Chronic, untreated or ineffectively treated FHV-1 can result in persistent squinting/tension within the eyelid muscles, which can lead to secondary inversion or rolling inward of the eyelids. This allows the haired portion of the eyelid to rub on the cornea and causes persistent irritation and discomfort.
This condition is typically the result of severe FHV-1, in which both the epithelial surfaces of the cornea and conjunctiva are ulcerated and subsequently heal together. Symblepharon can be mild and result in only slight alterations in tear flow (epiphora) or surface pigment. Or, it can lead to near complete blindness if the adhesions are severe.
Corneal sequestrums are regions of dead/necrotic cornea. This lesion is caused by either chronic irritation to the corneal surface; physiologic exophthalmos (“buggy”/prominent eyes) in Persian, Himalayan and Burmese cats; or chronic ulceration associated with FHV-1. The lesion is easily recognized by the brown discoloration of the cornea. There is a wide spectrum of appearances, anywhere from a faint, superficial amber hue, to a deep, dark black plaque within the corneal stroma.
This condition is an immune-mediated sequelae to a previous herpesvirus infection. The characteristic lesion consists of dense white chalky lesions and vascularization of the cornea. Cytology of these lesions will reveal the presence of eosinophils, which are white blood cells not normally present in the cornea.
Another immune manifestation of previous FHV-1, stromal keratitis is thought to result from a lingering presence of viral antigen within the corneal stroma. The characteristic lesion in this case is the smooth hazy white appearance and vascularization of the cornea.
DECREASED TEAR PRODUCTION:
This condition can result either from direct inflammation of the tear-producing gland or from scar tissue formation and damage to the ducts of the tear glands.