Uveitis is an umbrella terms for diseases affecting the middle part of the eye, called the uvea. They are most commonly classified according to the anatomical location of the inflammation: uveitis aterior (affecting the iris and ciliary muscle), uveitis itermidia (affecting the anterior chamber, vitreous humour) and uveitis posterior (affecting the retina and choroid). Macular oedemas are the most common cause for a deterioration of visual acuity, i.e. in particular uveitis posterior; these occur when fluid collects in the spot (macula) and can cause a severe deterioration of visual acuity in many patients. Often, in particular inflammatory macular oedemas are very difficult to treat.
An optic nerve that is altered or swollen due to an inflammation will result in a deterioration of visual acuity and hazy vision.
As is the case with the other forms of uveitis, uveitis posterior may also cause cataracts, glaucoma or else a drop in intraocular pressure (hypertension).