Is visual function affected in severe ocular allergies?

PURPOSE OF REVIEW: The purpose of the present review is to provide an overview on the clinical features and long-term complications of severe ocular allergies, with a special focus on the corneal involvement observed in these diseases, which may impair vision permanently. Furthermore, different treatment options are discussed based on the sight-threatening effects of corticosteroid use. RECENT FINDINGS: Recent data on the demographics, clinical and immunologic features of vernal and atopic keratoconjunctivitis are presented and discussed, and the evidence of a lack of literature addressing the issue of visual outcome in allergic diseases is underlined. The efficacy and possible long-term complications of their treatments are described, including visual impairment. SUMMARY: Diagnosis and treatment of patients with severe ocular allergy is a challenge for ophthalmologists due to the long-term corneal complications and the potential side-effects of topical corticosteroids that may induce cataract formation and glaucoma, and impair vision permanently. The review describes old and new concepts of management and possible complications such as severe, vision-threatening forms of allergic ocular disease. An update on their management and long-term complications may help clinicians to establish a common agreement on treatment options and researchers to design future studies based on similar outcomes, including visual acuity.

Chlamydial infections in small ruminants.

Chlamydophila abortus (formerly Chlamydia psittaci) is one of the most important causes of reproductive failure in sheep and goats, especially in intensively managed flocks. The disease is usually manifested as abortion in the last 2 to 3 weeks of gestation, regardless of when the animal was infected. Ewes that abort are resistant to future reproductive failure due to C. abortus, but they become inapparent carriers and persistently shed the organism from their reproductive tracts during estrus. Chlamydophila pecorum is the other member of the genus that affects small ruminants, and it is recognized as a primary cause of keratoconjunctivitis in sheep and goats and of polyarthritis in sheep.

Infectious bovine keratoconjunctivitis: a review.

The economic impact of infectious bovine keratoconjunctivitis (IBK) warrants continued investigation of the mechanisms by which Moraxella bovis survives on and colonizes the corneal surface. Virulent strains of M bovis produce hemolysin and exhibit different plasmid profiles than nonvirulent strains. Interactions among host, environment, vector, season, and concurrent infection influence the prevalence of IBK. Mycoplasma sp. or infectious bovine rhinotracheitis virus may enhance or hasten the disease process. The manifestations of IBK may range from mild conjunctivitis to severe ulceration, corneal perforation, and blindness. Treatment of IBK is dictated by economic considerations, intended animal use, and feasibility of administration. Antibiotic therapy is aimed at achieving drug concentrations in tears to meet or exceed the minimum inhibitory concentration for prolonged periods. At present, IBK is not a preventable disease. Affected animals must be separated from the herd and vector control vigorously instituted. Carrier animals must be identified and removed from the herd. Vaccination trials have been unsuccessful because of pili antigen cross-reactivity, variable strains, and uncontrolled environmental factors. Recent investigations have determined that M bovis may utilize host iron sources via iron-repressible outer membrane proteins and siderophores for growth. Elucidation of normal defense mechanisms of the bovine eye may lead to new strategies to enhance the immune response against M bovis.