Red eyes are one of the most common presentations to opticians providing care in the high street under MECS. Some red eyes are relatively innocent and are related to dry eyes. However if misdiagnosed they can lead to severe, sight-threatening conditions being missed.
Thorough evaluation with an appropriate history and examination can help to distinguish the sight-threatening from the benign red eye.
What are the causes?
Redness of the eye can be in one eye or in both eyes. It is the first sign of eye inflammation usually occurring due to engorgement of superficial blood vessels or can occur when a blood vessel bursts. Most of the cases tend to be benign as they are self-limiting or require minimal intervention. Only a handful of cases go on to be serious and in need of urgent referral.
In order to determine the underlying cause for the red eye, there are two key questions to ask in the history of the presenting complaint: 1) Is there any pain? 2) Is there any loss of vision? 3) is there light sensitivty, 4) recent eye trauma or surgery, 5) whether there is a history of contact lens use and, if so, contact lens hygiene.
If the red eye is associated with pain and light sensitivity / glare a white spot may be visible when the eye is viewed in the mirror. This is likely to indicate that there is an ulcer on the cornea. Corneal ulcers need to be assessed and treated urgently. They may be related to contact lens wear. If you have a sore eye with the contact lens removed you need to seek advise urgently.
Below is an image of a red eye showing a corneal ulcer on the lower part of the cornea. It shows as a hazy dot at the six o’clock position. The rectangular reflection to the left of the pupil is a from the light source used on the microscope.