glaucoma clinic attending to persons of the bantu tribes. race. it varies considerably according to race. gender. it affects women more than men. one report was that women were three times more likely than men to develop pex. age. older persons are more likely to develop pex. and persons younger than 50 are highly unlikely to have pex. a study in norway found that the prevalence of pex of persons aged 50–59 was 0.4% while it was 7.9% for persons aged 80–89 years. if a person is going to develop pex, the average age in which this will happen is between 69 and 75 years, according to the norwegian study. a second corroborating report suggested that it happens primarily to people 70 and older. while older people are more likely to develop pex, it is not seen as a "normal" part of aging. other diseases. sometimes pex is associated with the development of medical problems other than merely glaucoma. there are conflicting reports about whether pex is associated with problems of the heart or brain; one study suggested no correlations while other studies found statistical links with alzheimer's disease, senile dementia, cerebral atrophy, chronic cerebral ischemia, stroke, transient ischemic attacks, heart disease, and hearing loss. history pseudoexfoliation syndrome (pex) was first described by an ophthalmologist from finland named john g. lindberg in 1917. he built his own slit lamp to study the condition and reported "grey flakes on the lens capsule", as well as glaucoma in 50% of the eyes, and an "increasing prevalence of the condition with age." several decades later, an ocular pathologist named georgiana dvorak-theobald suggested the term pseudoexfoliation to distinguish it from a similar ailment which sometimes affected glassblowers called true exfoliation syndrome that was described by anton elschnig in 1922. the latter ailment is caused by heat or "infrared-related changes in the anterior lens capsule" and is characterized by "lamellar delamination of the lens capsule." sometimes the two terms "pseudoexfoliation" and "true exfoliation" are used interchangeably but the more precise usage is to treat each case separately. research scientists and doctors are actively exploring how pex happens, its causes, and how it might be prevented or mitigated. research activity to explore what causes glaucoma has been characterized as "intense". there has been research into the genetic basis of pex. one researcher speculated about a possible "two-hit hypothesis" in which a single mutation in the loxl1 gene puts people at risk for pex, but that a second still-to-be-found mutation has some effect on the proteins, possibly affecting bonds between chemicals, such that the proteins are more likely to clump together and disrupt the outflow of aqueous humor. alternative names exfoliation glaucoma; xfg pseudoexfoliation glaucoma pseudoexfoliation of the lens exfoliation syndrome; xfs