Blepharitis is a common condition where the edges of the eyelids (eyelid margins) become red and swollen (inflamed).
In most cases both eyes are affected, but one eye can be more affected than the other. The symptoms tend to be worse in the morning. Blepharitis is usually a long-term condition. Most people experience repeated episodes, separated by periods without symptoms.

There are three main types of blepharitis:

• Anterior blepharitis – where the inflammation affects the skin around the base of your eyelashes
• Posterior blepharitis – where the inflammation affects your Meibomian glands, found along the eyelid margins behind the base of the eyelashes
• Mixed blepharitis – a combination of both anterior and posterior blepharitis

Anterior blepharitis can be caused by either:

• A reaction to Staphylococcus bacteria – these usually live harmlessly on the skin of many people, but for unknown reasons they can cause the eyelids to become inflamed
• Seborrhoeic dermatitis – a skin condition that causes skin to become oily or flaky and sometimes irritate the eyelids, causing the Meibomian glands to block