye.

Patients sometimes need to take drops every day to keep their symptoms under control.

Dry eye can have many of the same symptoms as allergic eye disease, with the eye being red and possibly watery (‘My eyes are tearing how could it be dry eyes?’). The main exceptions are that people with dry eyes tend to complain more of burning and a foreign body sensation - like there is sand or gravel in the eye - rather than itchiness.

Dry eye is a multi-faceted disease with many different causes and treatments. Treatment ranges from simple re-wetting eye drops to long-term medications (both topical and oral), as well as non-medicinal treatments such as eyelid heating treatment.

So how do we determine the difference? The first question I ask patients who complain of red, watery, uncomfortable eyes is, “What is your MAIN symptom? Itching or burning?” The answer will likely direct which course of treatment we take, and as those treatments sometimes overlap, you may have a component of both dry eye and allergy.

That is important to distinguish because many of the treatments we use for allergies - like antihistamine eye drops - can sometimes make the dryness worse. Though neither of these conditions is 100% curable (except maybe for allergy, where if you remove the allergen, you obviously won’t get symptoms!). We have many tools in our treatment arsenal to keep the symptoms at bay.

Unfortunately, dry eye and allergy aren’t the only two things that can cause your eye to have the multiple symptoms of red, watery, itchy, burning eyes. There are other problems, such as Blepharitis, that can produce a similar appearance, as well as bacterial and viral infections.

So before embarking on a particular therapy, it is wise to have a good exam to help you get on the right track of improving your symptoms.

Article contributed by Dr. Jonathan Gerard

Have you ever seen a temporary black spot in your vision? How about jagged white lines? Something that looks like heat waves shimmering in your peripheral vision?

If you have, you may have been experiencing what is known as an ocular migraine. Ocular migraines occur when blood vessels spasm in the visual center of the brain (the occipital lobe) or the retina.

They can take on several different symptoms but typically last from a few minutes to an hour. They can take on either positive or negative visual symptoms, meaning they can produce what looks like a black blocked-out area in your vision (negative symptom), or they can produce visual symptoms that you see but know aren’t really there, like heat waves or jagged white lines that look almost like lightning streaks (positive symptoms).

Some people do get a headache after the visual symptoms but most do not. They get the visual symptoms, which resolve on their own in under an hour, and then generally just feel slightly out of sorts after the episode but don’t get a significant headache. The majority of episodes last about 20 minutes but can go on for an hour. The hallmark of this problem is that once the visual phenomenon resolves the vision returns completely back to normal with no residual change or defect.

If you have this happen for the first time it can be scary and it is a good idea to have a thorough eye exam by your ophthalmologist or optometrist soon after the episode to be sure there is nothing else causing the problem.

Many people who get ocular migraines tend to have them occur in clusters. They will have three or four episodes within a week and then may not have another one for several months or even years.

There are some characteristics that raise your risk for ocular migraines. The biggest one is a personal history of having migraine headaches. Having a family history of migraines also raises your risk, as does a history of motion sickness.

Although the symptoms can cause a great deal of anxiety, especially on the first occurrence, ocular migraines rarely cause any long-term problems and almost never require treatment as long as they are not accompanied by significant headaches.

So if symptoms like this suddenly occur in your vision, try to remain calm, pull over if you are driving, and wait for them to go away. If they persist for longer than an hour, you should seek immediate medical attention.

Article contributed by Dr. Brian Wnorowski, M.D.

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The spots, strings, or cobwebs that drift in and out of your vision are called “floaters,” and they are more prominent if you’re looking against a white background.

These floaters are tiny clumps of material floating inside the vitreous (jelly-like substance) that fills the inside of your eye. Floaters cast a shadow on the retina, which is the inner lining of the back of the eye that relays images to the brain.

As you get older, the vitreous gel pulls away from the retina and the traction on the retina causes flashing lights. These flashes can then occur for months. Once the vitreous gel completely separates from the back wall of the eye, you then have a posterior vitreous detachment (PVD), which is a common cause of new onset of floaters.

This condition is more common in people who:

• Are nearsighted.
• Are aphakic (absence of the lens of the eye).
• Have past trauma to the eye.
• Have had inflammation in the eye.

When a posterior vitreous detachment occurs, there is a concern that it can cause a retinal tear.

Symptoms of a retinal tear include:

• Sudden increase in number of floaters that are persistent and don't resolve.
• Increase in flashes.
• A shadow covering your side vision, or a decrease in vision.

In general, posterior vitreous detachment is unlikely to progress to a retinal detachment. Only about 15 percent of people with PVD develop a retinal tear.

If left untreated, approximately 40 percent of people with a symptomatic retinal tear will progress into a retinal detachment – and a retinal detachment needs prompt treatment to prevent vision loss.

Generally, most people become accustomed to the floaters in their eyes.

Surgery can be performed to remove the vitreous gel but there is no guarantee that all the floaters will be removed. And for most people, the risk of surgery is greater than the nuisance that the floaters present.

Similarly, there is a laser procedure that breaks the floaters up into smaller pieces in hopes of making them less noticeable. However, this is not a recognized standard treatment and it is not widely practiced.

In general, the usual recommendation for floaters and PVD is observation by an eye care specialist.

Article contributed by Jane Pan M.D.

The content of this blog cannot be reproduced or duplicated without the express written consent of Eye IQ. This blog provides general information and discussion about eye health and related subjects. The words and other content provided in this blog, and in any linked materials, are not intended and should not be construed as medical advice. If the reader or any other person has a medical concern, he or she should consult with an appropriately licensed physician.