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...

Do you have floaters in your vision?

Floaters are caused by thick areas in the gel-like fluid that fills the back cavity of your eye, called the vitreous.

Many people, especially highly near-sighted people, often see some degree of floaters for a good portion of their lives. Often, these floaters are in the periphery of your vision and may only be visible in certain lighting conditions. The most frequent conditions are when you are in bright sunlight and are looking toward the clear blue sky. This I know from personal experience as I have a floater in my left eye that I most often see when swimming outdoors. Every time I turn my head to the left to breathe I see this floater moving in my peripheral vision.

This is totally harmless other than when I’m swimming in the ocean and swear that sudden object in my peripheral vision is a shark bearing down on me. Some people who have floaters are not as lucky and the floater can be very central and almost constantly annoying,...