Ocular Manifestations of Systemic Disease

The eye can often be involved in systemic disease since it has readily visualised lymphatic tissue in the iris and vasculature in the conjunctiva, iris and retina which can provide a marker of the signs of many systemic diseases, as noted below.

Conjunctivitis can be associated with upper respiratory tract disease such as FHV-1

Mucosal signs of icterus or a haemorrhagic diathesis can also be noted in the conjunctiva while in the cornea the main condition in cats is FHV-1 which classically gives dendritic ulcers but more commonly leads to large superficial geographic ulcers. The virus may also be associated with eosinophilic keratitis and possibly also corneal sequestrum. Another set of lesions in the cornea associated with systemic diseases are keratic preciptates in uveitis. In the cat uveitis can be associated with FIV with an intermediate uveitis described in the literature but iritis occurring quite as commonly in this author’s experience. Other infectious diseases FIP, Toxoplasma and FeLV although this latter infection can be a difficult scenario since some report that it is only neoplastic involvement of the iris which is seen with FeLV while others maintain that iritis alone can be seen to occur with FeLV.) Recently also FHV-1 and Bartonella henslae have been associated with uveitis. The Goldmann-Witner coefficient comparing antibody titres in aqueous humour and serum can be used for assessing whether intraocular viral replication and subsequent immune reaction is occurring. A septic focus such as pyometritis can lead to an LPS-related uveitis while fungal disease such as cryptococcus, histoplasma, coccidiomycosis can lead to a posterior uveitis with retinal detachment. […]