A study in the American Journal of Ophthalmology, and reported in The Wall Street Journal, suggests that exposure to cats (and cockroaches!) may increase the risk for developing glaucoma.
People who had glaucoma had significantly higher levels of immunoglobulin E (IgE), a type of allergic antibody, to cats, compared with people without glaucoma, The Wall Street Journal reports. Dogs, on the other hand, might actually protect against glaucoma.
Researchers at the University of California, Los Angeles, looked 1,678 people, all of whom were in their 50s and 60s, who were enrolled in a larger study. The subjects all underwent allergy testing to dust mites, dogs, cats, cockroaches and rodents. Steroid use, which is also linked to glaucoma, was also noted in the subjects.
“Glaucoma was diagnosed in 5.1% of the subjects,” The Wall Street Journal reports. “Of these, 14.3% had significantly elevated IgE levels to cats and 19.1% to cockroaches. In contrast, 10% of the nonglaucoma subjects had elevated IgE for either cats or cockroaches. Levels of IgE to dog allergens were elevated in 6% of glaucoma patients and in 9.2% without glaucoma. Total IgE levels for all of the tested allergens weren’t associated with glaucoma, suggesting it is specifically the cat and cockroach allergens that are associated with the development of glaucoma.”
Allergens from cats (and cockroaches) my have properties that trigger antibodies targeting the optic nerve. Dog allergens behave differently — possibly because dogs are outside more.
There is a problem though: the study wasn’t able to assess different subtypes of glaucoma and the relationship with IgE. Researchers are saying that cross-reactions to other allergens may have affected certain antibody levels.