Blepharitis
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| 'Buttery ' meibomian secretions in posterior blepharitis |
How is it diagnosed?
In severe cases blepharitis is easy to diagnose, even with the naked eye. In mild disease the diagnosis is made with the slit lamp microscope.
Changes are present in the eyelid and may also be apparent in the tears and cornea.
Changes in the eyelid
The key changes on the eyelid margin are:
- Greasiness of the skin
- Crusting of the lashes
- Plugging of the meibomian glands
- Altered oily secretions
- Dilated blood vessels, known as telangectasia
- Eyelid cysts
- Scarring of the eyelid margin - pits and twisting
Severe blepharitis with marked inflammation of the eyelid margin
Changes in the tears
Key changes in the tears include:
- Thinning and 'breaking up' of the oily layer. The 'break-up time' of the tear film can be assessed by staining the tears with fluorescein dye and observing how long the oily layer remains stable before suddenly thinning.
- 'Blobs' of thickened oil
Changes in the cornea
Common corneal changes include:
- Patchy loss of cells of the epithelium, known as punctate keratopathy
- Inflammatory, 'marginal', ulcers
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| Thinning of the oily layer of the tears (dark patches) and loss of epitheial cells of the cornea (bright dots) |