Light Sensitivity May Be Due to Ocular Inflammation or an Iritis
A persistent or recurring red eye is not normal. Eye redness may be due to allergies , eye dryness , a chemical or irritant exposure , or due to an inflammatory condition. Iritis is an inflammatory condition inside the eyes that may cause eye redness, eye pain, or light sensitivity. Untreated, iritis may result in permanent scarring, glaucoma, and vision loss. There are a number of conditions that can cause eye redness. There is no substitute for a good eye examination to help ensure you are doing everything you can for your eyes.
A number of systemic diseases may be associated with an iritis. For a recurrent iritis or servere iritis, blood work is often done in an attempt to determine a cause for the iritis.
For more information on iritis you can read an article from the Mayo Clinic.